Snow Leopard AAC improvements..
Reply #36 – 2009-09-06 18:50:53
The new XLD version that just came out supports it already! I have played around with it a little bit and made some interesting observations:The new Quicktime includes the first AAC encoder that masters the infamous Emese sample transparently! For my ears at least. Nero was never able to handle it even at the highest bit rates and also LAME and Vorbis have always failed badly. This only works at the highest setting of Q127; at Q122 with only slightly less bit rate I can ABX it instantly, which is kind of strange. ABR 320 is also transparent. Interesting - I can easily ABX emese at Q127:WinABX v0.42 test report 09/06/2009 10:30:47 A file: H:\music\encoder_test_clips\emese.wav B file: H:\music\encoder_test_clips\emese.qt763.q127.wav Start position 00:00.0, end position 00:07.0 10:31:30 1/1 p=50.0% 10:31:33 2/2 p=25.0% 10:31:36 3/3 p=12.5% 10:31:40 4/4 p=6.2% 10:31:43 5/5 p=3.1% 10:31:46 6/6 p=1.6% 10:31:50 7/7 p=0.8% 10:31:54 8/8 p=0.4% 10:31:57 9/9 p=0.2%a 10:32:00 10/10 p< 0.1% 10:32:03 11/11 p< 0.1% 10:32:06 12/12 p< 0.1% 10:32:09 13/13 p< 0.1% 10:32:12 14/14 p< 0.1% 10:32:15 15/15 p< 0.1% 10:32:20 16/16 p< 0.1% Just to make sure we're on the same page, here's the "Tool" string from the m4a file as encoded by XLD and read in foobar2000:X Lossless Decoder, QuickTime 7.6.3, True VBR Quality 127 and the "Encoder Quality" setting was at Max. I used fb2k to convert to WAV for the ABX test, but I could easily detect the same artifacts when listening in iTunes under Snow Leopard (and I triple-checked that I had indeed encoded from the original emese.flac, as opposed to re-encoding from an MP3 or some other bonehead thing like that). HOWEVER, I cannot ABX the Show Me Your Spine sample at just Q90 (I CAN easily ABX LAME 3.98.2 V2), which is not too surprising as I've never been very sensitive to pre-echo artifacts.