libjxl

encode.h (69933B)

---

 /* Copyright (c) the JPEG XL Project Authors. All rights reserved.
  *
  * Use of this source code is governed by a BSD-style
  * license that can be found in the LICENSE file.
  */
 
 /** @addtogroup libjxl_encoder
  * @{
  * @file encode.h
  * @brief Encoding API for JPEG XL.
  */
 
 #ifndef JXL_ENCODE_H_
 #define JXL_ENCODE_H_
 
 #include <jxl/cms_interface.h>
 #include <jxl/codestream_header.h>
 #include <jxl/color_encoding.h>
 #include <jxl/jxl_export.h>
 #include <jxl/memory_manager.h>
 #include <jxl/parallel_runner.h>
 #include <jxl/stats.h>
 #include <jxl/types.h>
 #include <jxl/version.h>  // TODO(eustas): remove before v1.0
 #include <stddef.h>
 #include <stdint.h>
 
 #if defined(__cplusplus) || defined(c_plusplus)
 extern "C" {
 #endif
 
 /**
  * Encoder library version.
  *
  * @return the encoder library version as an integer:
  * MAJOR_VERSION * 1000000 + MINOR_VERSION * 1000 + PATCH_VERSION. For example,
  * version 1.2.3 would return 1002003.
  */
 JXL_EXPORT uint32_t JxlEncoderVersion(void);
 
 /**
  * Opaque structure that holds the JPEG XL encoder.
  *
  * Allocated and initialized with @ref JxlEncoderCreate().
  * Cleaned up and deallocated with @ref JxlEncoderDestroy().
  */
 typedef struct JxlEncoderStruct JxlEncoder;
 
 /**
  * Settings and metadata for a single image frame. This includes encoder options
  * for a frame such as compression quality and speed.
  *
  * Allocated and initialized with @ref JxlEncoderFrameSettingsCreate().
  * Cleaned up and deallocated when the encoder is destroyed with
  * @ref JxlEncoderDestroy().
  */
 typedef struct JxlEncoderFrameSettingsStruct JxlEncoderFrameSettings;
 
 /**
  * Return value for multiple encoder functions.
  */
 typedef enum {
   /** Function call finished successfully, or encoding is finished and there is
    * nothing more to be done.
    */
   JXL_ENC_SUCCESS = 0,
 
   /** An error occurred, for example out of memory.
    */
   JXL_ENC_ERROR = 1,
 
   /** The encoder needs more output buffer to continue encoding.
    */
   JXL_ENC_NEED_MORE_OUTPUT = 2,
 
 } JxlEncoderStatus;
 
 /**
  * Error conditions:
  * API usage errors have the 0x80 bit set to 1
  * Other errors have the 0x80 bit set to 0
  */
 typedef enum {
   /** No error
    */
   JXL_ENC_ERR_OK = 0,
 
   /** Generic encoder error due to unspecified cause
    */
   JXL_ENC_ERR_GENERIC = 1,
 
   /** Out of memory
    *  TODO(jon): actually catch this and return this error
    */
   JXL_ENC_ERR_OOM = 2,
 
   /** JPEG bitstream reconstruction data could not be
    *  represented (e.g. too much tail data)
    */
   JXL_ENC_ERR_JBRD = 3,
 
   /** Input is invalid (e.g. corrupt JPEG file or ICC profile)
    */
   JXL_ENC_ERR_BAD_INPUT = 4,
 
   /** The encoder doesn't (yet) support this. Either no version of libjxl
    * supports this, and the API is used incorrectly, or the libjxl version
    * should have been checked before trying to do this.
    */
   JXL_ENC_ERR_NOT_SUPPORTED = 0x80,
 
   /** The encoder API is used in an incorrect way.
    *  In this case, a debug build of libjxl should output a specific error
    * message. (if not, please open an issue about it)
    */
   JXL_ENC_ERR_API_USAGE = 0x81,
 
 } JxlEncoderError;
 
 /**
  * Id of encoder options for a frame. This includes options such as setting
  * encoding effort/speed or overriding the use of certain coding tools, for this
  * frame. This does not include non-frame related encoder options such as for
  * boxes.
  */
 typedef enum {
   /** Sets encoder effort/speed level without affecting decoding speed. Valid
    * values are, from faster to slower speed: 1:lightning 2:thunder 3:falcon
    * 4:cheetah 5:hare 6:wombat 7:squirrel 8:kitten 9:tortoise 10:glacier.
    * Default: squirrel (7).
    */
   JXL_ENC_FRAME_SETTING_EFFORT = 0,
 
   /** Sets the decoding speed tier for the provided options. Minimum is 0
    * (slowest to decode, best quality/density), and maximum is 4 (fastest to
    * decode, at the cost of some quality/density). Default is 0.
    */
   JXL_ENC_FRAME_SETTING_DECODING_SPEED = 1,
 
   /** Sets resampling option. If enabled, the image is downsampled before
    * compression, and upsampled to original size in the decoder. Integer option,
    * use -1 for the default behavior (resampling only applied for low quality),
    * 1 for no downsampling (1x1), 2 for 2x2 downsampling, 4 for 4x4
    * downsampling, 8 for 8x8 downsampling.
    */
   JXL_ENC_FRAME_SETTING_RESAMPLING = 2,
 
   /** Similar to ::JXL_ENC_FRAME_SETTING_RESAMPLING, but for extra channels.
    * Integer option, use -1 for the default behavior (depends on encoder
    * implementation), 1 for no downsampling (1x1), 2 for 2x2 downsampling, 4 for
    * 4x4 downsampling, 8 for 8x8 downsampling.
    */
   JXL_ENC_FRAME_SETTING_EXTRA_CHANNEL_RESAMPLING = 3,
 
   /** Indicates the frame added with @ref JxlEncoderAddImageFrame is already
    * downsampled by the downsampling factor set with @ref
    * JXL_ENC_FRAME_SETTING_RESAMPLING. The input frame must then be given in the
    * downsampled resolution, not the full image resolution. The downsampled
    * resolution is given by ceil(xsize / resampling), ceil(ysize / resampling)
    * with xsize and ysize the dimensions given in the basic info, and resampling
    * the factor set with ::JXL_ENC_FRAME_SETTING_RESAMPLING.
    * Use 0 to disable, 1 to enable. Default value is 0.
    */
   JXL_ENC_FRAME_SETTING_ALREADY_DOWNSAMPLED = 4,
 
   /** Adds noise to the image emulating photographic film noise, the higher the
    * given number, the grainier the image will be. As an example, a value of 100
    * gives low noise whereas a value of 3200 gives a lot of noise. The default
    * value is 0.
    */
   JXL_ENC_FRAME_SETTING_PHOTON_NOISE = 5,
 
   /** Enables adaptive noise generation. This setting is not recommended for
    * use, please use ::JXL_ENC_FRAME_SETTING_PHOTON_NOISE instead. Use -1 for
    * the default (encoder chooses), 0 to disable, 1 to enable.
    */
   JXL_ENC_FRAME_SETTING_NOISE = 6,
 
   /** Enables or disables dots generation. Use -1 for the default (encoder
    * chooses), 0 to disable, 1 to enable.
    */
   JXL_ENC_FRAME_SETTING_DOTS = 7,
 
   /** Enables or disables patches generation. Use -1 for the default (encoder
    * chooses), 0 to disable, 1 to enable.
    */
   JXL_ENC_FRAME_SETTING_PATCHES = 8,
 
   /** Edge preserving filter level, -1 to 3. Use -1 for the default (encoder
    * chooses), 0 to 3 to set a strength.
    */
   JXL_ENC_FRAME_SETTING_EPF = 9,
 
   /** Enables or disables the gaborish filter. Use -1 for the default (encoder
    * chooses), 0 to disable, 1 to enable.
    */
   JXL_ENC_FRAME_SETTING_GABORISH = 10,
 
   /** Enables modular encoding. Use -1 for default (encoder
    * chooses), 0 to enforce VarDCT mode (e.g. for photographic images), 1 to
    * enforce modular mode (e.g. for lossless images).
    */
   JXL_ENC_FRAME_SETTING_MODULAR = 11,
 
   /** Enables or disables preserving color of invisible pixels. Use -1 for the
    * default (1 if lossless, 0 if lossy), 0 to disable, 1 to enable.
    */
   JXL_ENC_FRAME_SETTING_KEEP_INVISIBLE = 12,
 
   /** Determines the order in which 256x256 regions are stored in the codestream
    * for progressive rendering. Use -1 for the encoder
    * default, 0 for scanline order, 1 for center-first order.
    */
   JXL_ENC_FRAME_SETTING_GROUP_ORDER = 13,
 
   /** Determines the horizontal position of center for the center-first group
    * order. Use -1 to automatically use the middle of the image, 0..xsize to
    * specifically set it.
    */
   JXL_ENC_FRAME_SETTING_GROUP_ORDER_CENTER_X = 14,
 
   /** Determines the center for the center-first group order. Use -1 to
    * automatically use the middle of the image, 0..ysize to specifically set it.
    */
   JXL_ENC_FRAME_SETTING_GROUP_ORDER_CENTER_Y = 15,
 
   /** Enables or disables progressive encoding for modular mode. Use -1 for the
    * encoder default, 0 to disable, 1 to enable.
    */
   JXL_ENC_FRAME_SETTING_RESPONSIVE = 16,
 
   /** Set the progressive mode for the AC coefficients of VarDCT, using spectral
    * progression from the DCT coefficients. Use -1 for the encoder default, 0 to
    * disable, 1 to enable.
    */
   JXL_ENC_FRAME_SETTING_PROGRESSIVE_AC = 17,
 
   /** Set the progressive mode for the AC coefficients of VarDCT, using
    * quantization of the least significant bits. Use -1 for the encoder default,
    * 0 to disable, 1 to enable.
    */
   JXL_ENC_FRAME_SETTING_QPROGRESSIVE_AC = 18,
 
   /** Set the progressive mode using lower-resolution DC images for VarDCT. Use
    * -1 for the encoder default, 0 to disable, 1 to have an extra 64x64 lower
    * resolution pass, 2 to have a 512x512 and 64x64 lower resolution pass.
    */
   JXL_ENC_FRAME_SETTING_PROGRESSIVE_DC = 19,
 
   /** Use Global channel palette if the amount of colors is smaller than this
    * percentage of range. Use 0-100 to set an explicit percentage, -1 to use the
    * encoder default. Used for modular encoding.
    */
   JXL_ENC_FRAME_SETTING_CHANNEL_COLORS_GLOBAL_PERCENT = 20,
 
   /** Use Local (per-group) channel palette if the amount of colors is smaller
    * than this percentage of range. Use 0-100 to set an explicit percentage, -1
    * to use the encoder default. Used for modular encoding.
    */
   JXL_ENC_FRAME_SETTING_CHANNEL_COLORS_GROUP_PERCENT = 21,
 
   /** Use color palette if amount of colors is smaller than or equal to this
    * amount, or -1 to use the encoder default. Used for modular encoding.
    */
   JXL_ENC_FRAME_SETTING_PALETTE_COLORS = 22,
 
   /** Enables or disables delta palette. Use -1 for the default (encoder
    * chooses), 0 to disable, 1 to enable. Used in modular mode.
    */
   JXL_ENC_FRAME_SETTING_LOSSY_PALETTE = 23,
 
   /** Color transform for internal encoding: -1 = default, 0=XYB, 1=none (RGB),
    * 2=YCbCr. The XYB setting performs the forward XYB transform. None and
    * YCbCr both perform no transform, but YCbCr is used to indicate that the
    * encoded data losslessly represents YCbCr values.
    */
   JXL_ENC_FRAME_SETTING_COLOR_TRANSFORM = 24,
 
   /** Reversible color transform for modular encoding: -1=default, 0-41=RCT
    * index, e.g. index 0 = none, index 6 = YCoCg.
    * If this option is set to a non-default value, the RCT will be globally
    * applied to the whole frame.
    * The default behavior is to try several RCTs locally per modular group,
    * depending on the speed and distance setting.
    */
   JXL_ENC_FRAME_SETTING_MODULAR_COLOR_SPACE = 25,
 
   /** Group size for modular encoding: -1=default, 0=128, 1=256, 2=512, 3=1024.
    */
   JXL_ENC_FRAME_SETTING_MODULAR_GROUP_SIZE = 26,
 
   /** Predictor for modular encoding. -1 = default, 0=zero, 1=left, 2=top,
    * 3=avg0, 4=select, 5=gradient, 6=weighted, 7=topright, 8=topleft,
    * 9=leftleft, 10=avg1, 11=avg2, 12=avg3, 13=toptop predictive average 14=mix
    * 5 and 6, 15=mix everything.
    */
   JXL_ENC_FRAME_SETTING_MODULAR_PREDICTOR = 27,
 
   /** Fraction of pixels used to learn MA trees as a percentage. -1 = default,
    * 0 = no MA and fast decode, 50 = default value, 100 = all, values above
    * 100 are also permitted. Higher values use more encoder memory.
    */
   JXL_ENC_FRAME_SETTING_MODULAR_MA_TREE_LEARNING_PERCENT = 28,
 
   /** Number of extra (previous-channel) MA tree properties to use. -1 =
    * default, 0-11 = valid values. Recommended values are in the range 0 to 3,
    * or 0 to amount of channels minus 1 (including all extra channels, and
    * excluding color channels when using VarDCT mode). Higher value gives slower
    * encoding and slower decoding.
    */
   JXL_ENC_FRAME_SETTING_MODULAR_NB_PREV_CHANNELS = 29,
 
   /** Enable or disable CFL (chroma-from-luma) for lossless JPEG recompression.
    * -1 = default, 0 = disable CFL, 1 = enable CFL.
    */
   JXL_ENC_FRAME_SETTING_JPEG_RECON_CFL = 30,
 
   /** Prepare the frame for indexing in the frame index box.
    * 0 = ignore this frame (same as not setting a value),
    * 1 = index this frame within the Frame Index Box.
    * If any frames are indexed, the first frame needs to
    * be indexed, too. If the first frame is not indexed, and
    * a later frame is attempted to be indexed, ::JXL_ENC_ERROR will occur.
    * If non-keyframes, i.e., frames with cropping, blending or patches are
    * attempted to be indexed, ::JXL_ENC_ERROR will occur.
    */
   JXL_ENC_FRAME_INDEX_BOX = 31,
 
   /** Sets brotli encode effort for use in JPEG recompression and
    * compressed metadata boxes (brob). Can be -1 (default) or 0 (fastest) to 11
    * (slowest). Default is based on the general encode effort in case of JPEG
    * recompression, and 4 for brob boxes.
    */
   JXL_ENC_FRAME_SETTING_BROTLI_EFFORT = 32,
 
   /** Enables or disables brotli compression of metadata boxes derived from
    * a JPEG frame when using @ref JxlEncoderAddJPEGFrame. This has no effect on
    * boxes added using @ref JxlEncoderAddBox. -1 = default, 0 = disable
    * compression, 1 = enable compression.
    */
   JXL_ENC_FRAME_SETTING_JPEG_COMPRESS_BOXES = 33,
 
   /** Control what kind of buffering is used, when using chunked image frames.
    * -1 = default (let the encoder decide)
    * 0 = buffers everything, basically the same as non-streamed code path
    (mainly for testing)
    * 1 = buffers everything for images that are smaller than 2048 x 2048, and
    *     uses streaming input and output for larger images
    * 2 = uses streaming input and output for all images that are larger than
    *     one group, i.e. 256 x 256 pixels by default
    * 3 = currently same as 2
    *
    * When using streaming input and output the encoder minimizes memory usage at
    * the cost of compression density. Also note that images produced with
    * streaming mode might not be progressively decodeable.
    */
   JXL_ENC_FRAME_SETTING_BUFFERING = 34,
 
   /** Keep or discard Exif metadata boxes derived from a JPEG frame when using
    * @ref JxlEncoderAddJPEGFrame. This has no effect on boxes added using
    * @ref JxlEncoderAddBox. When @ref JxlEncoderStoreJPEGMetadata is set to 1,
    * this option cannot be set to 0. Even when Exif metadata is discarded, the
    * orientation will still be applied. 0 = discard Exif metadata, 1 = keep Exif
    * metadata (default).
    */
   JXL_ENC_FRAME_SETTING_JPEG_KEEP_EXIF = 35,
 
   /** Keep or discard XMP metadata boxes derived from a JPEG frame when using
    * @ref JxlEncoderAddJPEGFrame. This has no effect on boxes added using
    * @ref JxlEncoderAddBox. When @ref JxlEncoderStoreJPEGMetadata is set to 1,
    * this option cannot be set to 0. 0 = discard XMP metadata, 1 = keep XMP
    * metadata (default).
    */
   JXL_ENC_FRAME_SETTING_JPEG_KEEP_XMP = 36,
 
   /** Keep or discard JUMBF metadata boxes derived from a JPEG frame when using
    * @ref JxlEncoderAddJPEGFrame. This has no effect on boxes added using
    * @ref JxlEncoderAddBox. 0 = discard JUMBF metadata, 1 = keep JUMBF metadata
    * (default).
    */
   JXL_ENC_FRAME_SETTING_JPEG_KEEP_JUMBF = 37,
 
   /** If this mode is disabled, the encoder will not make any image quality
    * decisions that are computed based on the full image, but stored only once
    * (e.g. the X quant multiplier in the frame header). Used mainly for testing
    * equivalence of streaming and non-streaming code.
    * 0 = disabled, 1 = enabled (default)
    */
   JXL_ENC_FRAME_SETTING_USE_FULL_IMAGE_HEURISTICS = 38,
 
   /** Enum value not to be used as an option. This value is added to force the
    * C compiler to have the enum to take a known size.
    */
   JXL_ENC_FRAME_SETTING_FILL_ENUM = 65535,
 
 } JxlEncoderFrameSettingId;
 
 /**
  * Creates an instance of @ref JxlEncoder and initializes it.
  *
  * @p memory_manager will be used for all the library dynamic allocations made
  * from this instance. The parameter may be NULL, in which case the default
  * allocator will be used. See jpegxl/memory_manager.h for details.
  *
  * @param memory_manager custom allocator function. It may be NULL. The memory
  *        manager will be copied internally.
  * @return @c NULL if the instance can not be allocated or initialized
  * @return pointer to initialized @ref JxlEncoder otherwise
  */
 JXL_EXPORT JxlEncoder* JxlEncoderCreate(const JxlMemoryManager* memory_manager);
 
 /**
  * Re-initializes a @ref JxlEncoder instance, so it can be re-used for encoding
  * another image. All state and settings are reset as if the object was
  * newly created with @ref JxlEncoderCreate, but the memory manager is kept.
  *
  * @param enc instance to be re-initialized.
  */
 JXL_EXPORT void JxlEncoderReset(JxlEncoder* enc);
 
 /**
  * Deinitializes and frees a @ref JxlEncoder instance.
  *
  * @param enc instance to be cleaned up and deallocated.
  */
 JXL_EXPORT void JxlEncoderDestroy(JxlEncoder* enc);
 
 /**
  * Sets the color management system (CMS) that will be used for color conversion
  * (if applicable) during encoding. May only be set before starting encoding. If
  * left unset, the default CMS implementation will be used.
  *
  * @param enc encoder object.
  * @param cms structure representing a CMS implementation. See @ref
  * JxlCmsInterface for more details.
  */
 JXL_EXPORT void JxlEncoderSetCms(JxlEncoder* enc, JxlCmsInterface cms);
 
 /**
  * Set the parallel runner for multithreading. May only be set before starting
  * encoding.
  *
  * @param enc encoder object.
  * @param parallel_runner function pointer to runner for multithreading. It may
  *        be NULL to use the default, single-threaded, runner. A multithreaded
  *        runner should be set to reach fast performance.
  * @param parallel_runner_opaque opaque pointer for parallel_runner.
  * @return ::JXL_ENC_SUCCESS if the runner was set, ::JXL_ENC_ERROR
  * otherwise (the previous runner remains set).
  */
 JXL_EXPORT JxlEncoderStatus
 JxlEncoderSetParallelRunner(JxlEncoder* enc, JxlParallelRunner parallel_runner,
                             void* parallel_runner_opaque);
 
 /**
  * Get the (last) error code in case ::JXL_ENC_ERROR was returned.
  *
  * @param enc encoder object.
  * @return the @ref JxlEncoderError that caused the (last) ::JXL_ENC_ERROR to
  * be returned.
  */
 JXL_EXPORT JxlEncoderError JxlEncoderGetError(JxlEncoder* enc);
 
 /**
  * Encodes a JPEG XL file using the available bytes. @p *avail_out indicates how
  * many output bytes are available, and @p *next_out points to the input bytes.
  * *avail_out will be decremented by the amount of bytes that have been
  * processed by the encoder and *next_out will be incremented by the same
  * amount, so *next_out will now point at the amount of *avail_out unprocessed
  * bytes.
  *
  * The returned status indicates whether the encoder needs more output bytes.
  * When the return value is not ::JXL_ENC_ERROR or ::JXL_ENC_SUCCESS, the
  * encoding requires more @ref JxlEncoderProcessOutput calls to continue.
  *
  * The caller must guarantee that *avail_out >= 32 when calling
  * @ref JxlEncoderProcessOutput; otherwise, ::JXL_ENC_NEED_MORE_OUTPUT will
  * be returned. It is guaranteed that, if *avail_out >= 32, at least one byte of
  * output will be written.
  *
  * This encodes the frames and/or boxes added so far. If the last frame or last
  * box has been added, @ref JxlEncoderCloseInput, @ref JxlEncoderCloseFrames
  * and/or @ref JxlEncoderCloseBoxes must be called before the next
  * @ref JxlEncoderProcessOutput call, or the codestream won't be encoded
  * correctly.
  *
  * @param enc encoder object.
  * @param next_out pointer to next bytes to write to.
  * @param avail_out amount of bytes available starting from *next_out.
  * @return ::JXL_ENC_SUCCESS when encoding finished and all events handled.
  * @return ::JXL_ENC_ERROR when encoding failed, e.g. invalid input.
  * @return ::JXL_ENC_NEED_MORE_OUTPUT more output buffer is necessary.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderProcessOutput(JxlEncoder* enc,
                                                     uint8_t** next_out,
                                                     size_t* avail_out);
 
 /**
  * Sets the frame information for this frame to the encoder. This includes
  * animation information such as frame duration to store in the frame header.
  * The frame header fields represent the frame as passed to the encoder, but not
  * necessarily the exact values as they will be encoded file format: the encoder
  * could change crop and blending options of a frame for more efficient encoding
  * or introduce additional internal frames. Animation duration and time code
  * information is not altered since those are immutable metadata of the frame.
  *
  * It is not required to use this function, however if have_animation is set
  * to true in the basic info, then this function should be used to set the
  * time duration of this individual frame. By default individual frames have a
  * time duration of 0, making them form a composite still. See @ref
  * JxlFrameHeader for more information.
  *
  * This information is stored in the @ref JxlEncoderFrameSettings and so is used
  * for any frame encoded with these @ref JxlEncoderFrameSettings. It is ok to
  * change between @ref JxlEncoderAddImageFrame calls, each added image frame
  * will have the frame header that was set in the options at the time of calling
  * @ref JxlEncoderAddImageFrame.
  *
  * The is_last and name_length fields of the @ref JxlFrameHeader are ignored,
  * use
  * @ref JxlEncoderCloseFrames to indicate last frame, and @ref
  * JxlEncoderSetFrameName to indicate the name and its length instead.
  * Calling this function will clear any name that was previously set with @ref
  * JxlEncoderSetFrameName.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param frame_header frame header data to set. Object owned by the caller and
  * does not need to be kept in memory, its information is copied internally.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus
 JxlEncoderSetFrameHeader(JxlEncoderFrameSettings* frame_settings,
                          const JxlFrameHeader* frame_header);
 
 /**
  * Sets blend info of an extra channel. The blend info of extra channels is set
  * separately from that of the color channels, the color channels are set with
  * @ref JxlEncoderSetFrameHeader.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param index index of the extra channel to use.
  * @param blend_info blend info to set for the extra channel
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelBlendInfo(
     JxlEncoderFrameSettings* frame_settings, size_t index,
     const JxlBlendInfo* blend_info);
 
 /**
  * Sets the name of the animation frame. This function is optional, frames are
  * not required to have a name. This setting is a part of the frame header, and
  * the same principles as for @ref JxlEncoderSetFrameHeader apply. The
  * name_length field of @ref JxlFrameHeader is ignored by the encoder, this
  * function determines the name length instead as the length in bytes of the C
  * string.
  *
  * The maximum possible name length is 1071 bytes (excluding terminating null
  * character).
  *
  * Calling @ref JxlEncoderSetFrameHeader clears any name that was
  * previously set.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param frame_name name of the next frame to be encoded, as a UTF-8 encoded C
  * string (zero terminated). Owned by the caller, and copied internally.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetFrameName(
     JxlEncoderFrameSettings* frame_settings, const char* frame_name);
 
 /**
  * Sets the bit depth of the input buffer.
  *
  * For float pixel formats, only the default @ref
  JXL_BIT_DEPTH_FROM_PIXEL_FORMAT
  * setting is allowed, while for unsigned pixel formats,
  * ::JXL_BIT_DEPTH_FROM_CODESTREAM setting is also allowed. See the comment
  on
  * @ref JxlEncoderAddImageFrame for the effects of the bit depth setting.
 
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param bit_depth the bit depth setting of the pixel input
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetFrameBitDepth(
     JxlEncoderFrameSettings* frame_settings, const JxlBitDepth* bit_depth);
 
 /**
  * Sets the buffer to read JPEG encoded bytes from for the next frame to encode.
  *
  * If @ref JxlEncoderSetBasicInfo has not yet been called, calling
  * @ref JxlEncoderAddJPEGFrame will implicitly call it with the parameters of
  * the added JPEG frame.
  *
  * If @ref JxlEncoderSetColorEncoding or @ref JxlEncoderSetICCProfile has not
  * yet been called, calling @ref JxlEncoderAddJPEGFrame will implicitly call it
  * with the parameters of the added JPEG frame.
  *
  * If the encoder is set to store JPEG reconstruction metadata using @ref
  * JxlEncoderStoreJPEGMetadata and a single JPEG frame is added, it will be
  * possible to losslessly reconstruct the JPEG codestream.
  *
  * If this is the last frame, @ref JxlEncoderCloseInput or @ref
  * JxlEncoderCloseFrames must be called before the next
  * @ref JxlEncoderProcessOutput call.
  *
  * Note, this can only be used to add JPEG frames for lossless compression. To
  * encode with lossy compression, the JPEG must be decoded manually and a pixel
  * buffer added using JxlEncoderAddImageFrame.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param buffer bytes to read JPEG from. Owned by the caller and its contents
  * are copied internally.
  * @param size size of buffer in bytes.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus
 JxlEncoderAddJPEGFrame(const JxlEncoderFrameSettings* frame_settings,
                        const uint8_t* buffer, size_t size);
 
 /**
  * Sets the buffer to read pixels from for the next image to encode. Must call
  * @ref JxlEncoderSetBasicInfo before @ref JxlEncoderAddImageFrame.
  *
  * Currently only some data types for pixel formats are supported:
  * - ::JXL_TYPE_UINT8, with range 0..255
  * - ::JXL_TYPE_UINT16, with range 0..65535
  * - ::JXL_TYPE_FLOAT16, with nominal range 0..1
  * - ::JXL_TYPE_FLOAT, with nominal range 0..1
  *
  * Note: the sample data type in pixel_format is allowed to be different from
  * what is described in the @ref JxlBasicInfo. The type in pixel_format,
  * together with an optional @ref JxlBitDepth parameter set by @ref
  * JxlEncoderSetFrameBitDepth describes the format of the uncompressed pixel
  * buffer. The bits_per_sample and exponent_bits_per_sample in the @ref
  * JxlBasicInfo describes what will actually be encoded in the JPEG XL
  * codestream. For example, to encode a 12-bit image, you would set
  * bits_per_sample to 12, while the input frame buffer can be in the following
  * formats:
  *  - if pixel format is in ::JXL_TYPE_UINT16 with default bit depth setting
  *    (i.e. ::JXL_BIT_DEPTH_FROM_PIXEL_FORMAT), input sample values are
  * rescaled to 16-bit, i.e. multiplied by 65535/4095;
  *  - if pixel format is in ::JXL_TYPE_UINT16 with @ref
  * JXL_BIT_DEPTH_FROM_CODESTREAM bit depth setting, input sample values are
  * provided unscaled;
  *  - if pixel format is in ::JXL_TYPE_FLOAT, input sample values are
  * rescaled to 0..1, i.e.  multiplied by 1.f/4095.f. While it is allowed, it is
  * obviously not recommended to use a pixel_format with lower precision than
  * what is specified in the @ref JxlBasicInfo.
  *
  * We support interleaved channels as described by the @ref JxlPixelFormat
  * "JxlPixelFormat":
  * - single-channel data, e.g. grayscale
  * - single-channel + alpha
  * - trichromatic, e.g. RGB
  * - trichromatic + alpha
  *
  * Extra channels not handled here need to be set by @ref
  * JxlEncoderSetExtraChannelBuffer.
  * If the image has alpha, and alpha is not passed here, it will implicitly be
  * set to all-opaque (an alpha value of 1.0 everywhere).
  *
  * The pixels are assumed to be encoded in the original profile that is set with
  * @ref JxlEncoderSetColorEncoding or @ref JxlEncoderSetICCProfile. If none of
  * these functions were used, the pixels are assumed to be nonlinear sRGB for
  * integer data types (::JXL_TYPE_UINT8, ::JXL_TYPE_UINT16), and linear
  * sRGB for floating point data types (::JXL_TYPE_FLOAT16, @ref
  * JXL_TYPE_FLOAT).
  *
  * Sample values in floating-point pixel formats are allowed to be outside the
  * nominal range, e.g. to represent out-of-sRGB-gamut colors in the
  * uses_original_profile=false case. They are however not allowed to be NaN or
  * +-infinity.
  *
  * If this is the last frame, @ref JxlEncoderCloseInput or @ref
  * JxlEncoderCloseFrames must be called before the next
  * @ref JxlEncoderProcessOutput call.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param pixel_format format for pixels. Object owned by the caller and its
  * contents are copied internally.
  * @param buffer buffer type to input the pixel data from. Owned by the caller
  * and its contents are copied internally.
  * @param size size of buffer in bytes. This size should match what is implied
  * by the frame dimensions and the pixel format.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderAddImageFrame(
     const JxlEncoderFrameSettings* frame_settings,
     const JxlPixelFormat* pixel_format, const void* buffer, size_t size);
 
 /**
  * The @ref JxlEncoderOutputProcessor structure provides an interface for the
  * encoder's output processing. Users of the library, who want to do streaming
  * encoding, should implement the required callbacks for buffering, writing,
  * seeking (if supported), and setting a finalized position during the encoding
  * process.
  *
  * At a high level, the processor can be in one of two states:
  * - With an active buffer: This indicates that a buffer has been acquired using
  *   `get_buffer` and encoded data can be written to it.
  * - Without an active buffer: In this state, no data can be written. A new
  * buffer must be acquired after releasing any previously active buffer.
  *
  * The library will not acquire more than one buffer at a given time.
  *
  * The state of the processor includes `position` and `finalized position`,
  * which have the following meaning.
  *
  * - position: Represents the current position, in bytes, within the output
  * stream where the encoded data will be written next. This position moves
  * forward with each `release_buffer` call as data is written, and can also be
  * adjusted through the optional seek callback, if provided. At this position
  * the next write will occur.
  *
  * - finalized position:  A position in the output stream that ensures all bytes
  * before this point are finalized and won't be changed by later writes.
  *
  * All fields but `seek` are required, `seek` is optional and can be NULL.
  */
 struct JxlEncoderOutputProcessor {
   /**
    * Required.
    * An opaque pointer that the client can use to store custom data.
    * This data will be passed to the associated callback functions.
    */
   void* opaque;
 
   /**
    * Required.
    * Acquires a buffer at the current position into which the library will write
    * the output data.
    *
    * If the `size` argument points to 0 and the returned value is NULL, this
    * will be interpreted as asking the output writing to stop. In such a case,
    * the library will return an error. The client is expected to set the size of
    * the returned buffer based on the suggested `size` when this function is
    * called.
    *
    * @param opaque user supplied parameters to the callback
    * @param size points to a suggested buffer size when called; must be set to
    * the size of the returned buffer once the function returns.
    * @return a pointer to the acquired buffer or NULL to indicate a stop
    * condition.
    */
   void* (*get_buffer)(void* opaque, size_t* size);
 
   /**
    * Required.
    * Notifies the user of library that the current buffer's data has been
    * written and can be released. This function should advance the current
    * position of the buffer by `written_bytes` number of bytes.
    *
    * @param opaque user supplied parameters to the callback
    * @param written_bytes the number of bytes written to the buffer.
    */
   void (*release_buffer)(void* opaque, size_t written_bytes);
 
   /**
    * Optional, can be NULL
    * Seeks to a specific position in the output. This function is optional and
    * can be set to NULL if the output doesn't support seeking. Can only be done
    * when there is no buffer. Cannot be used to seek before the finalized
    * position.
    *
    * @param opaque user supplied parameters to the callback
    * @param position the position to seek to, in bytes.
    */
   void (*seek)(void* opaque, uint64_t position);
 
   /**
    * Required.
    * Sets a finalized position on the output data, at a specific position.
    * Seeking will never request a position before the finalized position.
    *
    * Will only be called if there is no active buffer.
    *
    * @param opaque user supplied parameters to the callback
    * @param finalized_position the position, in bytes, where the finalized
    * position should be set.
    */
   void (*set_finalized_position)(void* opaque, uint64_t finalized_position);
 };
 
 /**
  * Sets the output processor for the encoder. This processor determines how the
  * encoder will handle buffering, writing, seeking (if supported), and
  * setting a finalized position during the encoding process.
  *
  * This should not be used when using @ref JxlEncoderProcessOutput.
  *
  * @param enc encoder object.
  * @param output_processor the struct containing the callbacks for managing
  * output.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetOutputProcessor(
     JxlEncoder* enc, struct JxlEncoderOutputProcessor output_processor);
 
 /**
  * Flushes any buffered input in the encoder, ensuring that all available input
  * data has been processed and written to the output.
  *
  * This function can only be used after @ref JxlEncoderSetOutputProcessor.
  * Before making the last call to @ref JxlEncoderFlushInput, users should call
  * @ref JxlEncoderCloseInput to signal the end of input data.
  *
  * This should not be used when using @ref JxlEncoderProcessOutput.
  *
  * @param enc encoder object.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderFlushInput(JxlEncoder* enc);
 
 /**
  * This struct provides callback functions to pass pixel data in a streaming
  * manner instead of requiring the entire frame data in memory at once.
  */
 struct JxlChunkedFrameInputSource {
   /**
    * A pointer to any user-defined data or state. This can be used to pass
    * information to the callback functions.
    */
   void* opaque;
 
   /**
    * Get the pixel format that color channel data will be provided in.
    * When called, `pixel_format` points to a suggested pixel format; if
    * color channel data can be given in this pixel format, processing might
    * be more efficient.
    *
    * This function will be called exactly once, before any call to
    * get_color_channel_at.
    *
    * @param opaque user supplied parameters to the callback
    * @param pixel_format format for pixels
    */
   void (*get_color_channels_pixel_format)(void* opaque,
                                           JxlPixelFormat* pixel_format);
 
   /**
    * Callback to retrieve a rectangle of color channel data at a specific
    * location. It is guaranteed that xpos and ypos are multiples of 8. xsize,
    * ysize will be multiples of 8, unless the resulting rectangle would be out
    * of image bounds. Moreover, xsize and ysize will be at most 2048. The
    * returned data will be assumed to be in the format returned by the
    * (preceding) call to get_color_channels_pixel_format, except the `align`
    * parameter of the pixel format will be ignored. Instead, the `i`-th row will
    * be assumed to start at position `return_value + i * *row_offset`, with the
    * value of `*row_offset` decided by the callee.
    *
    * Note that multiple calls to `get_color_channel_data_at` may happen before a
    * call to `release_buffer`.
    *
    * @param opaque user supplied parameters to the callback
    * @param xpos horizontal position for the data.
    * @param ypos vertical position for the data.
    * @param xsize horizontal size of the requested rectangle of data.
    * @param ysize vertical size of the requested rectangle of data.
    * @param row_offset pointer to a the byte offset between consecutive rows of
    * the retrieved pixel data.
    * @return pointer to the retrieved pixel data.
    */
   const void* (*get_color_channel_data_at)(void* opaque, size_t xpos,
                                            size_t ypos, size_t xsize,
                                            size_t ysize, size_t* row_offset);
 
   /**
    * Get the pixel format that extra channel data will be provided in.
    * When called, `pixel_format` points to a suggested pixel format; if
    * extra channel data can be given in this pixel format, processing might
    * be more efficient.
    *
    * This function will be called exactly once per index, before any call to
    * get_extra_channel_data_at with that given index.
    *
    * @param opaque user supplied parameters to the callback
    * @param ec_index zero-indexed index of the extra channel
    * @param pixel_format format for extra channel data
    */
   void (*get_extra_channel_pixel_format)(void* opaque, size_t ec_index,
                                          JxlPixelFormat* pixel_format);
 
   /**
    * Callback to retrieve a rectangle of extra channel `ec_index` data at a
    * specific location. It is guaranteed that xpos and ypos are multiples of
    * 8. xsize, ysize will be multiples of 8, unless the resulting rectangle
    * would be out of image bounds. Moreover, xsize and ysize will be at most
    * 2048. The returned data will be assumed to be in the format returned by the
    * (preceding) call to get_extra_channels_pixel_format_at with the
    * corresponding extra channel index `ec_index`, except the `align` parameter
    * of the pixel format will be ignored. Instead, the `i`-th row will be
    * assumed to start at position `return_value + i * *row_offset`, with the
    * value of `*row_offset` decided by the callee.
    *
    * Note that multiple calls to `get_extra_channel_data_at` may happen before a
    * call to `release_buffer`.
    *
    * @param opaque user supplied parameters to the callback
    * @param xpos horizontal position for the data.
    * @param ypos vertical position for the data.
    * @param xsize horizontal size of the requested rectangle of data.
    * @param ysize vertical size of the requested rectangle of data.
    * @param row_offset pointer to a the byte offset between consecutive rows of
    * the retrieved pixel data.
    * @return pointer to the retrieved pixel data.
    */
   const void* (*get_extra_channel_data_at)(void* opaque, size_t ec_index,
                                            size_t xpos, size_t ypos,
                                            size_t xsize, size_t ysize,
                                            size_t* row_offset);
 
   /**
    * Releases the buffer `buf` (obtained through a call to
    * `get_color_channel_data_at` or `get_extra_channel_data_at`). This function
    * will be called exactly once per call to `get_color_channel_data_at` or
    * `get_extra_channel_data_at`.
    *
    * @param opaque user supplied parameters to the callback
    * @param buf pointer returned by `get_color_channel_data_at` or
    * `get_extra_channel_data_at`
    */
   void (*release_buffer)(void* opaque, const void* buf);
 };
 
 /**
  * @brief Adds a frame to the encoder using a chunked input source.
  *
  * This function gives a way to encode a frame by providing pixel data in a
  * chunked or streaming manner, which can be especially useful when dealing with
  * large images that may not fit entirely in memory or when trying to optimize
  * memory usage. The input data is provided through callbacks defined in the
  * @ref JxlChunkedFrameInputSource struct. Once the frame data has been
  * completely retrieved, this function will flush the input and close it if it
  * is the last frame.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param is_last_frame indicates if this is the last frame.
  * @param chunked_frame_input struct providing callback methods for retrieving
  * pixel data in chunks.
  *
  * @return Returns a status indicating the success or failure of adding the
  * frame.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderAddChunkedFrame(
     const JxlEncoderFrameSettings* frame_settings, JXL_BOOL is_last_frame,
     struct JxlChunkedFrameInputSource chunked_frame_input);
 
 /**
  * Sets the buffer to read pixels from for an extra channel at a given index.
  * The index must be smaller than the num_extra_channels in the associated
  * @ref JxlBasicInfo. Must call @ref JxlEncoderSetExtraChannelInfo before @ref
  * JxlEncoderSetExtraChannelBuffer.
  *
  * TODO(firsching): mention what data types in pixel formats are supported.
  *
  * It is required to call this function for every extra channel, except for the
  * alpha channel if that was already set through @ref JxlEncoderAddImageFrame.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param pixel_format format for pixels. Object owned by the caller and its
  * contents are copied internally. The num_channels value is ignored, since the
  * number of channels for an extra channel is always assumed to be one.
  * @param buffer buffer type to input the pixel data from. Owned by the caller
  * and its contents are copied internally.
  * @param size size of buffer in bytes. This size should match what is implied
  * by the frame dimensions and the pixel format.
  * @param index index of the extra channel to use.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelBuffer(
     const JxlEncoderFrameSettings* frame_settings,
     const JxlPixelFormat* pixel_format, const void* buffer, size_t size,
     uint32_t index);
 
 /** Adds a metadata box to the file format. @ref JxlEncoderProcessOutput must be
  * used to effectively write the box to the output. @ref JxlEncoderUseBoxes must
  * be enabled before using this function.
  *
  * Boxes allow inserting application-specific data and metadata (Exif, XML/XMP,
  * JUMBF and user defined boxes).
  *
  * The box format follows ISO BMFF and shares features and box types with other
  * image and video formats, including the Exif, XML and JUMBF boxes. The box
  * format for JPEG XL is specified in ISO/IEC 18181-2.
  *
  * Boxes in general don't contain other boxes inside, except a JUMBF superbox.
  * Boxes follow each other sequentially and are byte-aligned. If the container
  * format is used, the JXL stream consists of concatenated boxes.
  * It is also possible to use a direct codestream without boxes, but in that
  * case metadata cannot be added.
  *
  * Each box generally has the following byte structure in the file:
  * - 4 bytes: box size including box header (Big endian. If set to 0, an
  *   8-byte 64-bit size follows instead).
  * - 4 bytes: type, e.g. "JXL " for the signature box, "jxlc" for a codestream
  *   box.
  * - N bytes: box contents.
  *
  * Only the box contents are provided to the contents argument of this function,
  * the encoder encodes the size header itself. Most boxes are written
  * automatically by the encoder as needed ("JXL ", "ftyp", "jxll", "jxlc",
  * "jxlp", "jxli", "jbrd"), and this function only needs to be called to add
  * optional metadata when encoding from pixels (using @ref
  * JxlEncoderAddImageFrame). When recompressing JPEG files (using @ref
  * JxlEncoderAddJPEGFrame), if the input JPEG contains EXIF, XMP or JUMBF
  * metadata, the corresponding boxes are already added automatically.
  *
  * Box types are given by 4 characters. The following boxes can be added with
  * this function:
  * - "Exif": a box with EXIF metadata, can be added by libjxl users, or is
  *   automatically added when needed for JPEG reconstruction. The contents of
  *   this box must be prepended by a 4-byte tiff header offset, which may
  *   be 4 zero bytes in case the tiff header follows immediately.
  *   The EXIF metadata must be in sync with what is encoded in the JPEG XL
  *   codestream, specifically the image orientation. While this is not
  *   recommended in practice, in case of conflicting metadata, the JPEG XL
  *   codestream takes precedence.
  * - "xml ": a box with XML data, in particular XMP metadata, can be added by
  *   libjxl users, or is automatically added when needed for JPEG reconstruction
  * - "jumb": a JUMBF superbox, which can contain boxes with different types of
  *   metadata inside. This box type can be added by the encoder transparently,
  *   and other libraries to create and handle JUMBF content exist.
  * - Application-specific boxes. Their typename should not begin with "jxl" or
  *   "JXL" or conflict with other existing typenames, and they should be
  *   registered with MP4RA (mp4ra.org).
  *
  * These boxes can be stored uncompressed or Brotli-compressed (using a "brob"
  * box), depending on the compress_box parameter.
  *
  * @param enc encoder object.
  * @param type the box type, e.g. "Exif" for EXIF metadata, "xml " for XMP or
  * IPTC metadata, "jumb" for JUMBF metadata.
  * @param contents the full contents of the box, for example EXIF
  * data. ISO BMFF box header must not be included, only the contents. Owned by
  * the caller and its contents are copied internally.
  * @param size size of the box contents.
  * @param compress_box Whether to compress this box as a "brob" box. Requires
  * Brotli support.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error, such as
  * when using this function without @ref JxlEncoderUseContainer, or adding a box
  * type that would result in an invalid file format.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderAddBox(JxlEncoder* enc,
                                              const JxlBoxType type,
                                              const uint8_t* contents,
                                              size_t size,
                                              JXL_BOOL compress_box);
 
 /**
  * Indicates the intention to add metadata boxes. This allows @ref
  * JxlEncoderAddBox to be used. When using this function, then it is required
  * to use @ref JxlEncoderCloseBoxes at the end.
  *
  * By default the encoder assumes no metadata boxes will be added.
  *
  * This setting can only be set at the beginning, before encoding starts.
  *
  * @param enc encoder object.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderUseBoxes(JxlEncoder* enc);
 
 /**
  * Declares that no further boxes will be added with @ref JxlEncoderAddBox.
  * This function must be called after the last box is added so the encoder knows
  * the stream will be finished. It is not necessary to use this function if
  * @ref JxlEncoderUseBoxes is not used. Further frames may still be added.
  *
  * Must be called between @ref JxlEncoderAddBox of the last box
  * and the next call to @ref JxlEncoderProcessOutput, or @ref
  * JxlEncoderProcessOutput won't output the last box correctly.
  *
  * NOTE: if you don't need to close frames and boxes at separate times, you can
  * use @ref JxlEncoderCloseInput instead to close both at once.
  *
  * @param enc encoder object.
  */
 JXL_EXPORT void JxlEncoderCloseBoxes(JxlEncoder* enc);
 
 /**
  * Declares that no frames will be added and @ref JxlEncoderAddImageFrame and
  * @ref JxlEncoderAddJPEGFrame won't be called anymore. Further metadata boxes
  * may still be added. This function or @ref JxlEncoderCloseInput must be called
  * after adding the last frame and the next call to
  * @ref JxlEncoderProcessOutput, or the frame won't be properly marked as last.
  *
  * NOTE: if you don't need to close frames and boxes at separate times, you can
  * use @ref JxlEncoderCloseInput instead to close both at once.
  *
  * @param enc encoder object.
  */
 JXL_EXPORT void JxlEncoderCloseFrames(JxlEncoder* enc);
 
 /**
  * Closes any input to the encoder, equivalent to calling @ref
  * JxlEncoderCloseFrames as well as calling @ref JxlEncoderCloseBoxes if needed.
  * No further input of any kind may be given to the encoder, but further @ref
  * JxlEncoderProcessOutput calls should be done to create the final output.
  *
  * The requirements of both @ref JxlEncoderCloseFrames and @ref
  * JxlEncoderCloseBoxes apply to this function. Either this function or the
  * other two must be called after the final frame and/or box, and the next
  * @ref JxlEncoderProcessOutput call, or the codestream won't be encoded
  * correctly.
  *
  * @param enc encoder object.
  */
 JXL_EXPORT void JxlEncoderCloseInput(JxlEncoder* enc);
 
 /**
  * Sets the original color encoding of the image encoded by this encoder. This
  * is an alternative to @ref JxlEncoderSetICCProfile and only one of these two
  * must be used. This one sets the color encoding as a @ref JxlColorEncoding,
  * while the other sets it as ICC binary data. Must be called after @ref
  * JxlEncoderSetBasicInfo.
  *
  * @param enc encoder object.
  * @param color color encoding. Object owned by the caller and its contents are
  * copied internally.
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR otherwise
  */
 JXL_EXPORT JxlEncoderStatus
 JxlEncoderSetColorEncoding(JxlEncoder* enc, const JxlColorEncoding* color);
 
 /**
  * Sets the original color encoding of the image encoded by this encoder as an
  * ICC color profile. This is an alternative to @ref JxlEncoderSetColorEncoding
  * and only one of these two must be used. This one sets the color encoding as
  * ICC binary data, while the other defines it as a @ref JxlColorEncoding. Must
  * be called after @ref JxlEncoderSetBasicInfo.
  *
  * @param enc encoder object.
  * @param icc_profile bytes of the original ICC profile
  * @param size size of the icc_profile buffer in bytes
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR otherwise
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetICCProfile(JxlEncoder* enc,
                                                     const uint8_t* icc_profile,
                                                     size_t size);
 
 /**
  * Initializes a @ref JxlBasicInfo struct to default values.
  * For forwards-compatibility, this function has to be called before values
  * are assigned to the struct fields.
  * The default values correspond to an 8-bit RGB image, no alpha or any
  * other extra channels.
  *
  * @param info global image metadata. Object owned by the caller.
  */
 JXL_EXPORT void JxlEncoderInitBasicInfo(JxlBasicInfo* info);
 
 /**
  * Initializes a @ref JxlFrameHeader struct to default values.
  * For forwards-compatibility, this function has to be called before values
  * are assigned to the struct fields.
  * The default values correspond to a frame with no animation duration and the
  * 'replace' blend mode. After using this function, For animation duration must
  * be set, for composite still blend settings must be set.
  *
  * @param frame_header frame metadata. Object owned by the caller.
  */
 JXL_EXPORT void JxlEncoderInitFrameHeader(JxlFrameHeader* frame_header);
 
 /**
  * Initializes a @ref JxlBlendInfo struct to default values.
  * For forwards-compatibility, this function has to be called before values
  * are assigned to the struct fields.
  *
  * @param blend_info blending info. Object owned by the caller.
  */
 JXL_EXPORT void JxlEncoderInitBlendInfo(JxlBlendInfo* blend_info);
 
 /**
  * Sets the global metadata of the image encoded by this encoder.
  *
  * If the @ref JxlBasicInfo contains information of extra channels beyond an
  * alpha channel, then @ref JxlEncoderSetExtraChannelInfo must be called between
  * @ref JxlEncoderSetBasicInfo and @ref JxlEncoderAddImageFrame. In order to
  * indicate extra channels, the value of `info.num_extra_channels` should be set
  * to the number of extra channels, also counting the alpha channel if present.
  *
  * @param enc encoder object.
  * @param info global image metadata. Object owned by the caller and its
  * contents are copied internally.
  * @return ::JXL_ENC_SUCCESS if the operation was successful,
  * ::JXL_ENC_ERROR otherwise
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetBasicInfo(JxlEncoder* enc,
                                                    const JxlBasicInfo* info);
 
 /**
  * Sets the upsampling method the decoder will use in case there are frames
  * with ::JXL_ENC_FRAME_SETTING_RESAMPLING set. This is useful in combination
  * with the ::JXL_ENC_FRAME_SETTING_ALREADY_DOWNSAMPLED option, to control
  * the type of upsampling that will be used.
  *
  * @param enc encoder object.
  * @param factor upsampling factor to configure (1, 2, 4 or 8; for 1 this
  * function has no effect at all)
  * @param mode upsampling mode to use for this upsampling:
  * -1: default (good for photographic images, no signaling overhead)
  * 0: nearest neighbor (good for pixel art)
  * 1: 'pixel dots' (same as NN for 2x, diamond-shaped 'pixel dots' for 4x/8x)
  * @return ::JXL_ENC_SUCCESS if the operation was successful,
  * ::JXL_ENC_ERROR otherwise
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetUpsamplingMode(JxlEncoder* enc,
                                                         int64_t factor,
                                                         int64_t mode);
 
 /**
  * Initializes a @ref JxlExtraChannelInfo struct to default values.
  * For forwards-compatibility, this function has to be called before values
  * are assigned to the struct fields.
  * The default values correspond to an 8-bit channel of the provided type.
  *
  * @param type type of the extra channel.
  * @param info global extra channel metadata. Object owned by the caller and its
  * contents are copied internally.
  */
 JXL_EXPORT void JxlEncoderInitExtraChannelInfo(JxlExtraChannelType type,
                                                JxlExtraChannelInfo* info);
 
 /**
  * Sets information for the extra channel at the given index. The index
  * must be smaller than num_extra_channels in the associated @ref JxlBasicInfo.
  *
  * @param enc encoder object
  * @param index index of the extra channel to set.
  * @param info global extra channel metadata. Object owned by the caller and its
  * contents are copied internally.
  * @return ::JXL_ENC_SUCCESS on success, ::JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelInfo(
     JxlEncoder* enc, size_t index, const JxlExtraChannelInfo* info);
 
 /**
  * Sets the name for the extra channel at the given index in UTF-8. The index
  * must be smaller than the num_extra_channels in the associated @ref
  * JxlBasicInfo.
  *
  * TODO(lode): remove size parameter for consistency with
  * @ref JxlEncoderSetFrameName
  *
  * @param enc encoder object
  * @param index index of the extra channel to set.
  * @param name buffer with the name of the extra channel.
  * @param size size of the name buffer in bytes, not counting the terminating
  * character.
  * @return JXL_ENC_SUCCESS on success, JXL_ENC_ERROR on error
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelName(JxlEncoder* enc,
                                                           size_t index,
                                                           const char* name,
                                                           size_t size);
 
 /**
  * Sets a frame-specific option of integer type to the encoder options.
  * The @ref JxlEncoderFrameSettingId argument determines which option is set.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param option ID of the option to set.
  * @param value Integer value to set for this option.
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR in case of an error, such as invalid or unknown option id, or
  * invalid integer value for the given option. If an error is returned, the
  * state of the
  * @ref JxlEncoderFrameSettings object is still valid and is the same as before
  * this function was called.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderFrameSettingsSetOption(
     JxlEncoderFrameSettings* frame_settings, JxlEncoderFrameSettingId option,
     int64_t value);
 
 /**
  * Sets a frame-specific option of float type to the encoder options.
  * The @ref JxlEncoderFrameSettingId argument determines which option is set.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param option ID of the option to set.
  * @param value Float value to set for this option.
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR in case of an error, such as invalid or unknown option id, or
  * invalid integer value for the given option. If an error is returned, the
  * state of the
  * @ref JxlEncoderFrameSettings object is still valid and is the same as before
  * this function was called.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderFrameSettingsSetFloatOption(
     JxlEncoderFrameSettings* frame_settings, JxlEncoderFrameSettingId option,
     float value);
 
 /** Forces the encoder to use the box-based container format (BMFF) even
  * when not necessary.
  *
  * When using @ref JxlEncoderUseBoxes, @ref JxlEncoderStoreJPEGMetadata or @ref
  * JxlEncoderSetCodestreamLevel with level 10, the encoder will automatically
  * also use the container format, it is not necessary to use
  * @ref JxlEncoderUseContainer for those use cases.
  *
  * By default this setting is disabled.
  *
  * This setting can only be set at the beginning, before encoding starts.
  *
  * @param enc encoder object.
  * @param use_container true if the encoder should always output the JPEG XL
  * container format, false to only output it when necessary.
  * @return JXL_ENC_SUCCESS if the operation was successful, JXL_ENC_ERROR
  * otherwise.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderUseContainer(JxlEncoder* enc,
                                                    JXL_BOOL use_container);
 
 /**
  * Configure the encoder to store JPEG reconstruction metadata in the JPEG XL
  * container.
  *
  * If this is set to true and a single JPEG frame is added, it will be
  * possible to losslessly reconstruct the JPEG codestream.
  *
  * This setting can only be set at the beginning, before encoding starts.
  *
  * @param enc encoder object.
  * @param store_jpeg_metadata true if the encoder should store JPEG metadata.
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR otherwise.
  */
 JXL_EXPORT JxlEncoderStatus
 JxlEncoderStoreJPEGMetadata(JxlEncoder* enc, JXL_BOOL store_jpeg_metadata);
 
 /** Sets the feature level of the JPEG XL codestream. Valid values are 5 and
  * 10, or -1 (to choose automatically). Using the minimum required level, or
  * level 5 in most cases, is recommended for compatibility with all decoders.
  *
  * Level 5: for end-user image delivery, this level is the most widely
  * supported level by image decoders and the recommended level to use unless a
  * level 10 feature is absolutely necessary. Supports a maximum resolution
  * 268435456 pixels total with a maximum width or height of 262144 pixels,
  * maximum 16-bit color channel depth, maximum 120 frames per second for
  * animation, maximum ICC color profile size of 4 MiB, it allows all color
  * models and extra channel types except CMYK and the JXL_CHANNEL_BLACK
  * extra channel, and a maximum of 4 extra channels in addition to the 3 color
  * channels. It also sets boundaries to certain internally used coding tools.
  *
  * Level 10: this level removes or increases the bounds of most of the level
  * 5 limitations, allows CMYK color and up to 32 bits per color channel, but
  * may be less widely supported.
  *
  * The default value is -1. This means the encoder will automatically choose
  * between level 5 and level 10 based on what information is inside the @ref
  * JxlBasicInfo structure. Do note that some level 10 features, particularly
  * those used by animated JPEG XL codestreams, might require level 10, even
  * though the @ref JxlBasicInfo only suggests level 5. In this case, the level
  * must be explicitly set to 10, otherwise the encoder will return an error.
  * The encoder will restrict internal encoding choices to those compatible with
  * the level setting.
  *
  * This setting can only be set at the beginning, before encoding starts.
  *
  * @param enc encoder object.
  * @param level the level value to set, must be -1, 5, or 10.
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR otherwise.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetCodestreamLevel(JxlEncoder* enc,
                                                          int level);
 
 /** Returns the codestream level required to support the currently configured
  * settings and basic info. This function can only be used at the beginning,
  * before encoding starts, but after setting basic info.
  *
  * This does not support per-frame settings, only global configuration, such as
  * the image dimensions, that are known at the time of writing the header of
  * the JPEG XL file.
  *
  * If this returns 5, nothing needs to be done and the codestream can be
  * compatible with any decoder. If this returns 10, @ref
  * JxlEncoderSetCodestreamLevel has to be used to set the codestream level to
  * 10, or the encoder can be configured differently to allow using the more
  * compatible level 5.
  *
  * @param enc encoder object.
  * @return -1 if no level can support the configuration (e.g. image dimensions
  * larger than even level 10 supports), 5 if level 5 is supported, 10 if setting
  * the codestream level to 10 is required.
  *
  */
 JXL_EXPORT int JxlEncoderGetRequiredCodestreamLevel(const JxlEncoder* enc);
 
 /**
  * Enables lossless encoding.
  *
  * This is not an option like the others on itself, but rather while enabled it
  * overrides a set of existing options (such as distance, modular mode and
  * color transform) that enables bit-for-bit lossless encoding.
  *
  * When disabled, those options are not overridden, but since those options
  * could still have been manually set to a combination that operates losslessly,
  * using this function with lossless set to ::JXL_FALSE does not
  * guarantee lossy encoding, though the default set of options is lossy.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param lossless whether to override options for lossless mode
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR otherwise.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetFrameLossless(
     JxlEncoderFrameSettings* frame_settings, JXL_BOOL lossless);
 
 /**
  * Sets the distance level for lossy compression: target max butteraugli
  * distance, lower = higher quality. Range: 0 .. 25.
  * 0.0 = mathematically lossless (however, use @ref JxlEncoderSetFrameLossless
  * instead to use true lossless, as setting distance to 0 alone is not the only
  * requirement). 1.0 = visually lossless. Recommended range: 0.5 .. 3.0. Default
  * value: 1.0.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param distance the distance value to set.
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR otherwise.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetFrameDistance(
     JxlEncoderFrameSettings* frame_settings, float distance);
 
 /**
  * Sets the distance level for lossy compression of extra channels.
  * The distance is as in @ref JxlEncoderSetFrameDistance (lower = higher
  * quality). If not set, or if set to the special value -1, the distance that
  * was set with
  * @ref JxlEncoderSetFrameDistance will be used.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param index index of the extra channel to set a distance value for.
  * @param distance the distance value to set.
  * @return ::JXL_ENC_SUCCESS if the operation was successful, @ref
  * JXL_ENC_ERROR otherwise.
  */
 JXL_EXPORT JxlEncoderStatus JxlEncoderSetExtraChannelDistance(
     JxlEncoderFrameSettings* frame_settings, size_t index, float distance);
 
 /**
  * Maps JPEG-style quality factor to distance.
  *
  * This function takes in input a JPEG-style quality factor `quality` and
  * produces as output a `distance` value suitable to be used with @ref
  * JxlEncoderSetFrameDistance and @ref JxlEncoderSetExtraChannelDistance.
  *
  * The `distance` value influences the level of compression, with lower values
  * indicating higher quality:
  * - 0.0 implies lossless compression (however, note that calling @ref
  * JxlEncoderSetFrameLossless is required).
  * - 1.0 represents a visually lossy compression, which is also the default
  * setting.
  *
  * The `quality` parameter, ranging up to 100, is inversely related to
  * 'distance':
  * - A `quality` of 100.0 maps to a `distance` of 0.0 (lossless).
  * - A `quality` of 90.0 corresponds to a `distance` of 1.0.
  *
  * Recommended Range:
  * - `distance`: 0.5 to 3.0.
  * - corresponding `quality`: approximately 96 to 68.
  *
  * Allowed Range:
  * - `distance`: 0.0 to 25.0.
  * - corresponding `quality`: 100.0 to 0.0.
  *
  * Note: the `quality` parameter has no consistent psychovisual meaning
  * across different codecs and libraries. Using the mapping defined by @ref
  * JxlEncoderDistanceFromQuality will result in a visual quality roughly
  * equivalent to what would be obtained with `libjpeg-turbo` with the same
  * `quality` parameter, but that is by no means guaranteed; do not assume that
  * the same quality value will result in similar file sizes and image quality
  * across different codecs.
  */
 JXL_EXPORT float JxlEncoderDistanceFromQuality(float quality);
 
 /**
  * Create a new set of encoder options, with all values initially copied from
  * the @p source options, or set to default if @p source is NULL.
  *
  * The returned pointer is an opaque struct tied to the encoder and it will be
  * deallocated by the encoder when @ref JxlEncoderDestroy() is called. For
  * functions taking both a @ref JxlEncoder and a @ref JxlEncoderFrameSettings,
  * only @ref JxlEncoderFrameSettings created with this function for the same
  * encoder instance can be used.
  *
  * @param enc encoder object.
  * @param source source options to copy initial values from, or NULL to get
  * defaults initialized to defaults.
  * @return the opaque struct pointer identifying a new set of encoder options.
  */
 JXL_EXPORT JxlEncoderFrameSettings* JxlEncoderFrameSettingsCreate(
     JxlEncoder* enc, const JxlEncoderFrameSettings* source);
 
 /**
  * Sets a color encoding to be sRGB.
  *
  * @param color_encoding color encoding instance.
  * @param is_gray whether the color encoding should be gray scale or color.
  */
 JXL_EXPORT void JxlColorEncodingSetToSRGB(JxlColorEncoding* color_encoding,
                                           JXL_BOOL is_gray);
 
 /**
  * Sets a color encoding to be linear sRGB.
  *
  * @param color_encoding color encoding instance.
  * @param is_gray whether the color encoding should be gray scale or color.
  */
 JXL_EXPORT void JxlColorEncodingSetToLinearSRGB(
     JxlColorEncoding* color_encoding, JXL_BOOL is_gray);
 
 /**
  * Enables usage of expert options.
  *
  * At the moment, the only expert option is setting an effort value of 11,
  * which gives the best compression for pixel-lossless modes but is very slow.
  *
  * @param enc encoder object.
  */
 JXL_EXPORT void JxlEncoderAllowExpertOptions(JxlEncoder* enc);
 
 /**
  * Function type for @ref JxlEncoderSetDebugImageCallback.
  *
  * The callback may be called simultaneously by different threads when using a
  * threaded parallel runner, on different debug images.
  *
  * @param opaque optional user data, as given to @ref
  *   JxlEncoderSetDebugImageCallback.
  * @param label label of debug image, can be used in filenames
  * @param xsize width of debug image
  * @param ysize height of debug image
  * @param color color encoding of debug image
  * @param pixels pixel data of debug image as big-endian 16-bit unsigned
  *   samples. The memory is not owned by the user, and is only valid during the
  *   time the callback is running.
  */
 typedef void (*JxlDebugImageCallback)(void* opaque, const char* label,
                                       size_t xsize, size_t ysize,
                                       const JxlColorEncoding* color,
                                       const uint16_t* pixels);
 
 /**
  * Sets the given debug image callback that will be used by the encoder to
  * output various debug images during encoding.
  *
  * This only has any effect if the encoder was compiled with the appropriate
  * debug build flags.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param callback used to return the debug image
  * @param opaque user supplied parameter to the image callback
  */
 JXL_EXPORT void JxlEncoderSetDebugImageCallback(
     JxlEncoderFrameSettings* frame_settings, JxlDebugImageCallback callback,
     void* opaque);
 
 /**
  * Sets the given stats object for gathering various statistics during encoding.
  *
  * This only has any effect if the encoder was compiled with the appropriate
  * debug build flags.
  *
  * @param frame_settings set of options and metadata for this frame. Also
  * includes reference to the encoder object.
  * @param stats object that can be used to query the gathered stats (created
  *   by @ref JxlEncoderStatsCreate)
  */
 JXL_EXPORT void JxlEncoderCollectStats(JxlEncoderFrameSettings* frame_settings,
                                        JxlEncoderStats* stats);
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }
 #endif
 
 #endif /* JXL_ENCODE_H_ */
 
 /** @}*/