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Decklink HD Extreme/Capture Basics?
Hello,
excuse me if some queries here have been posted elsewhere, but after browsing 10 pages of posts, I feel I am none the wiser vis a vis, what good are the SDI-inputs on this card for capturing?Other posts have noted that capturing HD/HDV via Firewire causes no re-compression and thus firewire intead of SDI input is recommended for one-format projects. Is this true?
Will capturing SD via SDI provide any real benefits other than greater color bit depth for compositing?
Are people happy with this card?
thanks for any comments and
best wishes, ninetto m. -
5 Replies
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The following article might be helpful It’s a bit dated but still applies.
https://www.kenstone.net/fcp_homepage/feature_capture_card.htmlI tend to capture my DV or HDV footage through a converter as an SDI signal and use 8 bit uncompressed or Prores codecs. I’ve had the HD Extreme card for about 2 years and and I’m very pleased with the image quality and frequent updates from BMD. The low price was a major factor in my purchase decision.
Dan Sparks
Tricom Video
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Hi Ninetto,
The question of “What is the point of capturing via uncompressed hardware when my camera/deck is compressed” comes up a lot. If you were simply planning to ingest DV or HDV material, perform a few cuts on a DV/HDV timeline and then output via Firewire to tape again, there would be little point in capturing via uncompressed hardware because it would cause generational loss through decompression and decompression back to tape.
However in almost any other scenario, there are significant benefits to capturing via uncompressed hardware.
Uncompressed hardware allows you to work with Realtime Effects without needing to render. This is true even if you capture, say DVCPRO HD video, and then play it out via uncompressed hardware. You’ll be able to use RT Effects this way in contrast to DV/DVCPRO HD/HDV where you will need to render the timeline before you can output via Firewire.
Another major benefit of working via uncompressed hardware is to avoid generational loss. If you work with compressed video via Firewire, every effect, every text overlay, every graphic overlay and every transition will lead to a render which will result in generational loss of quality. If you ever drop text or a graphic on top of video on a compressed timeline, you will immediately see that the edges of the text and graphics become soft. If you drop the same text and graphics on an uncompressed timeline, they will retain their sharpness.
So let us suppose you had shot with HDV and wanted to add some text and graphics and then burn a DVD or Blu-ray disc. If you want the text and graphics to retain maximum sharpness until the final encoding for DVD/Blu-ray, then working with an uncompressed timeline will be critical and the easiest way to achieve that is to capture your video via an uncompressed capture card such as a DeckLink card. You can test this even without an uncompressed capture card by taking your DV or HDV material and rendering it on an Apple uncompressed timeline. That will take a while but you can then drop graphics and text in to it and they will remain sharp without any need to render. Then create a DVD and look at the clarity of the resulting text and graphics. Compare this a DVD produced with the same DV/HDV material while working on a DV or HDV timeline with the same text and graphics. The difference is quite noticeable.
HDV is a useful but frustrating codec as it uses long-GOP encoding. This means that you cannot edit at any point. The frames are encoded in groups and so when you wish to make a cut after a particular frame, you might have to make the cut several frames earlier or later because that’s the way the HDV codec works. One way around this problem is to capture via uncompressed hardware such as a DeckLink or Intensity card or a Multibridge. If you don’t have enough space to store uncompressed video, you can capture the video using a professional editing codec such as ProRes or MJPEG. While this will compress your video, it will eliminate the long-GOP issue so you can edit anywhere you want on a timeline.
That’s a long answer to your short questions but I hope it helps make sense of why you might want to consider using an uncompressed workflow.
Regards,
Luke Maslen
Blackmagic Design -
Thanks very much for both posts, for the clarity and detail!
This card does seem to fulfill my present needs.
regards,
ninetto m. -
Ninetto,
I have DecklinkHD (PCI-X) with my old 2GhzDualG5 for almost a year. Finally this week I´m moving to a newMacPro (PCIe), but I have also bought a new DecklinkHD. Works fine for me. I usually work wirh DVCProHD 720p (25-50fps). The ingest/capture is made by P2 transfer, so I´m using Panasonic codec. The problem is when Final Cut Pro creates a sequence that matches this codec. It´s fine for most part of the job, but I always output a master sequence with Blackmagic 8-10 bit codec. The result is muuuuuch better. Red channel suffers a lot in DVCProHD sequences (it tends to pixelize). Renders are muuuuuch longer but the result is what it counts.
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Io utilizzo una Panasonic HVX-201A e volevo sapere se la Decklink hd extreme lavora bene con il formato DVCPRO HD? Grazie. Giuseppe
I use a Panasonic HVX-201A and I wanted to know whether the Decklink hd extreme works well with the format DVCPRO HD?
Thank you.
Joseph
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