[opus] OPUS vs MP3

[Jean-Marc Valin]

Hi,

Before I comment on the graphics you posted to visualize the difference
between two audio signals, I'd like to ask for your help in evaluating
my JPEG encoder. I've encoded an image with JPEG and then computed the
difference with the original. I then converted the difference to sound.
You can listen to the image difference on this clip:
https://jmvalin.ca/misc_stuff/diff.wav

Can you hear how good the visual quality is? Do you think it could be
improved to make JPEG sound better? Personally, I think JPEG could do
better on my subwoofer.

Cheers,

	Jean-Marc

On 10/18/2017 07:08 PM, encrupted anonymous wrote:
> 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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