H.264 stuttery playback on Vimeo

J

Jim2000

Well-known member
Hey Everyone,

I recently uploaded an HD 720 24p video to Vimeo and I'm noticing a lot of stuttering. I'm wondering if tweaking the motion settings while doing the initial H.264 compression would help.

In making my quicktime for upload, I exported my sequence out of After Effects Cs3 using H.264 compression. I had my motion set to current frame rate (23.976), and had the keyframes set for every 24 frames. If I changed the settings to set the keyframes every 12 frames, would this reduce the stuttering in Vimeo? Or is the stuttering the result of the compression Vimeo applies?

My other settings were compressor quality: high, encoding: best quality, and data rate: restrict to 5000 kbits/sec.

My video is a music video with lots of quick cuts, highly saturated colors, and movement. I've seen much smoother playing videos on Vimeo, but maybe they were smoother because there was less movement?

If you're interested, you can check out the video at: http://vimeo.com/1182687
 
Are you sure it isn't your computer staining to playback the HD feed they are streaming to you?

Other then that, the internet still isn't a perfect thing. I was getting a tiny bit of stuttering in some places, but when looking back over the same spot the stuttering would be in a different place. I would say it's on their end and there isn't much you can do about it.
 
Since I have a basic DSL connection, I always wait for the video to be fully buffered before playing it. I have a Dual 2.7 G5 with 4.5 gigs of ram, so I think my computer is capable of playing it back without stuttering.

On Vimeo, I've seen some HD videos that look way better than mine, with no stuttering, therefore, I'm wondering about my compression settings.
 
Hi Jim,

It played well here on a cable modem (nice video, too, I liked it!).

Vimeo suggests a keyframe at 30 (in your case 24), and I would likely try that. The redundant frame per second likely doesn't help or hurt you much, but it could smooth the playback a tiny amount.
 
Thanks for liking the video, Mike. I just replayed the video this morning, and the stuttering was less severe.

Because the H.264 quicktime I had created plays perfectly on my computer, I guess I'm just going to assume that the problems are on Vimeo's end.

I can't say, though, that I truly understand the concept of keyframes. Vimeo says to have them every 30 frames, but I've read on Creative Cow that one should use the formula of 10 x your Frame Rate, which, in my case would be a keyframe only every 240 frames....
 
Hi Jim,

Keyframe "smoothness" in playback is enhanced with less frames, in scrubbing the timeline with more keyframes.

Since yours is a playback project only, one per second would be appropriate.

I'm assuming their formula is one per second, rather than a raw count of the number of frames.

I would also recommend, FWIW, that you you use an absolute value of frames in the future, 24, instead of the NTSC value in TC amount. There could be a list a mile long to go with the NTSC TC, but if this is a Vimeo or any other web project, pushing the frames out in actual frames might make more sense.

If you're going back and forth, naturally, that advice would go South in a hurry. You could also have timing problems with audio that you would have to conform, too, and so on.

My best, and good luck.
 
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