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• Improve LPC order guess

  3 décembre 2014, par Martijn van Beurden

  Improve LPC order guess
  The recent compression preset retuning improved upon most material
  
  but it the few tracks that show regression are usually classical
  
  music. This patch improves compression by improving the LPC order
  
  guess, of which classical music benefits most.
  Improvement is 0.007% on average but up to 0.1%. I haven’t seen
  
  regressions for any of my test samples.
  Signed-off-by : Erik de Castro Lopo <erikd@mega-nerd.com>
  

  • [DH] src/libFLAC/lpc.c

• Convert m3u8 File URL to a GIF File [closed]

  30 juin 2023, par nxsi

  I have a m3u8 File URL that I got using the MusicKit API (Apple Music) which is an animated cover art for an album. (A quick side question on that. Is m3u8 the only format that Apple Music returns for animated cover arts ?)

  


  So, Now that I have that m3u8 file URL, I want to convert it to a GIF for the ease of use of GIFs.
I've tried using ffmpeg but I don't really seem to make it work at all with NodeJS.

  


  Here is a sample File URL of what Apple Music returns (https://mvod.itunes.apple.com/itunes-assets/HLSMusic116/v4/cb/ac/9e/cbac9e42-0c8a-9798-0016-52ce447cdc78/P359486356_default.m3u8)

  


  TLDR ;
1- Is m3u8 the only format of animated cover arts that the MusicKit api returns ?
2- Can I convert that m3u8 file URL to a GIF, If so, How ?
3- Are there any other ways than ffmpeg to use in NodeJS ?

  


  I've tried using ffmpeg and the furthest I got was a GIF that was corrupted and not done correctly.
Here is the command I tried :

  


  ffmpeg -i "https://mvod.itunes.apple.com/itunes-assets/HLSMusic116/v4/cb/ac/9e/cbac9e42-0c8a-9798-0016-52ce447cdc78/P359486356_default.m3u8" -vf "fps=10,scale=320:-1:flags=lanczos" output.gif


  


• FFmpeg amix + volume filters create saturated output ?

  1er septembre 2021, par Sonia Seddiki

  


  First of all, this is a question asked more out of curiosity than desperate need of fixing. I seem to have "fixed" it by upgrading from FFmpeg 3.4.6 to FFmpeg 4.3.1. Or so I think, at least the result is much better.

  


  


  I'm trying to mix 2 audio files (of the same length, so no scale variation here) using FFmpeg amix filter :

  


  

  • A music which starts pretty loud in the beginning and then is almost quiet until the end,

  


  • An audio that starts with silence (basically as long as the music is loud), then continues with a person speaking at an "average" volume

  


  


  Now, I learnt that the filter will divide each input volume by 1/nb_active_inputs (by 2 in my case then), so I added a volume filter on the output to multiply its volume by 2. My command basically looks like this :

  


  ffmpeg -i music.mp3 -i voice.mp3 -filter_complex amix=inputs=2:duration=first[mix];[mix]volume=2[out] -map [out] output.mp3


  


  After that complex filter, my final output is completely distorted. The voice sounds overall very loud and saturated.

  


  I'm not an expert with audio nor with FFmpeg so I assume I'm missing something. I'm trying to understand what is going on and why I am having this result since I use the same inputs, filters and filter options in both cases. Only the FFmpeg version differs.

  


  I've tried to read the code of af_amix.c for both versions but can't seem to find any explanation for that difference. I've seen that the 4.3.1 has a weights option for inputs but from what I understood, they default to 1.0 if not specified. Any clue would be much appreciated.