media/filters/jpeg_parser.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4 //
   5 #ifndef MEDIA_FILTERS_JPEG_PARSER_H_
   6 #define MEDIA_FILTERS_JPEG_PARSER_H_
   7
   8 #include <stddef.h>
   9 #include <stdint.h>
  10 #include "media/base/media_export.h"
  11
  12 namespace media {
  13
  14 enum JpegMarker {
  15   JPEG_SOF0 = 0xC0,   // start of frame (baseline)
  16   JPEG_SOF1 = 0xC1,   // start of frame (extended sequential)
  17   JPEG_SOF2 = 0xC2,   // start of frame (progressive)
  18   JPEG_SOF3 = 0xC3,   // start of frame (lossless))
  19   JPEG_SOF5 = 0xC5,   // start of frame (differential, sequential)
  20   JPEG_SOF6 = 0xC6,   // start of frame (differential, progressive)
  21   JPEG_SOF7 = 0xC7,   // start of frame (differential, lossless)
  22   JPEG_SOF9 = 0xC9,   // start of frame (arithmetic coding, extended)
  23   JPEG_SOF10 = 0xCA,  // start of frame (arithmetic coding, progressive)
  24   JPEG_SOF11 = 0xCB,  // start of frame (arithmetic coding, lossless)
  25   JPEG_SOF13 = 0xCD,  // start of frame (differential, arithmetic, sequential)
  26   JPEG_SOF14 = 0xCE,  // start of frame (differential, arithmetic, progressive)
  27   JPEG_SOF15 = 0xCF,  // start of frame (differential, arithmetic, lossless)
  28   JPEG_DHT = 0xC4,    // define huffman table
  29   JPEG_SOI = 0xD8,    // start of image
  30   JPEG_SOS = 0xDA,    // start of scan
  31   JPEG_DQT = 0xDB,    // define quantization table
  32   JPEG_DRI = 0xDD,    // define restart internal
  33   JPEG_MARKER_PREFIX = 0xFF,  // jpeg marker prefix
  34 };
  35
  36 const size_t kJpegMaxHuffmanTableNumBaseline = 2;
  37 const size_t kJpegMaxComponents = 4;
  38 const size_t kJpegMaxQuantizationTableNum = 4;
  39
  40 // Parsing result of JPEG DHT marker.
  41 struct JpegHuffmanTable {
  42   bool valid;
  43   uint8_t code_length[16];
  44   uint8_t code_value[256];
  45 };
  46
  47 // Parsing result of JPEG DQT marker.
  48 struct JpegQuantizationTable {
  49   bool valid;
  50   uint8_t value[64];  // baseline only supports 8 bits quantization table
  51 };
  52
  53 // Parsing result of a JPEG component.
  54 struct JpegComponent {
  55   uint8_t id;
  56   uint8_t horizontal_sampling_factor;
  57   uint8_t vertical_sampling_factor;
  58   uint8_t quantization_table_selector;
  59 };
  60
  61 // Parsing result of a JPEG SOF marker.
  62 struct JpegFrameHeader {
  63   uint16_t visible_width;
  64   uint16_t visible_height;
  65   uint16_t coded_width;
  66   uint16_t coded_height;
  67   uint8_t num_components;
  68   JpegComponent components[kJpegMaxComponents];
  69 };
  70
  71 // Parsing result of JPEG SOS marker.
  72 struct JpegScanHeader {
  73   uint8_t num_components;
  74   struct Component {
  75     uint8_t component_selector;
  76     uint8_t dc_selector;
  77     uint8_t ac_selector;
  78   } components[kJpegMaxComponents];
  79 };
  80
  81 struct JpegParseResult {
  82   JpegFrameHeader frame_header;
  83   JpegHuffmanTable dc_table[kJpegMaxHuffmanTableNumBaseline];
  84   JpegHuffmanTable ac_table[kJpegMaxHuffmanTableNumBaseline];
  85   JpegQuantizationTable q_table[kJpegMaxQuantizationTableNum];
  86   uint16_t restart_interval;
  87   JpegScanHeader scan;
  88   const char* data;
  89   size_t data_size;
  90 };
  91
  92 // Parses JPEG picture in |buffer| with |length|.  Returns true iff header is
  93 // valid and JPEG baseline sequential process is present. If parsed
  94 // successfully, |result| is the parsed result.
  95 // It's not a full featured JPEG parser implememtation. It only parses JPEG
  96 // baseline sequential process. For explanations of each struct and its
  97 // members, see JPEG specification at
  98 // http://www.w3.org/Graphics/JPEG/itu-t81.pdf.
  99 MEDIA_EXPORT bool ParseJpegPicture(const uint8_t* buffer,
 100                                    size_t length,
 101                                    JpegParseResult* result);
 102
 103 }  // namespace media
 104
 105 #endif  // MEDIA_FILTERS_JPEG_PARSER_H_