Clean cut (unwanted frame...) at DVinfo.net

Johnny Cheung · February 18th, 2004, 02:33 PM

My problem is that my mpeg1 looks fine when I see it on the computer, but when I made it a vcd and see it on the tv, I don't know why in some shots, the cut is not that clean, the next unwanted frame always appears at the end of the shot. I tried to check it on premire pro, but that unwanted frame is definitely not on the clip there...It is weird...
Does anyone know why?

Rob Lohman · February 18th, 2004, 04:13 PM

Sounds like something had gone wrong with interlacing. BUT,
the low resolution of a VCD should not have interlacing at all.
Could be your player is messing up? Can you try it on another
DVD player?

Glenn Chan · February 18th, 2004, 07:13 PM

It could be the way the VCD is encoded.

Johnny Cheung · February 19th, 2004, 03:42 AM

It actually looks the same on several players..

So i guess it is the VCd itself but not the player....do you mean if it is mpeg1 format, it shouldn't be about interlacing?

Rob Lohman · February 19th, 2004, 06:20 AM

That is correct. MPEG1 VCD is running at a low resolution 320x240
and thus only has one field to play with. And without the second
field you cannot have an interlacing problem solong as your
DVD player is not messing things up.

Julian Luttrell · February 19th, 2004, 07:39 AM

This _may_ result from your cut not coinciding with an I-frame in the resulting mpeg file.

Try changing your edit so the cut coincides with an i-frame exactly (the frame after the cut should be an I-frame).

With (say) an MPEG-encoding GOP of IBBPBBPBBPBBPBB (for example) you should make the cuts occur before frames 0, 15, 30, etc.

I am winging it a bit here because I have not myself seen the effect you describe.

Regards,

Julian

February 18th, 2004, 02:33 PM	#1
Johnny Cheung Regular Crew Join Date: Dec 2003 Location: San Francisco CA Posts: 38	Clean cut (unwanted frame...) My problem is that my mpeg1 looks fine when I see it on the computer, but when I made it a vcd and see it on the tv, I don't know why in some shots, the cut is not that clean, the next unwanted frame always appears at the end of the shot. I tried to check it on premire pro, but that unwanted frame is definitely not on the clip there...It is weird... Does anyone know why?

February 18th, 2004, 04:13 PM	#2
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	Sounds like something had gone wrong with interlacing. BUT, the low resolution of a VCD should not have interlacing at all. Could be your player is messing up? Can you try it on another DVD player? __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

February 19th, 2004, 06:20 AM	#5
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	That is correct. MPEG1 VCD is running at a low resolution 320x240 and thus only has one field to play with. And without the second field you cannot have an interlacing problem solong as your DVD player is not messing things up. __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

February 18th, 2004, 07:13 PM	#3
Glenn Chan Inner Circle Join Date: Jun 2003 Location: Toronto, Canada Posts: 4,750	It could be the way the VCD is encoded.

February 19th, 2004, 03:42 AM	#4
Johnny Cheung Regular Crew Join Date: Dec 2003 Location: San Francisco CA Posts: 38	It actually looks the same on several players.. So i guess it is the VCd itself but not the player....do you mean if it is mpeg1 format, it shouldn't be about interlacing?

February 19th, 2004, 07:39 AM	#6
Julian Luttrell Regular Crew Join Date: Oct 2002 Location: Cambridge, UK Posts: 164	This _may_ result from your cut not coinciding with an I-frame in the resulting mpeg file. Try changing your edit so the cut coincides with an i-frame exactly (the frame after the cut should be an I-frame). With (say) an MPEG-encoding GOP of IBBPBBPBBPBBPBB (for example) you should make the cuts occur before frames 0, 15, 30, etc. I am winging it a bit here because I have not myself seen the effect you describe. Regards, Julian