Flac - Mono Vs. Stereo Options

[Azevedo]

Hey everyone,

I have this audio source in stereo FLAC+CUE and used CUETools (libflake max compression) to split the CUE/FLAC into single tracks
Then, AS THE ORIGINAL CD IS MONO I converted the STEREO FLAC to MONO FLAC using sox:

sox.exe stereo.flac -C 8 mono.flac channels 1

The results:

Stereo:

CODE

Format                                   : FLAC
Format/Info                              : Free Lossless Audio Codec
Duration                                 : 3mn 22s
Bit rate mode                            : Variable
Bit rate                                 : 507 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 44.1 KHz
Bit depth                                : 16 bits
Stream size                              : 12.2 MiB (99%)
Writing library                          : Flake#0.1

Mono:

CODE

Format                                   : FLAC
Format/Info                              : Free Lossless Audio Codec
Duration                                 : 3mn 22s
Bit rate mode                            : Variable
Bit rate                                 : 353 Kbps
Channel(s)                               : 1 channel
Sampling rate                            : 44.1 KHz
Bit depth                                : 16 bits
Stream size                              : 8.51 MiB (100%)
Writing library                          : libFLAC 1.2.1 (UTC 2007-09-17)

Now I have these questions for you folks:

1. After these operations, the mono Flac audio still losslessly 'original'?
2. Why didn't I get 50% space saving when using -C 8 compression level?
3. Is it recommend to scan replay gain and store int on the flac's tag?
4. Is it recommended to encode flac audio in mono out of DUAL MONO?
I mean, dual mono isn't it such a waste?



Thanks

This post has been edited by Azevedo: Oct 20 2012, 14:48

[chi]

Then, AS THE ORIGINAL CD IS MONO I converted the STEREO FLAC to MONO FLAC using sox:
sox.exe stereo.flac -C 8 mono.flac channels 1

1. After these operations, the mono Flac audio still losslessly 'original'?

If the original CD really is mono (left channel = right channel), then more or less: SoX will have re-dithered the output. It had been better to use remix 1 instead of channels 1.

2. Why didn't I get 50% space saving when using -C 8 compression level?
4. Is it recommended to encode flac audio in mono out of DUAL MONO?
I mean, dual mono isn't it such a waste?

FLAC exploits similarities between stereo channels. So, when you hand it a “stereo” file that’s actually dual mono, it will essentially compress the second channel down to nothing.