Controlling HDV when capturing HDMI or HD-SDI

Most HDV editors are ecstatic when they hear about all of the many benefits of using HDMI capture in post-production, as explained in the two prior articles Why capture HDV via HDMI? and Universal HDV Deck. The next question is how to control when capturing via HDMI or HD-SDI, in order to retain timecode and recapture capability.

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Universal HDV deck (almost)

Up until now, post-production facilities that accept HDV footage have confronted a major dilemma: If they bought a JVC BR-HD50 deck (US$3,399 list), the only HD recordings they could play were HDV 720p from JVC (none of the HDV 1080i tapes from Canon or Sony). On the other hand, if they bought one of the professional Sony HDV decks (currently between US$2,480 and US$8,290 list), they could play any HDV 1080i tape, but as soon as they tried to play an HDV 720p tape, the IEEE-1394’s video output would mysteriously go blank. Out of desperation, some facilities went to the extreme of buying two HDV decks: one JVC and one Sony. In other cases, people bought a Sony HDV deck only, and then settled for an analog capture from HDV 720p recordings, with its noticeable D>A>D conversion as shown in this breathtaking video (courtesy of Convergent Design and JVC Italy), and in some cases (as with the HVR-M15 and HVR-M15A when playing HDV 720p tapes), a forced, undesired cross-conversion from 720p to 1080i. This is a nightmare for a purist! But hold on…

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Why capture HDV via HDMI?

For many reasons explained in my recent article, it makes a lot of sense to capture your HDV footage directly to an editing i-frame códec like ProRes422. One of the best way to do that nowadays from HDV is via HDMI. Editing directly from ProRes422 files (as opposed to hybrid editing or native editing, as explained in the prior article,) offers you visually frame-accurate editing, which is critical whenever your project includes:

• Critical multilayer editing
• Independently recorded 48 KHz audio which needs to be lip-synced

If you try to do either of those two things from your raw long-GOP HDV footage directly, you’ll find that what you see is rarely what you eventually get. This has nothing to do with choosing to shoot in HDV or not; but it has everything to do with how to post-produce your HDV footage, especially when your production will include either of those two demanding facets mentioned above. (If your production includes neither of those facets, and you are very short on space, then hybrid editing or native editing would work, but you would miss out on some of the other advantages you’re about to discover.)



Advantages of capturing via HDMI directly (or via HD-SDI) as opposed to other methods include:

• Avoiding unnecessary D>A (digital>analog) and A>D (analog>digital) conversions by keeping your HD signal as digital (as opposed to capturing via component analog). Click here to see a breathtaking comparison video, courtesy of Convergent Design and JVC Italy. The same HDV 720p25 footage was captured from the same HDV tape both via component analog HD and via HDMI>HD-SDI, and compared. This video is in 1280x720 in WMV. If you are on a Mac and have not done so yet, please download Flip4Mac’s free WMV component for QuickTime here, which will allow you to see WMV in your QuickTime Player.
• Taking advantage of the HDV deck’s correction circuit (which is unfortunately bypassed via IEEE-1394).
• You can get a more universal HDV player (see details later in the next article, Universal HDV deck, coming January 8th).
• You can save time and space (as opposed to capturing via 1394 and converting later)
• You retain Log & Capture, deck control, original timecode, and (as a result) recapture capability (as opposed to using FCP’s HDV-ProRes422 capture preset via 1394, where you sadly lose all of these four features)

The rest of this article has been moved to Allan’s PVC channel. Click here to view it.

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