Edit File: avifinfo.h
// Copyright (c) 2021, Alliance for Open Media. All rights reserved // // This source code is subject to the terms of the BSD 2 Clause License and // the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License // was not distributed with this source code in the LICENSE file, you can // obtain it at www.aomedia.org/license/software. If the Alliance for Open // Media Patent License 1.0 was not distributed with this source code in the // PATENTS file, you can obtain it at www.aomedia.org/license/patent. #ifndef AVIFINFO_H_ #define AVIFINFO_H_ #include <stddef.h> #include <stdint.h> #ifdef __cplusplus extern "C" { #endif //------------------------------------------------------------------------------ typedef enum { kAvifInfoOk, // The file was correctly parsed and the requested // information was extracted. It is not guaranteed // that the input bitstream is a valid complete // AVIF file. kAvifInfoNotEnoughData, // The input bitstream was correctly parsed until // now but bytes are missing. The request should be // repeated with more input bytes. kAvifInfoTooComplex, // The input bitstream was correctly parsed until // now but it is too complex. The parsing was // stopped to avoid any timeout or crash. kAvifInfoInvalidFile, // The input bitstream is not a valid AVIF file, // truncated or not. } AvifInfoStatus; typedef struct { uint32_t width, height; // In number of pixels. Ignores mirror and rotation. uint32_t bit_depth; // Likely 8, 10 or 12 bits per channel per pixel. uint32_t num_channels; // Likely 1, 2, 3 or 4 channels: // (1 monochrome or 3 colors) + (0 or 1 alpha) } AvifInfoFeatures; //------------------------------------------------------------------------------ // Fixed-size input API // Use this API if a raw byte array of fixed size is available as input. // Parses the 'data' and returns kAvifInfoOk if it is identified as an AVIF. // The file type can be identified in the first 12 bytes of most AVIF files. AvifInfoStatus AvifInfoIdentify(const uint8_t* data, size_t data_size); // Parses the identified AVIF 'data' and extracts its 'features'. // 'data' can be partial but must point to the beginning of the AVIF file. // The 'features' can be parsed in the first 450 bytes of most AVIF files. // 'features' are set to 0 unless kAvifInfoOk is returned. AvifInfoStatus AvifInfoGetFeatures(const uint8_t* data, size_t data_size, AvifInfoFeatures* features); //------------------------------------------------------------------------------ // Streamed input API // Use this API if the input bytes must be fetched and/or if the AVIF payload // size is unknown. Implement the two function signatures below and pass them to // AvifInfoRead*() with a 'stream', which can be anything (file, struct etc.). // Reads 'num_bytes' from the 'stream'. // The position in the 'stream' must be advanced by 'num_bytes'. // Returns a pointer to the 'num_bytes' or null if it cannot be fulfilled. // The returned data must remain valid until the next read. typedef const uint8_t* (*read_stream_t)(void* stream, size_t num_bytes); // Advances the position in the 'stream' by 'num_bytes'. typedef void (*skip_stream_t)(void* stream, size_t num_bytes); // Maximum number of bytes requested per read. There is no limit per skip. #define AVIFINFO_MAX_NUM_READ_BYTES 64 // Same as AvifInfo*() but takes a 'stream' as input. AvifInfo*Stream() does // not access the 'stream' directly but passes it as is to 'read' and 'skip'. // 'read' cannot be null. If 'skip' is null, 'read' is called instead. AvifInfoStatus AvifInfoIdentifyStream(void* stream, read_stream_t read, skip_stream_t skip); // Can be called right after AvifInfoIdentifyStream() with the same 'stream'. AvifInfoStatus AvifInfoGetFeaturesStream(void* stream, read_stream_t read, skip_stream_t skip, AvifInfoFeatures* features); //------------------------------------------------------------------------------ #ifdef __cplusplus } // extern "C" #endif #endif // AVIFINFO_H_