[opus] OPUS vs MP3

[Lucas Clemente Vella]

As far as your testing goes, doesn't seems to be a problem to me.

Since opus is a lossy compressor designed for human hearing, looking at
spectral analysis and difference between original and encoded audio seems
of little relevance for Opus purpose.

If you could tell apart the Opus file at that bitrate and the original file
in a double blind test, then it would be a finding worthy of investigation.


Em 30 de out de 2017 6:03 PM, "encrupted anonymous" <
sergeinakamoto at gmail.com> escreveu:

Good morning.

I've ran a test against MP3 format.

Code: (first convert tested audio file to 16 bit 48khz with sox.exe if
needed)
lame.exe -b 320 48khzfilein.wav -o fileout.mp3
lame --decode fileout.mp3 -o fileout.mp3.wav
opusenc.exe --bitrate 320 48khzfilein.wav fileout.opus
opusdec.exe fileout.opus fileout.opus.wav
wavdiff.exe 48khzfilein.wav fileout.mp3.wav -diff fileout.mp3.delta.wav
wavdiff.exe 48khzfilein.wav fileout.opus.wav -diff fileout.opus.delta.wav

Results: (compare two deltas with spek.exe - i've attached graphic file
from my test)
MP3 much better at 0-4 kHz, Opus little better at 12-20 kHz.
Plus I think 0-4 kHz is more important than 12-20.

Current Opus 1.2.1 is the best at 32 kbit/s for music.
But if you input 44100 Hz audio and give 96-512 kbit/s, Opus pretty badly
spends that much bitrate because of frame rate conversion.

That's all I wanted to say for now, good evening.

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