Jumpy playback for compressed video

[clubber2k]

Hi,

I have a 3D walkthrough I want to share online but the file size is huge, 1GB for 6.5 minutes.
I tried to follow some online tutorials on using xvid (and h.264) to compress video but the result is too jumpy and annoying.
not sure what the technical word for the jumpy is, but thats how it feels. its 25fps but feels like 5. original is smooth as butter.

here is the original, pretty smooth:
http://www.youtube.com/watch?v=3dw2TlK8G8k

here is the compressed jumpy version:
http://www.youtube.com/watch?v=qw2jVr1qehQ

original is 24000kpbs. anything under 20000kbps gets too jumpy.. all online tutorials talk about 3000-10000kbps, how do you get these rates to run smooth? I also tried handbrak and h.264 which is much better and less jumpy then the xvid one but it still is too jumpy(!) why?!

how do you get a 2 hour HD action movie to run smooth at 4GB and here I can't make a 6 minute video weight less the 1GB??
please help me.. or help me help myself in anyway. I must be missing some key issue..

thanks!!

[poisondeathray]

Your links don't work

original is 24000kpbs. anything under 20000kbps gets too jumpy.. all online tutorials talk about 3000-10000kbps, how do you get these rates to run smooth?

The bitrate usually has not much to do with playback "smoothness" (in fact, higher bitrates usually make it worse when streaming because of buffering; but youtube re-encodes videos to a low bitrate anyway, so it doesn't matter)

So something else is probably going on, or you're not describing it accurately

[clubber2k]

Your links don't work

original is 24000kpbs. anything under 20000kbps gets too jumpy.. all online tutorials talk about 3000-10000kbps, how do you get these rates to run smooth?

The bitrate usually has not much to do with playback "smoothness" (in fact, higher bitrates usually make it worse when streaming because of buffering; but youtube re-encodes videos to a low bitrate anyway, so it doesn't matter)

So something else is probably going on, or you're not describing it accurately

not sure what was wrong with the links. updated them.
bitrate must make a difference since when I plug in the xvid codec/windows video maker anything above 20000kbps it stops the jumping.

[poisondeathray]

The difference is the "original" is 29.97 fps , and has 501 frames

The "jumpy" is 25 fps , and has 418 frames

You've dropped frames to lower the FPS to 25, that's why it's "jumpy" . If you kept all the frames , but lowered the fps to 25, it would just play back slower and wouldn't be "jumpy"

[jagabo]

The first video is 29.97 fps but every 6th frame is a duplicate. That means the video started life as 25 fps and was converted to 29.97 fps by duplicating every 5th frame. The converted file is 25 fps but it was made from the 29.97 fps video by discarding 1 of every 6 frames -- but not preferentially the duplicate frames. So it has both duplicate and missing frames, making it extra jerky.

[poisondeathray]

The original is 29.97 fps but every 6th frame is a duplicate. That means the video started out as 25 fps. The converted file is 25 fps but it was made from the 29.97 fps video by discarding 1 of every 6 frames -- but not preferentially the duplicate frames. So it has both duplicate and missing frames, making it extra jerky.

nice catch, I missed that about the original

assuming it wasn't youtube's fault , and the "original" was 29.97 with duplicates, maybe something like this in avisynth

assumefps(30000,1001)
tdecimate(mode=0, cycleR=1, cycle=6)

[clubber2k]

Oh my!
you'r right!

how did I miss that?!
original was made from different 25fps clips and I used windows movie maker to add them togther. when I saved it wmv made it 29fps without me noticing. I'll try to re-export it at 25fps and then compress it in h.264

are you sure the bit-rate doesn't matter?
how do you know what the best bit-rate should be?
I checked the original files and the differe from 10,000 and up to 30,000 kbps..

anyway, thanks so much!!

[jagabo]

are you sure the bit-rate doesn't matter?

Bitrate effects the quality of the picture, not the smoothness of the playback. Except in the case where a device can't handle high bitrates (eg. DVD players, cell phones, etc.) or when a network connection cant' sustain the bitrate.

how do you know what the best bit-rate should be?

You don't, really. Different codecs, frame sizes, frame rates, even content, will required different bitrates. Some codecs support constant quality encoding -- you select the quality, the encoder uses whatever bitrate is required to deliver that quality.

[clubber2k]

o.k.
thanks!!

productive thread. learnt all I needed