flac compression/size discrepancies

[JJZolx]

When you say compare those files, do you mean compare the file size and percent compression? Or is there a software to compare something more detailed?

I just meant compare the Flac file size and compression.

[nelce]

so i took my ripped flac file and the downloaded flac file. decoded both to wav. re-encoded both wav files using the same flac encoder. my flac file ended up being 12.1mb and 74% compressed. the downloaded flac ended up being 23.4mb and 46% compressed. these numbers are about the same as the original flac files. so what does this mean?

[JJZolx]

Sounds like the audio in the two files is nothing alike. Are you sure one isn't mono and one stereo?

[nelce]

well according to the file it says they are both stereo. here are the comparisons below:

my file:

size: 12.13 mb (72% compressed0
original size: 42.72 mb
length: 4 mins 13 sec
channels: 2 (stereo)
sample rate: 44.1 Khz
sample size: 16 bit
bit rate: 1,411 kbps
encoder: FLAC reference libFLAC 1.2.1 20070917
audio quality: perfect(lossless)

their file:

size: 23.43 mb (46% compressed0
original size: 42.72 mb
length: 4 mins 13 sec
channels: 2 (stereo)
sample rate: 44.1 Khz
sample size: 16 bit
bit rate: 1,411 kbps
encoder: FLAC reference libFLAC 1.2.1 20070917
audio quality: perfect(lossless)

these are the files after i decoded to wav and reencoded to flac with the same program

[nelce]

here's another track from a completely different album that i ripped to flac, vs the same track encoded to flac by somebody else that i downloaded.

my flac: 13.27mb (75% compressed)
their flac: 25.87mb (51% compressed)

after converting both to wav, and reencoding to flac with the same program:

my flac: 13.46mb (75% compressed)
their flac: 25.9mb (51% compressed)


the common theme here seems to be that my cd rips to flac always seems to be significantly more compressed and smaller in size than any of these rips i'm downloading...

just curious as to what's going on...

[JJZolx]

Wikipedia has this to say about mono recordings on CC:

The Red Book CD specification includes two channels by default, and so a mono recording on CD either has one empty channel, or else the same signal being relayed to both channels simultaneously.

So ripping a mono recording on CD would still have two channels if it has the same signal on both channels. I'd also expect the Flac encoder to pick this up and compress accordingly.

Is it an older recording that may have been issued in both mono and stereo? This was fairly common in the early to mid 60s. I don't know if anyone is issuing anything other than spoken word CDs such as audio books in mono anymore.

[nelce]

I don't believe so. It's a Rachael Yamagata track...so should be modern. The other track was a Damien Rice track, once again modern. I don't believe either of those artists have released anything in mono.

It's so strange because I've been doing some searches, but nobody seems to be having this issue!

[JJZolx]

Can you email me those last two files? jim at zolx dot com

[nelce]

which two? sorry, just want to be sure i'm emailing the correct files

[JJZolx]

The second one you ripped and downloaded.