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mjpeg2jpeg_bsf.c
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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 
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 
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 
110  .name = "mjpeg2jpeg",
111  .filter = mjpeg2jpeg_filter,
112 };