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GreatKent
13th December 2004, 05:35
Is there any software can down-mix mp3 from stero to mono without re-encoding? Thx!!!
KpeX
13th December 2004, 05:57
Not that I know of, and it is probably not possible (losslessly) if the file is joint stereo, which the vast majority of mp3 encodings are.
GreatKent
13th December 2004, 08:51
Right, the file is joint-stereo.
The audio was recorded by a small portable mp3 player & there is only one mic on it. However my schoolmate set the record mode to 128kbit joint stereo. I suppose the left & right channels must be identical coz they both come from the same source. That why I am thinking of dropping one of the channels.
Slogra
13th December 2004, 21:47
Well, your mp3 probably uses Mid/Side stereo (a type of jointstereo). Then you probably won't gain much by throwing away one channel. Because with the Mid/Side method you store the Mid channel (the similarities of both channels) and a side channel (the differences of both channels). If your sound is really recorded as mono then the Mid channel will use all bits and the Side channel no bits. So you're already using the bits optimally.

I hope that made sense :p
GreatKent
14th December 2004, 08:15
I see. Unfortunately the file was recorded in CBR mode, the size is not reduced by using joint-stereo. I decided to leave the file alone coz the size isn't really too big anyway.
Thank you very much for all you help^^:thanks:
Slogra
14th December 2004, 17:37
Did i say anything about CBR/VBR? I think you misunderstood.

I meant to say that mono sound will sound better in joint-stereo, because it will "recognize" the mono sound as one channel and it will use all 128kbps for that one channel (the Mid channel).

While simple stereo mode just sees 2 channels and will give each of the two channels 64kbps, so it will sound worse.
GreatKent
14th December 2004, 23:34
Well..... you're talking about the sound quality while I interpreted it as file size. Sorry about that.
I think you are right, if my schoolmate set it to mono-mode instead of joint-stereo during recording, the sound quality would have been improved alot. But now it seems now much thing can be done. Thank you again for your help:)