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• MP4Box Dash mpd not working

  7 décembre 2017, par Durlabh Sharma

  I’m trying to make a DASH client with Exoplayer as client on Android side. I am able to create individual Dash streams for audio or video. But I am unable to create a stream that includes both audio and video in single mpd file.

  For video, command used is :

  MP4Box -dash 4000 -frag 4000 -rap -segment-name segment_ ../video_enc.mp4#video

  For audio, command is :

  MP4Box -dash 4000 -frag 4000 -rap -segment-name segment_ ../video_enc.mp4#audio

  They both work perfectly fine. But when I go to create a single mpd, it creates mpd but it just doesn’t work. Even after creating all segments and fragments, it still fails to playCommand used is :

  MP4Box -dash 4000 -frag 4000 -rap -bs-switching no -profile dashavc264:live -segment-name segment_ ../video_enc.mp4#audio ../video_enc.mp4#video

• Trouble with frame accuracy applying subcaps using .ass files to 23.976fps video [closed]

  25 août 2023, par WhatsYourFunction

  Currently testing .ass subcaps in a VFX workflow.
The goal is to drop specfic text over specific shots and the in/out points have to be frame accurate
We're working in a 23.976 project.

  


  Currently having no trouble using FFmpeg to generate frame-accurate subclips of individual shots from a full-show export by converting hh:mm:ss:ff to seconds and then handling the 24 to 23.976 offset, using the following alorithm :

  


  InPoint_Seconds = ConvertToSeconds(InPoint_Hmsf_FullShow) - ConvertToSeconds(Start_Hmsf_FullShow) // Convert from SMTPE Time Code to seconds.
InPoint_Seconds = InPoint_Seconds * (1001 / 1000) //Handle 24 to 23.976 offset
OutPoint_Seconds = [Same idea as above]
Duration_Seconds = Output_Seconds - InPoint_Seconds

> ffmpeg -ss InPoint_Seconds -t Duration_Seconds -i SourcePath -c copy DestPath


  


  So generating frame-accurate copies of portions of a larger file works with perfect accuracy

  


  BUT when applying the same logic to subcaps using .ass files, sometimes they land with frame accuracy, and sometimes they don't (They'll be 1 frame late at most, and it does not increase over the span of the source clip).

  


  Curious if anyone has any ideas.

  


• How would I create a radially offset mosaic of rtsp streams that transitions to a logo

  18 juillet 2018, par Jack

  I’m new to stack overflow, but I’ve been researching how to do this for a couple weeks to no avail. I’m hoping perhaps one of you has some knowledge I haven’t seen online yet.

  Here is a crude illustration of what I hope to accomplish. I have a video wall of eight monitors - four each of two different sizes. The way it’s set up now, all eight monitors are treated together as one big monitor displaying an oddly shaped cutout of a desktop.

  Eventually I need each individual monitor to display a separate RTSP stream for about thirty seconds, then have the entire display - all eight monitors in conjunction - to fade out into a large logo.

  My problem right now is that I don’t know of a way to mask an rtsp stream so it looks like this rather than this, let alone how to arrange them into a weirdly spaced, oddly angled, multiple aspect-ratio mosaic like in the original illustration.

  Thank you all for your time. I’m just an intern here without insane technical knowhow, but I’ll try to clarify as much as I can.

  -J