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Re: [media-and-entertainment] Frame accurate seeking of HTML5 MediaElement

From: GAUSMAN, PAUL <pg2483@att.com>
Date: Thu, 21 Jun 2018 12:38:48 +0000
To: François Daoust via GitHub <sysbot+gh@w3.org>
CC: "public-web-and-tv@w3.org" <public-web-and-tv@w3.org>
Message-ID: <48E3BE8C-164C-42F3-9BBD-A7BC891D879B@att.com>
Wouldn't the user agent buffer the steam back to the last I-frame and render all the frames up to and past the edit point? It could optionally re-frame the steam to a non-variable rate, too.

Thanks!
-Paul



> On Jun 21, 2018, at 4:27 AM, François Daoust via GitHub <sysbot+gh@w3.org> wrote:
> 
> @boushley Thanks, that is useful! From a user experience perspective, how would the frame-by-frame stepping work in your case, ideally?
> 
> 1. The user activates frame-by-frame stepping. Video playback is paused. The user controls which frame to render and when a new frame needs to be rendered (e.g. with a button or arrow keys). Under the hoods, the page seeks to the right frame, and video playback is effectively paused during the whole time.
> 2. The user activates frame-by-frame stepping. The video moves from one frame to the other in slow motion without user interaction. Under the hoods, the page does that by setting `playbackRate` to some low value such as `0.1`, and the user agent is responsible for playing back the video at that speed.
> 
> In both cases, it seems indeed hard to do frame by frame stepping without exposing the current frame/presentation time, and allowing the app to set it to some value to account for cases where the video uses variable framerate.
> 
> It seems harder to guarantee precision in 2. as seen in this thread [1], but perhaps that's doable when video is played back at low speed?
> 
> [1] https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_w3c_media-2Dand-2Dentertainment_issues_4-23issuecomment-2D396701652&d=DwIFaQ&c=LFYZ-o9_HUMeMTSQicvjIg&r=vx0yUsII8vRgr24aHXAFyQ&m=gFQTooo-tx7K2Jf5M_SbYEVgjQGIcr-iERY-ZSB1GTI&s=O-Uo_NlO-XLk83M8Q-p8ZNiQCi5mWTwnTtc_AKg_Dto&e=
> 
> -- 
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Received on Thursday, 21 June 2018 12:39:22 UTC

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