ffmpeg / libavcodec / h264_mp4toannexb_bsf.c @ 52486603
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/*
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* H.264 MP4 to Annex B byte stream format filter
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* Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/intreadwrite.h" |
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#include "avcodec.h" |
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typedef struct H264BSFContext { |
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uint8_t length_size; |
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uint8_t first_idr; |
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uint8_t *sps_pps_data; |
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uint32_t size; |
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} H264BSFContext; |
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static void alloc_and_copy(uint8_t **poutbuf, int *poutbuf_size, |
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const uint8_t *sps_pps, uint32_t sps_pps_size,
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const uint8_t *in, uint32_t in_size) {
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uint32_t offset = *poutbuf_size; |
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uint8_t nal_header_size = offset ? 3 : 4; |
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*poutbuf_size += sps_pps_size+in_size+nal_header_size; |
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*poutbuf = av_realloc(*poutbuf, *poutbuf_size); |
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if (sps_pps)
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memcpy(*poutbuf+offset, sps_pps, sps_pps_size); |
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memcpy(*poutbuf+sps_pps_size+nal_header_size+offset, in, in_size); |
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if (!offset)
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AV_WB32(*poutbuf+sps_pps_size, 1);
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else {
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(*poutbuf+offset+sps_pps_size)[0] = (*poutbuf+offset+sps_pps_size)[1] = 0; |
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(*poutbuf+offset+sps_pps_size)[2] = 1; |
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} |
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} |
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static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc, |
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AVCodecContext *avctx, const char *args, |
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uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size, |
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int keyframe) {
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H264BSFContext *ctx = bsfc->priv_data; |
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uint8_t unit_type; |
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int32_t nal_size; |
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uint32_t cumul_size = 0;
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const uint8_t *buf_end = buf + buf_size;
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/* nothing to filter */
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if (!avctx->extradata || avctx->extradata_size < 6) { |
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*poutbuf = (uint8_t*) buf; |
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*poutbuf_size = buf_size; |
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return 0; |
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} |
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/* retrieve sps and pps NAL units from extradata */
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if (!ctx->sps_pps_data) {
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uint16_t unit_size; |
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uint32_t total_size = 0;
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uint8_t *out = NULL, unit_nb, sps_done = 0; |
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const uint8_t *extradata = avctx->extradata+4; |
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static const uint8_t nalu_header[4] = {0, 0, 0, 1}; |
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/* retrieve length coded size */
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ctx->length_size = (*extradata++ & 0x3) + 1; |
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if (ctx->length_size == 3) |
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return AVERROR(EINVAL);
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/* retrieve sps and pps unit(s) */
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unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */ |
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if (!unit_nb) {
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unit_nb = *extradata++; /* number of pps unit(s) */
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sps_done++; |
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} |
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while (unit_nb--) {
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unit_size = AV_RB16(extradata); |
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total_size += unit_size+4;
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if (extradata+2+unit_size > avctx->extradata+avctx->extradata_size) { |
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av_free(out); |
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return AVERROR(EINVAL);
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} |
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out = av_realloc(out, total_size); |
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if (!out)
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return AVERROR(ENOMEM);
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memcpy(out+total_size-unit_size-4, nalu_header, 4); |
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memcpy(out+total_size-unit_size, extradata+2, unit_size);
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extradata += 2+unit_size;
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if (!unit_nb && !sps_done++)
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unit_nb = *extradata++; /* number of pps unit(s) */
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} |
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ctx->sps_pps_data = out; |
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ctx->size = total_size; |
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ctx->first_idr = 1;
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} |
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*poutbuf_size = 0;
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*poutbuf = NULL;
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do {
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if (buf + ctx->length_size > buf_end)
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goto fail;
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if (ctx->length_size == 1) |
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nal_size = buf[0];
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else if (ctx->length_size == 2) |
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nal_size = AV_RB16(buf); |
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else
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nal_size = AV_RB32(buf); |
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buf += ctx->length_size; |
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unit_type = *buf & 0x1f;
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if (buf + nal_size > buf_end || nal_size < 0) |
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goto fail;
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/* prepend only to the first type 5 NAL unit of an IDR picture */
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if (ctx->first_idr && unit_type == 5) { |
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alloc_and_copy(poutbuf, poutbuf_size, |
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ctx->sps_pps_data, ctx->size, |
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buf, nal_size); |
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ctx->first_idr = 0;
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} |
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else {
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alloc_and_copy(poutbuf, poutbuf_size, |
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NULL, 0, |
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buf, nal_size); |
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if (!ctx->first_idr && unit_type == 1) |
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ctx->first_idr = 1;
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} |
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buf += nal_size; |
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cumul_size += nal_size + ctx->length_size; |
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} while (cumul_size < buf_size);
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return 1; |
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fail:
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av_freep(poutbuf); |
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*poutbuf_size = 0;
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return AVERROR(EINVAL);
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} |
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static void h264_mp4toannexb_close(AVBitStreamFilterContext *bsfc) |
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{ |
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H264BSFContext *ctx = bsfc->priv_data; |
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av_freep(&ctx->sps_pps_data); |
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} |
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AVBitStreamFilter h264_mp4toannexb_bsf = { |
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"h264_mp4toannexb",
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sizeof(H264BSFContext),
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h264_mp4toannexb_filter, |
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h264_mp4toannexb_close, |
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}; |
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