Slightly lossy codec that doesn't lowpass audio?
Reply #38 – 2015-10-31 05:16:56
While we are at ADPCM, it would be still useful for videos where I wouldn't like to use MP3. I wonder if someone could help with FFmpeg command line parameters, i.e. how to encode a PCM wav file to ADPCM... and perhaps some quality settings? Hope you're still around. I have actually been working with ADPCM a lot recently (for an industrial application) and was able to use avconv (which should be the same as ffmpeg) with this command: avconv -i input.wav -acodec adpcm_ima_wav -trellis 4 output.wav The "trellis" parameter controls the amount of "lookahead" done. It can improve quality, but can get really slow at higher values (I think it accepts 1-16). I have also just finished up my own IMA ADPCM encoder / decoder which incorporates the same "dynamic noise shaping" as WavPack lossy, plus my own version of "lookahead" (which can also get very slow). I am attaching a binary if you'd like to try it out. I have been getting very high quality output from it, and it's a little easier to use than ffmpeg because it only does one thing (well, two). BUT, as others have said, ADPCM is not going to give you transparent results with 44.1 kHz source...it's easy to hear artifacts from time to time and there's no way to fix them. My version is slightly better than what's out there (I think), but it's still not good enough for serious listening. The only good thing about ADPCM is that everything seems to play it! edit: fixed "codebox"...thanks lvqcl!
Last Edit: 2015-10-31 16:52:37 by bryant