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View Full Version : DV->DVD need resizing due to different PAR ?

halsboss
27th June 2007, 09:01
This (last edited May 2006) http://www.transcoding.org/cgi-bin/transcode?DVtoDVD under section 2c says

The other reason to consider changing the video frame size is aspect ratio.

The 720-pixel-wide DV frame is actually slightly wider than the 720-pixel-wide DVD-Video frame--technically, the two formats have a slightly different pixel aspect ratio, and therefore display aspect ratio--so that if you encode DV directly to DVD without changing the size, the image will be slightly "squished" horizontally.

The difference is small enough that it's usually not visible, but if you want to get the correct aspect ratio, you can clip 16 pixels from the left and/or right borders to get a 704-pixel-wide frame, which is also legal for DVDs.


Is it still the case that PAL 720x756 16:9 DV -> DVD should be horizontally cropped 720 -> 704 prior to encoding ? Had a look at the FAQ here but didn't spot it.
wonkey_monkey
27th June 2007, 09:38
I was under the impression that the DVD player takes it all into account, so whether you give it the 720px wide video, or the 704px wide video, it will still display at the same ratio.

I could be wrong though, in which case it's all even more confusing.

David
Wilbert
27th June 2007, 22:36
Is it still the case that PAL 720x756 16:9 DV -> DVD should be horizontally cropped 720 -> 704 prior to encoding ? Had a look at the FAQ here but didn't spot it.
It depends ... If a dvd is ITU-compliant then the pars are the same and the article is incorrect. If the dvd is not ITU-compliant then the article is correct.
halsboss
28th June 2007, 00:16
Thankyou. The DV camcorder manual doesn't say (they never say enough, do they)...

I'm inclined to not clip the DV during conversion to DVD and "assume" cameras nowadays don't strictly act that way. Anyway 16 pixels is about 2% "horizontal squish" and noone'd notice on a home video... anyone know better ?
halsboss
28th June 2007, 02:03
Well, I guess here's another reason not to crop a DV camcorder 16:9 PAL 720x576 into 704x576 ...
According to the DVD specs, 16:9 Anamorphic is only supported on full D1 resolutions (720x576/480)

Having noted that, I've tried some at 704x576x16:9 and they work so far on a plain Sony DVD player even if not strictly "spec"...