Finally found the source of my choppiness, now I need help...

[Captain Satellite]

Here's my work flow. I record from DirecTV to my Panasonic DVD recorder in VR mode. Before anybody asks why in VR mode onto DVD-RAM, it's because I record and post 5 minute videoclips and I don't have to finalize a whole disc. I then convert this to .mpg in TDA. The DVD-RAM disc plays back fine on the recorder but when I convert it to .mpg and play that file on the computer, it is slightly choppy. You really only notice it with swift camera movements. The clip below was converted to .wmv. If I take that same file and produce a DVD from it, it DOES NOT play back choppy on the TV. Am I being too picky? It's not terrible but could it be better? You don't have to download the clip to watch. It can be played back online with high speed in Windows Media Player. Any help and feedback is appreciated. Oh, and please don't knock Panasonic recorders just for the sake of it, that **** really is getting old.


Click here to watch the video - please!

[jagabo]

Some likely issues:

When you watch on TV you see 60 fields per second. After converting to WMV you only have 30 frames per second. So you have half as many images per second.

I saw a few places where frames were repeated (panning scene about 32 secs in for example). So instead of seeing frames:

1 2 3 4 5 6...

You are probably getting:

1 1 3 3 5 5...

I believe WMV does this to reduce the bitrate when too much bitrate is required. The other choice would be to let the picture quality degrade.

[Captain Satellite]

Please re-read. The original .mpg file is where I believe it occurs. When you say let the picture quality degrade, what do you mean, a setting? What did you think of the quality of the clip? Thanks for the reply.

[jagabo]

Sorry, I thought the MPEG played fine and it was only the WMV file that had problems.

When you say let the picture quality degrade, what do you mean, a setting?

What I meant was that MMV decided to decrease the frame rate (by throwing away frames and repeating prior frames) rather than keep the frame rate and sacrifice image quality. I don't know if there is any way to control this behaviour.

You should examine the MPEG file with a program (VirtualDubMod for example) that will let you single step through the frames (or fields) and verify that the problematic segments do indeed have repeated frames.

I had a Panasonic DVD recorder to play with a while back. I could read VOB files directly off of DVD+RW and DVD+R media recorded by the DVD recorder, but my computer's DVD drive can't read DVD-RAM media at all. So I don't know if VirtualDubMod can read files directly from DVD-RAM. If it can, you should try that too.

Something else you should consider on the computer:

Computer monitors don't normally run at NTSC field rates. They cannot display 59.94 fields (or frames) per second video perfectly. With the monitor running at say, 72 frames per second, and a video at frames per second, you will see some frames for 1/72 seconds, and some for 2/72 seconds. Even if you run your computer monitor at 59.94 fps, you won't get perfectly smooth video because Windows can't guaranty that every frame will display exactly once. So video will always be a little choppy on a computer.