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/*
* H.264 MP4 to Annex B byte stream format filter
* Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
*
* 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
*/
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
typedef struct H264BSFContext {
uint8_t length_size;
uint8_t first_idr;
int extradata_parsed;
} H264BSFContext;
static int alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *sps_pps, uint32_t sps_pps_size,
const uint8_t *in, uint32_t in_size) {
uint32_t offset = *poutbuf_size;
uint8_t nal_header_size = offset ? 3 : 4;
void *tmp;
*poutbuf_size += sps_pps_size+in_size+nal_header_size;
tmp = av_realloc(*poutbuf, *poutbuf_size);
if (!tmp)
return AVERROR(ENOMEM);
*poutbuf = tmp;
if (sps_pps)
memcpy(*poutbuf+offset, sps_pps, sps_pps_size);
memcpy(*poutbuf+sps_pps_size+nal_header_size+offset, in, in_size);
if (!offset)
AV_WB32(*poutbuf+sps_pps_size, 1);
else {
(*poutbuf+offset+sps_pps_size)[0] = (*poutbuf+offset+sps_pps_size)[1] = 0;
(*poutbuf+offset+sps_pps_size)[2] = 1;
}
return 0;
}
static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
AVCodecContext *avctx, const char *args,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size,
int keyframe) {
H264BSFContext *ctx = bsfc->priv_data;
uint8_t unit_type;
int32_t nal_size;
uint32_t cumul_size = 0;
const uint8_t *buf_end = buf + buf_size;
/* nothing to filter */
if (!avctx->extradata || avctx->extradata_size < 6) {
*poutbuf = (uint8_t*) buf;
*poutbuf_size = buf_size;
return 0;
}
/* retrieve sps and pps NAL units from extradata */
if (!ctx->extradata_parsed) {
uint16_t unit_size;
uint64_t total_size = 0;
uint8_t *out = NULL, unit_nb, sps_done = 0;
const uint8_t *extradata = avctx->extradata+4;
static const uint8_t nalu_header[4] = {0, 0, 0, 1};
/* retrieve length coded size */
ctx->length_size = (*extradata++ & 0x3) + 1;
if (ctx->length_size == 3)
return AVERROR(EINVAL);
/* retrieve sps and pps unit(s) */
unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
if (!unit_nb) {
unit_nb = *extradata++; /* number of pps unit(s) */
sps_done++;
}
while (unit_nb--) {
void *tmp;
unit_size = AV_RB16(extradata);
total_size += unit_size+4;
if (total_size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE || extradata+2+unit_size > avctx->extradata+avctx->extradata_size) {
av_free(out);
return AVERROR(EINVAL);
}
tmp = av_realloc(out, total_size + FF_INPUT_BUFFER_PADDING_SIZE);
if (!tmp) {
av_free(out);
return AVERROR(ENOMEM);
}
out = tmp;
memcpy(out+total_size-unit_size-4, nalu_header, 4);
memcpy(out+total_size-unit_size, extradata+2, unit_size);
extradata += 2+unit_size;
if (!unit_nb && !sps_done++)
unit_nb = *extradata++; /* number of pps unit(s) */
}
memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
av_free(avctx->extradata);
avctx->extradata = out;
avctx->extradata_size = total_size;
ctx->first_idr = 1;
ctx->extradata_parsed = 1;
}
*poutbuf_size = 0;
*poutbuf = NULL;
do {
if (buf + ctx->length_size > buf_end)
goto fail;
if (ctx->length_size == 1)
nal_size = buf[0];
else if (ctx->length_size == 2)
nal_size = AV_RB16(buf);
else
nal_size = AV_RB32(buf);
buf += ctx->length_size;
unit_type = *buf & 0x1f;
if (buf + nal_size > buf_end || nal_size < 0)
goto fail;
/* prepend only to the first type 5 NAL unit of an IDR picture */
if (ctx->first_idr && unit_type == 5) {
if (alloc_and_copy(poutbuf, poutbuf_size,
avctx->extradata, avctx->extradata_size,
buf, nal_size) < 0)
goto fail;
ctx->first_idr = 0;
}
else {
if (alloc_and_copy(poutbuf, poutbuf_size,
NULL, 0,
buf, nal_size) < 0)
goto fail;
if (!ctx->first_idr && unit_type == 1)
ctx->first_idr = 1;
}
buf += nal_size;
cumul_size += nal_size + ctx->length_size;
} while (cumul_size < buf_size);
return 1;
fail:
av_freep(poutbuf);
*poutbuf_size = 0;
return AVERROR(EINVAL);
}
AVBitStreamFilter h264_mp4toannexb_bsf = {
"h264_mp4toannexb",
sizeof(H264BSFContext),
h264_mp4toannexb_filter,
};
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