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Jumpy playback?
I’ve made this movie: https://filer.fildeling.no/DN-Kilden_8.wmv in After Effects. As you can see the animation is quite “jumpy”. I’m not sure if “jumpy” is the correct word in English, but I think you will know what I mean. Does anybody know why this happens, and maybe what I can do about it?
There are animated compositions where symbols are footage, and the heads are masks.Thanks,
Thomas -
11 Replies
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I definitely see what you mean.
It almost looks to me like a frame rate issue. As if the footage started as 24p and was poorly converted to 30p. Check the frame rate of all your footage and comps and make sure they all match, and then check your output module.
Also, try rendering an uncompressed AVI master, and see if it has the same jumpiness.
Ethan Anderson
I CAN Learn Education Systems
http://www.icanlearn.com -
I looked at your file and it seems kind of big to me. the data rate is 936 KBS which is pretty high. if you open the advanced statistics it says that the frame rate is 25fps but that it’s skipping lots of frames. On my powerbook it’s actual playback rate is between 4 and 6 fps. I think your encoding settings are wrong. I don’t render wmv files but it seems to me that the data rate should be much lower for a movie of this size.
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Oh well, this is still giving me headache!
RealEthan: It’s not actually footage, it’s images made in Photoshop (psd), except the heads which are masks. Sorry, my fault. I used the wrong word.
sam.mltn: I thought so too, but on my computer the file runs with 25fps and it’s not dropping any frames. I’ve made an animation test: https://filer.fildeling.no/test_animation_3_1.wmv. This is just an animated solid layer with a mask and as you can see it is still jumpy with this anoying vibrations around the edges. I’ve posted the project here: https://filer.fildeling.no/test_project.aep.
Any idea, anyone?
Thanks,
Thomas -
when I check the advanced statistics the test still drops frames and only plays back at about 4 fps. I think the problem is the size. I didn’t set size to full when i looked at the previous example. this one is 1366 X 768 which is huge!!! it doesn’t surprise me that it will not playback smoothly. you need to render to an hd format like h264 QT for these big image sizes. As i said before I’m on a mac and don’t do wmv’s so I don’t have a suggestion for you about how to set up your render but i think it would be better compressed outside AE
the size also looks weird to me. it isn’t any of the standard presets so that may be the source of your trouble
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hi,
Interesting…and perplexing. I have an interest in this problem as recently I was given a 60GB Targa Sequence (8,000+ sequence) rendered at 3072×768 per file, created in AE. The movement of the sequence was identical to yours, i.e. progressive scan horizontally across screen from right to left. The difference with your sequence is that mine was much slower, and I did not have as much jitter as yours during the horizontal movement. The smoothest I got mine to move right across the 3072pixels full screen at 25fps was to set (force actually) the monitors and projectors to 75Hz Vertical refresh rate.
However, this solution did not work with your test files…until I did a 4x duration of the relevant area of your timeline (6 secs x 4 = 24 secs), set your Test Comp at 100fps (AE only allowed 99fps maximum though), and rendered to Uncompressed 1366×768 AVI at the Comp framerate. Then took this result into a special software I have (AVStumpfl’s Wings Platinum – dongled Module version) which has built-in WMV and MainConcept’s MPEG-2 encoders, and re-rendered the Uncompressed at 25fps to both WMV and MPEG-2 at the extended duration.
Because of the slower movement across the 1366 screen area, albeit at 4x the duration, the jitter was minimal. Elecard’s MPEG-2 player reported a Jitter of 1, versus 8 with your original files. Windows Media Player does not have this Jitter Report feature, but playback was similarly smooth (very little jitter) with the 1366×768 1000Mbps file I rendered. This was regardless whether I played it from my single 7,200rpm SATA-1 C: drive or my 2-drive RAID 0 (also 7,200rpm SATA-1 drives).
I think the whole problem is a relationship between the vertical refresh rate of the monitor/projector, the graphics card’s vertical refresh rate settings, the horizontal distance travelled over the time frame, and the framerate of the movie, plus progressive scan. I’m not sure of the wherefore and whatfore of this complicated relationship, but I do know that the only solution I have found so far is to slow the movement down to a sweet rate that agrees with all these, and to set/force your monitor and graphics card’s refresh rate to be a multiple of the movie’s framerate when using progressive scan movies.
Thomas Leong
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all you have to do is open up the advanced tab in the statistics window of the windows media player and you’ll see that the data rate is too high for the WMV that has been rendered so windows media player is dropping frames, which is exactly what it was designed to do. The data rate is just too high for the compression scheme that was chosen.
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I don’t agree about the datarate being too high for WMV. I’ve done above 7,000Mbps WMV encodes and played them back without hassle, albeit not at 1366×768, but, from memory, at least 1420×576. They were also non-interlaced, but the movements were not horizontally across screen. So in the tests I did for this case in hand, 1,000mbps is a low datarate for me…too low from where I come from (projected multidisplays/panoramics).
In any case, what I see of the playback of the posted files was not framedrops. It was a sort of consistent jittering of all the horizontal motion at the edges of the images as they move across screen. Not a mis-interpreted field render, since there are no fields. Frame drops would show up as a skip and jump, but these did not. Not on my system anyway – just a modest P4 2.8HT with 2-drive SATA RAID 0. It would framedrop on my single drive system, until I re-rendered the test.aep submitted at the 4x duration, etc.
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I saw what looked like a pulldown stutter, combined with the oft-unavoidable judder caused by regular horizontal motion across a frame.
Did somebody get clever and add pulldown to this?
For the judder, search the COW for “judder”, try searching the archives, and try searching under my name. This has been discussed.
Steve
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Stepping through frame by frame, there is a ‘stop frame’ at every 6th frame (or was it 5th?…2.30am my time, no longer at the office). Not sure if this is a sign of pulldown. In any case, the juddering as you call it happens at the other frames too. So if there is a pulldown inadvertently added, it is not the main cause of the judder.
I still reckon it is the monitor’s refresh rate…as if, with my not-too-fast monitors anyway, the progressive scan cannot keep up with the fast motion of successive frames. Got to admit I was watching it on LCD monitors. Got to hook up the Triniton CRT and watch the original clip again, tomorrow.
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well. on my windows media player, if I check view, statistics, advanced then it shows me that the frame is 25 for the first clip and 30 for the second and that the media player is dropping frame to play it back. I admit that I don’t know much about windows media, but it seems to me that if the player is dropping frames to playback, the frames are there and the encoding setup is wrong somehow. I can’t find any way to check what the encoding settings are, but the player is definitely dropping frames. It says so right in the statistics palette.
If this happened in a quicktime I’d just change some of the encoding settings until the player would playback in real time.
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