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 33static 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 != 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 90AVBitStreamFilter mjpega_dump_header_bsf = { 91 "mjpegadump", 92 0, 93 mjpega_dump_header, 94}; 95