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- /*
- * MJPEG A dump header bitstream filter
- * Copyright (c) 2006 Baptiste Coudurier
- *
- * This file is part of Libav.
- *
- * Libav 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.
- *
- * Libav 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 Libav; 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 != 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);
- 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 = {
- "mjpegadump",
- 0,
- mjpega_dump_header,
- };
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