[opus] Opus vs AAC (endurance test)

[encrupted anonymous]

using iTunes i've noticed that AAC is
very good at re-encoding own lossy sound.
let's test Opus!

neroaacenc.exe -q 0.75 -if 000.wav -of 001.m4a
neroaacdec.exe -if 001.m4a -of aac001.wav
wavdiff.exe 000.wav aac001.wav
Comparing 000.wav - aac001.wav...
Max diff: -17.3867dB
RMS diff: -33.0851dB
Mean diff: -32.4582dB

opusenc.exe --bitrate 512 "000.wav" 001.opus
opusdec.exe 001.opus opus001.wav
wavdiff 000.wav opus001.wav
Comparing 000.wav - opus001.wav...
Max diff: -22.5646dB
RMS diff: -39.0425dB
Mean diff: -38.7372dB

Opus @482kbps is much better than AAC @288kbps.
now let's see what happens after 10 passes

Comparing 000.wav - aac010.wav...
Max diff: -16.1286dB
RMS diff: -32.3361dB
Mean diff: -31.715dB

AAC stepped back just a little

Comparing 000.wav - opus010.wav...
Max diff: -7.61385dB
RMS diff: -20.3666dB
Mean diff: -20.1286dB

Opus made complete disaster, but HF looks
good (so it isn't an error in frames
synchronisation of wavdiff program).

And no, i'm not going to do ABX test at high
bitrates because i'm not wavdiff.exe, and i'm
not going to do ABX tests at low bitrates
because i don not use them.

FLAC is good, but MIDI is better. Lossy codecs
"reverse-engeneering" audio back to MIDI, that's
what they do :)


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