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Discussion Starter · #1 ·
I'm currently running an AIW 7500 with a 17" LCD monitor and am researching transitioning to a HTPC configuration with a Monivision style monitor. I capture alot of sporting events with alot of fast motion and would like to see as smooth motion as possible.


My understanding is that if one captures at XXX x 240 with NTSC/interlaced signal, then you drop every other frame. To capture both interlaced frames you need to capture at XXX x 480. The problem then becomes how best to display this interlaced output on a monitor during playback. So far I haven't been happy with the results I've obtained trying to deinterlace with various software.


I have used MMC 7.7 for capturing to mpeg2 and Showshifter 2.0 to capture divx.


Thank you in advance.
 

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If you're using MMC 7.7+, edit the MPEG capture preset and uncheck the "deinterlace" option ("Capture Interlaced" in MMC 8.1, which has much better quality for interlaced captures).

This will capture an interlaced MPEG that will only be deinterlaced on playback using the hw deinterlacer.
 

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In my opinion you should try to preserve the captured signal as much as possible and let the player handle the deinterlacing.


That means capture at x480 30Hz, but set the encoder to an interlaced encoding mode. That means that the encoder preserves the two fields that it just captured.


DivX supports this since version 5.0.3. The problem with DivX is that the player does not yet support the feature hence you will see all the interlacing symptoms during playback. I hope this will be addressed in future versions.


What I do is capture at x480 30Hz without much compression using HUFFYUV and then use TMPEG to convert the interlaced file into an interlaced MPEG2 file. DVD players have decent deinterlacing (BOB+...) built in.


Alternatively I tried capturing at x240 60Hz, but I get problems with my hardware. However that is really the nicest solution.


Check out http://www.100fps.com for a great interlacing/deinterlacing discussion.


Thanks, Thomas
 

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Discussion Starter · #4 ·
Quote:
This will capture an interlaced MPEG that will only be deinterlaced on playback using the hw deinterlacer.
Created a custom mpg2 capture profile in MMC7.7.


352x480, uncheck deinterlace, NTSC, VBR 2.3Mbs.


The player won't play this back I believe due to mpg2 licensing. Playback with Videolan showed interlacing artifacts.

Quote:
What I do is capture at x480 30Hz without much compression using HUFFYUV and then use TMPEG to convert the interlaced file into an interlaced MPEG2 file. DVD players have decent deinterlacing (BOB+...) built in.
I like this philosophy and it would be my choice for medium quality capture and storage. Is the hardware deinterlacing only in stadalone DVD players or also in DVD ROM drives that one might have in a HTPC?

Quote:
Alternatively I tried capturing at x240 60Hz, but I get problems with my hardware. However that is really the nicest solution.
How do you capture at 60Hz? I've only seen the 30Hz option. I agree this would be a great option.



I've had some success with capturing at 352x480 MJPEG19. Then I recompress using WMV9 encoder, VBR 2Mbs, deinterlace.


If I use Showshifter to accomplish this recompression with WMV9 codec there is a deinterlace setting called "HalfHeight, DoubleRate". this essentially converts the 352x480 @30Hz to 352x240 @60Hz while also doing the compression. This route has also yielded very good results for fast motion sports. I haven't found this option in WMV9 encoder but it must be there somewhere.
 

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Is the hardware deinterlacing only in stadalone DVD players or also in DVD ROM drives that one might have in a HTPC?
To my knowledge deinterlacing of an MPEG (or other format) streams is done by the player software. I believe the DirectX framework is actually doing much of the deinterlacing if the encoded stream contains the right information.


It is definitely not done by DVD ROM, if it there is hardware support then the graphics adapter would be a good candidate, but I don't know any such hardware.

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How do you capture at 60Hz? I've only seen the 30Hz option. I agree this would be a great option.
Depends on the capture hardware and the codec. I used ATI AIW 7500, VirtualDub + HUFFYUV. I don't think Showshift allows you to capture at 60Hz.
 
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