- From: Jan-Ivar Bruaroey <jib@mozilla.com>
- Date: Sat, 31 Aug 2013 03:43:59 -0400
- To: "public-webrtc@w3.org" <public-webrtc@w3.org>
- Message-ID: <52219EBF.4070908@mozilla.com>
In Firefox, we let users of gUM webpages choose which source to allow from a subset dictated by the webpage, or choose to allow none. I believe this dictated subset is overly narrow when optional gUM constraints are in play. To illustrate: Consider two phones A and B. Phone A has both a front camera and a back camera. Phone B has only a back camera. A webpage C has this constraint = { optional: [{ facingMode:"user" }] } Meaning the webpage prefers the front camera, but will work with any camera. Result: On Phone A, the webpage user may choose the front camera or nothing. On Phone B, the webpage user may choose the back camera or nothing. I think instead it should be: On Phone A, the webpage user may choose the front camera (preferred), back camera, or nothing. On Phone B, the webpage user may choose the back camera or nothing. Reason: From a permissions standpoint, I argue the user has as right to withhold knowledge of Phone A's front camera, making it indistinguishable from Phone B. Benefit: Lets a webpage affect which source is the default without limiting choice. e.g. lets pages on Firefox for Android default to front camera without removing back option in dropdown. I believe a browser could implement this today without a webpage knowing (and be blackbox spec-compliant): 1. Run the full set of tracks through the algorithm to arrive at the "preferred" set (like today). 2. Run discarded tracks through algorithm again, but *individually* and keep ones that now make it through as "non-preferred". 3. These tracks are valid from the webpage's point of view (it doesn't know the size of the set) The reason this works is that our (unchanged) core "remove-from-list" algorithm ignores zero-reducing optional constraints, which makes it more lenient the smaller the starting set is. I'm curious what people think. .: Jan-Ivar :.
Received on Saturday, 31 August 2013 07:44:27 UTC