HydrogenAudio

Lossy Audio Compression => Opus => Topic started by: mzso on 2018-04-08 10:18:53

Title: How viable is Opus for encoding multi-channel audio?
Post by: mzso on 2018-04-08 10:18:53
Hi!

I'm wondering how opus fares these days for multi-channel audio. Can I expect proper channel orders in files and during playback? Can I expect efficient encoding of audio without artifacts for multi-channel also? (Including the data appropriately divided between the channels)

Are there any recommended and/or specific settings for multi-channel?
Title: Re: How viable is Opus for encoding multi-channel audio?
Post by: magicgoose on 2018-04-08 12:51:49
Can I expect proper channel orders in files and during playback? Can I expect efficient encoding of audio without artifacts for multi-channel also? (Including the data appropriately divided between the channels)
Yes. (I tested only with 5.1 though.)
It'd be a good idea to test the correctness of channel layout anyway.

Are there any recommended and/or specific settings for multi-channel?
Default settings, just as for stereo.
You'd probably want to use a higher quality setting, because it is an approximation of total bitrate, not per channel or per coupled channel pair.
For example, if you are satisfied with `--bitrate 128` for stereo, it'd likely be reasonable to use `--bitrate 256` for 5.1.
Title: Re: How viable is Opus for encoding multi-channel audio?
Post by: mzso on 2018-04-08 13:23:26
Yes. (I tested only with 5.1 though.)
It'd be a good idea to test the correctness of channel layout anyway.


Default settings, just as for stereo.
You'd probably want to use a higher quality setting, because it is an approximation of total bitrate, not per channel or per coupled channel pair.
For example, if you are satisfied with `--bitrate 128` for stereo, it'd likely be reasonable to use `--bitrate 256` for 5.1.


Thanks for the tips. I expected to raise the bitrate. I was just wondering how well it's utilized between channels. Whether there's any bitrate wasted for silent channels, or others are starved.
Title: Re: How viable is Opus for encoding multi-channel audio?
Post by: Phanton_13 on 2018-04-08 20:22:38
Even if is a little outdated this demo about opus surround encoding improvements https://people.xiph.org/~xiphmont/demo/opus/demo3.shtml explains what you whant.
Title: Re: How viable is Opus for encoding multi-channel audio?
Post by: mzso on 2018-04-08 20:39:06
Even if is a little outdated this demo about opus surround encoding improvements https://people.xiph.org/~xiphmont/demo/opus/demo3.shtml explains what you whant.
Thanks.
Title: Re: How viable is Opus for encoding multi-channel audio?
Post by: Fairy on 2018-04-09 08:12:25
Maybe offtopic, but is there a plugin for foobar that enables these gauges so you can see the bitrate in realtime, like on that site?

Would love such an option in foobar :)
Title: Re: How viable is Opus for encoding multi-channel audio?
Post by: mzso on 2018-04-09 11:14:01
Maybe offtopic, but is there a plugin for foobar that enables these gauges so you can see the bitrate in realtime, like on that site?

Would love such an option in foobar :)
Foobar does this by default in the statusbar.
Title: Re: How viable is Opus for encoding multi-channel audio?
Post by: Klimis on 2018-04-09 12:18:54
It may not be a scientific answer but as for bitrates, I found that 288kbps is the golden cut of transparency for me on multichannel (5.1) audio. I had to go though through listening isolated channels which may not  be considered a legit way of quality checks. Give it a test though.
Title: Re: How viable is Opus for encoding multi-channel audio?
Post by: Fairy on 2018-04-10 11:00:34
Maybe offtopic, but is there a plugin for foobar that enables these gauges so you can see the bitrate in realtime, like on that site?

Would love such an option in foobar :)
Foobar does this by default in the statusbar.

Yes, but as numbers. Would be nice to have some gauge or even a history (line) option.

Too bad this is not possible (?) with FLAC. Only the average bitrate is shown.