HDMI Video capture with Intensity - first impressions
The Intensity HDMI card has arrived from BlackMagic, its makers, and I am just starting to put it through its paces. Early signs are promising and I have successfully captured 1080i footage from a Sony HDR-SR1 into Final Cut Pro 5.1.2 without any problems.
For UNCOMPRESSED storage, you will need a RAID disk array capable of around 150MB/sec sustained write for high definition video, but the Intensity provides a couple of built in hardware compression routines that let you capture, compress modestly, and store to a single SATA or IDE hard disk.
Using the Blackmagic Disk Speed Tool which came supplied with the card, I discovered that my Intel based MacPro tower with standard fit SATA drive could sustain 48.3MB/sec, thus in theory only requiring 3 x compression to work.
The card ships with some fun looking high definition live video mixing software called Blackmagic On-Air, but you will need two cards if you want to mix sources like this. It does not look like you would be able to mix an HDMI source with a standard definition source or a source from somewhere else.
I will extend this post over time but wanted to share these early findings.
11th March Update
Most people in the market for this card will probably not be the types to have a RAID disk array sitting around, and so are probably interested in the compression options it comes with. Remember that it is the speed of the average hard drive that is preventing uncompressed storage, and not the card itself.
To be fair, the only real benefit of uncompressed storage would be if you are planning on capturing live video (i.e. as you are shooting) from a camera such as the Sony SR1. All consumer and prosumer high definition camcorders compress the video before storing it internally, so playing back video from any of these cameras and capturing it via the HDMI output will mean that it has already been through one compression / decompression cycle.
While there is good logic in saying that you should not want to put it through another cycle, there's a law of diminishing returns here. The very best you could do with uncompressed capture is to replicate perfectly the already 'compressed' picture. Recompressing it a second time will likely not make much difference. The second compression routine will make use of many of the same averaging 'blocks' and should not introduce anywhere near the same number of new artifacts as the original compression routine.
The Intensity HDMI capture card offers two built in hardware compression options - DVC Pro HD and JPG.
Frame grab using Intensity HDMI Card (DVC PRO HD compression)
Frame grab using Intensity HDMI Card (JPEG compression)
Using JPG results in smaller file sizes (6mb per second in my tests) versus 15mb per second for DVC Pro HD. This correlates to compression ratios of 10x and 25x respectively.
Although the compression ratio using JPG is greater, I personally preferred the picture using JPG. You can see the full frames by clicking on the images above.
You will need a PCI Express slot for the Intensity card, this is not the same as a regular PCI slot or a PCI-X slot! Do check this on your machine.
The Intensity HDMI card IS HDCP compliant, meaning you will not be able to record copy protected content using it.
I'm away for the next couple of weeks but will pick up this review on my return.
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