Cog/ThirdParty/avif/include/avif/avif.h

// Copyright 2019 Joe Drago. All rights reserved.
// SPDX-License-Identifier: BSD-2-Clause

#ifndef AVIF_AVIF_H
#define AVIF_AVIF_H

#include <stddef.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

// ---------------------------------------------------------------------------
// Export macros

// AVIF_BUILDING_SHARED_LIBS should only be defined when libavif is being built
// as a shared library.
// AVIF_DLL should be defined if libavif is a shared library. If you are using
// libavif as CMake dependency, through CMake package config file or through
// pkg-config, this is defined automatically.
//
// Here's what AVIF_API will be defined as in shared build:
// |       |        Windows        |                  Unix                  |
// | Build | __declspec(dllexport) | __attribute__((visibility("default"))) |
// |  Use  | __declspec(dllimport) |                                        |
//
// For static build, AVIF_API is always defined as nothing.

#if defined(_WIN32)
#define AVIF_HELPER_EXPORT __declspec(dllexport)
#define AVIF_HELPER_IMPORT __declspec(dllimport)
#elif defined(__GNUC__) && __GNUC__ >= 4
#define AVIF_HELPER_EXPORT __attribute__((visibility("default")))
#define AVIF_HELPER_IMPORT
#else
#define AVIF_HELPER_EXPORT
#define AVIF_HELPER_IMPORT
#endif

#if defined(AVIF_DLL)
#if defined(AVIF_BUILDING_SHARED_LIBS)
#define AVIF_API AVIF_HELPER_EXPORT
#else
#define AVIF_API AVIF_HELPER_IMPORT
#endif // defined(AVIF_BUILDING_SHARED_LIBS)
#else
#define AVIF_API
#endif // defined(AVIF_DLL)

// ---------------------------------------------------------------------------
// Constants

// AVIF_VERSION_DEVEL should always be 0 for official releases / version tags,
// and non-zero during development of the next release. This should allow for
// downstream projects to do greater-than preprocessor checks on AVIF_VERSION
// to leverage in-development code without breaking their stable builds.
#define AVIF_VERSION_MAJOR 0
#define AVIF_VERSION_MINOR 9
#define AVIF_VERSION_PATCH 3
#define AVIF_VERSION_DEVEL 1
#define AVIF_VERSION \
	((AVIF_VERSION_MAJOR * 1000000) + (AVIF_VERSION_MINOR * 10000) + (AVIF_VERSION_PATCH * 100) + AVIF_VERSION_DEVEL)

typedef int avifBool;
#define AVIF_TRUE 1
#define AVIF_FALSE 0

#define AVIF_DIAGNOSTICS_ERROR_BUFFER_SIZE 256

// A reasonable default for maximum image size to avoid out-of-memory errors or integer overflow in
// (32-bit) int or unsigned int arithmetic operations.
#define AVIF_DEFAULT_IMAGE_SIZE_LIMIT (16384 * 16384)

// a 12 hour AVIF image sequence, running at 60 fps (a basic sanity check as this is quite ridiculous)
#define AVIF_DEFAULT_IMAGE_COUNT_LIMIT (12 * 3600 * 60)

#define AVIF_QUANTIZER_LOSSLESS 0
#define AVIF_QUANTIZER_BEST_QUALITY 0
#define AVIF_QUANTIZER_WORST_QUALITY 63

#define AVIF_PLANE_COUNT_YUV 3

#define AVIF_SPEED_DEFAULT -1
#define AVIF_SPEED_SLOWEST 0
#define AVIF_SPEED_FASTEST 10

typedef enum avifPlanesFlag {
	AVIF_PLANES_YUV = (1 << 0),
	AVIF_PLANES_A = (1 << 1),

	AVIF_PLANES_ALL = 0xff
} avifPlanesFlag;
typedef uint32_t avifPlanesFlags;

enum avifChannelIndex {
	// rgbPlanes
	AVIF_CHAN_R = 0,
	AVIF_CHAN_G = 1,
	AVIF_CHAN_B = 2,

	// yuvPlanes
	AVIF_CHAN_Y = 0,
	AVIF_CHAN_U = 1,
	AVIF_CHAN_V = 2
};

// ---------------------------------------------------------------------------
// Version

AVIF_API const char* avifVersion(void);
AVIF_API void avifCodecVersions(char outBuffer[256]);
AVIF_API unsigned int avifLibYUVVersion(void); // returns 0 if libavif wasn't compiled with libyuv support

// ---------------------------------------------------------------------------
// Memory management

AVIF_API void* avifAlloc(size_t size);
AVIF_API void avifFree(void* p);

// ---------------------------------------------------------------------------
// avifResult

typedef enum avifResult {
	AVIF_RESULT_OK = 0,
	AVIF_RESULT_UNKNOWN_ERROR,
	AVIF_RESULT_INVALID_FTYP,
	AVIF_RESULT_NO_CONTENT,
	AVIF_RESULT_NO_YUV_FORMAT_SELECTED,
	AVIF_RESULT_REFORMAT_FAILED,
	AVIF_RESULT_UNSUPPORTED_DEPTH,
	AVIF_RESULT_ENCODE_COLOR_FAILED,
	AVIF_RESULT_ENCODE_ALPHA_FAILED,
	AVIF_RESULT_BMFF_PARSE_FAILED,
	AVIF_RESULT_NO_AV1_ITEMS_FOUND,
	AVIF_RESULT_DECODE_COLOR_FAILED,
	AVIF_RESULT_DECODE_ALPHA_FAILED,
	AVIF_RESULT_COLOR_ALPHA_SIZE_MISMATCH,
	AVIF_RESULT_ISPE_SIZE_MISMATCH,
	AVIF_RESULT_NO_CODEC_AVAILABLE,
	AVIF_RESULT_NO_IMAGES_REMAINING,
	AVIF_RESULT_INVALID_EXIF_PAYLOAD,
	AVIF_RESULT_INVALID_IMAGE_GRID,
	AVIF_RESULT_INVALID_CODEC_SPECIFIC_OPTION,
	AVIF_RESULT_TRUNCATED_DATA,
	AVIF_RESULT_IO_NOT_SET, // the avifIO field of avifDecoder is not set
	AVIF_RESULT_IO_ERROR,
	AVIF_RESULT_WAITING_ON_IO, // similar to EAGAIN/EWOULDBLOCK, this means the avifIO doesn't have necessary data available yet
	AVIF_RESULT_INVALID_ARGUMENT, // an argument passed into this function is invalid
	AVIF_RESULT_NOT_IMPLEMENTED, // a requested code path is not (yet) implemented
	AVIF_RESULT_OUT_OF_MEMORY
} avifResult;

AVIF_API const char* avifResultToString(avifResult result);

// ---------------------------------------------------------------------------
// avifROData/avifRWData: Generic raw memory storage

typedef struct avifROData {
	const uint8_t* data;
	size_t size;
} avifROData;

// Note: Use avifRWDataFree() if any avif*() function populates one of these.

typedef struct avifRWData {
	uint8_t* data;
	size_t size;
} avifRWData;

// clang-format off
// Initialize avifROData/avifRWData on the stack with this
#define AVIF_DATA_EMPTY { NULL, 0 }
// clang-format on

AVIF_API void avifRWDataRealloc(avifRWData* raw, size_t newSize);
AVIF_API void avifRWDataSet(avifRWData* raw, const uint8_t* data, size_t len);
AVIF_API void avifRWDataFree(avifRWData* raw);

// ---------------------------------------------------------------------------
// avifPixelFormat

typedef enum avifPixelFormat {
	// No pixels are present
	AVIF_PIXEL_FORMAT_NONE = 0,

	AVIF_PIXEL_FORMAT_YUV444,
	AVIF_PIXEL_FORMAT_YUV422,
	AVIF_PIXEL_FORMAT_YUV420,
	AVIF_PIXEL_FORMAT_YUV400
} avifPixelFormat;
AVIF_API const char* avifPixelFormatToString(avifPixelFormat format);

typedef struct avifPixelFormatInfo {
	avifBool monochrome;
	int chromaShiftX;
	int chromaShiftY;
} avifPixelFormatInfo;

AVIF_API void avifGetPixelFormatInfo(avifPixelFormat format, avifPixelFormatInfo* info);

// ---------------------------------------------------------------------------
// avifChromaSamplePosition

typedef enum avifChromaSamplePosition {
	AVIF_CHROMA_SAMPLE_POSITION_UNKNOWN = 0,
	AVIF_CHROMA_SAMPLE_POSITION_VERTICAL = 1,
	AVIF_CHROMA_SAMPLE_POSITION_COLOCATED = 2
} avifChromaSamplePosition;

// ---------------------------------------------------------------------------
// avifRange

typedef enum avifRange {
	AVIF_RANGE_LIMITED = 0,
	AVIF_RANGE_FULL = 1
} avifRange;

// ---------------------------------------------------------------------------
// CICP enums - https://www.itu.int/rec/T-REC-H.273-201612-I/en

enum {
	// This is actually reserved, but libavif uses it as a sentinel value.
	AVIF_COLOR_PRIMARIES_UNKNOWN = 0,

	AVIF_COLOR_PRIMARIES_BT709 = 1,
	AVIF_COLOR_PRIMARIES_IEC61966_2_4 = 1,
	AVIF_COLOR_PRIMARIES_UNSPECIFIED = 2,
	AVIF_COLOR_PRIMARIES_BT470M = 4,
	AVIF_COLOR_PRIMARIES_BT470BG = 5,
	AVIF_COLOR_PRIMARIES_BT601 = 6,
	AVIF_COLOR_PRIMARIES_SMPTE240 = 7,
	AVIF_COLOR_PRIMARIES_GENERIC_FILM = 8,
	AVIF_COLOR_PRIMARIES_BT2020 = 9,
	AVIF_COLOR_PRIMARIES_XYZ = 10,
	AVIF_COLOR_PRIMARIES_SMPTE431 = 11,
	AVIF_COLOR_PRIMARIES_SMPTE432 = 12, // DCI P3
	AVIF_COLOR_PRIMARIES_EBU3213 = 22
};
typedef uint16_t avifColorPrimaries; // AVIF_COLOR_PRIMARIES_*

// outPrimaries: rX, rY, gX, gY, bX, bY, wX, wY
AVIF_API void avifColorPrimariesGetValues(avifColorPrimaries acp, float outPrimaries[8]);
AVIF_API avifColorPrimaries avifColorPrimariesFind(const float inPrimaries[8], const char** outName);

enum {
	// This is actually reserved, but libavif uses it as a sentinel value.
	AVIF_TRANSFER_CHARACTERISTICS_UNKNOWN = 0,

	AVIF_TRANSFER_CHARACTERISTICS_BT709 = 1,
	AVIF_TRANSFER_CHARACTERISTICS_UNSPECIFIED = 2,
	AVIF_TRANSFER_CHARACTERISTICS_BT470M = 4, // 2.2 gamma
	AVIF_TRANSFER_CHARACTERISTICS_BT470BG = 5, // 2.8 gamma
	AVIF_TRANSFER_CHARACTERISTICS_BT601 = 6,
	AVIF_TRANSFER_CHARACTERISTICS_SMPTE240 = 7,
	AVIF_TRANSFER_CHARACTERISTICS_LINEAR = 8,
	AVIF_TRANSFER_CHARACTERISTICS_LOG100 = 9,
	AVIF_TRANSFER_CHARACTERISTICS_LOG100_SQRT10 = 10,
	AVIF_TRANSFER_CHARACTERISTICS_IEC61966 = 11,
	AVIF_TRANSFER_CHARACTERISTICS_BT1361 = 12,
	AVIF_TRANSFER_CHARACTERISTICS_SRGB = 13,
	AVIF_TRANSFER_CHARACTERISTICS_BT2020_10BIT = 14,
	AVIF_TRANSFER_CHARACTERISTICS_BT2020_12BIT = 15,
	AVIF_TRANSFER_CHARACTERISTICS_SMPTE2084 = 16, // PQ
	AVIF_TRANSFER_CHARACTERISTICS_SMPTE428 = 17,
	AVIF_TRANSFER_CHARACTERISTICS_HLG = 18
};
typedef uint16_t avifTransferCharacteristics; // AVIF_TRANSFER_CHARACTERISTICS_*

enum {
	AVIF_MATRIX_COEFFICIENTS_IDENTITY = 0,
	AVIF_MATRIX_COEFFICIENTS_BT709 = 1,
	AVIF_MATRIX_COEFFICIENTS_UNSPECIFIED = 2,
	AVIF_MATRIX_COEFFICIENTS_FCC = 4,
	AVIF_MATRIX_COEFFICIENTS_BT470BG = 5,
	AVIF_MATRIX_COEFFICIENTS_BT601 = 6,
	AVIF_MATRIX_COEFFICIENTS_SMPTE240 = 7,
	AVIF_MATRIX_COEFFICIENTS_YCGCO = 8,
	AVIF_MATRIX_COEFFICIENTS_BT2020_NCL = 9,
	AVIF_MATRIX_COEFFICIENTS_BT2020_CL = 10,
	AVIF_MATRIX_COEFFICIENTS_SMPTE2085 = 11,
	AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_NCL = 12,
	AVIF_MATRIX_COEFFICIENTS_CHROMA_DERIVED_CL = 13,
	AVIF_MATRIX_COEFFICIENTS_ICTCP = 14
};
typedef uint16_t avifMatrixCoefficients; // AVIF_MATRIX_COEFFICIENTS_*

// ---------------------------------------------------------------------------
// avifDiagnostics

typedef struct avifDiagnostics {
	// Upon receiving an error from any non-const libavif API call, if the toplevel structure used
	// in the API call (avifDecoder, avifEncoder) contains a diag member, this buffer may be
	// populated with a NULL-terminated, freeform error string explaining the most recent error in
	// more detail. It will be cleared at the beginning of every non-const API call.
	//
	// Note: If an error string contains the "[Strict]" prefix, it means that you encountered an
	// error that only occurs during strict decoding. If you disable strict mode, you will no
	// longer encounter this error.
	char error[AVIF_DIAGNOSTICS_ERROR_BUFFER_SIZE];
} avifDiagnostics;

AVIF_API void avifDiagnosticsClearError(avifDiagnostics* diag);

// ---------------------------------------------------------------------------
// Optional transformation structs

typedef enum avifTransformFlag {
	AVIF_TRANSFORM_NONE = 0,

	AVIF_TRANSFORM_PASP = (1 << 0),
	AVIF_TRANSFORM_CLAP = (1 << 1),
	AVIF_TRANSFORM_IROT = (1 << 2),
	AVIF_TRANSFORM_IMIR = (1 << 3)
} avifTransformFlag;
typedef uint32_t avifTransformFlags;

typedef struct avifPixelAspectRatioBox {
	// 'pasp' from ISO/IEC 14496-12:2015 12.1.4.3

	// define the relative width and height of a pixel
	uint32_t hSpacing;
	uint32_t vSpacing;
} avifPixelAspectRatioBox;

typedef struct avifCleanApertureBox {
	// 'clap' from ISO/IEC 14496-12:2015 12.1.4.3

	// a fractional number which defines the exact clean aperture width, in counted pixels, of the video image
	uint32_t widthN;
	uint32_t widthD;

	// a fractional number which defines the exact clean aperture height, in counted pixels, of the video image
	uint32_t heightN;
	uint32_t heightD;

	// a fractional number which defines the horizontal offset of clean aperture centre minus (width-1)/2. Typically 0.
	uint32_t horizOffN;
	uint32_t horizOffD;

	// a fractional number which defines the vertical offset of clean aperture centre minus (height-1)/2. Typically 0.
	uint32_t vertOffN;
	uint32_t vertOffD;
} avifCleanApertureBox;

typedef struct avifImageRotation {
	// 'irot' from ISO/IEC 23008-12:2017 6.5.10

	// angle * 90 specifies the angle (in anti-clockwise direction) in units of degrees.
	uint8_t angle; // legal values: [0-3]
} avifImageRotation;

typedef struct avifImageMirror {
	// 'imir' from ISO/IEC 23008-12:2017 6.5.12 (Draft Amendment 2):
	//
	//     'mode' specifies how the mirroring is performed:
	//
	//     0 indicates that the top and bottom parts of the image are exchanged;
	//     1 specifies that the left and right parts are exchanged.
	//
	//     NOTE In Exif, orientation tag can be used to signal mirroring operations. Exif
	//     orientation tag 4 corresponds to mode = 0 of ImageMirror, and Exif orientation tag 2
	//     corresponds to mode = 1 accordingly.
	//
	// Legal values: [0, 1]
	//
	// NOTE: As of HEIF Draft Amendment 2, the name of this variable has changed from 'axis' to 'mode' as
	//       the logic behind it has been *inverted*. Please use the wording above describing the legal
	//       values for 'mode' and update any code that previously may have used `axis` to use
	//       the *opposite* value (0 now means top-to-bottom, where it used to mean left-to-right).
	uint8_t mode;
} avifImageMirror;

// ---------------------------------------------------------------------------
// avifCropRect - Helper struct/functions to work with avifCleanApertureBox

typedef struct avifCropRect {
	uint32_t x;
	uint32_t y;
	uint32_t width;
	uint32_t height;
} avifCropRect;

// These will return AVIF_FALSE if the resultant values violate any standards, and if so, the output
// values are not guaranteed to be complete or correct and should not be used.
AVIF_API avifBool avifCropRectConvertCleanApertureBox(avifCropRect* cropRect,
                                                      const avifCleanApertureBox* clap,
                                                      uint32_t imageW,
                                                      uint32_t imageH,
                                                      avifPixelFormat yuvFormat,
                                                      avifDiagnostics* diag);
AVIF_API avifBool avifCleanApertureBoxConvertCropRect(avifCleanApertureBox* clap,
                                                      const avifCropRect* cropRect,
                                                      uint32_t imageW,
                                                      uint32_t imageH,
                                                      avifPixelFormat yuvFormat,
                                                      avifDiagnostics* diag);

// ---------------------------------------------------------------------------
// avifImage

typedef struct avifImage {
	// Image information
	uint32_t width;
	uint32_t height;
	uint32_t depth; // all planes must share this depth; if depth>8, all planes are uint16_t internally

	avifPixelFormat yuvFormat;
	avifRange yuvRange;
	avifChromaSamplePosition yuvChromaSamplePosition;
	uint8_t* yuvPlanes[AVIF_PLANE_COUNT_YUV];
	uint32_t yuvRowBytes[AVIF_PLANE_COUNT_YUV];
	avifBool imageOwnsYUVPlanes;

	avifRange alphaRange;
	uint8_t* alphaPlane;
	uint32_t alphaRowBytes;
	avifBool imageOwnsAlphaPlane;
	avifBool alphaPremultiplied;

	// ICC Profile
	avifRWData icc;

	// CICP information:
	// These are stored in the AV1 payload and used to signal YUV conversion. Additionally, if an
	// ICC profile is not specified, these will be stored in the AVIF container's `colr` box with
	// a type of `nclx`. If your system supports ICC profiles, be sure to check for the existence
	// of one (avifImage.icc) before relying on the values listed here!
	avifColorPrimaries colorPrimaries;
	avifTransferCharacteristics transferCharacteristics;
	avifMatrixCoefficients matrixCoefficients;

	// Transformations - These metadata values are encoded/decoded when transformFlags are set
	// appropriately, but do not impact/adjust the actual pixel buffers used (images won't be
	// pre-cropped or mirrored upon decode). Basic explanations from the standards are offered in
	// comments above, but for detailed explanations, please refer to the HEIF standard (ISO/IEC
	// 23008-12:2017) and the BMFF standard (ISO/IEC 14496-12:2015).
	//
	// To encode any of these boxes, set the values in the associated box, then enable the flag in
	// transformFlags. On decode, only honor the values in boxes with the associated transform flag set.
	avifTransformFlags transformFlags;
	avifPixelAspectRatioBox pasp;
	avifCleanApertureBox clap;
	avifImageRotation irot;
	avifImageMirror imir;

	// Metadata - set with avifImageSetMetadata*() before write, check .size>0 for existence after read
	avifRWData exif;
	avifRWData xmp;
} avifImage;

AVIF_API avifImage* avifImageCreate(int width, int height, int depth, avifPixelFormat yuvFormat);
AVIF_API avifImage* avifImageCreateEmpty(void); // helper for making an image to decode into
AVIF_API void avifImageCopy(avifImage* dstImage, const avifImage* srcImage, avifPlanesFlags planes); // deep copy
AVIF_API void avifImageDestroy(avifImage* image);

AVIF_API void avifImageSetProfileICC(avifImage* image, const uint8_t* icc, size_t iccSize);

// Warning: If the Exif payload is set and invalid, avifEncoderWrite() may return AVIF_RESULT_INVALID_EXIF_PAYLOAD
AVIF_API void avifImageSetMetadataExif(avifImage* image, const uint8_t* exif, size_t exifSize);
AVIF_API void avifImageSetMetadataXMP(avifImage* image, const uint8_t* xmp, size_t xmpSize);

AVIF_API void avifImageAllocatePlanes(avifImage* image, avifPlanesFlags planes); // Ignores any pre-existing planes
AVIF_API void avifImageFreePlanes(avifImage* image, avifPlanesFlags planes); // Ignores already-freed planes
AVIF_API void avifImageStealPlanes(avifImage* dstImage, avifImage* srcImage, avifPlanesFlags planes);

// ---------------------------------------------------------------------------
// Understanding maxThreads
//
// libavif's structures and API use the setting 'maxThreads' in a few places. The intent of this
// setting is to limit concurrent thread activity/usage, not necessarily to put a hard ceiling on
// how many sleeping threads happen to exist behind the scenes. The goal of this setting is to
// ensure that at any given point during libavif's encoding or decoding, no more than *maxThreads*
// threads are simultaneously **active and taking CPU time**.
//
// As an important example, when encoding an image sequence that has an alpha channel, two
// long-lived underlying AV1 encoders must simultaneously exist (one for color, one for alpha). For
// each additional frame fed into libavif, its YUV planes are fed into one instance of the AV1
// encoder, and its alpha plane is fed into another. These operations happen serially, so only one
// of these AV1 encoders is ever active at a time. However, the AV1 encoders might pre-create a
// pool of worker threads upon initialization, so during this process, twice the amount of worker
// threads actually simultaneously exist on the machine, but half of them are guaranteed to be
// sleeping.
//
// This design ensures that AV1 implementations are given as many threads as possible to ensure a
// speedy encode or decode, despite the complexities of occasionally needing two AV1 codec instances
// (due to alpha payloads being separate from color payloads). If your system has a hard ceiling on
// the number of threads that can ever be in flight at a given time, please account for this
// accordingly.

// ---------------------------------------------------------------------------
// Optional YUV<->RGB support

// To convert to/from RGB, create an avifRGBImage on the stack, call avifRGBImageSetDefaults() on
// it, and then tweak the values inside of it accordingly. At a minimum, you should populate
// ->pixels and ->rowBytes with an appropriately sized pixel buffer, which should be at least
// (->rowBytes * ->height) bytes, where ->rowBytes is at least (->width * avifRGBImagePixelSize()).
// If you don't want to supply your own pixel buffer, you can use the
// avifRGBImageAllocatePixels()/avifRGBImageFreePixels() convenience functions.

// avifImageRGBToYUV() and avifImageYUVToRGB() will perform depth rescaling and limited<->full range
// conversion, if necessary. Pixels in an avifRGBImage buffer are always full range, and conversion
// routines will fail if the width and height don't match the associated avifImage.

// If libavif is built with libyuv fast paths enabled, libavif will use libyuv for conversion from
// YUV to RGB if the following requirements are met:
//
// * YUV depth: 8
// * RGB depth: 8
// * rgb.chromaUpsampling: AVIF_CHROMA_UPSAMPLING_AUTOMATIC, AVIF_CHROMA_UPSAMPLING_FASTEST
// * rgb.format: AVIF_RGB_FORMAT_RGBA, AVIF_RGB_FORMAT_BGRA (420/422 support for AVIF_RGB_FORMAT_ABGR, AVIF_RGB_FORMAT_ARGB)
// * CICP is one of the following combinations (CP/TC/MC/Range):
//   * x/x/[2|5|6]/Full
//   * [5|6]/x/12/Full
//   * x/x/[1|2|5|6|9]/Limited
//   * [1|2|5|6|9]/x/12/Limited

typedef enum avifRGBFormat {
	AVIF_RGB_FORMAT_RGB = 0,
	AVIF_RGB_FORMAT_RGBA, // This is the default format set in avifRGBImageSetDefaults().
	AVIF_RGB_FORMAT_ARGB,
	AVIF_RGB_FORMAT_BGR,
	AVIF_RGB_FORMAT_BGRA,
	AVIF_RGB_FORMAT_ABGR
} avifRGBFormat;
AVIF_API uint32_t avifRGBFormatChannelCount(avifRGBFormat format);
AVIF_API avifBool avifRGBFormatHasAlpha(avifRGBFormat format);

typedef enum avifChromaUpsampling {
	AVIF_CHROMA_UPSAMPLING_AUTOMATIC = 0, // Chooses best trade off of speed/quality (prefers libyuv, else uses BEST_QUALITY)
	AVIF_CHROMA_UPSAMPLING_FASTEST = 1, // Chooses speed over quality (prefers libyuv, else uses NEAREST)
	AVIF_CHROMA_UPSAMPLING_BEST_QUALITY = 2, // Chooses the best quality upsampling, given settings (avoids libyuv)
	AVIF_CHROMA_UPSAMPLING_NEAREST = 3, // Uses nearest-neighbor filter (built-in)
	AVIF_CHROMA_UPSAMPLING_BILINEAR = 4 // Uses bilinear filter (built-in)
} avifChromaUpsampling;

typedef struct avifRGBImage {
	uint32_t width; // must match associated avifImage
	uint32_t height; // must match associated avifImage
	uint32_t depth; // legal depths [8, 10, 12, 16]. if depth>8, pixels must be uint16_t internally
	avifRGBFormat format; // all channels are always full range
	avifChromaUpsampling chromaUpsampling; // Defaults to AVIF_CHROMA_UPSAMPLING_AUTOMATIC: How to upsample non-4:4:4 UV (ignored for 444) when converting to RGB.
	                                       // Unused when converting to YUV. avifRGBImageSetDefaults() prefers quality over speed.
	avifBool ignoreAlpha; // Used for XRGB formats, treats formats containing alpha (such as ARGB) as if they were
	                      // RGB, treating the alpha bits as if they were all 1.
	avifBool alphaPremultiplied; // indicates if RGB value is pre-multiplied by alpha. Default: false
	avifBool isFloat; // indicates if RGBA values are in half float (f16) format. Valid only when depth == 16. Default: false

	uint8_t* pixels;
	uint32_t rowBytes;
} avifRGBImage;

// Sets rgb->width, rgb->height, and rgb->depth to image->width, image->height, and image->depth.
// Sets rgb->pixels to NULL and rgb->rowBytes to 0. Sets the other fields of 'rgb' to default
// values.
AVIF_API void avifRGBImageSetDefaults(avifRGBImage* rgb, const avifImage* image);
AVIF_API uint32_t avifRGBImagePixelSize(const avifRGBImage* rgb);

// Convenience functions. If you supply your own pixels/rowBytes, you do not need to use these.
AVIF_API void avifRGBImageAllocatePixels(avifRGBImage* rgb);
AVIF_API void avifRGBImageFreePixels(avifRGBImage* rgb);

// The main conversion functions
AVIF_API avifResult avifImageRGBToYUV(avifImage* image, const avifRGBImage* rgb);
AVIF_API avifResult avifImageYUVToRGB(const avifImage* image, avifRGBImage* rgb);

// Premultiply handling functions.
// (Un)premultiply is automatically done by the main conversion functions above,
// so usually you don't need to call these. They are there for convenience.
AVIF_API avifResult avifRGBImagePremultiplyAlpha(avifRGBImage* rgb);
AVIF_API avifResult avifRGBImageUnpremultiplyAlpha(avifRGBImage* rgb);

// ---------------------------------------------------------------------------
// YUV Utils

AVIF_API int avifFullToLimitedY(int depth, int v);
AVIF_API int avifFullToLimitedUV(int depth, int v);
AVIF_API int avifLimitedToFullY(int depth, int v);
AVIF_API int avifLimitedToFullUV(int depth, int v);

// ---------------------------------------------------------------------------
// Codec selection

typedef enum avifCodecChoice {
	AVIF_CODEC_CHOICE_AUTO = 0,
	AVIF_CODEC_CHOICE_AOM,
	AVIF_CODEC_CHOICE_DAV1D, // Decode only
	AVIF_CODEC_CHOICE_LIBGAV1, // Decode only
	AVIF_CODEC_CHOICE_RAV1E, // Encode only
	AVIF_CODEC_CHOICE_SVT // Encode only
} avifCodecChoice;

typedef enum avifCodecFlag {
	AVIF_CODEC_FLAG_CAN_DECODE = (1 << 0),
	AVIF_CODEC_FLAG_CAN_ENCODE = (1 << 1)
} avifCodecFlag;
typedef uint32_t avifCodecFlags;

// If this returns NULL, the codec choice/flag combination is unavailable
AVIF_API const char* avifCodecName(avifCodecChoice choice, avifCodecFlags requiredFlags);
AVIF_API avifCodecChoice avifCodecChoiceFromName(const char* name);

typedef struct avifCodecConfigurationBox {
	// [skipped; is constant] unsigned int (1)marker = 1;
	// [skipped; is constant] unsigned int (7)version = 1;

	uint8_t seqProfile; // unsigned int (3) seq_profile;
	uint8_t seqLevelIdx0; // unsigned int (5) seq_level_idx_0;
	uint8_t seqTier0; // unsigned int (1) seq_tier_0;
	uint8_t highBitdepth; // unsigned int (1) high_bitdepth;
	uint8_t twelveBit; // unsigned int (1) twelve_bit;
	uint8_t monochrome; // unsigned int (1) monochrome;
	uint8_t chromaSubsamplingX; // unsigned int (1) chroma_subsampling_x;
	uint8_t chromaSubsamplingY; // unsigned int (1) chroma_subsampling_y;
	uint8_t chromaSamplePosition; // unsigned int (2) chroma_sample_position;

	// unsigned int (3)reserved = 0;
	// unsigned int (1)initial_presentation_delay_present;
	// if (initial_presentation_delay_present) {
	//     unsigned int (4)initial_presentation_delay_minus_one;
	// } else {
	//     unsigned int (4)reserved = 0;
	// }
} avifCodecConfigurationBox;

// ---------------------------------------------------------------------------
// avifIO

struct avifIO;

// Destroy must completely destroy all child structures *and* free the avifIO object itself.
// This function pointer is optional, however, if the avifIO object isn't intended to be owned by
// a libavif encoder/decoder.
typedef void (*avifIODestroyFunc)(struct avifIO* io);

// This function should return a block of memory that *must* remain valid until another read call to
// this avifIO struct is made (reusing a read buffer is acceptable/expected).
//
// * If offset exceeds the size of the content (past EOF), return AVIF_RESULT_IO_ERROR.
// * If offset is *exactly* at EOF, provide a 0-byte buffer and return AVIF_RESULT_OK.
// * If (offset+size) exceeds the contents' size, it must truncate the range to provide all
//   bytes from the offset to EOF.
// * If the range is unavailable yet (due to network conditions or any other reason),
//   return AVIF_RESULT_WAITING_ON_IO.
// * Otherwise, provide the range and return AVIF_RESULT_OK.
typedef avifResult (*avifIOReadFunc)(struct avifIO* io, uint32_t readFlags, uint64_t offset, size_t size, avifROData* out);

typedef avifResult (*avifIOWriteFunc)(struct avifIO* io, uint32_t writeFlags, uint64_t offset, const uint8_t* data, size_t size);

typedef struct avifIO {
	avifIODestroyFunc destroy;
	avifIOReadFunc read;

	// This is reserved for future use - but currently ignored. Set it to a null pointer.
	avifIOWriteFunc write;

	// If non-zero, this is a hint to internal structures of the max size offered by the content
	// this avifIO structure is reading. If it is a static memory source, it should be the size of
	// the memory buffer; if it is a file, it should be the file's size. If this information cannot
	// be known (as it is streamed-in), set a reasonable upper boundary here (larger than the file
	// can possibly be for your environment, but within your environment's memory constraints). This
	// is used for sanity checks when allocating internal buffers to protect against
	// malformed/malicious files.
	uint64_t sizeHint;

	// If true, *all* memory regions returned from *all* calls to read are guaranteed to be
	// persistent and exist for the lifetime of the avifIO object. If false, libavif will make
	// in-memory copies of samples and metadata content, and a memory region returned from read must
	// only persist until the next call to read.
	avifBool persistent;

	// The contents of this are defined by the avifIO implementation, and should be fully destroyed
	// by the implementation of the associated destroy function, unless it isn't owned by the avifIO
	// struct. It is not necessary to use this pointer in your implementation.
	void* data;
} avifIO;

AVIF_API avifIO* avifIOCreateMemoryReader(const uint8_t* data, size_t size);
AVIF_API avifIO* avifIOCreateFileReader(const char* filename);
AVIF_API void avifIODestroy(avifIO* io);

// ---------------------------------------------------------------------------
// avifDecoder

// Some encoders (including very old versions of avifenc) do not implement the AVIF standard
// perfectly, and thus create invalid files. However, these files are likely still recoverable /
// decodable, if it wasn't for the strict requirements imposed by libavif's decoder. These flags
// allow a user of avifDecoder to decide what level of strictness they want in their project.
typedef enum avifStrictFlag {
	// Disables all strict checks.
	AVIF_STRICT_DISABLED = 0,

	// Requires the PixelInformationProperty ('pixi') be present in AV1 image items. libheif v1.11.0
	// or older does not add the 'pixi' item property to AV1 image items. If you need to decode AVIF
	// images encoded by libheif v1.11.0 or older, be sure to disable this bit. (This issue has been
	// corrected in libheif v1.12.0.)
	AVIF_STRICT_PIXI_REQUIRED = (1 << 0),

	// This demands that the values surfaced in the clap box are valid, determined by attempting to
	// convert the clap box to a crop rect using avifCropRectConvertCleanApertureBox(). If this
	// function returns AVIF_FALSE and this strict flag is set, the decode will fail.
	AVIF_STRICT_CLAP_VALID = (1 << 1),

	// Requires the ImageSpatialExtentsProperty ('ispe') be present in alpha auxiliary image items.
	// avif-serialize 0.7.3 or older does not add the 'ispe' item property to alpha auxiliary image
	// items. If you need to decode AVIF images encoded by the cavif encoder with avif-serialize
	// 0.7.3 or older, be sure to disable this bit. (This issue has been corrected in avif-serialize
	// 0.7.4.) See https://github.com/kornelski/avif-serialize/issues/3 and
	// https://crbug.com/1246678.
	AVIF_STRICT_ALPHA_ISPE_REQUIRED = (1 << 2),

	// Maximum strictness; enables all bits above. This is avifDecoder's default.
	AVIF_STRICT_ENABLED = AVIF_STRICT_PIXI_REQUIRED | AVIF_STRICT_CLAP_VALID | AVIF_STRICT_ALPHA_ISPE_REQUIRED
} avifStrictFlag;
typedef uint32_t avifStrictFlags;

// Useful stats related to a read/write
typedef struct avifIOStats {
	size_t colorOBUSize;
	size_t alphaOBUSize;
} avifIOStats;

struct avifDecoderData;

typedef enum avifDecoderSource {
	// Honor the major brand signaled in the beginning of the file to pick between an AVIF sequence
	// ('avis', tracks-based) or a single image ('avif', item-based). If the major brand is neither
	// of these, prefer the AVIF sequence ('avis', tracks-based), if present.
	AVIF_DECODER_SOURCE_AUTO = 0,

	// Use the primary item and the aux (alpha) item in the avif(s).
	// This is where single-image avifs store their image.
	AVIF_DECODER_SOURCE_PRIMARY_ITEM,

	// Use the chunks inside primary/aux tracks in the moov block.
	// This is where avifs image sequences store their images.
	AVIF_DECODER_SOURCE_TRACKS,

	// Decode the thumbnail item. Currently unimplemented.
	// AVIF_DECODER_SOURCE_THUMBNAIL_ITEM
} avifDecoderSource;

// Information about the timing of a single image in an image sequence
typedef struct avifImageTiming {
	uint64_t timescale; // timescale of the media (Hz)
	double pts; // presentation timestamp in seconds (ptsInTimescales / timescale)
	uint64_t ptsInTimescales; // presentation timestamp in "timescales"
	double duration; // in seconds (durationInTimescales / timescale)
	uint64_t durationInTimescales; // duration in "timescales"
} avifImageTiming;

typedef enum avifProgressiveState {
	// The current AVIF/Source does not offer a progressive image. This will always be the state
	// for an image sequence.
	AVIF_PROGRESSIVE_STATE_UNAVAILABLE = 0,

	// The current AVIF/Source offers a progressive image, but avifDecoder.allowProgressive is not
	// enabled, so it will behave as if the image was not progressive and will simply decode the
	// best version of this item.
	AVIF_PROGRESSIVE_STATE_AVAILABLE,

	// The current AVIF/Source offers a progressive image, and avifDecoder.allowProgressive is true.
	// In this state, avifDecoder.imageCount will be the count of all of the available progressive
	// layers, and any specific layer can be decoded using avifDecoderNthImage() as if it was an
	// image sequence, or simply using repeated calls to avifDecoderNextImage() to decode better and
	// better versions of this image.
	AVIF_PROGRESSIVE_STATE_ACTIVE
} avifProgressiveState;
AVIF_API const char* avifProgressiveStateToString(avifProgressiveState progressiveState);

typedef struct avifDecoder {
	// --------------------------------------------------------------------------------------------
	// Inputs

	// Defaults to AVIF_CODEC_CHOICE_AUTO: Preference determined by order in availableCodecs table (avif.c)
	avifCodecChoice codecChoice;

	// Defaults to 1. -- NOTE: Please see the "Understanding maxThreads" comment block above
	int maxThreads;

	// avifs can have multiple sets of images in them. This specifies which to decode.
	// Set this via avifDecoderSetSource().
	avifDecoderSource requestedSource;

	// If this is true and a progressive AVIF is decoded, avifDecoder will behave as if the AVIF is
	// an image sequence, in that it will set imageCount to the number of progressive frames
	// available, and avifDecoderNextImage()/avifDecoderNthImage() will allow for specific layers
	// of a progressive image to be decoded. To distinguish between a progressive AVIF and an AVIF
	// image sequence, inspect avifDecoder.progressiveState.
	avifBool allowProgressive;

	// Enable any of these to avoid reading and surfacing specific data to the decoded avifImage.
	// These can be useful if your avifIO implementation heavily uses AVIF_RESULT_WAITING_ON_IO for
	// streaming data, as some of these payloads are (unfortunately) packed at the end of the file,
	// which will cause avifDecoderParse() to return AVIF_RESULT_WAITING_ON_IO until it finds them.
	// If you don't actually leverage this data, it is best to ignore it here.
	avifBool ignoreExif;
	avifBool ignoreXMP;

	// This represents the maximum size of a image (in pixel count) that libavif and the underlying
	// AV1 decoder should attempt to decode. It defaults to AVIF_DEFAULT_IMAGE_SIZE_LIMIT, and can be
	// set to a smaller value. The value 0 is reserved.
	// Note: Only some underlying AV1 codecs support a configurable size limit (such as dav1d).
	uint32_t imageSizeLimit;

	// This provides an upper bound on how many images the decoder is willing to attempt to decode,
	// to provide a bit of protection from malicious or malformed AVIFs citing millions upon
	// millions of frames, only to be invalid later. The default is AVIF_DEFAULT_IMAGE_COUNT_LIMIT
	// (see comment above), and setting this to 0 disables the limit.
	uint32_t imageCountLimit;

	// Strict flags. Defaults to AVIF_STRICT_ENABLED. See avifStrictFlag definitions above.
	avifStrictFlags strictFlags;

	// --------------------------------------------------------------------------------------------
	// Outputs

	// All decoded image data; owned by the decoder. All information in this image is incrementally
	// added and updated as avifDecoder*() functions are called. After a successful call to
	// avifDecoderParse(), all values in decoder->image (other than the planes/rowBytes themselves)
	// will be pre-populated with all information found in the outer AVIF container, prior to any
	// AV1 decoding. If the contents of the inner AV1 payload disagree with the outer container,
	// these values may change after calls to avifDecoderRead*(),avifDecoderNextImage(), or
	// avifDecoderNthImage().
	//
	// The YUV and A contents of this image are likely owned by the decoder, so be sure to copy any
	// data inside of this image before advancing to the next image or reusing the decoder. It is
	// legal to call avifImageYUVToRGB() on this in between calls to avifDecoderNextImage(), but use
	// avifImageCopy() if you want to make a complete, permanent copy of this image's YUV content or
	// metadata.
	avifImage* image;

	// Counts and timing for the current image in an image sequence. Uninteresting for single image files.
	int imageIndex; // 0-based
	int imageCount; // Always 1 for non-progressive, non-sequence AVIFs.
	avifProgressiveState progressiveState; // See avifProgressiveState declaration
	avifImageTiming imageTiming; //
	uint64_t timescale; // timescale of the media (Hz)
	double duration; // in seconds (durationInTimescales / timescale)
	uint64_t durationInTimescales; // duration in "timescales"

	// This is true when avifDecoderParse() detects an alpha plane. Use this to find out if alpha is
	// present after a successful call to avifDecoderParse(), but prior to any call to
	// avifDecoderNextImage() or avifDecoderNthImage(), as decoder->image->alphaPlane won't exist yet.
	avifBool alphaPresent;

	// stats from the most recent read, possibly 0s if reading an image sequence
	avifIOStats ioStats;

	// Additional diagnostics (such as detailed error state)
	avifDiagnostics diag;

	// --------------------------------------------------------------------------------------------
	// Internals

	// Use one of the avifDecoderSetIO*() functions to set this
	avifIO* io;

	// Internals used by the decoder
	struct avifDecoderData* data;
} avifDecoder;

AVIF_API avifDecoder* avifDecoderCreate(void);
AVIF_API void avifDecoderDestroy(avifDecoder* decoder);

// Simple interfaces to decode a single image, independent of the decoder afterwards (decoder may be destroyed).
AVIF_API avifResult avifDecoderRead(avifDecoder* decoder, avifImage* image); // call avifDecoderSetIO*() first
AVIF_API avifResult avifDecoderReadMemory(avifDecoder* decoder, avifImage* image, const uint8_t* data, size_t size);
AVIF_API avifResult avifDecoderReadFile(avifDecoder* decoder, avifImage* image, const char* filename);

// Multi-function alternative to avifDecoderRead() for image sequences and gaining direct access
// to the decoder's YUV buffers (for performance's sake). Data passed into avifDecoderParse() is NOT
// copied, so it must continue to exist until the decoder is destroyed.
//
// Usage / function call order is:
// * avifDecoderCreate()
// * avifDecoderSetSource() - optional, the default (AVIF_DECODER_SOURCE_AUTO) is usually sufficient
// * avifDecoderSetIO*()
// * avifDecoderParse()
// * avifDecoderNextImage() - in a loop, using decoder->image after each successful call
// * avifDecoderDestroy()
//
// NOTE: Until avifDecoderParse() returns AVIF_RESULT_OK, no data in avifDecoder should
//       be considered valid, and no queries (such as Keyframe/Timing/MaxExtent) should be made.
//
// You can use avifDecoderReset() any time after a successful call to avifDecoderParse()
// to reset the internal decoder back to before the first frame. Calling either
// avifDecoderSetSource() or avifDecoderParse() will automatically Reset the decoder.
//
// avifDecoderSetSource() allows you not only to choose whether to parse tracks or
// items in a file containing both, but switch between sources without having to
// Parse again. Normally AVIF_DECODER_SOURCE_AUTO is enough for the common path.
AVIF_API avifResult avifDecoderSetSource(avifDecoder* decoder, avifDecoderSource source);
// Note: When avifDecoderSetIO() is called, whether 'decoder' takes ownership of 'io' depends on
// whether io->destroy is set. avifDecoderDestroy(decoder) calls avifIODestroy(io), which calls
// io->destroy(io) if io->destroy is set. Therefore, if io->destroy is not set, then
// avifDecoderDestroy(decoder) has no effects on 'io'.
AVIF_API void avifDecoderSetIO(avifDecoder* decoder, avifIO* io);
AVIF_API avifResult avifDecoderSetIOMemory(avifDecoder* decoder, const uint8_t* data, size_t size);
AVIF_API avifResult avifDecoderSetIOFile(avifDecoder* decoder, const char* filename);
AVIF_API avifResult avifDecoderParse(avifDecoder* decoder);
AVIF_API avifResult avifDecoderNextImage(avifDecoder* decoder);
AVIF_API avifResult avifDecoderNthImage(avifDecoder* decoder, uint32_t frameIndex);
AVIF_API avifResult avifDecoderReset(avifDecoder* decoder);

// Keyframe information
// frameIndex - 0-based, matching avifDecoder->imageIndex, bound by avifDecoder->imageCount
// "nearest" keyframe means the keyframe prior to this frame index (returns frameIndex if it is a keyframe)
// These functions may be used after a successful call (AVIF_RESULT_OK) to avifDecoderParse().
AVIF_API avifBool avifDecoderIsKeyframe(const avifDecoder* decoder, uint32_t frameIndex);
AVIF_API uint32_t avifDecoderNearestKeyframe(const avifDecoder* decoder, uint32_t frameIndex);

// Timing helper - This does not change the current image or invoke the codec (safe to call repeatedly)
// This function may be used after a successful call (AVIF_RESULT_OK) to avifDecoderParse().
AVIF_API avifResult avifDecoderNthImageTiming(const avifDecoder* decoder, uint32_t frameIndex, avifImageTiming* outTiming);

// ---------------------------------------------------------------------------
// avifExtent

typedef struct avifExtent {
	uint64_t offset;
	size_t size;
} avifExtent;

// Streaming data helper - Use this to calculate the maximal AVIF data extent encompassing all AV1
// sample data needed to decode the Nth image. The offset will be the earliest offset of all
// required AV1 extents for this frame, and the size will create a range including the last byte of
// the last AV1 sample needed. Note that this extent may include non-sample data, as a frame's
// sample data may be broken into multiple extents and interleaved with other data, or in
// non-sequential order. This extent will also encompass all AV1 samples that this frame's sample
// depends on to decode (such as samples for reference frames), from the nearest keyframe up to this
// Nth frame.
//
// If avifDecoderNthImageMaxExtent() returns AVIF_RESULT_OK and the extent's size is 0 bytes, this
// signals that libavif doesn't expect to call avifIO's Read for this frame's decode. This happens if
// data for this frame was read as a part of avifDecoderParse() (typically in an idat box inside of
// a meta box).
//
// This function may be used after a successful call (AVIF_RESULT_OK) to avifDecoderParse().
AVIF_API avifResult avifDecoderNthImageMaxExtent(const avifDecoder* decoder, uint32_t frameIndex, avifExtent* outExtent);

// ---------------------------------------------------------------------------
// avifEncoder

struct avifEncoderData;
struct avifCodecSpecificOptions;

// Notes:
// * If avifEncoderWrite() returns AVIF_RESULT_OK, output must be freed with avifRWDataFree()
// * If (maxThreads < 2), multithreading is disabled
//   * NOTE: Please see the "Understanding maxThreads" comment block above
// * Quality range: [AVIF_QUANTIZER_BEST_QUALITY - AVIF_QUANTIZER_WORST_QUALITY]
// * To enable tiling, set tileRowsLog2 > 0 and/or tileColsLog2 > 0.
//   Tiling values range [0-6], where the value indicates a request for 2^n tiles in that dimension.
// * Speed range: [AVIF_SPEED_SLOWEST - AVIF_SPEED_FASTEST]. Slower should make for a better quality
//   image in less bytes. AVIF_SPEED_DEFAULT means "Leave the AV1 codec to its default speed settings"./
//   If avifEncoder uses rav1e, the speed value is directly passed through (0-10). If libaom is used,
//   a combination of settings are tweaked to simulate this speed range.
typedef struct avifEncoder {
	// Defaults to AVIF_CODEC_CHOICE_AUTO: Preference determined by order in availableCodecs table (avif.c)
	avifCodecChoice codecChoice;

	// settings (see Notes above)
	int maxThreads;
	int minQuantizer;
	int maxQuantizer;
	int minQuantizerAlpha;
	int maxQuantizerAlpha;
	int tileRowsLog2;
	int tileColsLog2;
	int speed;
	int keyframeInterval; // How many frames between automatic forced keyframes; 0 to disable (default).
	uint64_t timescale; // timescale of the media (Hz)

	// stats from the most recent write
	avifIOStats ioStats;

	// Additional diagnostics (such as detailed error state)
	avifDiagnostics diag;

	// Internals used by the encoder
	struct avifEncoderData* data;
	struct avifCodecSpecificOptions* csOptions;
} avifEncoder;

AVIF_API avifEncoder* avifEncoderCreate(void);
AVIF_API avifResult avifEncoderWrite(avifEncoder* encoder, const avifImage* image, avifRWData* output);
AVIF_API void avifEncoderDestroy(avifEncoder* encoder);

typedef enum avifAddImageFlag {
	AVIF_ADD_IMAGE_FLAG_NONE = 0,

	// Force this frame to be a keyframe (sync frame).
	AVIF_ADD_IMAGE_FLAG_FORCE_KEYFRAME = (1 << 0),

	// Use this flag when encoding a single image. Signals "still_picture" to AV1 encoders, which
	// tweaks various compression rules. This is enabled automatically when using the
	// avifEncoderWrite() single-image encode path.
	AVIF_ADD_IMAGE_FLAG_SINGLE = (1 << 1)
} avifAddImageFlag;
typedef uint32_t avifAddImageFlags;

// Multi-function alternative to avifEncoderWrite() for image sequences.
//
// Usage / function call order is:
// * avifEncoderCreate()
// * Set encoder->timescale (Hz) correctly
// * avifEncoderAddImage() ... [repeatedly; at least once]
//   OR
// * avifEncoderAddImageGrid() [exactly once, AVIF_ADD_IMAGE_FLAG_SINGLE is assumed]
// * avifEncoderFinish()
// * avifEncoderDestroy()
//

AVIF_API avifResult avifEncoderAddImage(avifEncoder* encoder, const avifImage* image, uint64_t durationInTimescales, avifAddImageFlags addImageFlags);
AVIF_API avifResult avifEncoderAddImageGrid(avifEncoder* encoder,
                                            uint32_t gridCols,
                                            uint32_t gridRows,
                                            const avifImage* const* cellImages,
                                            avifAddImageFlags addImageFlags);
AVIF_API avifResult avifEncoderFinish(avifEncoder* encoder, avifRWData* output);

// Codec-specific, optional "advanced" tuning settings, in the form of string key/value pairs. These
// should be set as early as possible, preferably just after creating avifEncoder but before
// performing any other actions.
// key must be non-NULL, but passing a NULL value will delete that key, if it exists.
// Setting an incorrect or unknown option for the current codec will cause errors of type
// AVIF_RESULT_INVALID_CODEC_SPECIFIC_OPTION from avifEncoderWrite() or avifEncoderAddImage().
AVIF_API void avifEncoderSetCodecSpecificOption(avifEncoder* encoder, const char* key, const char* value);

// Helpers
AVIF_API avifBool avifImageUsesU16(const avifImage* image);

// Returns AVIF_TRUE if input begins with a valid FileTypeBox (ftyp) that supports
// either the brand 'avif' or 'avis' (or both), without performing any allocations.
AVIF_API avifBool avifPeekCompatibleFileType(const avifROData* input);

#ifdef __cplusplus
} // extern "C"
#endif

#endif // ifndef AVIF_AVIF_H