AJA IoHD capturing HD-SDI 720 live: Can I re-conform later based on timecode?

[James Press]

I'm exploring the possibility of capturing the HD-SDI signal live from a Red One as it's recording, via an AJA IoHD, and using 'log and capture' ('capture now') to get that into FCP, so we can have a fast on-set preview. Ideally we'd be able to make a very rough cut on-set because we're able to identify the (parts of ) takes we like. This would mean that later when we ingest the r3ds and transcode them to ProRes for the online edit we could reconnect the media (based on time code) to the rough edit performed on-set. Is this possible?? Obviously the file names of the AJA-captured footage would be different (unless we name them on set, which I suppose is possible) to the r3ds, but it seems to me that the key is whether the timecode is the same on both sets of footage??

[Frank Martin]

Why not just use proxies?

[James Press]

Thanks Frank. Proxies work but we'd need to take the drives off the camera and ingest, which takes a little bit of time--not a big deal but that method is not as fast or unintrusive as the AJA route. However, maybe it's a more sensible option as the re-conform is 100% using proxies. Thinking, thinking....

[Tom.Wong]

as far as I know, the metadata you get from RED sdk based software (RCX, Storm) is the best you can get, much better than you'd get over sdi. Transcoding to your editorial with that, via rocket is your best bet for the smoothest conform later on. Timecode can be pretty reliable, but nowhere near as good as the full extent of what th R3D itself has to offer, that carries into the transcoded files.

If it's a short piece, you may be alright, if you have the chance or resources though, I'd def shoot off a few clips and do a test conform before diving into this. I'm not 100% on protocols for the RED sdi, and how much info it actually carries over, but this isn't a common everyday workflow for a reason... common for other digital cinema cams, but not for RED.

[A.Fetchko]

Also keep in mind.... the 720P signal is going to be 59.94 regardless of the framerate you have set the red to..... further complicating things.

[James Press]

Also keep in mind.... the 720P signal is going to be 59.94 regardless of the framerate you have set the red to..... further complicating things.

Good point but I don't think that's the case. We always set the monitor out to 50Hz/50p otherwise our monitors wouldn't work here in Oz.

[Nick Shaw]

Good point but I don't think that's the case. We always set the monitor out to 50Hz/50p otherwise our monitors wouldn't work here in Oz.

You can change the SDI between 59.94 and 50, but you can't set it to eg 25 to match your shooting frame rate. So the files recorded externally will not be frame for frame with the R3Ds, which makes re-conform difficult. QTake HD can remove the 'padding' frames as it records to create a file which matches frame for frame, but as far as I am aware is currently the only system capable of doing this.