Recherche avancée

Sur d’autres sites (3504)

• Extract closed captions VTT from stream using ffmpeg

  15 avril 2021, par EK0

  I can extract closed caption information from an mp4 file using ffmpeg v. 3.4.7 thus :

  


  ffmpeg -f lavfi -i movie="sample.mp4[out+subcc]" -map 0:1 -c:s webvtt /tmp/output.vtt


  


  The file was obtained by capturing a live HLS stream containing closed captions. I would like to extract the closed captions directly from the stream, instead after storing the video in a file. I've tried various things, including :

  


  ffmpeg -f lavfi -i movie="http://example.com/stream.m3u8[out+subcc]" -map 0:0 -c:s webvtt /tmp/output.vtt


  


  But the movie filter does not recognize the URL, even though the ffmpeg filter documentation says that the file name for the movie filter is "not necessarily a file ; it can also be a device or a stream accessed through some protocol" :

  


  


  [Parsed_movie_0 @ 0x264ad80] Failed to avformat_open_input 'http'
  
[lavfi @ 0x2647e80] Error initializing filter 'movie' with args 'http://example.com/stream.m3u8' ;
  
movie=http://example.com/stream.m3u8[out+subcc] : No such file or directory

  


  


  When I capture the video form the stream like this :

  


  ffmpeg -i http://example.com/stream.m3u8 /tmp/output.mp4


  


  ffmpeg reports that the stream does contain closed captions (which is where the captured video file sample.mp4 got them) :

  


  


  Stream #0:0 : Video : h264 (High) ([27][0][0][0] / 0x001B), yuv420p(tv, bt709), 480x270 [SAR 1:1 DAR 16:9], Closed Captions, 14.99 fps, 14.99 tbr, 90k tbn, 29.97 tbc

  


  


  Is it possible to do this ? Thanks for any pointers.

  


• Stitching 6 video files into one 360 video in Ubuntu Linux

  1er mai 2020, par Essam Gouda

  I used 2 raspberry PIs to record 2 different videos in sync using a OSC server so the videos are perfectly in sync and I send them to a Linux server so I can stitch these videos and produce one 360 video file so far I have tried doing that on 2 videos just for testing purposes using two methods :
1- only ffmpeg :
By simply concatinating two videos into one but this doesn't produce a 360 video as seen here

  



  2- using ffmpeg and hugin following this tutorial (https://medium.com/@xorgol/stitching-multi-camera-360-video-an-open-source-workflow-bb8b1e72925) :
The problem here is I needed to do this method on each video file I have and then concatenate both videos to produce this result

  



  The original video can be seen here its captured using the RPI camera module V2 using a lens that provide a resolution of 3280x2464.


  



  I don't mind a bit of overlapping or anything I just need to produce a 360 video from 2 videos using two vamera with 180 degrees FOV and be able to view them using a 360 video player so your help is appreciated.

  


• Sync Video Multitrack Recording (with video.js and FFMpeg ?) [closed]

  28 avril 2020, par finnk

  I am writing a web application that gives the ability to record multiple videos and merge them into a single split-screen video. The videos have to be synchronous with each other, so if the user had already recorded a video, it will playback on the next recording. So the captured video(s) play(s) while recording.
Right now, I implemented it by using video.js and videojs-record. 
I merge the videos server-side using FFmpeg( client-side would be much better, but I didn't figure out how to achieve this)

  



  When I start the record, the playback of each recorded video begins as well. 
This approach produces, of course, a small latency between the videos.

  



  Any suggestions on how to sync the recordings ?

  



  Do you know ay better other libraries ?

  



  Thank you & Best regards,