W3C home > Mailing lists > Public > public-media-capture@w3.org > February 2014

Re: Constraints and MediaRecorder

From: Robert O'Callahan <robert@ocallahan.org>
Date: Mon, 3 Feb 2014 18:01:02 +1300
Message-ID: <CAOp6jLb_2PKe6zvUtt31g4GjXwaQ92cZN5_2-h+bhJ92GjMbLQ@mail.gmail.com>
To: Harald Alvestrand <harald@alvestrand.no>
Cc: "public-media-capture@w3.org" <public-media-capture@w3.org>
On Mon, Feb 3, 2014 at 4:59 PM, Harald Alvestrand <harald@alvestrand.no>wrote:

>  My use case for constraints is always the case where the JS application
> (not the UA) has to make the call between:
> - I'd like things to be like that, but I'd rather have something working
> than nothing
> - I have to have it like that, and I can't live with having it any other
> way
The somewhat OBE case that comes to mind first is if we set a constraint of


 [mandatory or optional]:
>    width: 640
>    height: 480
> and the only available codec is H.261, which can't do more than 352x288.

> Would you rather have grainy video or no video? Only the application
> knows, and for the UA to do what the application wants, there has to be API
> expressiveness that allows the UA to express what it wants.

Can you point to a real-life example of an application that would rather
just fail than get low-resolution video --- one where that's likely to be a
possibility in practice?

For MIME type, I can see that some applications would just want to reject
"bad" types in some cases. Such applications can just start recording, then
check the value of "type" and react accordingly if it's not a type it can
use (e.g. by stopping the recorder and giving feedback to the user).

If there is a convincing answer to my question above, then we can handle it
the same way --- equip MediaRecorder with attributes returning the size of
encoded video frames.

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Received on Monday, 3 February 2014 05:01:31 UTC

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