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• libavformat / Remuxing from mpegts to mp4 generate wrong AAC profile

  13 juillet 2017, par axeo

  I have problem with remuxing MPEG-TS to MP4 via API. AAC profile on the output file changed after remux from LC to default (codecpar->profile equals -1). I even took example from ffmpeg.org, added bitstream filter for removing ADTS headers from AAC, removed deprecated functions but the problem exists too. Video stream with this code totally the same as in input.

  This is my modified code :

  #include <libavutil></libavutil>timestamp.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  
  
  
  
  static void log_packet(const AVFormatContext *fmt_ctx, const AVPacket *pkt, const char *tag)
  
  {
  
      AVRational *time_base = &amp;fmt_ctx->streams[pkt->stream_index]->time_base;
  
      printf("%s: pts:%s pts_time:%s dts:%s dts_time:%s duration:%s duration_time:%s stream_index:%d\n",
  
             tag,
  
             av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, time_base),
  
             av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, time_base),
  
             av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, time_base),
  
             pkt->stream_index);
  
  }
  
  int main(int argc, char **argv)
  
  {
  
      AVOutputFormat *ofmt = NULL;
  
      AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
  
      AVPacket pkt;
  
      const char *in_filename, *out_filename;
  
      int ret, i;
  
      if (argc &lt; 3) {
  
          printf("usage: %s input output\n"
  
                 "API example program to remux a media file with libavformat and libavcodec.\n"
  
                 "The output format is guessed according to the file extension.\n"
  
                 "\n", argv[0]);
  
          return 1;
  
      }
  
      in_filename  = argv[1];
  
      out_filename = argv[2];
  
      avformat_network_init();
  
      av_register_all();
  
      if ((ret = avformat_open_input(&amp;ifmt_ctx, in_filename, 0, 0)) &lt; 0) {
  
          fprintf(stderr, "Could not open input file '%s'", in_filename);
  
          goto end;
  
      }
  
      if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) &lt; 0) {
  
          fprintf(stderr, "Failed to retrieve input stream information");
  
          goto end;
  
      }
  
      av_dump_format(ifmt_ctx, 0, in_filename, 0);
  
      avformat_alloc_output_context2(&amp;ofmt_ctx, NULL, NULL, out_filename);
  
      if (!ofmt_ctx) {
  
          fprintf(stderr, "Could not create output context\n");
  
          ret = AVERROR_UNKNOWN;
  
          goto end;
  
      }
  
      ofmt = ofmt_ctx->oformat;
  
      for (i = 0; i &lt; ifmt_ctx->nb_streams; i++) {
  
          AVStream *in_stream = ifmt_ctx->streams[i];
  
          AVStream *out_stream = avformat_new_stream(ofmt_ctx, NULL);
  
          if (!out_stream) {
  
              fprintf(stderr, "Failed allocating output stream\n");
  
              ret = AVERROR_UNKNOWN;
  
              goto end;
  
          }
  
          ret = avcodec_parameters_copy(out_stream->codecpar, in_stream->codecpar);
  
          if (ret &lt; 0) {
  
              fprintf(stderr, "Failed to copy context from input to output stream codec context\n");
  
              goto end;
  
          }
  
  //        if (ofmt_ctx->oformat->flags &amp; AVFMT_GLOBALHEADER)
  
  //            out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
          out_stream->codecpar->codec_tag = 0;
  
      }
  
      av_dump_format(ofmt_ctx, 0, out_filename, 1);
  
      if (!(ofmt->flags &amp; AVFMT_NOFILE)) {
  
          ret = avio_open(&amp;ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
  
          if (ret &lt; 0) {
  
              fprintf(stderr, "Could not open output file '%s'", out_filename);
  
              goto end;
  
          }
  
      }
  
      ret = avformat_write_header(ofmt_ctx, NULL);
  
      if (ret &lt; 0) {
  
          fprintf(stderr, "Error occurred when opening output file\n");
  
          goto end;
  
      }
  
      while (1) {
  
          AVStream *in_stream, *out_stream;
  
          ret = av_read_frame(ifmt_ctx, &amp;pkt);
  
          if (ret &lt; 0)
  
              break;
  
          in_stream  = ifmt_ctx->streams[pkt.stream_index];
  
          out_stream = ofmt_ctx->streams[pkt.stream_index];
  
  //        log_packet(ifmt_ctx, &amp;pkt, "in");
  
          /* copy packet */
  
          pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);
  
          pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);
  
          pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
  
          pkt.pos = -1;
  
  //        log_packet(ofmt_ctx, &amp;pkt, "out");
  
  
  
          if (in_stream->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
  
  
  
              ret = av_interleaved_write_frame(ofmt_ctx, &amp;pkt);
  
              if (ret &lt; 0) {
  
                  fprintf(stderr, "Error muxing packet\n");
  
              }
  
  
  
          } else if (in_stream->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
  
  
  
              AVBSFContext *avbsctx;
  
              AVPacket filtered_packet = {0};
  
  
  
              const AVBitStreamFilter *bsf = av_bsf_get_by_name("aac_adtstoasc");
  
  
  
              av_bsf_alloc(bsf, &amp;avbsctx);
  
              avcodec_parameters_copy(avbsctx->par_in, in_stream->codecpar);
  
              av_bsf_init(avbsctx);
  
              av_bsf_send_packet(avbsctx, &amp;pkt);
  
  
  
              while (1) {
  
                  ret = av_bsf_receive_packet(avbsctx, &amp;filtered_packet);
  
                  if (ret &lt; 0) {
  
                      av_packet_unref(&amp;filtered_packet);
  
                      break;
  
                  }
  
                  ret = av_interleaved_write_frame(ofmt_ctx, &amp;filtered_packet);
  
                  av_packet_unref(&amp;filtered_packet);
  
              }
  
              av_bsf_free(&amp;avbsctx);
  
          }
  
          av_packet_unref(&amp;pkt);
  
      }
  
      av_write_trailer(ofmt_ctx);
  
  end:
  
      avformat_close_input(&amp;ifmt_ctx);
  
      /* close output */
  
      if (ofmt_ctx &amp;&amp; !(ofmt->flags &amp; AVFMT_NOFILE))
  
          avio_close(ofmt_ctx->pb);
  
      avformat_free_context(ofmt_ctx);
  
      if (ret &lt; 0 &amp;&amp; ret != AVERROR_EOF) {
  
          fprintf(stderr, "Error occurred: %s\n", av_err2str(ret));
  
          return 1;
  
      }
  
      return 0;
  
  }

  If I do the same operation with ffmpeg binary - all is OK. AAC-LC stream stay unchanged in output file.

  ffmpeg -i input.ts -y -bsf:a aac_adtstoasc -acodec copy -vn output.mp4

  What I’m doing wrong ? I tried look at ffmpeg sources, but it is very complicated.

  Thanks.

  P.S.
  I’ve also added this string to example out_stream->codecpar->codec_tag = 0;, otherwise I’m getting error that codec_tag is not compatible with output codec. May be I need to workaround this somehow ?

• h264dec : fix Lossless Decoding (Profile 244) for 8x8 Intra Prediction

  15 juin 2017, par Yogender Kumar Gupta

  h264dec : fix Lossless Decoding (Profile 244) for 8x8 Intra Prediction
  CC : libav-stable@libav.org
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] libavcodec/h264_mb.c
  • [DBH] libavcodec/h264pred.c
  • [DBH] libavcodec/h264pred.h
  • [DBH] libavcodec/h264pred_template.c

• vp9 : set color range to MPEG for intraonly profile 0

  19 août 2017, par James Zern

  vp9 : set color range to MPEG for intraonly profile 0
  this is undocumented in the vp9 bitstream and decoding specification
  
  doc, but matches libvpx
  Reviewed-by : "Ronald S. Bultje" <rsbultje@gmail.com>
  
  Signed-off-by : James Zern <jzern@google.com>
  

  • [DH] libavcodec/vp9.c