/* * 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; uint8_t *sps_pps_data; uint32_t size; } H264BSFContext; static void 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; *poutbuf_size += sps_pps_size+in_size+nal_header_size; *poutbuf = av_realloc(*poutbuf, *poutbuf_size); 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; } } 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; uint32_t nal_size, cumul_size = 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->sps_pps_data) { uint16_t unit_size; uint32_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--) { unit_size = AV_RB16(extradata); total_size += unit_size+4; if (extradata+2+unit_size > avctx->extradata+avctx->extradata_size) { av_free(out); return AVERROR(EINVAL); } out = av_realloc(out, total_size); if (!out) return AVERROR(ENOMEM); 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) */ } ctx->sps_pps_data = out; ctx->size = total_size; ctx->first_idr = 1; } *poutbuf_size = 0; *poutbuf = NULL; do { 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; /* prepend only to the first type 5 NAL unit of an IDR picture */ if (ctx->first_idr && unit_type == 5) { alloc_and_copy(poutbuf, poutbuf_size, ctx->sps_pps_data, ctx->size, buf, nal_size); ctx->first_idr = 0; } else { alloc_and_copy(poutbuf, poutbuf_size, NULL, 0, buf, nal_size); 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; } static void h264_mp4toannexb_close(AVBitStreamFilterContext *bsfc) { H264BSFContext *ctx = bsfc->priv_data; av_freep(&ctx->sps_pps_data); } AVBitStreamFilter h264_mp4toannexb_bsf = { "h264_mp4toannexb", sizeof(H264BSFContext), h264_mp4toannexb_filter, h264_mp4toannexb_close, };