VBR vs. ABR in post-3.90 LAME's

[Rhaegar Targaryen]

Would anyone care to explain how/why ABR is superior to VBR in the newer LAME's? It sounds like that for bitrates between 120 and 150 (exactly what we want for DivX audio tracks) ABR nets superior overrall quality results compared to VBR. How exactly is this possible, when the range of ABR is 112 to 160, while VBR is allowed to use the whole spectrum, say from 96 to 320?

Of course, when I say ABR I am referring to "--alt-preset xxx", xxx=120-150.

[LotionBoy]

VBR is tweaked for high bitrates. Limiting the bitrate messes up the file-size and the quality is not as good. the boys over at www.hydrogenaudio.com recomend ABR for low bitrates and since Dibrom over there wrote the alt settings, I am inclined to believe him. Check the forum over at hydrogen for more discussion on this.

LotionBoy

[tangent]

Theoretically, VBR should be better than ABR if implemented properly. Low bitrate VBR for lame isn't exactly implemented properly because the VBR algorithm used isn't suited for lower bitrates. I haven't seen any reports on exactly why this is so, but I do know that to lower the bitrate, -V raises the ATH curve, not exactly the optimal solution.

So for now, I would use --alt-preset standard for ~192kbps, --alt-preset extreme for ~256 kbps, and --alt-preset <bitrate> for anything below 192kbps.

http://www.hydrogenaudio.org/forums/showthread.php?s=&threadid=260

If you really want good VBR implementation at all bitrates, high or low, try Ogg Vorbis -q settings.

[ChristianHJW]

We are not far away from being able to use Vorbis in our DivX movies. AVI format is probably not the best one for this ( doesnt support VBR audio correctly ), so we are testing the Ogg format ( 1st implementation from Tobias W. ) with 1st stunning results and preparing a new L-GPL movie format ( TMF/MCS ) for the future ......