Subject: Re: [rtcweb] Is support for non square pixels MTI
From: Sergio Garcia Murillo <[email-masked]>
To: [email-masked]
Date: Wed, 31 Aug 2016 17:53:16 +0200
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>

On 31/08/2016 17:27, Randell Jesup wrote:
> So we should be defining how MediaStreamTracks and PeerConnections 
> deal with this.  Must all MSTs be square pixels always?  (and what if 
> the source just isn't, must it be converted to square at the input 
> point (typically GetUserMedia)?  Can PeerConnection carry a 
> non-square-pixel stream (separate from the MST requirement) for use 
> outside of the W3 environment?  If so, how is it signaled?  (I suspect 
> there's some way to do so in the SDP, haven't checked). 

At least in H264, pixel aspect ratio is handled internally by the 
encoder/decoder and signaled on the sar-understood, sar-supported sdp 
fmtp attributes. Not sure if VP8 has something similar.

Best regards

Sergio