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