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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 
29 #include "libavutil/error.h"
30 #include "libavutil/mem.h"
31 
32 #include "avcodec.h"
33 #include "mjpeg.h"
34 
35 static const uint8_t jpeg_header[] = {
36  0xff, 0xd8, // SOI
37  0xff, 0xe0, // APP0
38  0x00, 0x10, // APP0 header size (including
39  // this field, but excluding preceding)
40  0x4a, 0x46, 0x49, 0x46, 0x00, // ID string 'JFIF\0'
41  0x01, 0x01, // version
42  0x00, // bits per type
43  0x00, 0x00, // X density
44  0x00, 0x00, // Y density
45  0x00, // X thumbnail size
46  0x00, // Y thumbnail size
47 };
48 
49 static const int dht_segment_size = 420;
50 static const uint8_t dht_segment_head[] = { 0xFF, 0xC4, 0x01, 0xA2, 0x00 };
51 static const uint8_t dht_segment_frag[] = {
52  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
53  0x0a, 0x0b, 0x01, 0x00, 0x03, 0x01, 0x01, 0x01, 0x01, 0x01,
54  0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
55 };
56 
57 static uint8_t *append(uint8_t *buf, const uint8_t *src, int size)
58 {
59  memcpy(buf, src, size);
60  return buf + size;
61 }
62 
64 {
65  buf = append(buf, dht_segment_head, sizeof(dht_segment_head));
66  buf = append(buf, avpriv_mjpeg_bits_dc_luminance + 1, 16);
67  buf = append(buf, dht_segment_frag, sizeof(dht_segment_frag));
68  buf = append(buf, avpriv_mjpeg_val_dc, 12);
69  *(buf++) = 0x10;
70  buf = append(buf, avpriv_mjpeg_bits_ac_luminance + 1, 16);
71  buf = append(buf, avpriv_mjpeg_val_ac_luminance, 162);
72  *(buf++) = 0x11;
73  buf = append(buf, avpriv_mjpeg_bits_ac_chrominance + 1, 16);
74  buf = append(buf, avpriv_mjpeg_val_ac_chrominance, 162);
75  return buf;
76 }
77 
79  AVCodecContext *avctx, const char *args,
80  uint8_t **poutbuf, int *poutbuf_size,
81  const uint8_t *buf, int buf_size,
82  int keyframe)
83 {
84  int input_skip, output_size;
85  uint8_t *output, *out;
86 
87  if (buf_size < 12) {
88  av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
89  return AVERROR_INVALIDDATA;
90  }
91  if (memcmp("AVI1", buf + 6, 4)) {
92  av_log(avctx, AV_LOG_ERROR, "input is not MJPEG/AVI1\n");
93  return AVERROR_INVALIDDATA;
94  }
95  input_skip = (buf[4] << 8) + buf[5] + 4;
96  if (buf_size < input_skip) {
97  av_log(avctx, AV_LOG_ERROR, "input is truncated\n");
98  return AVERROR_INVALIDDATA;
99  }
100  output_size = buf_size - input_skip +
101  sizeof(jpeg_header) + dht_segment_size;
102  output = out = av_malloc(output_size);
103  if (!output)
104  return AVERROR(ENOMEM);
105  out = append(out, jpeg_header, sizeof(jpeg_header));
106  out = append_dht_segment(out);
107  out = append(out, buf + input_skip, buf_size - input_skip);
108  *poutbuf = output;
109  *poutbuf_size = output_size;
110  return 1;
111 }
112 
114  .name = "mjpeg2jpeg",
115  .filter = mjpeg2jpeg_filter,
116 };