| 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 | }; |