Recherche avancée

Sur d’autres sites (6945)

• ffmpeg conditional copy or encode audio stream

  31 octobre 2017, par PieterV

  My objective is to DirectPlay all my content in Plex.
  To do this, I have to conditionally re-encode some audio and video streams, to a format that can be played without the server having to transcode on the fly.

  I am currently using HanbrakeCLI to encode video to x264 and audio to a compatible format.

  I use the "—aencoder copy —audio-fallback ac3" options, to copy the audio stream as is if in a supported format, i.e. aac/ac3/eac3/truehd/dts/dtshd/mp3/flac, or to encode to ac3 if not a supported format.

  I want to switch away from HandbrakeCLI because it does not support copying video streams, sometimes my media has a good video stream, but the audio needs to be encoded only, e.g. WMV with a VC1 video and WMAPro audio stream.

  A commandline for HandbrakeCLI looks like :

      // Create the HandbrakeCLI commandline and execute
  
      // https://handbrake.fr/docs/en/latest/cli/cli-guide.html
  
      string commandline = $"--input \"{inputname}\" --output \"{outputname}\" --format av_mkv --encoder x264 " +
  
                           $"--encoder-preset medium --quality {Settings.Default.VideoEncodeQuality} --subtitle 1,2,3,4 --audio 1,2,3,4 " +
  
                           $"--aencoder copy --audio-fallback ac3";

  In ffmpeg I would use :

      // Create the FFmpeg commandline and execute
  
      // https://trac.ffmpeg.org/wiki/Encode/H.264
  
      string commandline = $"-i \"{inputname}\" -c:v libx264 -crf {Settings.Default.VideoEncodeQuality} -preset medium -c:a copy -f matroska \"{outputname}\"";

  Is there an equivalent to HandbrakeCLI’s "—audio-fallback ac3" in ffmpeg ?

  I.e. I want the video to be encoded to x264, all audio tracks copied if the track is aac or ac3 or eac3 or truehd or dts or dtshd or mp3 or flac, and if not, encoded as ac3, while also copying all the subtitles and chapters as is.

• Remove dv1394 input device

  26 septembre 2017, par Josh de Kock

  Remove dv1394 input device
  Support for this device has been removed in the Linux kernel since v2.6.37.
  
  dv1394 has been superseded by libiec61883 which is functionally equivalent.
  Signed-off-by : Josh de Kock <josh@itanimul.li>
  
  Signed-off-by : Diego Biurrun <diego@biurrun.de>
  

  • [DBH] configure
  • [DBH] doc/general.texi
  • [DBH] doc/indevs.texi
  • [DBH] libavdevice/Makefile
  • [DBH] libavdevice/alldevices.c
  • [DBH] libavdevice/dv1394.c
  • [DBH] libavdevice/dv1394.h
  • [DBH] libavdevice/version.h

• How does FFMPEG copy work ?

  24 novembre 2017, par Tyler Brooks

  How can I implement the equivalent of this command :

  ffmpeg -i test.h264 -vcodec copy -hls_time 5 -hls_list_size 0 foo.m3u8

  My understanding is that you do something like this (pseudo code for clarity) :

  avformat_open_input(&ctx_in, "test.h264", NULL, NULL);
  
  avformat_find_stream_info(ctx_in, NULL);
  
  
  
  avformat_alloc_output_context2(&ctx_out, NULL, "hls", "foo.m3u8");
  
  strm_out = avformat_new_stream(ctx_out, NULL);
  
  strm_out->time_base = (AVRational){1000000, FRAMERATE};
  
  
  
  strm_out->codecpar->codec_id = AV_CODEC_ID_H264;
  
  strm_out->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
  
  strm_out->codecpar->width = width;
  
  strm_out->codecpar->height = height;
  
  strm_out->codecpar->bit_rate = bitrate;
  
  strm_out->codecpar->codec_tag = 0;
  
  
  
  avcodec_parameters_copy(ctx_out->streams[0]->codecpar,
  
    ctx_in->streams[0]->codecpar);
  
  
  
  avformat_write_header(ctx_out, NULL);
  
  
  
  while(1) {
  
    AVPacket pkt;
  
  
  
    ret = av_read_frame(ctx_in, &pkt);
  
    if (ret < 0)
  
      break;
  
  
  
    pkt.pos = -1;
  
    pkt.stream_index = 0;
  
    pkt.dts = AV_NOPTS_VALUE;
  
    pkt.pts = AV_NOPTS_VALUE;
  
    pkt.pts = SOME_DURATION;
  
  
  
    av_write_frame(ctx_out, &pkt);
  
    av_packet_unref(&pkt);
  
  }
  
  avformat_close_input(&ctx_in);
  
  av_write_trailer(ctx_out);
  
  avformat_free_context(ctx_out);

  I crash on the avformat_find_stream_info() call. I think this is the case because an H264 elemental stream is not really a container (which avformat wants).

  What is the proper way to implement the FFMPEG ’copy’ command of an elemental stream ?