// Copyright 2015 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef MEDIA_PARSERS_JPEG_PARSER_H_ #define MEDIA_PARSERS_JPEG_PARSER_H_ #include #include #include "media/parsers/media_parsers_export.h" namespace media { // It's not a full featured JPEG parser implementation. It only parses JPEG // baseline sequential process (invalid or progressive JPEGs should fail but not // crash). For explanations of each struct and its members, see JPEG // specification at http://www.w3.org/Graphics/JPEG/itu-t81.pdf. enum JpegMarker { JPEG_SOF0 = 0xC0, // start of frame (baseline) JPEG_SOF1 = 0xC1, // start of frame (extended sequential) JPEG_SOF2 = 0xC2, // start of frame (progressive) JPEG_SOF3 = 0xC3, // start of frame (lossless)) JPEG_DHT = 0xC4, // define huffman table JPEG_SOF5 = 0xC5, // start of frame (differential, sequential) JPEG_SOF6 = 0xC6, // start of frame (differential, progressive) JPEG_SOF7 = 0xC7, // start of frame (differential, lossless) JPEG_SOF9 = 0xC9, // start of frame (arithmetic coding, extended) JPEG_SOF10 = 0xCA, // start of frame (arithmetic coding, progressive) JPEG_SOF11 = 0xCB, // start of frame (arithmetic coding, lossless) JPEG_SOF13 = 0xCD, // start of frame (differential, arithmetic, sequential) JPEG_SOF14 = 0xCE, // start of frame (differential, arithmetic, progressive) JPEG_SOF15 = 0xCF, // start of frame (differential, arithmetic, lossless) JPEG_RST0 = 0xD0, // restart JPEG_RST1 = 0xD1, // restart JPEG_RST2 = 0xD2, // restart JPEG_RST3 = 0xD3, // restart JPEG_RST4 = 0xD4, // restart JPEG_RST5 = 0xD5, // restart JPEG_RST6 = 0xD6, // restart JPEG_RST7 = 0xD7, // restart JPEG_SOI = 0xD8, // start of image JPEG_EOI = 0xD9, // end of image JPEG_SOS = 0xDA, // start of scan JPEG_DQT = 0xDB, // define quantization table JPEG_DRI = 0xDD, // define restart internal JPEG_APP0 = 0xE0, // start of application segment (APP0) JPEG_APP1 = 0xE1, // start of application segment (APP1) JPEG_MARKER_PREFIX = 0xFF, // jpeg marker prefix }; // JPEG format uses 2 bytes to denote the size of a segment, and the size // includes the 2 bytes used for specifying it. Therefore, maximum data size // allowed is: 65535 - 2 = 65533. constexpr size_t kMaxMarkerSizeAllowed = 65533; // JPEG header only uses 2 bytes to represent width and height. constexpr int kMaxDimension = 65535; constexpr size_t kDctSize = 64; constexpr size_t kNumDcRunSizeBits = 16; constexpr size_t kNumAcRunSizeBits = 16; constexpr size_t kNumDcCodeWordsHuffVal = 12; constexpr size_t kNumAcCodeWordsHuffVal = 162; constexpr size_t kJpegDefaultHeaderSize = 67 + (kDctSize * 2) + (kNumDcRunSizeBits * 2) + (kNumDcCodeWordsHuffVal * 2) + (kNumAcRunSizeBits * 2) + (kNumAcCodeWordsHuffVal * 2); constexpr size_t kJFIFApp0Size = 16; constexpr size_t kJFIFApp1HeaderSize = 4; const size_t kJpegMaxHuffmanTableNumBaseline = 2; const size_t kJpegMaxComponents = 4; const size_t kJpegMaxQuantizationTableNum = 4; // Parsing result of JPEG DHT marker. struct JpegHuffmanTable { bool valid; uint8_t code_length[16]; uint8_t code_value[162]; }; // K.3.3.1 "Specification of typical tables for DC difference coding" MEDIA_PARSERS_EXPORT extern const JpegHuffmanTable kDefaultDcTable[kJpegMaxHuffmanTableNumBaseline]; // K.3.3.2 "Specification of typical tables for AC coefficient coding" MEDIA_PARSERS_EXPORT extern const JpegHuffmanTable kDefaultAcTable[kJpegMaxHuffmanTableNumBaseline]; // Parsing result of JPEG DQT marker. struct JpegQuantizationTable { bool valid; uint8_t value[kDctSize]; // baseline only supports 8 bits quantization table }; MEDIA_PARSERS_EXPORT extern const uint8_t kZigZag8x8[64]; // Table K.1 Luminance quantization table // Table K.2 Chrominance quantization table MEDIA_PARSERS_EXPORT extern const JpegQuantizationTable kDefaultQuantTable[2]; // Parsing result of a JPEG component. struct JpegComponent { uint8_t id; uint8_t horizontal_sampling_factor; uint8_t vertical_sampling_factor; uint8_t quantization_table_selector; }; // Parsing result of a JPEG SOF marker. struct JpegFrameHeader { uint16_t visible_width; uint16_t visible_height; uint16_t coded_width; uint16_t coded_height; uint8_t num_components; JpegComponent components[kJpegMaxComponents]; }; // Parsing result of JPEG SOS marker. struct JpegScanHeader { uint8_t num_components; struct Component { uint8_t component_selector; uint8_t dc_selector; uint8_t ac_selector; } components[kJpegMaxComponents]; }; struct JpegParseResult { JpegFrameHeader frame_header; JpegHuffmanTable dc_table[kJpegMaxHuffmanTableNumBaseline]; JpegHuffmanTable ac_table[kJpegMaxHuffmanTableNumBaseline]; JpegQuantizationTable q_table[kJpegMaxQuantizationTableNum]; uint16_t restart_interval; JpegScanHeader scan; const char* data; // The size of compressed data of the first image. size_t data_size; // The size of the first entire image including header. size_t image_size; }; // Parses JPEG picture in |buffer| with |length|. Returns true iff header is // valid and JPEG baseline sequential process is present. If parsed // successfully, |result| is the parsed result. MEDIA_PARSERS_EXPORT bool ParseJpegPicture(const uint8_t* buffer, size_t length, JpegParseResult* result); // Parses the first image of JPEG stream in |buffer| with |length|. Returns // true iff header is valid and JPEG baseline sequential process is present. // If parsed successfully, |result| is the parsed result. MEDIA_PARSERS_EXPORT bool ParseJpegStream(const uint8_t* buffer, size_t length, JpegParseResult* result); } // namespace media #endif // MEDIA_PARSERS_JPEG_PARSER_H_