Format : FLACFormat/Info : Free Lossless Audio CodecDuration : 3mn 22sBit rate mode : VariableBit rate : 507 KbpsChannel(s) : 2 channelsSampling rate : 44.1 KHzBit depth : 16 bitsStream size : 12.2 MiB (99%)Writing library : Flake#0.1
Format : FLACFormat/Info : Free Lossless Audio CodecDuration : 3mn 22sBit rate mode : VariableBit rate : 353 KbpsChannel(s) : 1 channelSampling rate : 44.1 KHzBit depth : 16 bitsStream size : 8.51 MiB (100%)Writing library : libFLAC 1.2.1 (UTC 2007-09-17)
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 11. 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?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.
Thanks chi. So let's see if i get it. Flac compress stereo like "joint stereo"? It has a mono stream with stereo differences L/R to produce the stereo from the mono?
Quote from: Azevedo on 20 October, 2012, 11:03:30 AMThanks chi. So let's see if i get it. Flac compress stereo like "joint stereo"? It has a mono stream with stereo differences L/R to produce the stereo from the mono?That's pretty much it. For 2 channel streams, FLAC encoders will try left/difference, difference/right, average/difference and independent, and will use the combination that makes the smallest frame.
Actually it depends on the encoder and settings chosen... libFLAC / flac / flac.exe will not try too hard to figure out the best stereo coding when using the -0, -1, -3, or -4 presets.I've never seen a CD with mono content that was truly mono (both channels identical). They always ran the mono signal through stereo media or gear on its way into digital, or they dither, so there's always some stereo background noise and slight variations in the channels. This is normally handled very well by mid-side coding. But if the signal is panned the least bit off-center, mid-side coding stops being efficient real quick, so you may find your converted-to-true-mono content compresses better in those situations.To answer the original question, no, changing a near-mono stereo signal into true single-channel mono is not lossless. It's only lossless if the two channels are identical. However it may actually make the sound more pleasant when you make it true mono. Sometimes the most appealing option is to just take one channel, whichever sounds better to you. Other times you may find it better to combine the channels; this tends to reduce the signal to noise ratio, but may result in some unappealing sound if the non-noise part of the audio is ever out of phase. And sometimes you may prefer not to make things mono at all... I find that when listening with headphones, true mono tends to sound "distant" to me, especially when it's played right after something in stereo. Some stereo noise, however unintentional it may be, actually helps...
This method with Audacity confirmed it is REALLY mono:http://forum.videohelp.com/threads/307834-...ual-Mono-Stereo
sox.exe file.flac -n remix -m 1,2i stats
Min level 0.000000Max level 0.000000Pk lev dB -inf