Blame view

ffmpeg-4.2.2/libavcodec/mjpegenc.h 4.13 KB
aac5773f   hucm   功能基本完成,接口待打磨
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
  /*
   * MJPEG encoder
   * Copyright (c) 2000, 2001 Fabrice Bellard
   * Copyright (c) 2003 Alex Beregszaszi
   * Copyright (c) 2003-2004 Michael Niedermayer
   *
   * Support for external huffman table, various fixes (AVID workaround),
   * aspecting, new decode_frame mechanism and apple mjpeg-b support
   *                                  by Alex Beregszaszi
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * MJPEG encoder.
   */
  
  #ifndef AVCODEC_MJPEGENC_H
  #define AVCODEC_MJPEGENC_H
  
  #include <stdint.h>
  
  #include "mjpeg.h"
  #include "mpegvideo.h"
  #include "put_bits.h"
  
  /**
   * Buffer of JPEG frame data.
   *
   * Optimal Huffman table generation requires the frame data to be loaded into
   * a buffer so that the tables can be computed.
   * There are at most mb_width*mb_height*12*64 of these per frame.
   */
  typedef struct MJpegHuffmanCode {
      // 0=DC lum, 1=DC chrom, 2=AC lum, 3=AC chrom
      uint8_t table_id; ///< The Huffman table id associated with the data.
      uint8_t code;     ///< The exponent.
      uint16_t mant;    ///< The mantissa.
  } MJpegHuffmanCode;
  
  /**
   * Holds JPEG frame data and Huffman table data.
   */
  typedef struct MJpegContext {
      //FIXME use array [3] instead of lumi / chroma, for easier addressing
      uint8_t huff_size_dc_luminance[12];     ///< DC luminance Huffman table size.
      uint16_t huff_code_dc_luminance[12];    ///< DC luminance Huffman table codes.
      uint8_t huff_size_dc_chrominance[12];   ///< DC chrominance Huffman table size.
      uint16_t huff_code_dc_chrominance[12];  ///< DC chrominance Huffman table codes.
  
      uint8_t huff_size_ac_luminance[256];    ///< AC luminance Huffman table size.
      uint16_t huff_code_ac_luminance[256];   ///< AC luminance Huffman table codes.
      uint8_t huff_size_ac_chrominance[256];  ///< AC chrominance Huffman table size.
      uint16_t huff_code_ac_chrominance[256]; ///< AC chrominance Huffman table codes.
  
      /** Storage for AC luminance VLC (in MpegEncContext) */
      uint8_t uni_ac_vlc_len[64 * 64 * 2];
      /** Storage for AC chrominance VLC (in MpegEncContext) */
      uint8_t uni_chroma_ac_vlc_len[64 * 64 * 2];
  
      // Default DC tables have exactly 12 values
      uint8_t bits_dc_luminance[17];   ///< DC luminance Huffman bits.
      uint8_t val_dc_luminance[12];    ///< DC luminance Huffman values.
      uint8_t bits_dc_chrominance[17]; ///< DC chrominance Huffman bits.
      uint8_t val_dc_chrominance[12];  ///< DC chrominance Huffman values.
  
      // 8-bit JPEG has max 256 values
      uint8_t bits_ac_luminance[17];   ///< AC luminance Huffman bits.
      uint8_t val_ac_luminance[256];   ///< AC luminance Huffman values.
      uint8_t bits_ac_chrominance[17]; ///< AC chrominance Huffman bits.
      uint8_t val_ac_chrominance[256]; ///< AC chrominance Huffman values.
  
      size_t huff_ncode;               ///< Number of current entries in the buffer.
      MJpegHuffmanCode *huff_buffer;   ///< Buffer for Huffman code values.
  } MJpegContext;
  
  /**
   * Enum for the Huffman encoding strategy.
   */
  enum HuffmanTableOption {
      HUFFMAN_TABLE_DEFAULT = 0, ///< Use the default Huffman tables.
      HUFFMAN_TABLE_OPTIMAL = 1, ///< Compute and use optimal Huffman tables.
      NB_HUFFMAN_TABLE_OPTION = 2
  };
  
  static inline void put_marker(PutBitContext *p, enum JpegMarker code)
  {
      put_bits(p, 8, 0xff);
      put_bits(p, 8, code);
  }
  
  int  ff_mjpeg_encode_init(MpegEncContext *s);
  void ff_mjpeg_encode_close(MpegEncContext *s);
  void ff_mjpeg_encode_mb(MpegEncContext *s, int16_t block[12][64]);
  
  #endif /* AVCODEC_MJPEGENC_H */