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• How can i make the dashjs player respect the stream window from ffmpeg ?

  7 mars 2021, par Octavia Kitsune

  I created the following command to i run on the serverside turn a source url into a cmaf dash stream :

  


  ffmpeg -loglevel error -re -i SOURCEURL -c copy -f dash -dash_segment_type mp4 -remove_at_exit 1 -seg_duration 2 -target_latency 1 -frag_type duration -frag_duration 0.1 -window_size 10 -extra_window_size 3 -streaming 1 -ldash 1 -use_template 1 -use_timeline 0 -index_correction 1 -tune zerolatency -fflags "+nobuffer+flush_packets" -format_options "movflags=cmaf" -adaptation_sets "id=0,streams=0 id=1,streams=1" -utc_timing_url "http://time.akamai.com/?iso&ms" stream/main.mpd


  


  And on the clientside i run a dashjs player with the following configuration :

  


    const video = document.getElementById('video')
  const player = dashjs.MediaPlayer().create()

  player.initialize(video, false, true)
  player.updateSettings({
    streaming: {
      stallThreshold: 0.05,
      lowLatencyEnabled: true,
      liveDelay: 1,
      liveCatchup: {
        minDrift: 1,
        playbackRate: 0.3,
        mode: 'liveCatchupModeDefault'
      },
      abr: {
        useDefaultABRRules: true,
        ABRStrategy: 'abrLoLP',
        fetchThroughputCalculationMode:
          'abrFetchThroughputCalculationMoofParsing'
      }
    }
  })


  


  My problem is, that dashjs loads a few segements and then tries to grab segments that error with a 404. It seems the segments it asks for fall out ot the window the stream defines.

  


  So i wonder how i can align my dashjs with my stream configuration so that it does respect the window defined by the stream, to basically simulate a livestream from any kind of videosource ?

  


• How do I encode a series of WebP image files into a WebM video ? [on hold]

  18 mars 2015, par Tony Nardi

  I have looked into tools like ffmpeg, libvpx, and VP8. I have not found any examples that illustrate the exact problem I am attempting to solve.

  My goal is to use a command, like the one found here to encode a series of image files to a video. I would prefer, however, to use WebP as my series of images and encode them to a WebM video.

  I have also looked at using the VP8 encoder directly, but the examples assume using a YUV input file.

  Also, there is an example here to convert PNG files to a WebM video. This is very close to what I want to do !

  I am fairly new to all of these concepts and tools, but it seems like WebP is pretty much a single WebM frame with a different container format. It seems pretty simple in theory to encode many WebP images to a single WebM video.

  Any help, whether a solution or documents for me to read, would be greatly appreciated. Thanks !

• avformat/mp3dec : improve junk skipping heuristic

  20 octobre 2015, par wm4

  avformat/mp3dec : improve junk skipping heuristic
  Commit 2b3e9bbfb529e6bde238aeb511b55ebe461664c8 caused problems for a
  
  certain API user :
  https://code.google.com/p/chromium/issues/detail?id=537725
  
  https://code.google.com/p/chromium/issues/detail?id=542032
  The problem seems rather arbitrary, because if there’s junk, anything
  
  can happen. In this case, the imperfect junk skipping just caused it to
  
  read different junk, from what I can see.
  We can improve the accuracy of junk detection by a lot by checking if 2
  
  consecutive frames use the same configuration. While in theory it might
  
  be completely fine for the 1st frame to have a different format than the
  
  2nd frame, it’s exceedingly unlikely, and I can’t think of a legitimate
  
  use-case.
  This is approximately the same mpg123 does for junk skipping. The
  
  set of compared header bits is the same as the libavcodec mp3 parser
  
  uses for similar purposes.
  

  • [DH] libavformat/mp3dec.c