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• ffmpeg concat demuxer dropping audio after first clip

  6 septembre 2020, par marcman

  I'm trying to concatenate a video collection that all should be the same type and format. It seems to work like expected when the original sources are the same type, but when they're different types the demuxer drops audio. I understand that the demux requires all inputs to have the same codecs, but I believe I am doing that already.

  


  This is my workflow (pseudocode with Python-like for loop) :

  


  for i, video in enumerate(all_videos):&#xA;    # Call command for transcoding and filtering&#xA;    # I allow this command to be called on mp4, mov, and avi files&#xA;    # The point of this filter is:&#xA;    # (1) to superimpose a timestamp on the bottom right of the video&#xA;    # (2) to scale and pad the videos to a common output resolution (the specific numbers below are just copied from a video I ran, but they are filled in automatically for each given video by the rest of my script)&#xA;    # (3) To transcode all videos to the same common format&#xA;    ffmpeg \&#xA;        -y \&#xA;        -loglevel quiet \&#xA;        -stats \&#xA;        -i video_<i>.{mp4, mov, avi} \&#xA;        -vcodec libx264 \&#xA;        -acodec aac \&#xA;        -vf "scale=607:1080, pad=width=1920:height=1080:x=656:y=0:color=black, drawtext=expansion=strftime: basetime=$(date &#x2B;%s -d&#x27;2020-08-27 16:42:26&#x27;)000000 : fontcolor=white : text=&#x27;%^b %d, %Y%n%l\\:%M%p&#x27; : fontsize=36 : y=1080-4*lh : x=1263-text_w-2*max_glyph_w" \&#xA;        tmpdir/video_<i>.mp4&#xA;&#xA;&#xA;# create file_list.txt, e.g.&#xA;#&#xA;# file &#x27;/abspath/to/tmpdir/video_1.mp4&#x27;&#xA;# file &#x27;/abspath/to/tmpdir/video_2.mp4&#x27;&#xA;# file &#x27;/abspath/to/tmpdir/video_3.mp4&#x27;&#xA;# ...&#xA;&#xA;&#xA;ffmpeg \&#xA;    -f concat \&#xA;    -safe 0 \&#xA;    -i file_list.txt \&#xA;    -c copy \&#xA;    all_videos.mp4&#xA;</i></i>

  


  In my test case, my inputs are 3 videos in this order :

  


  

  1. a camcorder video output in H.264+aac in a mp4

  


  2. an iphone video in mov format

  


  3. an iphone video in mp4 format

  


  


  When I review each of the intermediate mp4-transcoded videos in tmpdir they all playback audio and video just fine and the filtering works as expected. However, when I review the final concatenated output, only the first clip (the camcorder video) has sound. When all the videos are from the camcorder, there is no audio issue—they all have sound.

  


  When I output ffmpeg warnings and errors, the only thing that shows up is an expected warning about the timestamp :

  


  [mp4 @ 0x55997ce85300] Non-monotonous DTS in output stream 0:1; previous: 5909504, current: 5430298; changing to 5909505. This may result in incorrect timestamps in the output file.
[mp4 @ 0x55997ce85300] Non-monotonous DTS in output stream 0:1; previous: 5909505, current: 5431322; changing to 5909506. This may result in incorrect timestamps in the output file.
[mp4 @ 0x55997ce85300] Non-monotonous DTS in output stream 0:1; previous: 5909506, current: 5432346; changing to 5909507. This may result in incorrect timestamps in the output file.
[mp4 @ 0x55997ce85300] Non-monotonous DTS in output stream 0:1; previous: 5909507, current: 5433370; changing to 5909508. This may result in incorrect timestamps in the output file.
...


  


  What might I be doing wrong here ? I'm testing in both the Ubuntu 20.04 "Videos" applications as well as VLC Player and both demonstrate the same problem. I'd prefer to use the demuxer if possible for speed as re-encoding during concatenation is quite expensive.

  


  NOTE : This is a different issue than laid out here, in which some of the videos had no audio. In my case, all videos have both video and audio.

  


• Using ffmpeg to build a streaming server to stream static media files (broadcast behaviour)

  15 février 2018, par MiDaa

  I’ve read some online articles and SO questions, most of them are about streaming MY video to SERVER like youtube or switch.

  This is about a project of interest, here are what it should do.

  • Work on a Linux server
  • Serve media(preferably multiple format like mp4 mkv) files to client through rtp protocol maybe ?
  • Server could set a specific time to start the streaming or end it
  • Server could pause and resume the streaming(?)
  • Multiple clients connect and play the stream at same time(sounds like a basic feature)

  After some research, I found that ffmpeg is a great open-source candidate for such a project but as a newbie in this area, I’m having a tough time understanding how this whole thing work.

  As this(ffmpeg doc) states, it looks like just a one liner command. But I don’t find anything fit my feature listed above.

  Can ffmpeg be used to achieve those ? If not appriciate any suggesstion on where I should be looking at.

  EDIT :

  • Target devices : iPad,iPhone, Android phones should be able to watch the stream using a web browser(assume a modern browser)

• ffmpeg stream video file from ubuntu to youtube

  14 mars 2018, par user3010452

  I’m trying to create a stream to youtube. I could see how preview button changes into enable state. However it never actually changes from offline.
  And it gives me several error. What am I doing wrong ?

       ffmpeg -i video.flv -f flv rtmp://a.rtmp.youtube.com/live2/XXXXXX
  
  
  
  
  
    ffmpeg version 2.8.11-0ubuntu0.16.04.1 Copyright (c) 2000-2017 the FFmpeg developers
  
  
  
        built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
  
        configuration: --prefix=/usr --extra-version=0ubuntu0.16.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
  
        libavutil      54. 31.100 / 54. 31.100
  
        libavcodec     56. 60.100 / 56. 60.100
  
        libavformat    56. 40.101 / 56. 40.101
  
        libavdevice    56.  4.100 / 56.  4.100
  
        libavfilter     5. 40.101 /  5. 40.101
  
        libavresample   2.  1.  0 /  2.  1.  0
  
        libswscale      3.  1.101 /  3.  1.101
  
        libswresample   1.  2.101 /  1.  2.101
  
        libpostproc    53.  3.100 / 53.  3.100
  
      Input #0, flv, from 'video.flv':
  
        Metadata:
  
          major_brand     : qt  
  
          minor_version   : 0
  
          compatible_brands: qt  
  
          com.apple.quicktime.creationdate: 2017-07-20T21:44:12+0700
  
          com.apple.quicktime.make: Apple
  
          com.apple.quicktime.model: iPhone 6s Plus
  
          com.apple.quicktime.software: 10.3.2
  
          encoder         : Lavf57.83.100
  
        Duration: 00:01:15.24, start: 0.000000, bitrate: 4454 kb/s
  
          Stream #0:0: Video: flv1, yuv420p, 1920x1080, 200 kb/s, 29.97 fps, 29.97 tbr, 1k tbn, 1k tbc
  
          Stream #0:1: Audio: adpcm_swf, 44100 Hz, mono, s16, 176 kb/s
  
      Output #0, flv, to 'rtmp://a.rtmp.youtube.com/XXXXXX':
  
        Metadata:
  
          major_brand     : qt  
  
          minor_version   : 0
  
          compatible_brands: qt  
  
          com.apple.quicktime.creationdate: 2017-07-20T21:44:12+0700
  
          com.apple.quicktime.make: Apple
  
          com.apple.quicktime.model: iPhone 6s Plus
  
          com.apple.quicktime.software: 10.3.2
  
          encoder         : Lavf56.40.101
  
          Stream #0:0: Video: flv1 (flv) ([2][0][0][0] / 0x0002), yuv420p, 1920x1080, q=2-31, 200 kb/s, 29.97 fps, 1k tbn, 29.97 tbc
  
          Metadata:
  
            encoder         : Lavc56.60.100 flv
  
          Stream #0:1: Audio: mp3 (libmp3lame) ([2][0][0][0] / 0x0002), 44100 Hz, mono, s16p
  
          Metadata:
  
            encoder         : Lavc56.60.100 libmp3lame
  
      Stream mapping:
  
        Stream #0:0 -> #0:0 (flv1 (flv) -> flv1 (flv))
  
        Stream #0:1 -> #0:1 (adpcm_swf (native) -> mp3 (libmp3lame))
  
      Press [q] to stop, [?] for help
  
      [flv @ 0x162bac0] Failed to update header with correct duration.ate=4125.4kbits/s    
  
      [flv @ 0x162bac0] Failed to update header with correct filesize.
  
      frame= 2255 fps=114 q=31.0 Lsize=   37863kB time=00:01:15.24 bitrate=4122.0kbits/s    
  
      video:37194kB audio:588kB subtitle:0kB other streams:0kB global 

  headers:0kB mixing overhead : 0.213941%