i recall reading somewhere that it's recommended to use -mm to encode recordings that were made in mono in order to save bits. it made sense to me, why reserve space for two channels when the source only contains one.

but when i tried --alt present standard -mm, it made a cbr 128 file in mono.

any suggestions or can i not have a good vbr mono encode?

you might find some info here: http://www.hydrogenaudio.org/forums/index....f=15&t=4042&hl=

Try this:

--alt-preset standard -b32

I think the reason you got a "CBR 128k" file is because --aps never usually encodes lower than 128k (except for digital silence). The above might well give you a lower bitrate, but check the quality & make sure it isn't messed up.

I believe Dibrom suggested --alt-preset standard -b80 for mono files, so I've been using that for any songs I have that are mono. I actually converted them to a mono .wav beforehand too, though I don't know if that is strictly necessary or not

Thanks for the links and suggestions. First of all it *seemed* like a cbr 128 file but it was actually a vbr file that didn't vary much (99% 128 frames, 1% 32 frames).

Shorty, I too was curious if I needed to convert the wav to mono in soundforge since the ripped cd track is still technically stereo (even though both channels are identical).

So I tried both ways: the resulting encode (after soundforge's mono conversion, then not using -mm) was the same as not using soundforge (ie using the "stereo" wav) and encoding with -mm.

In both instances my savings ended up being only 400k (down from a 4mb stereo encode of a mono track) but over many discs it will be appreciated.

One thing I'm wondering is, why is it that very little is deemed worthy of over 128 bits in lame's mono vbr world? Is it the difference between channels that requires high bitrates? For example, i tried encoding several loud, modern stereo recordings with plenty of high frequencies and transients with the --aps -mm switch and the best i could get was 91% 128 frames, 6% 160, and the rest 32, averaging 128. The normal --aps hits all the high bitrate frames like usual, ending up with a average 210kbps. Just something i noticed.

Thanks for the input.

BTW, I experimented some with mono files this morning, and found that --alt-preset standard -b96 seems to work the best for me. SQ is uniformly good, and file size is approximately 50% of stereo, which is what you'd expect given 50% less information to encode.

Also, the above uses all "standard" frame sizes, whereas I got a lot of 80kbps frames using Dibrom's suggested -b80 (suggests potential compatibility issues).

Edit -- "One thing I'm wondering is, why is it that very little is deemed worthy of over 128 bits in lame's mono vbr world?" My guess is that higher bitrates aren't needed... we're talking about mono (half the information), so double that and you'd get 256kbps... which is quite a bit higher than --aps averages on most stereo files.

BTW:

when using joint stereo, Mono recordings should be encoded in midband only ... or did I get something wrong ?

80kbit/s is a standard Bitrate (I think that's what you mean).