HydrogenAudio

CD-R and Audio Hardware => Vinyl => Topic started by: hciman77 on 2008-12-21 17:55:11

Title: Does FLAC compress more aggressively with 24/96 rips of vinyl ?
Post by: hciman77 on 2008-12-21 17:55:11
I was reading a discussion in another forum about FLAC and 24/96 PCM vinyl rips. The poster was bemused that FLAC was able to get 70% compression of these vinyl rips.

My thought was that there would be more data redundancy on a 24/96 rip of vinyl for FLAC to exploit. Given that a LP might only have a dynamic range of =< 80db and a 24 bit rip allows up to ~ 144db then FLAC could be more concise as it were. Am I hopelessly off target here ?
Title: Does FLAC compress more aggressively with 24/96 rips of vinyl ?
Post by: SoleBastard on 2008-12-21 18:07:31
Well, your idea is right and it applies most definitely with a lossy encoder with reasonable settings (e.g. lame -V 2). FLAC is known to behave very poorly with 24bit/96kHz sources. I have encoded dozens of DVD-A and Blu-ray with FLAC and 70% compression is quite normal. Actually it is on the small side so I guess your theory is correct but in a more conservative way than you might have hoped for 
Title: Does FLAC compress more aggressively with 24/96 rips of vinyl ?
Post by: itisljar on 2008-12-22 07:32:55
I got some 24/96 vinyl rips from the 'net (shame on me), to test just that. It seems that the compression ratio for these high quality files is less than when encoding CD audio, and I guess that is because in 24/96 files there is much more audio data to compress.

Ivan
Title: Does FLAC compress more aggressively with 24/96 rips of vinyl ?
Post by: Axon on 2008-12-22 08:10:24
The increased noise levels (particularly in the ultrasound) wreak havoc on lossless compression levels.

The solution, of course, is lossyWAV.
Title: Does FLAC compress more aggressively with 24/96 rips of vinyl ?
Post by: bandpass on 2008-12-22 13:25:18
Or just save as 16-bit FLAC---you'll only be discarding noise.
Even 15-bit is probably enough for vinyl: norm. to -6dB, dither to 16-bit, then FLAC.

  -bandpass
Title: Does FLAC compress more aggressively with 24/96 rips of vinyl ?
Post by: pdq on 2008-12-22 16:11:32
Or just save as 16-bit FLAC---you'll only be discarding noise.
Even 15-bit is probably enough for vinyl: norm. to -6dB, dither to 16-bit, then FLAC.

  -bandpass

Or, as Axon said, use lossyWAV and then the 24 bit FLAC will take up less space than the 16 bit FLAC without lossyWAV would occupy.