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ffmpeg/libavcodec/h264_mp4toannexb_bsf.c

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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 <string.h>
#include "libavutil/intreadwrite.h"
#include "libavutil/mem.h"
#include "avcodec.h"
typedef struct H264BSFContext {
int32_t sps_offset;
int32_t pps_offset;
uint8_t length_size;
uint8_t new_idr;
uint8_t idr_sps_seen;
uint8_t idr_pps_seen;
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;
int err;
*poutbuf_size += sps_pps_size + in_size + nal_header_size;
if ((err = av_reallocp(poutbuf,
*poutbuf_size + FF_INPUT_BUFFER_PADDING_SIZE)) < 0) {
*poutbuf_size = 0;
return err;
}
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_extradata_to_annexb(H264BSFContext *ctx, AVCodecContext *avctx, const int padding)
{
uint16_t unit_size;
uint64_t total_size = 0;
uint8_t *out = NULL, unit_nb, sps_done = 0,
sps_seen = 0, pps_seen = 0;
const uint8_t *extradata = avctx->extradata + 4;
static const uint8_t nalu_header[4] = { 0, 0, 0, 1 };
int length_size = (*extradata++ & 0x3) + 1; // retrieve length coded size
ctx->sps_offset = ctx->pps_offset = -1;
/* retrieve sps and pps unit(s) */
unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
if (!unit_nb) {
goto pps;
} else {
ctx->sps_offset = 0;
sps_seen = 1;
}
while (unit_nb--) {
int err;
unit_size = AV_RB16(extradata);
total_size += unit_size + 4;
if (total_size > INT_MAX - padding) {
av_log(avctx, AV_LOG_ERROR,
"Too big extradata size, corrupted stream or invalid MP4/AVCC bitstream\n");
av_free(out);
return AVERROR(EINVAL);
}
if (extradata + 2 + unit_size > avctx->extradata + avctx->extradata_size) {
av_log(avctx, AV_LOG_ERROR, "Packet header is not contained in global extradata, "
"corrupted stream or invalid MP4/AVCC bitstream\n");
av_free(out);
return AVERROR(EINVAL);
}
if ((err = av_reallocp(&out, total_size + padding)) < 0)
return err;
memcpy(out + total_size - unit_size - 4, nalu_header, 4);
memcpy(out + total_size - unit_size, extradata + 2, unit_size);
extradata += 2 + unit_size;
pps:
if (!unit_nb && !sps_done++) {
unit_nb = *extradata++; /* number of pps unit(s) */
if (unit_nb) {
ctx->pps_offset = (extradata - 1) - (avctx->extradata + 4);
pps_seen = 1;
}
}
}
if (out)
memset(out + total_size, 0, padding);
if (!sps_seen)
av_log(avctx, AV_LOG_WARNING,
"Warning: SPS NALU missing or invalid. "
"The resulting stream may not play.\n");
if (!pps_seen)
av_log(avctx, AV_LOG_WARNING,
"Warning: PPS NALU missing or invalid. "
"The resulting stream may not play.\n");
av_free(avctx->extradata);
avctx->extradata = out;
avctx->extradata_size = total_size;
return length_size;
}
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;
int i;
uint8_t unit_type;
int32_t nal_size;
uint32_t cumul_size = 0;
const uint8_t *buf_end = buf + buf_size;
int ret = 0;
/* 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) {
ret = h264_extradata_to_annexb(ctx, avctx, FF_INPUT_BUFFER_PADDING_SIZE);
if (ret < 0)
return ret;
ctx->length_size = ret;
ctx->new_idr = 1;
ctx->idr_sps_seen = 0;
ctx->idr_pps_seen = 0;
ctx->extradata_parsed = 1;
}
*poutbuf_size = 0;
*poutbuf = NULL;
do {
ret= AVERROR(EINVAL);
if (buf + ctx->length_size > buf_end)
goto fail;
for (nal_size = 0, i = 0; i<ctx->length_size; i++)
nal_size = (nal_size << 8) | buf[i];
buf += ctx->length_size;
unit_type = *buf & 0x1f;
if (buf + nal_size > buf_end || nal_size < 0)
goto fail;
if (unit_type == 7)
ctx->idr_sps_seen = ctx->new_idr = 1;
else if (unit_type == 8) {
ctx->idr_pps_seen = ctx->new_idr = 1;
/* if SPS has not been seen yet, prepend the AVCC one to PPS */
if (!ctx->idr_sps_seen) {
if (ctx->sps_offset == -1)
av_log(avctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n");
else {
if ((ret = alloc_and_copy(poutbuf, poutbuf_size,
avctx->extradata + ctx->sps_offset,
ctx->pps_offset != -1 ? ctx->pps_offset : avctx->extradata_size - ctx->sps_offset,
buf, nal_size)) < 0)
goto fail;
ctx->idr_sps_seen = 1;
goto next_nal;
}
}
}
/* if this is a new IDR picture following an IDR picture, reset the idr flag.
* Just check first_mb_in_slice to be 0 as this is the simplest solution.
* This could be checking idr_pic_id instead, but would complexify the parsing. */
if (!ctx->new_idr && unit_type == 5 && (buf[1] & 0x80))
ctx->new_idr = 1;
/* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */
if (ctx->new_idr && unit_type == 5 && !ctx->idr_sps_seen && !ctx->idr_pps_seen) {
if ((ret=alloc_and_copy(poutbuf, poutbuf_size,
avctx->extradata, avctx->extradata_size,
buf, nal_size)) < 0)
goto fail;
ctx->new_idr = 0;
/* if only SPS has been seen, also insert PPS */
} else if (ctx->new_idr && unit_type == 5 && ctx->idr_sps_seen && !ctx->idr_pps_seen) {
if (ctx->pps_offset == -1) {
av_log(avctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
if ((ret = alloc_and_copy(poutbuf, poutbuf_size,
NULL, 0, buf, nal_size)) < 0)
goto fail;
} else if ((ret = alloc_and_copy(poutbuf, poutbuf_size,
avctx->extradata + ctx->pps_offset, avctx->extradata_size - ctx->pps_offset,
buf, nal_size)) < 0)
goto fail;
} else {
if ((ret=alloc_and_copy(poutbuf, poutbuf_size,
NULL, 0, buf, nal_size)) < 0)
goto fail;
if (!ctx->new_idr && unit_type == 1) {
ctx->new_idr = 1;
ctx->idr_sps_seen = 0;
ctx->idr_pps_seen = 0;
}
}
next_nal:
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 ret;
}
AVBitStreamFilter ff_h264_mp4toannexb_bsf = {
.name = "h264_mp4toannexb",
.priv_data_size = sizeof(H264BSFContext),
.filter = h264_mp4toannexb_filter,
};
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