再从stsz box中取得sample总数,即总帧数sample_count,用总帧数除以总时长即平均帧率,计算公式为
frame_rate = sample_count/(duration/timescale)
解决方法:通过查询mp4帧率计算得到答案:
av_dict_set(&opt, "video_track_timescale", "90000", 0);
备注:
AVDictionary *opt=NULL;
av_dict_set_int(&opt,"video_track_timescale",25,0);
ret=avformat_write_header(ofmt_ctx,&opt);
而且pts只能+1递增。时间基没有设置也能十分正常播放。
timescale指一秒钟按时钟滴答数计算是多少,如果你设置1000,则一秒钟是以1000计算,你设置成25,那一秒钟就以25计算,所以你pts只能+1。 因为你设置了video_track_timescale所以不需要设置时间基
保存帧:
int mp4savePacket(int status,AVPacket *tmppacket){
tmppacket->flags |= AV_PKT_FLAG_KEY;
tmppacket->pts +=last_pts;
// tmppacket->pts = av_rescale_q((frame_num)*30000, outfmt_ctx->streams[0]->codec->time_base,outfmt_ctx->streams[0]->time_base);//替换了
frame_num++;
tmppacket->dts += last_dts;
tmppacket->stream_index = 0;
tmppacket->duration=1;
LOGE(3,"record_status ok,record_status = %d frame index %d %d %d\n",record_status,frame_num, tmppacket->duration,tmppacket->pts);
//LOGE(3,"mpacket, 16Byte = %d,%d ",tmppacket.data[0],tmppacket.data[1]);
av_interleaved_write_frame(outfmt_ctx, tmppacket);
av_free_packet(tmppacket);