If I'm ripping mono CDs...

[forgotten_hell]

Do I need to do anything different in EAC? I use LAME to encode it through EAC as V0, and when I put it in iTunes for syncing I wanted to see what it said for the bitrates and noticed the mono CDs were listed with a significantly lower bitrate than the stereo ones (obviously it said VBR beside it but still). Am I doing something wrong or misunderstanding something? I'm new to this whole world of EAC and getting really good rips and stuff.

Thanks.

 

[Ham Sandwich]

LAME automagically does the right thing when it detects that the audio is mono. No need to change anything. The bitrate of the mono files will be less as there is less audio to encode, but the sound quality should still be the same as the other V0 files.

 

[dura]

I think it is the joined stereo option of VBR; what it seems to do is check if the L+R channel are identical (which of course they are in mono) and record the double signal only once. Clever way of extra compression without extra loss.

 

[somestranger26]

Quote:

Originally Posted by dura /img/forum/go_quote.gif I think it is the joined stereo option of VBR; what it seems to do is check if the L+R channel are identical (which of course they are in mono) and record the double signal only once. Clever way of extra compression without extra loss.

Actually it just encodes it in mono, not joint stereo. Note the available options for LAME in dBpoweramp:

Quote:

Originally Posted by Ham Sandwich /img/forum/go_quote.gif The bitrate of the mono files will be less as there is less audio to encode, but the sound quality should still be the same as the other V0 files.

Approximately half the bitrate is typical for mono, so ~160kbps or so for V0.

 

[Slogra]

I would be very surprised if it actually uses mono. That would mean it has to go through the whole file to detect if the channels are exactly the same. I don't think any software will do that.

Standard is joint stereo. This means it will use both joint stereo for mono-isch frames and stereo for frames with huge channel differences.

To explain the other lame options:
Mono will only use one channel.

Forced joint stereo means it uses joint stereo, even for frames which have big differences in each channel (where stereo would be more logical).

Stereo means that each channel is encoded seperately, but when one channel is harder to encode more bits will go to that channel, and less to the other.

Dual mono will use the same bitrate for each channel. I.e. for a 128kbps cbr mp3 it will use exactly 64kbps for each channel.

 

[Ham Sandwich]

Quote:

Originally Posted by Slogra /img/forum/go_quote.gif I would be very surprised if it actually uses mono. That would mean it has to go through the whole file to detect if the channels are exactly the same. I don't think any software will do that.

All the encoder would care about is if the block of audio that it is currently encoding is mono. It doesn't care about the rest of the file. The file could start out mono and switch to stereo in the middle and LAME (with the standard presets) would encode the first half as if it is mono and switch to stereo for the rest.

 

[leeperry]

FLAC -8 will detect dual mono automatically and compress in mono

I realize you wanna do mp3's, but mp3's lose bits overtime...you need to realize that: http://www.head-fi.org/forums/f133/w...better-451369/

 

[Slogra]

Quote:

Originally Posted by Ham Sandwich /img/forum/go_quote.gif All the encoder would care about is if the block of audio that it is currently encoding is mono. It doesn't care about the rest of the file. The file could start out mono and switch to stereo in the middle and LAME (with the standard presets) would encode the first half as if it is mono and switch to stereo for the rest.

That is a nice idea, but I guess that is not possible within the spec of mp3, else it would've already be done by the lame developers.

 

[Ham Sandwich]

Quote:

Originally Posted by Slogra /img/forum/go_quote.gif That is a nice idea, but I guess that is not possible within the spec of mp3, else it would've already be done by the lame developers.

We're getting close to splitting hairs. The discussion started about ripping mono CDs. There's no such thing as a true mono from a CD rip. What you get are two identical channels in stereo. So for the purpose here we're working with mono that is actually stereo. In that case LAME will do its thing with joint stereo and the pseudo-mono tracks will get encoded at a lower bitrate (about half the bitrate) compared to a true stereo track.

If you're talking about true mono tracks then yes, the discussion is different and I'm not sure if any MP3 encoder or decoder could switch from true mono to true stereo in the middle of a file.

 

[SirDrexl]

Yeah, if you rip the stereo and mono versions of a song from the Beatles remasters, the WAVs are the same size because the mono is really two of the same channel. However, if you compress each WAV to FLAC, the resulting mono file will be smaller than the stereo file, more than half the size but still much smaller.

For example, "Nowhere Man" sizes are:

Mono WAV and stereo WAV: 28MB each
Mono FLAC: 10.5MB
Stereo FLAC: 17MB

That's another benefit of lossless compression: the ability to recognize redundancies and adjust for them without affecting quality.