Interlacing artifacts on TV, why?

[Frisco]

I have read that I NOT shout use de-interlacing, when showing the capture TV-broadcasting, on a TV (playing from my computer).

I’m capture PAL (768x576), normal TV- broadcasting, whit a Pinnacle DC10 plus (MJPEG codecs). I then convert the capture TV- broadcasting to DivX5. I then always use my Matrox 550 – TV-out to se the result on TV (I have the same problem whit ASUS 7700 Deluxe).

When I NOT de-interlacing there is a lot of interlacing artifacts in the moving part of the movie, on the TV (and on the monitor).

When I de-interlacing the TV-broadcasting there is none interlacing artifacts, on the TV (and on then monitor).

Why do I have to de-interlacing, when showing the capture PAL TV-brodcasting on the TV, (playing from the computer) ?

Thanks for any advice.

[Zhnujm]

most gfx card with tv-out are not perfect for interlaced video playback. with the asus card (i think its a nvidia chip) you can try these solutions:
use tvtool with 800x600 + fullscreen enabled
use tvtool with 768x576 (only fullscreen available)
of course you have to play in fullscreen, any resizing will destroy the interlacing.
any other mode will resize the picture before sending to tv and so also destroy the interlacing.
a high bitrate is also better if you use a codec that has no support for interlacing.

[Pojken Purken]

To my knowledge neither DivX 5 nor the earlier versions supports interlaced frames (in contrary to MPEG2). Encoding interlaced video with DivX without deinterlacing will create progressive frames with MAJOR interlacing artifacts that certainly will show up on both TV and monitor as you describe. Also, the compression ratio will suffer negatively resulting in larger files. So, unless you're encoding in MPEG2 (or another format that supports interlaced frames, like MJPEG f.e.) you should definitly deinterlace your video first.

Regards
PP

[Zhnujm]

the settings above worked for me with divx3/xvid. they dont support interlaced frames (xvid not yet).