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Compressor 1080i MPEG2 issues

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Brian Wiklem
Compressor 1080i MPEG2 issues
on Jul 29, 2008 at 6:23:18 pm

Where to start...

I've been capturing some 1080i HD material from a Decklink Intensity Pro using the component video input, set to 7.5IRE, recording uncompressed 8-bit 4:2:2 video to a RAID0 set up of 2 320GB Seagate 7200.11 drives (the Black Magic disk speed shows 249MBps write speed, more than twice as fast as required for 1080i).

I end up with a 200-300GB Quicktime (uncompressed file) that I send to Compressor with the following settings:

- 1920x1080
- 2-pass VBR (19.7 minimum, 24 maximum)
- no filters or other processing applied (other than crop)
- Transport stream (M2T)
- Crop (33 on left, 10 on bottom, 37 on right, 37 on top - see below)
- frame rate of 29.97 (other frame rates are grayed out/can't be selected)
- field order: upper first (I have the same issue below even when progressive is selected)

So what's the problem? This:

http://i35.tinypic.com/25upude.jpg

When the camera is panning left/right, I'm getting these odd anomalies. These do not appear in the source, nor the uncompressed Quicktime file.

I tried doing a progressive encode instead of interlaced (field order upper first), but the problem is still there. When the video is on a still shot or there is no horizontal movement, these issues are not present.

I moved to a Mac from PC (originally used Premiere and Mainconcept Pro) but have never experienced these issues, and I'm not sure what the issue is or setting.

Whether I playback in Quicktime or VLC on the Mac, interlaced or with blended frames, the problem is there.

Lastly, I can't imagine the cropping of the video is the issue. I crop slightly because on capture, there is bare black area on the left/bottom/top.

Any ideas or help is appreciated.





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Daniel Low
Re: Compressor 1080i MPEG2 issues
on Jul 29, 2008 at 10:41:08 pm

Try it without cropping.

If you crop without deinterlacing you mess up your fields and the result is what you see in the pic.

When you do crop you need to make sure that you retain the correct aspect ratio, your cropping values don't do that.

Cropping values must always be even numbers.

__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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Brian Wiklem
Re: Compressor 1080i MPEG2 issues
on Jul 29, 2008 at 10:56:16 pm

Thanks for the feedback. Couple more questions:

1. I did do a version where I cropped and deinterlaced (output a progressive image), but the problem was still there (as opposed to crop and leaving it interlaced). Will cropping with even numbers fix that issue?

2. Would deinterlacing the original, exporting that, then plugging it back in and cropping work?

I just want to be sure that I can crop, and if deinterlacing and making the cropping with even numbers will fix it/make it work.

Thanks again, I appreciate the help (I've been pulling my hair out).



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Daniel low
Re: Compressor 1080i MPEG2 issues
on Jul 29, 2008 at 11:06:50 pm

first of all use a proper compression application.

Next, the correct order should be; deinterlace then crop then scale

__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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Daniel Low
Re: Compressor 1080i MPEG2 issues
on Jul 29, 2008 at 11:15:15 pm

Sorry, I missed that you are using compressor, but I'm confused by what you call 'plugging back in'. Compressor will do all you need in one go, just make sure you are using compressors 'frame controls'. If you are unfamiliar with them I've answered a bunch of posts recently on this forum about them.

__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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Brian Wiklem
Re: Compressor 1080i MPEG2 issues
on Aug 1, 2008 at 7:54:19 pm

haven't delved back in yet, as I'm researching the frame controls. Additionally, had a HDD problem occur, but will respond once I've tried it out. Will report back with frame controls.



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Brian Wiklem
Re: Compressor 1080i MPEG2 issues
on Aug 22, 2008 at 6:36:19 pm

Frame Controls worked - couldn't find anything in the forum descript about them, but combed the manual based on your topic of frame controls, worked like a charm (takes forever to process though).



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Brian Wiklem
Re: Compressor 1080i MPEG2 issues
on Aug 22, 2008 at 6:36:28 pm

Frame Controls worked - couldn't find anything in the forum descript about them, but combed the manual based on your topic of frame controls, worked like a charm (takes forever to process though).



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Daniel Low
Re: Compressor 1080i MPEG2 issues
on Aug 22, 2008 at 8:58:32 pm

Various parameters in those frame controls can be 'turned down' reducing the quality by a certain degree, but speeding up the process. Like anything with compression, it's a compromise between quality and speed.

__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


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