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2ba45a60 DM |
1 | /* |
2 | * MJPEG A dump header bitstream filter | |
3 | * Copyright (c) 2006 Baptiste Coudurier | |
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 | * @file | |
24 | * MJPEG A dump header bitstream filter | |
25 | * modifies bitstream to be decoded by quicktime | |
26 | */ | |
27 | ||
28 | #include "avcodec.h" | |
29 | #include "bytestream.h" | |
30 | #include "mjpeg.h" | |
31 | ||
32 | ||
33 | static int mjpega_dump_header(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args, | |
34 | uint8_t **poutbuf, int *poutbuf_size, | |
35 | const uint8_t *buf, int buf_size, int keyframe) | |
36 | { | |
37 | uint8_t *poutbufp; | |
38 | unsigned dqt = 0, dht = 0, sof0 = 0; | |
39 | int i; | |
40 | ||
41 | if (avctx->codec_id != AV_CODEC_ID_MJPEG) { | |
42 | av_log(avctx, AV_LOG_ERROR, "mjpega bitstream filter only applies to mjpeg codec\n"); | |
43 | return 0; | |
44 | } | |
45 | ||
46 | *poutbuf_size = 0; | |
47 | *poutbuf = av_malloc(buf_size + 44 + FF_INPUT_BUFFER_PADDING_SIZE); | |
48 | poutbufp = *poutbuf; | |
49 | bytestream_put_byte(&poutbufp, 0xff); | |
50 | bytestream_put_byte(&poutbufp, SOI); | |
51 | bytestream_put_byte(&poutbufp, 0xff); | |
52 | bytestream_put_byte(&poutbufp, APP1); | |
53 | bytestream_put_be16(&poutbufp, 42); /* size */ | |
54 | bytestream_put_be32(&poutbufp, 0); | |
55 | bytestream_put_buffer(&poutbufp, "mjpg", 4); | |
56 | bytestream_put_be32(&poutbufp, buf_size + 44); /* field size */ | |
57 | bytestream_put_be32(&poutbufp, buf_size + 44); /* pad field size */ | |
58 | bytestream_put_be32(&poutbufp, 0); /* next ptr */ | |
59 | ||
60 | for (i = 0; i < buf_size - 1; i++) { | |
61 | if (buf[i] == 0xff) { | |
62 | switch (buf[i + 1]) { | |
63 | case DQT: dqt = i + 46; break; | |
64 | case DHT: dht = i + 46; break; | |
65 | case SOF0: sof0 = i + 46; break; | |
66 | case SOS: | |
67 | bytestream_put_be32(&poutbufp, dqt); /* quant off */ | |
68 | bytestream_put_be32(&poutbufp, dht); /* huff off */ | |
69 | bytestream_put_be32(&poutbufp, sof0); /* image off */ | |
70 | bytestream_put_be32(&poutbufp, i + 46); /* scan off */ | |
71 | bytestream_put_be32(&poutbufp, i + 46 + AV_RB16(buf + i + 2)); /* data off */ | |
72 | bytestream_put_buffer(&poutbufp, buf + 2, buf_size - 2); /* skip already written SOI */ | |
73 | *poutbuf_size = poutbufp - *poutbuf; | |
74 | return 1; | |
75 | case APP1: | |
76 | if (i + 8 < buf_size && AV_RL32(buf + i + 8) == AV_RL32("mjpg")) { | |
77 | av_log(avctx, AV_LOG_ERROR, "bitstream already formatted\n"); | |
78 | memcpy(*poutbuf, buf, buf_size); | |
79 | *poutbuf_size = buf_size; | |
80 | return 1; | |
81 | } | |
82 | } | |
83 | } | |
84 | } | |
85 | av_freep(poutbuf); | |
86 | av_log(avctx, AV_LOG_ERROR, "could not find SOS marker in bitstream\n"); | |
87 | return 0; | |
88 | } | |
89 | ||
90 | AVBitStreamFilter ff_mjpega_dump_header_bsf = { | |
91 | .name = "mjpegadump", | |
92 | .filter = mjpega_dump_header, | |
93 | }; |