H.264 encoded clips stutter/jerk in Internet Explorer Created Oct 13, 2009

H.264 clips stutter no matter the browser I use. In fullscreen it's worse. I'm sorry to make this kind of comparing, but JW FLV player is much faster with these files

That video looks like the fps is off. Was the source the same fps as the this one?

Got a link to download the file?

Thanks for your repliess.

You can download the file here:http://www.stockfood.de/FOOTAGE/99/06/990616_p.mov

The source file has 29.75 fps, the shown file has 24 fps. However, I guess the framerate is not related to this problem. If I open this file on a local player like VLC it does not stutter, therefore the file should be OK. I am also wondering, why it works on Firefox but not on Internet Explorer.

Its a frame rate issue. Generally dropping the fps doesn't work well.

Opening something in vlc is completely different than flash. VLC will play just about anything well, no matter how messed up it is. Flash is a lot more picky.

Try re-encoding it at its default fps 29.75. You also may want to use mp4 instead of mov.

Do you have a link to the source video, -the 29.75fps version.

@madeinlisboa LOL

When I downloaded your mov file I found your server could barely muster 400 kbps throughput to me (via a 10+ mbps broadband connection), yet your mov video is encoded at 752 kbps. Your video tries to play out twice as fast as your server is able to send it (at least for me).

There is very little action in your video, so dropping the frame rate by half shouldn't hurt anything. It may not help, either.

Is this the length of the video you're shooting for? I'd convert this to On2 VP6 format, at 400 kbps. There is no reason to use H.264. Remember that wish H.264 anyone with an older version of Flash won't be able to view it. A lot of people are still using versions prior to v9r115, which is the first version that supports H.264. All versions from 8 onward support VP6. (Flowplayer won't work with Flash 8, but it'll work with the first version of v9 onward.)

(And no, Edge, I'm not looking for another debate about H.264 vs. FLV! <g> I'm just saying for a video of this type, H.264 isn't worth the issues and the loss of viewability.)

If you MUST stick with H.264, cut the datarate, and if you have to, reduce frame rate from the original 29.97 to to 15 fps. (I don't think you meant to write 29.75, as that's not a standard frame rate for anything.) Also, DO NOT use Quicktime to create the file. QT sucks for creating vids for Flash Player.

PS: When I tried playing your mov file directly in Firefox using the Quicktime plugin it stuttered there, too.

I also just noticed that your clip is lacking an audio stream. Avoid that. Nearly all video players use the audio timestamps for the sync source. Syncing off the audio clock allows the player to use the audio driver or audio card in the PC, rather than having to derive a playback reference off the system clock.

You will often get smoother playback when you have an audio stream, even if there is no audio to be heard. It doesn't add that much data overhead if you select a low bitrate and sampling.

For what he's doing flv vp6 is the way to go.

But his issues are most likely from reducing the fps from what ever number it was before.

Also I was able to download his file at 2.3MB/2300k a sec.

Are the issues with stuttering and the frame rates something you see in the converters you use? Going from a fractional frame rate (29.97 is NTSC, which is never an "even" number) to some other frame rate shouldn't be causing the kind of stuttering talked about here. (In fact, I don't see any stuttering when playing the video directly in Quicktime. I only saw it one or twice, and briefly, when first playing the video in the Quicktime embedded player in Firefox.)

Some math here ... down-converting 29.97 to 24 fps is a frame reduction of 0.8008 (infinity). From 30 to 24 would be 0.8000. Simplifying it a bit the difference is about one part in a thousand, or one frame about every 30-odd seconds.

A good converter should then simply lop off one frame every half minute to keep proper sync with the original. There should not be any visible artifacts. I regularly go from NTSC video to 25 and even 12 fps and never get any stuttering. This is for FLV, though (Sorenson and VP6).

Is this something you regularly see with H.264?

PS: Still getting <500 kbps throughput. Must not be my lucky day...

On paper reducing the fps by a correct divider should work and for some media it does. But often no matter what I try it results in jerky playback via flash.

There's been media where I've recalculated the fps several times and still had bad results using several different encoders. I finally came to the conclusion its just not worth the time to re-encode.

It could have to do with the current h.264 implementation in flash but honestly I have no clue and never really looked into it. Most of the media I work with see's little reduction in file size, its just not enough to make me want to spend time figured out if it's going to work or not.

And I very very rarely have this issue with vp6 flv. And when I do its usually because the source was botched from the get go.

As for the server speeds, might be bad routing from his server to you. This is just a cable connection. Albeit a fast one ;)
http://static.vizmu.com/images/2.3mb.jpg

Edit:
I just ran a wget 'server to server' his box capped at 10-12MB/s

Hi,

thanks for all your posts. I hoped the latest version could fix this problem, so I just updated flow player. Unfortunately this did not change anything, the problem still remains.

We tried different encoded files of this clip, but each version stuttered.

During testing I realized some interesting fact. I wrote a reduced test page which just contains our brand and the player. On this test page the clip plays almost well, whereas the same clip stutters a lot on our detailed page. (Internet Explorer)

Test page:
http://www.stockfood.de/preview_test.asp

Detailed page
http://www.stockfood.de/results.asp?image=990616

Do you see any reason for this?
Thanks a lot in advance,

Alex

The meta data is no good in that file. As gmccomb said not having an audio track can cause issues, but I suspect the encoding process in general is insufficient "meta data wise" for web based viewing.

Try this file. I don't think it will fix the jumpy behavior. But at least it has a few keyframes.
http://vizmu.com/flash/990616_p.mp4

If you still have the original @ 29.75fps, re-encoding it again from source at the default fps would be the way to go. Do you have a link to the original file?

Hi Edge,

thanks for your help. I tried the file you posted, but as you already assumed it stutters, too. Sorry, I cannot give you the original file, because this is a product we sell.

What exactly do you mean by "insufficient metadata wise" besides audio and keyframes? The file was encoded by "Episode Encoder" from telestream.

I am still wondering why the problem only occurs in Internet Explorer. In all other browsers the playback by Flowplayer is fine. Why is there a difference between two pages with the same file?

I am pretty sure this is a hardware issue. The H.264 requires a lot of processing power, and IE is a shitty browser. Since the video is playing within flash I would assume it isn't associated with IE, but then again the plugin has to run inside IE so it could be affecting it.

I was able to play the video smoothly on IE6, IE7 and FF3. My machine is a core2duo E8400+ with a 256mb graphics card.

Is your system pretty slow? Can you try another computer?

Keyframes.
If you try and scrub/navigate to different parts of the video via the flowplayer controlbar you will notice in your test pages the video always goes back to the beginning. It should navigate to the time you selected if it has loaded via the controlbar, not restart. If you test the mp4 I posted above in your player test page you will see the difference.

As per the IE only issue.
I also see the issue in FF and chrome on both test pages you posted above. But as degenerate said IE is a piece of "work" to put it gently. IE never seems to allow flash to use the system resources it sometimes requires to play media correctly. Thus the jumpiness is more profound.

I would almost bet money that if you encode it at its original fps the jumpiness would be gone. I'm unsure if its because h.264's implementation in flash is relatively new, but lowering the fps "even if done correctly" more often than not results in jumpy playback when using h.264 files in flash.

Here's some info on keyframes
http://en.wikipedia.org/wiki/Video_compression_picture_types#Intra_coded_frames_.28or_slices_or_I.E2.80.91frames_or_Key_frames.29