How to recode AVI VBR->CBR mp3 lossless

[BitBasher]

I posted a brief tutorial over on the VirtualDUB forums on how I am able to recode (not transcode) VBR MP3 audio streams to CBR without loss.

FYI: http://forums.virtualdub.org/index.php?act=ST&f=4&t=14819&

This method works for me. It may not work with all VBR MP3 audio streams, but so far I've been successful. YMMV!

Bit.

[CWR03]

Without loss? That's not possible when you're going from one lossy format to another.

[squid_80]

As I understand it the format doesn't really change, just the bitrate - padded to be constant instead of variable.

[BitBasher]

Without loss? That's not possible when you're going from one lossy format to another.

I'll be a bit more specific. MP3 is a lossy format. Transcoding from one format to another typically results in more loss (loss of quality). Keep saving a JPEG image over and over and eventually it looks like crap.

Using MP3Repacker, you are not introducing MORE loss. That is, the recode itself is lossless and the resulting CBR audio stream has suffered no "noise" from a transcode.

Of course the original VBR MP3 audio track itself is lossy from whatever it came from - I can't change that - I can only try to keep 100% of it.

Bit.

[Irakli]

@BitBasher

Thanks a lot for sharing information about Mp3Packer! This is indeed wonderful program. I just tested it with with my lame -V 2 --vbr-new encoded file (208kbps avg. bitrate, or 6.62MB), which was turned into 256kbps CBR file (8.15 MB). I used foobar2000 with bit comparator plugin and two files are bit-to-bit identical. Conclusion: this program really works 100% losslessly!

Regards,
Irakli