I've done a lot of testing and I hope this mailing list is the place to post as I find using forums tedius with my screen reading software as I'm blind. If any developers are interested in pursuing this I'd be happy to work with them. It appears that ffmpeg compression level 12 uses -l 32. I realize that ffmpeg uses it's own library for flac compression, but it still has to conform to flac standards. I have a library of pop, rock, and country of about 28,500 files. I've always used ffmpeg because generally it gave me better compression. With the release of flac 1.40 using -8 alone gave me better compression on about 21,000 files. adding -p made flac 1.40 do better on another 1,000 files or so. Adding --lax -l 32 made flac 1.40 do better on all but 113 files and adding -e (painful for time) do better on another 100 or so files. My conclusion is that ffmpeg's library is doing something that -e does, but not using a lot of CPU so perhaps this could be studied and flac could be updated to improve compression further with reasonable CPU usage. I have all of the files and could provide the ones where -e is necessary and the few where ffmpeg still does better with -8pe --lax -l 32. Please let me know how I can assist further. -- Michael D. Lawler email mailto:mdlawler at lawlers.us
Op di 27 sep. 2022 om 14:22 schreef Michael D. Lawler <mdlawler at lawlers.us>:> My conclusion is that ffmpeg's library is doing something that -e > does, but not using a lot of CPU so perhaps this could be studied and > flac could be updated to improve compression further with reasonable > CPU usage. I have all of the files and could provide the ones where > -e is necessary and the few where ffmpeg still does better with -8pe > --lax -l 32. >One important difference between libflac and ffmpeg is that they use different blocksizes. FLAC as you've used it will default to blocksize 4096 no matter what sample rate the input is. ffmpeg will adapt its blocksize to the samplerate. For 44.1kHz and 48kHz, it uses blocksize 4608. In the past it has been shown this benefits certain kinds of music, but the 4096 used by libflac does better for others. ffmpeg uses a larger blocksize for higher samplerates and a smaller blocksize for lower samplerates. This might be the reason you're seeing this difference. Perhaps you can find out what the sample rates are of the files that ffmpeg compresses better than libflac. If those are mainly 44.1kHz or 48kHz, you can try to improve on it with libFALC by adding -b 4608 Kind regards, Martijn van Beurden -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.xiph.org/pipermail/flac/attachments/20220927/f53b6111/attachment.htm>