Monitoring HD Video

Posted on by Larry

[ This article was first published in the March, 2009, issue of
Larry’s Final Cut Pro Newsletter. Click here to subscribe. ]

Maly Gabor sent me the following question:

Why do I need a card like Blackmagic Design Intensity Pro to output my video on and LCD TV? When it comes to monitoring your work on an LCD TV, why can’t I just connect my Imac to and LCD TV through a DVI-HDMI cable and achieve the same results? I read all the great stuff about these cards but this simple question is not answered anywhere (or at least I have not found it).

Larry continues: This struck me as a really good question, so I sent it off to Dan May, president of Blackmagic Design/US, for an answer. Dan wrote:

The trick with DVI output of your graphics card is that it is going to give you the ‘Preview’ quality that Final Cut is playing back for you and this might not be consistent. The output of the DVI is actually always going to output an full raster and full frame rate, but the data it is being handed may not. When you have a clip that is just playing back in Final Cut Pro then you should likely be getting all the data out the DVI output to the monitor. However if you start working with transitions, color corrections, and complex or compressed files then often times Final Cut Pro will play back in real time, but what you see on your PREVIEW monitor is scaled back (be it line scaling and/or lower frame rate). This is what is actually being handed to the Graphics card and then scaled out to the monitor. Think of it like taking a large BMP file that is being saved to a smaller resolution, then opened and resaved as a higher resolution. There is data being lost in the final image you are seeing. Obviously how beefy your system is will determine how much real time you are getting, and thus determine how often your going to run into that non full raster PREVIEW that may not look up to par.


When you are using a Blackmagic card what actually happens when you add an effect is that the effect is processed and then output in full raster and full frame rate. So as long as FCP can play it back what you are seeing is what you are getting that out to your monitor as it should be seen, not as a preview. Even when clips can’t play back (or say such as the case in After Effects) what you are scrubbing through is still full resolution high quality video.


So look, if I’m just doing a video for my wife’s birthday this year does the DVI output suffice? Yes it probably does (assuming your wife isn’t a colorist I suppose).


If I’m doing an edit that is going to go be heavily edited with color corrections and titles, someone’s paying for this or it is going to be critically viewed then IMHO it is worth getting that consistent high quality output.

Larry replies: Thanks, Dan, for filling us in.


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