Vorbis Encoders

Vorbis-OptSort

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

AoTuV encoders are optimized encoders for higher quality.

• AoTuV beta2 was adopted as a part of Vorbis 1.1 of Xiph.Org.
• AoTuV beta4 improved 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.
• The latest release is AoTuV beta 4.51, which improves quality at q<3 (versus AoTuV beta4).
• The latest test release is aoTuV pre-beta5 [20060321].

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:

http://audiotests.free.fr/tests/2005.07/80/80TEST_PLOTS_04.png

 "  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:

http://audiotests.free.fr/tests/2005.07/96/96TEST_PLOTS_04.png

• 180Kbps comparison of many audio codec on classical music

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.

• Home page (Japan)
• Home Page (google traduction)
• Home Page (English, not up to date)