[whatwg] need a way to set output format from StreamRecorder

Anne van Kesteren annevk at opera.com
Tue Nov 23 09:24:02 PST 2010

On Fri, 19 Nov 2010 19:50:42 +0100, Per-Erik Brodin  
<per-erik.brodin at ericsson.com> wrote:
> We are about to start implementing stream.record() and StreamRecorder.  
> The spec currently says that “the file must be in a format supported by  
> the user agent for use in audio and video elements” which is a  
> reasonable restriction. However, there is currently no way to set the  
> output format of the resulting File that you get from recorder.stop().  
> It is unlikely that specifying a default format would be sufficient if  
> you in addition to container formats and codecs consider resolution,  
> color depth, frame rate etc. for video and sample size and rate, number  
> of channels etc. for audio.
> Perhaps an argument should be added to record() that specifies the  
> output format from StreamRecorder as a MIME type with parameters? Since  
> record() should probably throw when an unsupported type is supplied, it  
> would perhaps be useful to have a canRecordType() or similar to be able  
> to test for supported formats.

But if we want interoperability for streams, also taking into account P2P  
messaging, we need a single format. Otherwise users with different  
browsers could end up not being able to communicate.

Anne van Kesteren

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