Decklink v5 driver possible problem?

[Sean Oneil]

Try it without any extra plugins and see if that makes a difference. Plugins have been causing problems with FCP5.

[Jonathan White]

Thanks for the response but this is a clean install and I haven’t got around to installing extra plugins yet…

I forgot to mention the line is appearing when a PAL DV timeline is output on SDI as 8 bit uncompressed..

Don’t get the line when monitoring downconverted HDV footage so maybe it’s a setting issue???

Johnny

[Rob Alexander]

Hi, yes I’m seeing it too – I sent a note to Blackmagic tech support last night but haven’t had a reply yet. The reason you’re not seeing it in 4:3 is that you’re probably not viewing the underscanned image, if you have the option on your monitor try it, I’ll bet the line’s there. Whereas 16:9 on a 4:3 screen you alway see the full vertical resolution and that’s why it’s there.

I think this is a PAL specific issue, as DV (+DV50 for that matter) doesn’t conform to the normal PAL field priority, prioritising the lower field rather than the upper one. Thus the decklink has to compensate for this to get a correct video signal out.

As I understand it, the PAL video gets dropped by a line to make it work in DV, but when output through the card gets shifted up a line to put it back in the correct PAL sequence. The problem is that in doing this the video signal is then missing 1 line at the bottom, and in the digital domain no video shows up green, hence the line at the bottom of the screen. I’m guessing that BM need to write something into the driver to fill this line up.

Do please correct me if I’m wrong anybody – and BM, please can we have a fix.

Ta,
Rob

[Jonathan White]

Thanks Rob,

You’re spot on, the line shows up with underscan. It’s good to have someone with your technical savvy on the case.
Does this green line mean I shouldn’t record to tape? (I can always go back to 4.5 as I have a dual boot system at the moment for laying to tape.)

Thanks again,

Johnny

[Rob Alexander]

Don’t output to tape with the green line as it will show up. If you’re staying in the DV realm I’d go back to 4.5 (although I thought sequences aren’t backwards compatible) else put the media into an uncompressed timeline and render (zzzzzz) or conform it Uncompressed.

lets hope BM are on the case.

Rob

[Rob Alexander]

…. unless you’re going firewire in/out, then I’d guess it’ll be OK because the decklink’s not actually having to do any conversion – but you’d have to try it to find out.

Rob