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  1. /*
  2.  * MJPEG/AVI1 to JPEG/JFIF bitstream format filter
  3.  * Copyright (c) 2010 Adrian Daerr and Nicolas George
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. /*
  23.  * Adapted from mjpeg2jpeg.c, with original copyright:
  24.  * Paris 2010 Adrian Daerr, public domain
  25.  */
  26.  
  27. #include <string.h>
  28. #include "avcodec.h"
  29. #include "mjpeg.h"
  30.  
  31. static const uint8_t jpeg_header[] = {
  32.     0xff, 0xd8,                     // SOI
  33.     0xff, 0xe0,                     // APP0
  34.     0x00, 0x10,                     // APP0 header size (including
  35.                                     // this field, but excluding preceding)
  36.     0x4a, 0x46, 0x49, 0x46, 0x00,   // ID string 'JFIF\0'
  37.     0x01, 0x01,                     // version
  38.     0x00,                           // bits per type
  39.     0x00, 0x00,                     // X density
  40.     0x00, 0x00,                     // Y density
  41.     0x00,                           // X thumbnail size
  42.     0x00,                           // Y thumbnail size
  43. };
  44.  
  45. static const int dht_segment_size = 420;
  46. static const uint8_t dht_segment_head[] = { 0xFF, 0xC4, 0x01, 0xA2, 0x00 };
  47. static const uint8_t dht_segment_frag[] = {
  48.     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
  49.     0x0a, 0x0b, 0x01, 0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01,
  50.     0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
  51. };
  52.  
  53. static uint8_t *append(uint8_t *buf, const uint8_t *src, int size)
  54. {
  55.     memcpy(buf, src, size);
  56.     return buf + size;
  57. }
  58.  
  59. static uint8_t *append_dht_segment(uint8_t *buf)
  60. {
  61.     buf = append(buf, dht_segment_head, sizeof(dht_segment_head));
  62.     buf = append(buf, avpriv_mjpeg_bits_dc_luminance + 1, 16);
  63.     buf = append(buf, dht_segment_frag, sizeof(dht_segment_frag));
  64.     buf = append(buf, avpriv_mjpeg_val_dc, 12);
  65.     *(buf++) = 0x10;
  66.     buf = append(buf, avpriv_mjpeg_bits_ac_luminance + 1, 16);
  67.     buf = append(buf, avpriv_mjpeg_val_ac_luminance, 162);
  68.     *(buf++) = 0x11;
  69.     buf = append(buf, avpriv_mjpeg_bits_ac_chrominance + 1, 16);
  70.     buf = append(buf, avpriv_mjpeg_val_ac_chrominance, 162);
  71.     return buf;
  72. }
  73.  
  74. static int mjpeg2jpeg_filter(AVBitStreamFilterContext *bsfc,
  75.                              AVCodecContext *avctx, const char *args,
  76.                              uint8_t **poutbuf, int *poutbuf_size,
  77.                              const uint8_t *buf, int buf_size,
  78.                              int keyframe)
  79. {
  80.     int input_skip, output_size;
  81.     uint8_t *output, *out;
  82.  
  83.     if (buf_size < 12) {
  84.         av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
  85.         return AVERROR_INVALIDDATA;
  86.     }
  87.     if (memcmp("AVI1", buf + 6, 4)) {
  88.         av_log(avctx, AV_LOG_ERROR, "input is not MJPEG/AVI1\n");
  89.         return AVERROR_INVALIDDATA;
  90.     }
  91.     input_skip = (buf[4] << 8) + buf[5] + 4;
  92.     if (buf_size < input_skip) {
  93.         av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
  94.         return AVERROR_INVALIDDATA;
  95.     }
  96.     output_size = buf_size - input_skip +
  97.                   sizeof(jpeg_header) + dht_segment_size;
  98.     output = out = av_malloc(output_size);
  99.     if (!output)
  100.         return AVERROR(ENOMEM);
  101.     out = append(out, jpeg_header, sizeof(jpeg_header));
  102.     out = append_dht_segment(out);
  103.     out = append(out, buf + input_skip, buf_size - input_skip);
  104.     *poutbuf = output;
  105.     *poutbuf_size = output_size;
  106.     return 1;
  107. }
  108.  
  109. AVBitStreamFilter ff_mjpeg2jpeg_bsf = {
  110.     .name           = "mjpeg2jpeg",
  111.     .filter         = mjpeg2jpeg_filter,
  112. };
  113.