On May 4, 2010, at 8:47 PM, Philip Jägenstedt wrote: > On Wed, 05 May 2010 07:23:45 +0800, Silvia Pfeiffer <silviapfeiffer1@gmail.com> wrote: >> On Wed, May 5, 2010 at 4:50 AM, Jim Allan <jimallan@tsbvi.edu> wrote: >> >>> * Speech whose playback rate has been adjusted by the user maintains >>> pitch in order to limit degradation of the speech quality. > > Unless the browser has some way of knowing that the audio is speech, the only thing one can do is apply pitch correction for all audio. I know some version of WebKit does something like this, and would support a DOM attribute to give authors explicit control over it. > Indeed WebKit does pitch correction by default. We have an experimental DOM attribute, webkitPreservesPitch, that allows a script to turn it off [1]. > >>> 4.9.11 Adjust Playback Contrast and Brightness. User has ability to control >>> the contrast and brightness of the content within the playback viewport. >> >> This is actually a very similar issue to the playback rate. Again, we >> have to answer the question whether this is something that we want to >> give the Web page author the ability to influence or just something >> between the UA and the user. > > This is a bit tricky. Since the <video> may be drawn to a <canvas> at any time, the browser would either have to keep track of two video frames (one unadjusted and one adjusted) or make use of 3D hardware that can apply the adjustment very late in the rendering as a fragment shader or similar. On some devices neither of these will be possible, so this should at most be a "nice to have" feature. > Contrast/Brightness control can be *extremely* computationally expensive and may not be possible on all supported hardware platforms. eric [1] http://trac.webkit.org/browser/trunk/WebCore/html/HTMLMediaElement.idl#L81
Received on Wednesday, 5 May 2010 04:10:53 UTC