Quantcast Encoding: DV Passthrough Deinterlace to Original Framerate? - digitalFAQ.com Forums [Archives]
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03-30-2004, 10:51 PM
Icarus3000 Icarus3000 is offline
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If I use my DV camera as a passthrough device to capture old VHS tapes, the "captured" file on my PC is now 29.97 interlaced.

Would I be correct to say I can run the "30i to 24p" script safely on this video, REGARDLESS of the ORIGINAL format?

ie: doesn't matter if the original was 23.976, telecined, PAL, whatever...

Is this true, or do I still need to consider the original source?

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Icarus
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03-31-2004, 12:57 AM
BobNET BobNET is offline
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Quote:
Originally Posted by Icarus3000
Is this true, or do I still need to consider the original source?
It acts just like any other capture device, so you still have to consider the original source. That is, a telecined video should be inverse-telecined for the best quality, but real 29.97 can be processed with the 30i -> 24p script.

As for PAL input with an NTSC camera, I've never tried so I don't know what the results will be. If the camera even accepts it, I expect the fields of the video to be really messed up...
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03-31-2004, 02:28 PM
Icarus3000 Icarus3000 is offline
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It was my understanding that using a DV camera for capture isn't quite the same as an analog capture card, because the DV camera converts the output to 29.97 interlaced. I thought the DV camera converts the video to 29.97 interlaced so that all output from the DV camera is "real 29.97 interlaced" regardless of the original source.

You are suggesting that I'm wrong (which has been known to happen from time to time ). Can you explain what is wrong with my understanding above?

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Icarus
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03-31-2004, 07:39 PM
BobNET BobNET is offline
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Quote:
Originally Posted by Icarus3000
It was my understanding that using a DV camera for capture isn't quite the same as an analog capture card, because the DV camera converts the output to 29.97 interlaced. I thought the DV camera converts the video to 29.97 interlaced so that all output from the DV camera is "real 29.97 interlaced" regardless of the original source.
But the signal coming from a VCR (an NTSC one at least) is already 29.97 interlaced, either because it's a real 29.97 source or because it was a 23.976 source that was telecined before it was even put on VHS. Either way, the DV camera receives a 29.97 signal that appears to be interlaced so it doesn't have to do any conversion.

It's similar to using DVD2AVI -- all NTSC DVDs are 29.97fps (just like all NTSC video tapes), so DVD2AVI has to decide whether its telecined, interlaced, or progressive video and sometimes gets it wrong...

I don't know how it would work for PAL. If the camera is able to read the signal at all it will probably look something like the output of the ConvertFPS() function in AviSynth -- part of the previous frame will be captured along with the current frame since the framerates don't match. But if you try it I wouldn't mind hearing what it actually looks like
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