The excellent performances of newer Nero AAC encoder (2.9.998 “fast”) lead me to compare it with other strong competitors. Unfortunately, there are not so many potential challengers.
• lame MP3: I’m using it every day, and though I like his new VBR mode (-V 5), I’m sure it’s not strong enough with my music to fully compete with the new AAC VBR encoder.
• wma9 PRO: I’m fond of this encoder, working very well with classical music. I don’t know how perform the newest 9.1 encoder. Unfortunately, two years after the first release of WMA9PRO, there’s still apparently no dedicated portable player supporting it (except maybe telephone or PDA). The industry is still manufacturing electronic components and players for standard WMA, which is not a very competitive format.
• ogg vorbis: since Aoyumi works, vorbis improved a lot (last year, with classical music, quality was behind lame ABR for my taste). aoTuV encoders (and now official 1.1) have drastically reduced the hiss/coarseness problems, which annoys me a lot with classical music (maybe other genres are affected too, I can’t really say). Unfortunately, the problem is only reduced, and not fully corrected. Nevertheless, I consider vorbis as one of the most robust format. Latest aoTuV beta 3, announcing an even lower coarseness level and a better pre-echo performance, could be a potential champion. I’d personally consider it a priori as the most dangerous challenger for strong AAC encoders.
I didn’t include wma9PRO in the following test. I don’t know that much this encoder: Is there one VBR profile close to ~130 kbps? Which one? Is it reliable, or is CBR/VBR2-pass a better solution? Answers are needed before including this format in a comparison test, and I don’t have time enough to answer them by myself.
Therefore, I’ve restricted the comparison to vorbis and Nero AAC. As encoder, I had some choice (official 1.1, megamix, aoTuV beta 2/3). I’ve privileged aoTuV encoder, because Aoyumi’s works are mainly focused on the most important vorbis problem (coarseness). I hesitated a moment between beta 2 and beta 3. I’ve finally opted for beta 3 without preliminary investigations: this test is a good occasion to see how reliable the new beta is, and if potential problems will handicap the format during this test, they will at last be detected, and probably quickly corrected.
I don’t know which vorbis setting would be the fairest to compete with Nero –internet. –q 4,00 is the roundest, and probably one of the most popular. In order to prevent (or at least to limit) some excessive difference, I’ve used –q 4,25. With my computer, I can’t obtain quickly a full and reliable bitrate table. But the comparison based on the tested samples is very satisfying:
- Nero encodings: 136,2 kbps
- aoTuV –q 4,25 encodings: 136,5 kbps
…hard to find closest settings :·)
The testing conditions (hardware, software, methodology…) are the same as those described in the global AAC comparison. Samples are also the same. One difference: I didn’t searched to ABX the difference between the encoded files and the reference ones (already done with all AAC encodings in previous test), but focused my efforts to a direct comparison between the two encoded files. Again, I’ve fixed a dual limit to the number of trials: eight if easy, sixteen trials if less easy. I have respected these limits, without any exception. First second of each sample was systematically discarded from listening.
Now, results:
vorbis aoTuV beta 3: Nice quality, but still coarseness issue. It’s fortunately limited, and with some samples, I simply can’t detect it (problem was systematically audible with older vorbis encoder). Very limited pre-echo problems: Aoyumi has apparently solved most issues in this area. However there is a deep ringing artefact with the organ (Bruhns) sample. I’ve in addition noticed a very strange problem, occurring with solo violin on two different samples (Avison first, and then Mozart-Sonata): it sounded like a noise-reduction processed recording, but additional hiss was audible on the same time. This paradox also happened to the old experimental Quantum Knot’s encoder (v. 3.5 aka vorbis “classical edition”). I don’t know: maybe Aoyumi did similar tuning to aoTuV beta 3? I had to investigate further…
compared to Nero AAC: better with harpsichord (note that aoTuV allocates even more bits for this instrument than Nero AAC!) on Couperin and Bach (excellent encoding) samples. I’m badly surprised by poor performances on Bayle sample: I’d expect from a VBR encoder to detect the difficulty (micro-attack). With aoTuV, both bitrate and quality are low… Noise/hiss/coarseness are like a signature with most samples, and often betray vorbis presence.
STATISTICS
You could try with the following table:
NERO AOTUV
4,0 2,0
4,5 4,5
5,0 3,5
4,5 3,5
4,5 1,5
5,0 5,0
3,5 2,5
3,5 4,5
4,0 4,5
4,5 4,0
4,0 1,5
4,0 3,0
3,0 3,5
3,0 3,5
3,0 2,0
Conclusions are the same with ANOVA and Tukey parametric:
« NERO is better than AOTUV ».
• ABX logs are available here
• SAMPLES (11 MB) are available here. Keep them: I can’t keep them very long time online.