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• Envelope pattern in SoX (Sound eXchange) or ffmpeg

  26 mai 2016, par pJay

  I’ve been using SoX to generate white noise. I’m after a way of modulating the volume across the entire track in a way that will create a pattern similar to this :

  White noise envelope effect

  I’ve experimented with fade, but that fades in to 100% volume and fades out to 0% volume, which is just a pain in this instance.

  The tremolo effect isn’t quite what I’m after either, as the frequency of the pattern will be changing over time.

  The only other alternative is to split the white noise file into separate files, apply fade and then apply trim to either end so it doesn’t fade all the way, but this seems like a lot of unnecessary processing.

  I’ve been checking out this example Using SoX to change the volume level of a range of time in an audio file, but I don’t think it’s quite what I’m after.

  I’m using the command-line in Ubuntu with SoX, but I’m open to suggestions with ffmpeg, or any other Linux based command-line solution.

• ffmpeg convert mp4 video to rgba stream

  6 juin 2020, par Karric

  I'm looking to process the frames of an mp4 video as an rgba matrix, much like what can be done with HTML5 canvas.

  



  This SU question/answer seemed promising : https://superuser.com/questions/1230385/convert-video-into-low-resolution-rgb32-format

  



  But the output is not as promised. A 800KB mp4 file produced a 56MB out.bin file that seems to be gibberish, not an rgba matrix.

  



  If anyone can clarify or provide alternate suggestions, that'd be great.

  


• Bluemix node js build pack to support webm speech to text conversion

  22 août 2018, par Nimmy Mohandas

  Even after adding ffmpeg to bluemix node js build pack(I tried this https://github.com/BlueChasm/nodejs-buildpack-ffmpeg), it doesn’t support webm audio format conversion.Could anyone please suggest alternate ways to support this issue ?