[whatwg] HTML5 video: frame accuracy / SMPTE

Andrew Scherkus scherkus at chromium.org
Fri Jan 21 10:01:43 PST 2011

Based on the discussion on the WebKit bug [1] I wanted to quickly make sure
we're all on the same page with respect to seeking.

My fix for Chromium was rounding up/down to the nearest frame however I
agree that seeking should always land within the duration of a frame as
opposed to rounding.  I'll land a fix for this later today.


[1] https://bugs.webkit.org/show_bug.cgi?id=52697

On Wed, Jan 19, 2011 at 12:54 AM, Philip Jägenstedt <philipj at opera.com>wrote:

> On Wed, 19 Jan 2011 05:01:14 +0100, Rob Coenen <coenen.rob at gmail.com>
> wrote:
>  I'm really happy to see that Chromium has landed a fix for frame-accurate
>> seeking, making SMPTE timecode compliant operations with HTML5 video
>> possible.
>> The fix for Firefox is underway (
>> https://bugzilla.mozilla.org/show_bug.cgi?id=626273 ) and I have filed
>> bugs
>> at both Webkit/Safari ( https://bugs.webkit.org/show_bug.cgi?id=52697)
>> and
>> Microsoft Internet Explorer 9 (
>> https://connect.microsoft.com/IE/feedback/details/636755 )
>> BTW I tried with Opera 11, but it would only allow me to seek to full
>> seconds, not frames?
> Thanks for pointing this out, it turns out that when seeking I was
> accidentally truncating to seconds when converting the double to the
> internal time representation (uint64 nanoseconds). Remember kids, the cast
> operator takes precedence over multiplication! Anyway, this is now fixed and
> will be in a future Opera release.
> --
> Philip Jägenstedt
> Core Developer
> Opera Software

More information about the whatwg mailing list