DV blanking issues?

[Glenn Chan]

re: https://www.screeneditors.com/forums/printthread.php?s=ae26eb5947907fbee22987b250cc2c3b&threadid=55

I think they are all just spreading misinformation?

What I believe they’re talking about:
Fixing these kinds of errors lowers the quality of the pictures. On DV and DVCPro programs the quality drops away quite fast as the picture is blown up to reach the edges. This not only reduces the markets for your program but is also going to limit the life of your program.
DV frame size is 720X480.
Many editing systems that follow the ITU 601 spec use a frame size of 720X486. (They can probably do 720X480 too.)

They may be trying to scale the video up so the 720X480 picture fills the 720X486 dimensions. There’s really no reason to do this, although some editing systems may do this by default. What you should be doing is moving the image down 2 or 4 pixels (but not 3), with no scaling/resizing.

Or they can be talking about something else entirely… there’s such thing as a blanking interval, but shooting DV doesn’t affect that.
Read about analog video at https://www.danalee.ca/ttt/analog_video.htm
*Some of the little details may be wrong, but I don’t know of any better sources on the internet that are free, as easy to read, and as correct. Poynton’s books and SMPTE publications would be more technically-accurate sources.

**Those figures are for NTSC, not PAL.

2- DV generation loss is pretty low in a properly configured editing system using a decent DV codec. see https://codecs.onerivermedia.com/articles/adam_dv.htm

You can however use lossless codecs while editing, so generation loss isn’t really an issue.
Also, firewire/ieee transfer is lossless (while sdi is not). SDI/digibeta dubbing to SDI/digibeta over and over will actually pickup generation loss, while firewire/DV to firewire/DV won’t (SDI/DV to SDI/DV will however).

3- Adam Wilt (video engineer who writes for dv mag and has the excellent DV FAQ) rates DV as 9.0/10 for picture quality, and betaSP 8.9/10 as far as the FORMATS go.

In practice however, you’ll probably get better results with betaSP for non-technical reasons. The budgets are generally bigger, the cameras better (tens of thousands versus thousands), there’s a greater knowledge/experience base for betaSP, etc.

And of course, shooting digibeta will yield better technical quality. And 35mm is likely better yet.

4- the online will be 8bit uncompressed thru AJA component input.
You might get slightly better quality if you maintain a digital workflow by capturing through SDI. Going to analog will add a generation.

If you want to be assinine, you kind of incur a generation if you capture through SDI. see https://www.lafcpug.org/feature_capture_card.html

Disclaimer: Take what I say with a grain of salt! I’m still learning about this stuff and I’ve been wrong many times. I have tried to point out references to sources that are much more well-informed.

Disclaimer 2: Even experts are sometimes wrong (although this is a lot rarer).

See https://www.poynton.com/papers/YUV_and_luminance_harmful.html
If you read that article, the author points out that many textbooks on digital video are kind of wrong.