- From: Rob Coenen <coenen.rob@gmail.com>
- Date: Tue, 11 Jan 2011 17:54:52 +0000
just a follow up question in relation to SMPTE / frame accurate playback: As far as I can tell there is nothing specified in the HTML5 specs that will allow us to determine the actual frame rate (FPS) of a movie? In order to do proper time-code calculations it's essential to know both the video.duration and video.fps - and all I can find in the specs is video.duration, nothing in video.fps -Rob On Mon, Jan 10, 2011 at 9:32 PM, Kevin Marks <kevinmarks at gmail.com> wrote: > If you really want to test timecode, you need to get into SMPTE drop-frame > timecode too (possibly the single most annoying standards decision of. all > time was choosing 30000/1001 as the framerate of NTSC video) > > Eric, can you make BipBop movie for this? - Like the ones used in this > demo: > > > http://developer.apple.com/library/mac/#documentation/NetworkingInternet/Conceptual/StreamingMediaGuide/UsingHTTPLiveStreaming/UsingHTTPLiveStreaming.html > > http://devimages.apple.com/iphone/samples/bipbopgear3.html > > > On Mon, Jan 10, 2011 at 11:18 AM, Rob Coenen <coenen.rob at gmail.com> wrote: > >> Thanks for the update. >> I have been testing with WebKit nightly / 75294 on MacOSX 10.6.6 / 13" >> Macbook Pro, Core Duo. >> >> Here's a test movie that I created a while back. Nevermind the video >> quality- the burned-in timecodes are 100% correct, I have verified this by >> exploring each single frame by hand. >> >> >> http://www.massive-interactive.nl/html5_video/transcoded_03_30_TC_sec_ReviewTest.mp4 >> >> Please let me know once you guys have downloaded the file, I like to >> remove >> it from my el-cheapo hosting account ASAP. >> >> thanks, >> >> Rob >> >> >> On Mon, Jan 10, 2011 at 2:54 PM, Eric Carlson <eric.carlson at apple.com >> >wrote: >> >> > >> > On Jan 9, 2011, at 11:14 AM, Rob Coenen wrote: >> > >> > I have written a simple test using a H264 video with burned-in timecode >> > (every frame is visually marked with the actual SMPTE timecode) >> > Webkit is unable to seek to the correct timecode using 'currentTime', >> it's >> > always a whole bunch of frames off from the requested position. I reckon >> it >> > simply seeks to the nearest keyframe? >> > >> > WebKit's HTMLMediaElement implementation uses different media engines >> on >> > different platforms (eg. QuickTime, QTKit, GStreamer, etc). Each media >> > engine has somewhat different playback characteristics so it is >> impossible >> > to say what you are experiencing without more information. Please file a >> bug >> > report at https://bugs.webkit.org/ with your test page and video file, >> and >> > someone will look into it. >> > >> > eric >> > >> > >> > >
Received on Tuesday, 11 January 2011 09:54:52 UTC