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// 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" {
// ---------------------------------------------------------------------------
// 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 a CMake dependency, through a 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")))
#if defined(AVIF_DLL)
#endif // defined(AVIF_BUILDING_SHARED_LIBS)
#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 \
typedef int avifBool;
#define AVIF_TRUE 1
#define AVIF_FALSE 0
// A reasonable default for maximum image size (in pixel count) 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 reasonable default for maximum image dimension (width or height).
// 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)
typedef enum avifPlanesFlag
AVIF_PLANES_YUV = (1 << 0),
AVIF_PLANES_A = (1 << 1),
} avifPlanesFlag;
typedef uint32_t avifPlanesFlags;
typedef enum avifChannelIndex
// These can be used as the index for the yuvPlanes and yuvRowBytes arrays in avifImage.
} avifChannelIndex;
// ---------------------------------------------------------------------------
// 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_IO_NOT_SET, // the avifIO field of avifDecoder is not set
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_CANNOT_CHANGE_SETTING, // a setting that can't change is changed during encoding
AVIF_RESULT_INCOMPATIBLE_IMAGE // the image is incompatible with already encoded images
} 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
// The avifRWData input must be zero-initialized before being manipulated with these functions.
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
// Note to libavif maintainers: The lookup tables in avifImageYUVToRGBLibYUV
// rely on the ordering of this enum values for their correctness. So changing
// the values in this enum will require auditing avifImageYUVToRGBLibYUV for
// correctness.
typedef enum avifPixelFormat
// No YUV pixels are present. Alpha plane can still be present.
} 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
} avifChromaSamplePosition;
// ---------------------------------------------------------------------------
// avifRange
typedef enum avifRange
} avifRange;
// ---------------------------------------------------------------------------
// CICP enums -
// This is actually reserved, but libavif uses it as a sentinel value.
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);
// This is actually reserved, but libavif uses it as a sentinel value.
typedef uint16_t avifTransferCharacteristics; // AVIF_TRANSFER_CHARACTERISTICS_*
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.
} avifDiagnostics;
AVIF_API void avifDiagnosticsClearError(avifDiagnostics * diag);
// ---------------------------------------------------------------------------
// Optional transformation structs
typedef enum avifTransformFlag
} avifTransformFlag;
typedef uint32_t avifTransformFlags;
typedef struct avifPixelAspectRatioBox
// 'pasp' from ISO/IEC 14496-12:2015
// 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
// 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;
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(uint32_t width, uint32_t height, uint32_t depth, avifPixelFormat yuvFormat);
AVIF_API avifImage * avifImageCreateEmpty(void); // helper for making an image to decode into
AVIF_API avifResult avifImageCopy(avifImage * dstImage, const avifImage * srcImage, avifPlanesFlags planes); // deep copy
AVIF_API avifResult avifImageSetViewRect(avifImage * dstImage, const avifImage * srcImage, const avifCropRect * rect); // shallow copy, no metadata
AVIF_API void avifImageDestroy(avifImage * image);
AVIF_API void avifImageSetProfileICC(avifImage * image, const uint8_t * icc, size_t iccSize);
// Sets Exif metadata. Attempts to parse the Exif metadata for Exif orientation. Sets
// image->transformFlags, image->irot and image->imir if the Exif metadata is parsed successfully,
// otherwise leaves image->transformFlags, image->irot and image->imir unchanged.
// 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);
// Sets XMP metadata.
AVIF_API void avifImageSetMetadataXMP(avifImage * image, const uint8_t * xmp, size_t xmpSize);
AVIF_API avifResult 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 a version of libyuv offering a fast conversion between RGB and YUV for
// the given inputs, libavif will use it. See reformat_libyuv.c for the details.
// libyuv is faster but may have slightly less precision than built-in conversion, so avoidLibYUV
// AVIF_CHROMA_DOWNSAMPLING_BEST_QUALITY is used, to get the most precise but slowest results.
// Note to libavif maintainers: The lookup tables in avifImageYUVToRGBLibYUV
// rely on the ordering of this enum values for their correctness. So changing
// the values in this enum will require auditing avifImageYUVToRGBLibYUV for
// correctness.
typedef enum avifRGBFormat
AVIF_RGB_FORMAT_RGBA, // This is the default format set in avifRGBImageSetDefaults().
// RGB_565 format uses five bits for the red and blue components and six
// bits for the green component. Each RGB pixel is 16 bits (2 bytes), which
// is packed as follows:
// uint16_t: [r4 r3 r2 r1 r0 g5 g4 g3 g2 g1 g0 b4 b3 b2 b1 b0]
// r4 and r0 are the MSB and LSB of the red component respectively.
// g5 and g0 are the MSB and LSB of the green component respectively.
// b4 and b0 are the MSB and LSB of the blue component respectively.
// This format is only supported for YUV -> RGB conversion and when
// avifRGBImage.depth is set to 8.
} 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 (uses BILINEAR libyuv if available,
// or falls back to NEAREST libyuv if available, or falls back to BILINEAR built-in)
AVIF_CHROMA_UPSAMPLING_FASTEST = 1, // Chooses speed over quality (same as NEAREST)
AVIF_CHROMA_UPSAMPLING_BEST_QUALITY = 2, // Chooses the best quality upsampling, given settings (same as BILINEAR)
AVIF_CHROMA_UPSAMPLING_NEAREST = 3, // Uses nearest-neighbor filter
AVIF_CHROMA_UPSAMPLING_BILINEAR = 4 // Uses bilinear filter
} avifChromaUpsampling;
typedef enum avifChromaDownsampling
AVIF_CHROMA_DOWNSAMPLING_AUTOMATIC = 0, // Chooses best trade off of speed/quality (same as AVERAGE)
AVIF_CHROMA_DOWNSAMPLING_FASTEST = 1, // Chooses speed over quality (same as AVERAGE)
AVIF_CHROMA_DOWNSAMPLING_BEST_QUALITY = 2, // Chooses the best quality upsampling (same as AVERAGE)
AVIF_CHROMA_DOWNSAMPLING_AVERAGE = 3, // Uses averaging filter
AVIF_CHROMA_DOWNSAMPLING_SHARP_YUV = 4 // Uses sharp yuv filter (libsharpyuv), available for 4:2:0 only, ignored for 4:2:2
} avifChromaDownsampling;
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; // How to upsample from 4:2:0 or 4:2:2 UV when converting to RGB (ignored for 4:4:4 and 4:0:0).
// Ignored when converting to YUV. Defaults to AVIF_CHROMA_UPSAMPLING_AUTOMATIC.
avifChromaDownsampling chromaDownsampling; // How to downsample to 4:2:0 or 4:2:2 UV when converting from RGB (ignored for 4:4:4 and 4:0:0).
// Ignored when converting to RGB. Defaults to AVIF_CHROMA_DOWNSAMPLING_AUTOMATIC.
avifBool avoidLibYUV; // If AVIF_FALSE and libyuv conversion between RGB and YUV (including upsampling or downsampling if any)
// is available for the avifImage/avifRGBImage combination, then libyuv is used. Default is AVIF_FALSE.
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
} avifCodecChoice;
typedef enum avifCodecFlag
} 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);
// ---------------------------------------------------------------------------
// 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),
// * 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.
// 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.)
// 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.
// 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 and
// Maximum strictness; enables all bits above. This is avifDecoder's default.
} 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.
// Use the primary item and the aux (alpha) item in the avif(s).
// This is where single-image avifs store their image.
// Use the chunks inside primary/aux tracks in the moov block.
// This is where avifs image sequences store their images.
// Decode the thumbnail item. Currently unimplemented.
} 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.
// 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.
// 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.
} 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;
// If this is false, avifDecoderNextImage() will start decoding a frame only after there are
// enough input bytes to decode all of that frame. If this is true, avifDecoder will decode each
// subimage or grid cell as soon as possible. The benefits are: grid images may be partially
// displayed before being entirely available, and the overall decoding may finish earlier.
// Must be set before calling avifDecoderNextImage() or avifDecoderNthImage().
// WARNING: Experimental feature.
avifBool allowIncremental;
// 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 an 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 represents the maximum dimension of an image (width or height) that libavif should
// attempt to decode. It defaults to AVIF_DEFAULT_IMAGE_DIMENSION_LIMIT. Set it to 0 to ignore
// the limit.
uint32_t imageDimensionLimit;
// 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);
// When avifDecoderNextImage() or avifDecoderNthImage() returns AVIF_RESULT_WAITING_ON_IO, this
// function can be called next to retrieve the number of top rows that can be immediately accessed
// from the luma plane of decoder->image, and alpha if any. The corresponding rows from the chroma planes,
// if any, can also be accessed (half rounded up if subsampled, same number of rows otherwise).
// decoder->allowIncremental must be set to true before calling avifDecoderNextImage() or
// avifDecoderNthImage(). Returns decoder->image->height when the last call to avifDecoderNextImage() or
// avifDecoderNthImage() returned AVIF_RESULT_OK. Returns 0 in all other cases.
// WARNING: Experimental feature.
AVIF_API uint32_t avifDecoderDecodedRowCount(const avifDecoder * decoder);
// ---------------------------------------------------------------------------
// 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
// * 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.
// If autoTiling is set to AVIF_TRUE, libavif ignores tileRowsLog2 and tileColsLog2 and
// automatically chooses suitable tiling values.
// * 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.
// * Some encoder settings can be changed after encoding starts. Changes will take effect in the next
// call to avifEncoderAddImage().
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 speed;
int keyframeInterval; // How many frames between automatic forced keyframes; 0 to disable (default).
uint64_t timescale; // timescale of the media (Hz)
// changeable encoder settings
int minQuantizer;
int maxQuantizer;
int minQuantizerAlpha;
int maxQuantizerAlpha;
int tileRowsLog2;
int tileColsLog2;
avifBool autoTiling;
// 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
// Force this frame to be a keyframe (sync frame).
// 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.
} 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()
// durationInTimescales is ignored if AVIF_ADD_IMAGE_FLAG_SINGLE is set in addImageFlags.
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,
// to be consumed by the codec in the next avifEncoderAddImage() call.
// See the codec documentation to know if a setting is persistent or applied only to the next frame.
// key must be non-NULL, but passing a NULL value will delete the pending 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 // ifndef AVIF_AVIF_H