1 // Copyright (c) 2021, Alliance for Open Media. All rights reserved 2 // 3 // This source code is subject to the terms of the BSD 2 Clause License and 4 // the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License 5 // was not distributed with this source code in the LICENSE file, you can 6 // obtain it at www.aomedia.org/license/software. If the Alliance for Open 7 // Media Patent License 1.0 was not distributed with this source code in the 8 // PATENTS file, you can obtain it at www.aomedia.org/license/patent. 9 10 #ifndef AVIFINFO_H_ 11 #define AVIFINFO_H_ 12 13 #include <stddef.h> 14 #include <stdint.h> 15 16 #ifdef __cplusplus 17 extern "C" { 18 #endif 19 20 //------------------------------------------------------------------------------ 21 22 typedef enum { 23 kAvifInfoOk, // The file was correctly parsed and the requested 24 // information was extracted. It is not guaranteed 25 // that the input bitstream is a valid complete 26 // AVIF file. 27 kAvifInfoNotEnoughData, // The input bitstream was correctly parsed until 28 // now but bytes are missing. The request should be 29 // repeated with more input bytes. 30 kAvifInfoTooComplex, // The input bitstream was correctly parsed until 31 // now but it is too complex. The parsing was 32 // stopped to avoid any timeout or crash. 33 kAvifInfoInvalidFile, // The input bitstream is not a valid AVIF file, 34 // truncated or not. 35 } AvifInfoStatus; 36 37 typedef struct { 38 uint32_t width, height; // In number of pixels. Ignores mirror and rotation. 39 uint32_t bit_depth; // Likely 8, 10 or 12 bits per channel per pixel. 40 uint32_t num_channels; // Likely 1, 2, 3 or 4 channels: 41 // (1 monochrome or 3 colors) + (0 or 1 alpha) 42 } AvifInfoFeatures; 43 44 //------------------------------------------------------------------------------ 45 // Fixed-size input API 46 // Use this API if a raw byte array of fixed size is available as input. 47 48 // Parses the 'data' and returns kAvifInfoOk if it is identified as an AVIF. 49 // The file type can be identified in the first 12 bytes of most AVIF files. 50 AvifInfoStatus AvifInfoIdentify(const uint8_t* data, size_t data_size); 51 52 // Parses the identified AVIF 'data' and extracts its 'features'. 53 // 'data' can be partial but must point to the beginning of the AVIF file. 54 // The 'features' can be parsed in the first 450 bytes of most AVIF files. 55 // 'features' are set to 0 unless kAvifInfoOk is returned. 56 AvifInfoStatus AvifInfoGetFeatures(const uint8_t* data, size_t data_size, 57 AvifInfoFeatures* features); 58 59 //------------------------------------------------------------------------------ 60 // Streamed input API 61 // Use this API if the input bytes must be fetched and/or if the AVIF payload 62 // size is unknown. Implement the two function signatures below and pass them to 63 // AvifInfoRead*() with a 'stream', which can be anything (file, struct etc.). 64 65 // Reads 'num_bytes' from the 'stream'. 66 // The position in the 'stream' must be advanced by 'num_bytes'. 67 // Returns a pointer to the 'num_bytes' or null if it cannot be fulfilled. 68 // The returned data must remain valid until the next read. 69 typedef const uint8_t* (*read_stream_t)(void* stream, size_t num_bytes); 70 // Advances the position in the 'stream' by 'num_bytes'. 71 typedef void (*skip_stream_t)(void* stream, size_t num_bytes); 72 73 // Maximum number of bytes requested per read. There is no limit per skip. 74 #define AVIFINFO_MAX_NUM_READ_BYTES 64 75 76 // Same as AvifInfo*() but takes a 'stream' as input. AvifInfo*Stream() does 77 // not access the 'stream' directly but passes it as is to 'read' and 'skip'. 78 // 'read' cannot be null. If 'skip' is null, 'read' is called instead. 79 AvifInfoStatus AvifInfoIdentifyStream(void* stream, read_stream_t read, 80 skip_stream_t skip); 81 // Can be called right after AvifInfoIdentifyStream() with the same 'stream'. 82 AvifInfoStatus AvifInfoGetFeaturesStream(void* stream, read_stream_t read, 83 skip_stream_t skip, 84 AvifInfoFeatures* features); 85 86 //------------------------------------------------------------------------------ 87 88 #ifdef __cplusplus 89 } // extern "C" 90 #endif 91 92 #endif // AVIFINFO_H_ 93
