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• Record rtsp stream to a file to be played later

  16 avril 2021, par Саня Рыбалко

  everyone.
  
I have a UWP app, which can stream rtsp streams from online ip cameras by means of FFmpegInterop NuGet package. This is how I use the FFmpegInteropMSS object to set mediaElement's source to the rtsp stream :
  

  


          FFmpegInteropMSS ffmpeg = await FFmpegInterop.FFmpegInteropMSS.CreateFromUriAsync("rtsp://88.84.52.66/axis-media/media.amp");
        MediaStreamSource streamSource = ffmpeg.GetMediaStreamSource();
        mediaElement.SetMediaStreamSource(streamSource);
        mediaElement.Play();


  


  But I have run into a problem - I need to make it possible to record the stream in a local file to be played later. I have found out this is possible while using ffmpeg console, but I would prefer to use some c# tools(not only FFmpegInterop library) to do it.
  
Thanks for your help in advance.

  


• Videos encoded by FFMPEG (mpeg codec) cannot be played on iOS14

  28 septembre 2020, par vanste25

  I have a piece of code that uses ffmpeg with default mpeg codec to merge multiple videos and audio songs.

  


  ffmpeg -i input1.mp4 -i input2.mp4 -filter_complex "concat=n=2:v=1:a=1" -f MOV -vn -y output.mp4


  


  Everything worked on iOS13 and after the update to iOS14, videos are black and cannot be played by any player. Sound is there and it's good.
I tried to switch to h264 and it works good, but as you already know, h264 is under GPL and it is expensive and requires code to be open sourced which is not acceptable for me.

  


  What was changed ? Anything in release notes ?
Is that a bug ? Or a feature ?

  


  Thanks

  


• h.264 video in mp4 container jumps when played in VLC

  30 avril 2013, par Jayanth Nayak

  I have H.264 video and AAC audio generated in Andriod phone recieved wirelessly using SIP protocol and muxed using FFMPEG APIs, The generated mp4 when played through VLC or other player is never in Sync.
  when I see the time bar of Video, it skips after a certain duration.

  For example :
  in a video of 20s, the time bar seeks upto 14s properly, then it jumps to 18s and finishes at 20. The audio plays properly.

  I have following questions :

  1. Is PTS DTS calculations really required for muxing WITHOUT Encoding ? :

  we used

  PTS = (90000 * (1/FPS) * FrameNumber) - although this did not work :(

  currently FFMPEG is taking care of it internally.

  ---

  1. Why the video jumps ? is it because of less number of frames or wrong PTS values or something else ?

  ---

  1. For the following cases although There is jump, I am getting a good AV sync
     -15,20,25 FPS qCIF & AAC Audio

     But for 15 & 20 FPS of qVGA & VGA the audio lags by 0.5 seconds and for 25 FPS, the Video is just playing fast.
     thus why is there a delay for qVGA and VGA but not present for qCIF ? any dependency of Resolution on Time Stamp (PTS) calculation ??

     Analysis of 25 FPS Video showed that there are enough number of frames for 10s but the total time for the video shown by VLC is 14s. Why is this so ? and again, this video also jumps from 9s to 13s.