yading@10: /*
yading@10:  * MJPEG A dump header bitstream filter
yading@10:  * Copyright (c) 2006 Baptiste Coudurier
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * MJPEG A dump header bitstream filter
yading@10:  * modifies bitstream to be decoded by quicktime
yading@10:  */
yading@10: 
yading@10: #include "avcodec.h"
yading@10: #include "bytestream.h"
yading@10: #include "mjpeg.h"
yading@10: 
yading@10: 
yading@10: static int mjpega_dump_header(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args,
yading@10:                               uint8_t **poutbuf, int *poutbuf_size,
yading@10:                               const uint8_t *buf, int buf_size, int keyframe)
yading@10: {
yading@10:     uint8_t *poutbufp;
yading@10:     unsigned dqt = 0, dht = 0, sof0 = 0;
yading@10:     int i;
yading@10: 
yading@10:     if (avctx->codec_id != AV_CODEC_ID_MJPEG) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "mjpega bitstream filter only applies to mjpeg codec\n");
yading@10:         return 0;
yading@10:     }
yading@10: 
yading@10:     *poutbuf_size = 0;
yading@10:     *poutbuf = av_malloc(buf_size + 44 + FF_INPUT_BUFFER_PADDING_SIZE);
yading@10:     poutbufp = *poutbuf;
yading@10:     bytestream_put_byte(&poutbufp, 0xff);
yading@10:     bytestream_put_byte(&poutbufp, SOI);
yading@10:     bytestream_put_byte(&poutbufp, 0xff);
yading@10:     bytestream_put_byte(&poutbufp, APP1);
yading@10:     bytestream_put_be16(&poutbufp, 42); /* size */
yading@10:     bytestream_put_be32(&poutbufp, 0);
yading@10:     bytestream_put_buffer(&poutbufp, "mjpg", 4);
yading@10:     bytestream_put_be32(&poutbufp, buf_size + 44); /* field size */
yading@10:     bytestream_put_be32(&poutbufp, buf_size + 44); /* pad field size */
yading@10:     bytestream_put_be32(&poutbufp, 0);             /* next ptr */
yading@10: 
yading@10:     for (i = 0; i < buf_size - 1; i++) {
yading@10:         if (buf[i] == 0xff) {
yading@10:             switch (buf[i + 1]) {
yading@10:             case DQT:  dqt  = i + 46; break;
yading@10:             case DHT:  dht  = i + 46; break;
yading@10:             case SOF0: sof0 = i + 46; break;
yading@10:             case SOS:
yading@10:                 bytestream_put_be32(&poutbufp, dqt); /* quant off */
yading@10:                 bytestream_put_be32(&poutbufp, dht); /* huff off */
yading@10:                 bytestream_put_be32(&poutbufp, sof0); /* image off */
yading@10:                 bytestream_put_be32(&poutbufp, i + 46); /* scan off */
yading@10:                 bytestream_put_be32(&poutbufp, i + 46 + AV_RB16(buf + i + 2)); /* data off */
yading@10:                 bytestream_put_buffer(&poutbufp, buf + 2, buf_size - 2); /* skip already written SOI */
yading@10:                 *poutbuf_size = poutbufp - *poutbuf;
yading@10:                 return 1;
yading@10:             case APP1:
yading@10:                 if (i + 8 < buf_size && AV_RL32(buf + i + 8) == AV_RL32("mjpg")) {
yading@10:                     av_log(avctx, AV_LOG_ERROR, "bitstream already formatted\n");
yading@10:                     memcpy(*poutbuf, buf, buf_size);
yading@10:                     *poutbuf_size = buf_size;
yading@10:                     return 1;
yading@10:                 }
yading@10:             }
yading@10:         }
yading@10:     }
yading@10:     av_freep(poutbuf);
yading@10:     av_log(avctx, AV_LOG_ERROR, "could not find SOS marker in bitstream\n");
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVBitStreamFilter ff_mjpega_dump_header_bsf = {
yading@10:     "mjpegadump",
yading@10:     0,
yading@10:     mjpega_dump_header,
yading@10: };