Recherche avancée

Sur d’autres sites (8305)

• find the timestamp of a sound sample of an mp3 with linux or python

  23 juin 2020, par cardamom

  I am slowly working on a project which where it would be very useful if the computer could find where in an mp3 file a certain sample occurs. I would restrict this problem to meaning a fairly exact snippet of the audio, not just for example the chorus in a song on a different recording by the same band where it would become more some kind of machine learning problem. Am thinking if it has no noise added and comes from the same file, it should somehow be possible to locate the time at which it occurs without machine learning, just like grep can find the lines in a textfile where a word occurs.

  


  In case you don't have an mp3 lying around, can set up the problem with some music available on the net which is in the public domain, so nobody complains :

  


  curl https://web.archive.org/web/20041019004300/http://www.navyband.navy.mil/anthems/ANTHEMS/United%20Kingdom.mp3 --output godsavethequeen.mp3


  


  It's a minute long :

  


  exiftool godsavethequeen.mp3 | grep Duration
Duration                        : 0:01:03 (approx)


  


  Now cut out a bit between 30 and 33 seconds (the bit which goes la la la la..) :

  


  ffmpeg -ss 30 -to 33 -i godsavethequeen.mp3 gstq_sample.mp3


  


  both files in the folder :

  


  $ ls -la
-rw-r--r-- 1 cardamom cardamom   48736 Jun 23 00:08 gstq_sample.mp3
-rw-r--r-- 1 cardamom cardamom 1007055 Jun 22 23:57 godsavethequeen.mp3


  


  This is what am after :

  


  $ findsoundsample gstq_sample.mp3 godsavethequeen.mp3
start 30 end 33


  


  Am happy if it is a bash script or a python solution, even using some kind of python library. Sometimes if you use the wrong tool, the solution might work but look horrible, so whichever tool is more suitable. This is a one minute mp3, have not thought yet about performance just about getting it done at all, but would like some scalability, eg find ten seconds somewhere in half an hour.

  


• ffmpeg split video H264 stutters on Windows Media Player

  9 mars 2019, par Juan Foegen

  I am converting and splitting wmv and mp4 into new mp4 files. I am using ffmpeg to do the conversion with simply :
  ffmpeg -i inputfile.wmv -vcodec libx264 -ss 00:00:10 -t 00:00:15 outputfile.mp4

  So when I create my split video it plays fine on other video players, like VLC, but stutters when initially playing on Windows Media Player and even shows a blank screen for a moment and then after about 5 seconds, the video will play normally. If I then select play again without reloading, Windows Media Player will play the video fine, with no stuttering.

  If I REMOVE the start parameter when doing the conversion, then the resulting video will play without issues on all my players, INCLUDING Windows Media Player.

  I have tried changing the frame rate, the bit rate and altered different optimization options mentioned here - https://trac.ffmpeg.org/wiki/Encode/H.264

  I need the split video to play on Windows machines on Windows Media Player and on the web streamed using the video element. This is why I chose H264 codec and MP4.

  Has anyone had issues playing ffmpeg split videos using H264 codec with Windows Media Player ? I am using the latest version of ffmpeg. Anyone have any other suggestions on any different settings I could try to adjust ?

  Thanks

• Possible to Combine Live m3u8 stream with PIP overlay from WebRTC source ?

  25 octobre 2015, par user1258530

  Can someone tell me what server-side technology (perhaps ffmpeg), one could use in order to :

  1) display this full-screen live-streaming video :

  http://aolhdshls-lh.akamaihd.net/i/gould_1@134793/master.m3u8

  2) and overlay it in the lower-right corner with a live video coming from a webRTC video-chat stream ?

  3) and send that combined stream into a new m3u8 live-stream

  4) Note that it needs to be a server-side solution - - - cannot launch multiple video players in this case (needs to pass the resulting stream to SmartTV’s which only have one video-decoder at a time)

  The closest example I’ve found so far is this article :

  https://trac.ffmpeg.org/wiki/Create%20a%20mosaic%20out%20of%20several%20input%20videos

  Which isn’t really live, nor is it really doing overlays.

  any advice is greatly appreciated.