jerky playback of videos > 2 min

cbramham wrote on 2/13/2011, 1:16 AM
The problem is jerky playback of rendered videos of duration more than about 2 minutes. This is no doubt related to other threads, but here are the specifics. Help much appreciated.

I am shooting on a SONY XR500 in 1920-1080 format, and using Vegas Platinum 10, build 179.

Match media settings gives HD 1080-50i (1920x1080; 25,000 fps).
Field order: Upper field first.
Pixel aspect ratio: 1 square
Framerate; 25.000
Rendering quality: Best
Deinterlace method: Blend

I am rendering an m2ts file
I have checked the boxes (stretch video to output frame – don’t letterbox) and save project markers in video.

Rendering itself works perfectly. The first 2 minutes of playback are completely smooth After about 2 minutes, jerky playback of the m2ts files is seen in windows media player and after uploading the m2ts file to youtube.

Here is what I’ve tried:

1. Rendering those later segments as a loop generates a smooth video. The problem is time dependent. Removing overlays and video effects doesn’t help.

2. Changing the bitrate from 16000 to 4000 results in a smooth video, but of horrendous quality. I can’t go in that direction.

3. No help from all permutations of progressive scan/upperfield/ no deinterlace/ blend and interpolate. I assume that for playback on computers progressive scan should be used? It didn’t help though. (I’ll use blu-ray for playback on TV/PS3).

4. I am shooting nature videos, which are quiet but can have plenty of movement (waves, fluttering leaves, flying birds). But, again, the problem only appears after 2 minutes

5. Same result with 1, 2, or 4 rendering threads. Using i7CPU, 8 Gbytes RAM, 2.8 GHz, 64 bit. Don’t think it could be a memory problem.

7. Do I need to make a custom template with higher fps. I’ve seen that discussed.

8. I bought Platinum after first using the demo version. It did it’s reinstall thing. Would it help to reinstall from scratch?

Much obliged with your help on this. It seems like a rendering problem, not a player problem, as progressive scan doesn’t help.

Comments

Eugenia wrote on 2/13/2011, 1:51 AM
There is no reason to export back as MTS. For personal viewing and Youtube, just use MP4, which has no such problems as Sony AVC's encoder has. http://eugenia.queru.com/2007/11/09/exporting-with-vegas-for-vimeo-hd/
cbramham wrote on 2/13/2011, 3:36 AM
Eugenia - Thank you very much. That worked.
I have a couple questions, just to make sure everthing is optimal.

Match properties enters upper field and blend into the form, but I should change it to progressive and deinterlace interpolate for display on computer and upload to internet sites?

In the export options under variable bitrate, it doesn't have the option of max 16 Mbps and avg 8 Mbps. I used 20 and 10. It looks fine. Do you think this is optimal.

Thanks!

Eugenia wrote on 2/13/2011, 5:33 AM
>but I should change it to progressive

No, you leave the basic footage properties in tact in the project properties dialog. The project must reflect the source footage. The progressiveness will come when you export as progressive at the end.

> and deinterlace interpolate

The interpolation and "best" quality are the only things you should change in the "matched" project properties dialog.

>In the export options under variable bitrate, it doesn't have the option

You type it.
cbramham wrote on 2/13/2011, 9:52 AM
Thanks a lot .
cbramham wrote on 2/13/2011, 1:29 PM

The audio on the mp4 video is noticeably weaker than what I got with m2ts. It's ok, but makes me wonder if there are known differences in audio quality. I'm using 192 k bitrate. Massively increasing the track volume Fx produces only small increases in mp4 volume .
Eugenia wrote on 2/13/2011, 1:44 PM
M2TS uses higher bitrate and maybe 5.1 too. AAC is better suited for delivery purposes though. I personally don't have a problem with how it sounds.