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- Date: Thu, 16 Aug 2012 21:38:35 +0000
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https://www.w3.org/Bugs/Public/show_bug.cgi?id=18571 --- Comment #3 from Ralph Giles <giles@mozilla.com> 2012-08-16 21:38:35 UTC --- (In reply to comment #1) > Vorbis encodes at different bitrates do not guarentee that the exact same frame > durations will be picked at each instant in the timeline. I think the point of what Aaron is saying is that Vorbis (and Opus) are variable-frame-size codecs, and and as such there's no reason to expect that the frame boundaries will align between two different encodes. That said, we should not specify 'render as silence'. That will cause an audible drop out (or pop if you do it without any cross-fade). We should specify that implementations cross-lap the streams in a way that preserves the sample index when switching streams. A bad implementation could indeed pad with silence, but a good one would do intelligent reconstruction to bridge the gap, the way packet-loss concealment works in voip. This is the technique described on the crosslap page, implemented by the libvorbisfile crosslap API, and described by Monty at OVC a couple of years ago. -- Configure bugmail: https://www.w3.org/Bugs/Public/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the QA contact for the bug.
Received on Thursday, 16 August 2012 21:38:36 UTC