Can you capture live from HD-SDI port?

[AnthonyD42]

I'm doing a green screen shoot and want to preview some of the keys by capturing live from the HD-SDI output into Final Cut through a BlackMagic card.

I've done this from an F-900 but never tried it with a RED. Has anyone tried this? Can you think of a reason it would not work?

 

[Olivier Madar]

I'm doing a green screen shoot and want to preview some of the keys by capturing live from the HD-SDI output into Final Cut through a BlackMagic card.

I've done this from an F-900 but never tried it with a RED. Has anyone tried this? Can you think of a reason it would not work?

Yes, I tryed.
It is not possible (was ?) under 17. I found how to have smooth images, but I have a small rectangle outside the image that I could not make disappear.

 

[Vladimir Eugene]

I believe Brad did this. RED HD-SDI via Black Magic to Mac tower he used a very inexpensive software he developed to replace the greenscreen with the background. brad (at) dvdxdv.com

If you shot him an email, I'm confident he would know the answer.

 

[RivaiC]

which Blackmagic ? BM told me that they dont support progressive frame (P) which leaves you AJA as the only choice ?

 

[Matthew Riggieri]

I have done this exact setup. The problem is that the HD-SDI signal the RED sends out is not clocked so well from what i have been told and does not play nice with BMD card. I had to use a downconverter to switch to just plain ol SDI before capturing. Still worked great though. The look around area is kinda pain, but as long as you know this, you shouldn't have any issues.

Matt

 

[James Press]

I've done this using AJA IoHD so I assume you could with a BlackMagic card too. Bear in mind however that its not a great image. Obviously the resolution is 720p; and the look is baked in. Also, unless you have both the EVF and the LCD attached, the image on the HDSDI output will include the frame guides and time counter, so you'll have to crop that in post, narrowing your image. Also, you won't be able to (easily) link that footage to the r3ds If you were to use the HD SDI material for a rough cut (for example), instead of using because it will have different time code (you can work around this but it won't be automatic).

What was your reason for wanting to do the HD SDI capture?

 

[Dave Blackham]

Perhaps some one from Red can comment. There was some criticism of the image quality form the HDSDI out when the BBC did an assessment of it on build 15. Has this improved on more recent builds or the latest build 20 ?

 

[jimhare]

The criticism may be caused by misunderstanding the process.

It should be considered a preview out, like the TAP off a 35mm camera. No one would try to record that signal and use it for anything.

 

[James Press]

The criticism may be caused by misunderstanding the process.

It should be considered a preview out, like the TAP off a 35mm camera. No one would try to record that signal and use it for anything.

Exacto. That's why I asked what the purpose for it was. It's very convenient if you need an instant/real time copy of your footage for framing/content purposes but poor (I could use harsher words, but it's not 'awful', just not what I would consider broadcast quality, although when compared to some broadcast material...) for any serious use. To maximise its potential you should set a 'look' (RSX file) in RedAlert to appear as good as you can get it/ appear as you want it to look like, and then take that into the camera (either by the SD card or manual adjusting the settings) so that the preview HD SDI absorbs that look. Even so, I found inconsistencies between the live HD SDI view and the r3d footage viewed in RedAlert after the event.

We use the HD SDI output as our Skype camera feed for video conferencing talent into our 'talk back/interview' style shoot (they don't know how good an image they're getting!) BUT would not use the signal as part of a programme.

 

[Ben Holmes]

Why not have a laptop on set with AE and REDAlert, and just render off a shot and try a quick comp. Using a proper keyer, like the excellent keylight in AE CS4, or Primatte, will give you a much better idea of how your key works. Actually, nowadays, the keyer are so good, it's amazing what you can get away with....