[winswitch] codec2

Antoine Martin antoine at nagafix.co.uk
Wed Jun 1 07:24:47 BST 2016

On 01/06/16 11:24, Michael Durkin wrote:
> Codec2 is for audio compression / low bit rates
So you're talking about this:

Xpra uses GStreamer for sound support in the python client and server
and GStreamer has no support for codec2.
You can find which codecs your client supports with:
xpra attach --speaker-codec=help
And for the server:
xpra start --speaker-codec=help

Even if it did have support for codec2, I don't see much point in trying
to save a few bytes when opus or vorbis do an excellent job of it
already, and the pixel updates are likely to dwarf the sound data (not
the total, but discrete events).
What we could do is provide more fine tuning over the existing sound
codecs, in the same way that video compression has "speed" and "quality"
knobs. Feel free to file a ticket for that.


> http://loyc-etc.blogspot.com/2012/09/opus-codec-to-end-all-codecs.html
> mentions that codec2 beats opus by a factor of 3
> a little more info .. but i'm not sure codec2 is useful to xpra ....
> http://www.rowetel.com/blog/?page_id=452
> Ubuntu 16 , only patch done is for Ubuntu/Debian ...
> Oh ... i think we both made the same mistake avcodec2 does not = codec2
> On Tue, May 31, 2016 at 7:56 PM, Antoine Martin <antoine at nagafix.co.uk>
> wrote:
>> On 01/06/16 01:38, Michael Durkin wrote:
>>> Im wondering how .. if its needed, im not sure , to use codec2 instead of
>>> opus ...
>> They are completely unrelated.
>> * dec_avcodec2 is a video decoder which uses ffmpeg, it is needed for
>> decoding h264, hevc, etc..
>> * opus is a sound codec
>> Both are optional but recommended. If you have vorbis or even mp3, opus
>> is probably not worth the effort if you are having problems.
>> h264 on the other hand, is strongly recommended as it is the most
>> efficient video codec.
>>> I see a patch for V0.15 but not sure if it is already implements in V0.17
>>> code ... or use a run switch ...
>> Please be specific. What distro? What patch?
>>> Also i see a thread on the server (to client) for xpra sound but not one
>>> for client microphone to server .... is that not possible ?
>> I don't understand the question.
>> As of version 0.15, the sound runs in a separate process, not thread.
>> If you start the microphone forwarding, you will get an extra process.
>> Cheers
>> Antoine
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