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| pathfinder |
| Posted: Nov 20 2002, 05:08 AM |
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Unregistered
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TV filter's comment says: "Processes data in NTSC native YIQ format". I wonder will it cause any distortion if I use it on PAL signal? In other words how does PAL chrominance differ from NTSC?
I found a suggested filter chain for processing VHS captures which includes this filter. The article was written for PAL material. However a doubt remains every time I read TV filter describtion... The chain is:
TV chroma shift up
TV chroma average 3X3
unsharp mask 3/15/0
hue-saturation-intensity: hue 0.8
DNR 10-12
hue-saturation-intensity: hue 1.2
If the source is very noisy unsharp mask was suggested to be set to 5/15/0 and slight bluring used after DNR - general convolution: center 212, rest 5. |
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| fccHandler |
| Posted: Nov 20 2002, 05:45 AM |
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Administrator n00b
Group: Moderators
Posts: 3961
Member No.: 280
Joined: 13-September 02
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That's an excellent question! (NTSC YIQ vs. PAL) Unfortunately, I don't know the answer, and I'll be very surprised if anyone else does.
Your suggested filter chain looks extravagant to me, but I guess it depends on the quality of your VHS source. I try to use as few filters as possible, and I think I get great results most of the time, but only you can judge what works best for you.
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May the FOURCC be with you... |
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| phaeron |
| Posted: Nov 21 2002, 03:15 AM |
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Virtualdub Developer
Group: Administrator
Posts: 7773
Member No.: 61
Joined: 30-July 02
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I found out after I initially wrote that filter that working in YIQ space gives you nothing, since the conversions to and from RGB space are linear, and the averaging operations are linear, so the operation can equivalently be done in RGB space. And, in fact, later versions of VirtualDub do the chroma averaging in [Y, R-Y, G-Y, B-Y] space rather than YIQ or YUV. So, no, it doesn't matter that your video was originally encoded in PAL.
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| pathfinder |
| Posted: Nov 28 2002, 02:18 PM |
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Unregistered
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Cool
Thanks, to all |
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