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Re: Multichannel files and ChannelSplitter channel layout issue

From: Michael Weitnauer <weitnauer@irt.de>
Date: Tue, 22 Nov 2016 18:29:40 +0100
Cc: Paul Adenot <padenot@mozilla.com>, Vincent Jousse <contact@ftsoftware.fr>
Message-Id: <5A55B1E6-8A11-4726-BC07-A061DF103B4C@irt.de>
To: Hongchan Choi <hongchan@google.com>, "public-audio@w3.org Group" <public-audio@w3.org>

> Am 18.11.2016 um 17:41 schrieb Hongchan Choi <hongchan@google.com>:
> 
> Yes, I mentioned this pain point in the last W3C WebVR workshop. The multichannel audio is still not in the category of 'the majority use case', so browser implementors neglected it.
> 
> Since WebAudio is getting the stream from the HTMLMediaElement, so I was expecting the element to do work for me.
> 
> On a related note, it would be really great to be able to check the valid channel count of the original media from the MediaStream* sources. It turns out to be there is no way to figure this out from the developer's perspective.

That would be indeed great! 

Further, it would be great if one could make use of more than 8 channels (seems to be the limit for both Firefox and Chrome) in a multichannel file / stream. Especially for Higher Order Ambisonics and object-based audio that would be very helpful, as starting and controlling multiple audio elements simultaneously (as a workaround) does not work very well..

> 
> Why don't we start a thread in the WebAudio issue tracker and get more people involved if needed?

Happy to help and to share further observations. 

Michael



> 
> -Hongchan
> 
> On Fri, Nov 18, 2016 at 3:13 AM Paul Adenot <padenot@mozilla.com <mailto:padenot@mozilla.com>> wrote:
> On Fri, Nov 18, 2016 at 8:03 AM, Michael Weitnauer <weitnauer@irt.de <mailto:weitnauer@irt.de>> wrote:
> Hi, 
> 
> I ran into the same issue when I started using multichannel audio for a different purpose (https://github.com/IRT-Open-Source/bogJS <https://github.com/IRT-Open-Source/bogJS>). As I found out, the situation is even worse as you can absolutely not rely on consistent behavior of the same browser on different platforms, especially in the case of Firefox which uses the system decoders as far as I know. But I agree, even the different channel orders between the major browsers are a real pain. 
> 
> The plan for Firefox is to always remap to SMTPE order regardless of how the file was decoded. We are actively working on this, so it might not be available on release.
> 
> I agree it is necessary to spec this. What would be an appropriate venue for this ?
> 
> Thanks,
> Paul.

---------------------------------------------------------
Michael Weitnauer
AV Technologies

Institut fuer Rundfunktechnik GmbH (IRT)
R&D Institute of ARD, ZDF, DRadio, ORF and SRG/SSR
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Received on Tuesday, 22 November 2016 17:30:20 UTC

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