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Re: [Bug 21618] New: MediaStreams with no tracks need to not be Ended

From: Harald Alvestrand <harald@alvestrand.no>
Date: Tue, 09 Apr 2013 10:05:45 +0200
Message-ID: <5163CBD9.5070801@alvestrand.no>
To: Martin Thomson <martin.thomson@gmail.com>
CC: "public-media-capture@w3.org" <public-media-capture@w3.org>
On 04/09/2013 12:43 AM, Martin Thomson wrote:
> This is just buggy.  As discussed in some thread, a MediaStream state
> - if it exists at all - should just be a rollup of MediaStreamTrack
> states.  That would make c) invalid, which is the real problem here.
> Then the state of a MediaStream with no tracks becomes largely
> acedemic.  Maybe it is ended because it has no un-ended tracks.  Maybe
> it is un-ended because all of its tracks are not ended.

I'm happy to remove the restriction on adding tracks to an ended 
MediaStream (allowing it to be unended), and saying that 
MediaStream.ended is true if all the tracks are ended.
We can flip a coin on what the ended status is for an empty MediaStream, 
as long as we document where the coin landed. I don't care, but it needs 
to be documented.

Or we could just remove MediaStream.ended entirely, and say it's the 
app's business to query all the tracks if it wants to.

> On 8 April 2013 05:19,  <bugzilla@jessica.w3.org> wrote:
>> https://www.w3.org/Bugs/Public/show_bug.cgi?id=21618
>>              Bug ID: 21618
>>             Summary: MediaStreams with no tracks need to not be Ended
>>      Classification: Unclassified
>>             Product: WebRTC Working Group
>>             Version: unspecified
>>            Hardware: PC
>>                  OS: Linux
>>              Status: NEW
>>            Severity: normal
>>            Priority: P2
>>           Component: Media Capture and Streams
>>            Assignee: public-media-capture@w3.org
>>            Reporter: harald@alvestrand.no
>>                  CC: public-media-capture@w3.org
>> According to the current specs:
>> a) it is possible to create a MediaStream that has no tracks.
>> b) if all the tracks in a MediaStream are ended, the state of the MediaStream
>> is ended
>> c) You can't add tracks to a MediaStream that's ended.
>> b) is ambiguous for the case where there are no tracks: Is it ended or not?
>> If it is ended, creating a MediaStream with no tracks becomes useless, and
>> removing all tracks from a MediaStream will end it - rendering it useless.
>> If it is not ended, the MediaStream is useful - but it also becomes possible to
>> "un-end" a MediaStream by removing all its tracks.
>> A decision is sought.
>> --
>> You are receiving this mail because:
>> You are on the CC list for the bug.
>> You are the assignee for the bug.
Received on Tuesday, 9 April 2013 08:06:23 UTC

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