pixelation during playback

[Jay Knobbe]

I was given a short 5 min video to edit, stabilize some shaky footage, etc. The file was transfered from a camera (Possibly Nikon) to a Mac, then burned to a dvd.

I downloaded the MP4 file to my video drive.

When I play it back from the time line or source monitor it starts out smooth & clear, within 5 seconds it pixelates, then pops back to smooth & clear, then pixelates and so on.

If I play it thru Windows Media Player, it plays fine. No pixelation

The video is 960 x540, 29fps.

The sequence setting I chose is as follows;

Edit Mode: DSLR - I have no way of knowing if the file came from a DSLR or a Point & Shoot

Timebase: 29.97 fps

Frame size: 1920 x 1080 - Chose this since it is the video specs, x2.

Display format: 30fps drop frame timecode

Can someone tell me what is causing my pixelation and how to fix it?

My PC is pretty new with 12gb ram, i930, 2 raid 0, WD Velo OS drive, 4 tb storage and is optimized to use CS 5.5

Also, The edited video will be delivered on a dvd. With the 960 x 540 size viewed on a 50" TV, how will this look? Am I going to see some dinky little video?

All help is appreciated.

[Ann Bens]

Am i ready this correctly.
A clip that is 960x540 in a 1920x1080 sequence?
Thats not right.
To get the right sequence do this:
Export clip to mpeg2-dvd.
BTW this clip will look awful on a HDtv unless you have a dvd player with upscaler or a BD-player.

[Jay Knobbe]

Thanks for the reply, Ann

I chose that sequence setting because it was the closest from what I had to pick from ( at least it was the video size, x2 )

The finished video will be delivered on a DVD. I just found out it will be played back using a laptop (not certain if it's upscaling. def not blu-ray) and projected onto a 60" screen

Ann, if I understand correctly, I will export the clip to mpg2-dvd, and then edit it?

So I have a better understanding, could you tell me why I need to export to mpg2 to be able to edit?

Thank you

[Ann Bens]

No you misunderstood.
When you drag your mp4 into this New Item icon you get a new sequence with your movie in it
Edit this like it is.
Then export to mpeg2-dvd.
Import the files into Encore
Make menu, burn.
You need good dvd software for the laptop
Something like PowerDVD.

[Sareesh Sudhakaran]

Maybe I'm mistaken but the source monitor is not a video player - it is not meant for real-time full quality playback. The computer resources used by an editing program are utilized differently. And MP4 is a demanding codec - that just compounds the problem.

Try lowering the source monitor resolution. Hope this helps.

[Jay Knobbe]

As soon as I applied a video effect plug-in such as Mercalli or Magic Bullet Looks, the video was fine. Played back with no pixelation at all. Looked great.

Any ideas why?

[Sareesh Sudhakaran]

Pixelation is caused by a lag in data, assuming it isn't present in the source footage.

First, a question: Which camera shoots 29fps at 960x540? Or was that a typo?

If your pixelation is in sync with your video - i.e., if it happens like clockwork, then it's probably caused by the 29fps vs 29.97fps mismatch. If your video is progressive, but your timeline is interlaced, or vice versa, it could compound the problem. You are interpreting the footage with 30fps drop frame, but the footage isn't that.

Furthermore, you are scaling your video by a factor of 2 at the same time. This won't improve your quality one bit.

Why the pixelation doesn't show up when applying plug-ins, I can only guess:
It's probably because effects are non-destructive, and in order for it to playback in pseudo-realtime, the NLE must load the entire sequence in memory. When playing back source footage, however, it only uses the buffer and relies on the hard drive for playback. This is only a guess, mind you. NLE's keep their tricks (and quirks) secret. You could try to change the buffer and RAM settings and it might have an impact (hopefully positive) on the playback.

Here's a possible workflow.

Choose a custom project at 960x540 at 30fps progressive, not 59.94i. Edit native and finish. Export as 720x480 widescreen (1204x480) at 29.97p to Encore.

The typical viewing distance of a 50" monitor is 12-15 feet or more. It should look as good as the source footage. If you're not too happy, apply a bit of sharpening before you render to Encore. With this workflow, you are only rendering everything once. Hope this helps.