Vorbis-OptSort improves source code of the Vorbis codec library (libvorbis-1.0) to accelerate encoding time about 10% (not apply clean on 1.1.2).
AoTuV encoders are optimized encoders for higher quality. AoTuV beta2 was adopted as a part of Vorbis 1.1 of Xiph.Org. The latest release is AoTuV beta 4.51 which improves quality at all bitrates (versus xiph.org 1.1.2) and can also go down to 32 Kb/s (q-2). Note that this patch also include the Vorbis-OptSort patch. Quality test of AoTuV beta4 vs. libvorbis 1.1.1:
- 80Kbps comparison of many audio codec and libvorbis 1.1.1 vs. AoTuV beta4
- libvorbis 1.1.1 ABR vs libvorbis 1.1.1 VBR vs AoTuV beta4 VBR summary:
" on group1, all encoders are tied (although aoTuV is better than 1.1.1 with 90% confidence). It’s a disappointment for me, because I’ve seriously expected from aoTuV to reduce the level of coarseness/fatness on this specific musical genre. However, slight improvements were often perceptible – it’s better than nothing. With some samples, a slight regression was also perceptible: additional distortion or apparently restrictive lowpass (noticed with harpsichord). Interesting to note that ABR doesn’t perform badly, except on critical samples (bitrate stayed at ~85 kbps when VBR encodings reached 160!); ABR also sounded a bit better with some samples (tonal one). Good point to ABR (just note that encoding speed is dramatically slow compared to VBR). on group 2, differences are much more defined. ABR appeared as clearly worse than VBR and aoTuV beta 4 outdid 1.1.1 on VBR mode. Obviously, the changes Aoyumi made on vorbis are much more effective on various music. on average, aoTuV beta 4 was better than 1.1.1 (not a surprise I would say)."
"Vorbis (aoTuV beta 4, VBR –q 0,9): this is by far the most enjoying thing I’ve heard at this bitrate. I was highly surprised by results I’ve got with the 150 classical samples; I was literally astonished by the final score obtained with the 35 remaining samples! Vorbis is obviously an amazing tool at this bitrate." guruboolez
- 96Kbps comparison of many audio codec and libvorbis 1.1.1 vs. AoTuV beta4 (french)
- Google traduction
- libvorbis 1.1.1 vs AoTuV beta4 summary:
- Comment on AoTuV beta 4:
"Vorbis: Vorbis is now –thanks to Aoyumi– an excellent audio format for 180 kbps encodings (and classical music). It has apparently no flaws (lowest note was 3.5) but only minor problems audible from time to time: additional noise, fatness, or softened details. One third of the tested samples are transparent to my ears with aoTuV encodings. My own limits are close to be reached." guruboolez
"Vorbis: Vorbis is now impressive. Last year constant noise boost or coarseness spoiled the performance of this format. I was surprised to hear those problems on –q6,00 setting supposed to be free of them due to lossless coupling. Aoyumi has apparently identifies precisely the cause of this problem and he worked to solve it. Not entirely though: some remaining trails are still audible with few samples but the intensity is now really frail (at least on the tested samples). Other artifacts are also corrected: micro-attacks on Orion_II (sample 09) are now much less dusty (aoTuV performed even better than any other tested format at this bitrate!). Performance are remarkable and the slightly gain in bitrate consumption is the icing on the cake. Just a question: Does aoTuV mean Tuned for Victory? Or Tuned by Visitors? From what planet is Aoyumi coming from? By the way, I wouldn’t say anymore than Vorbis is not mature enough. At least not for classical, which appeared to be a weak point for this format" guruboolez
Optimized Ogg Vorbis Encoders
These encoders are highly optimized encoders developed by the Ogg Vorbis Acceleration Project that are much faster than the standard builds with negligible to no effects on audio quality.