Understanding the AJ-HD1400 and 720p25

We have recently purchased a Panasonic AJ-HD1400
DVCPRO HD deck at work – it’s a confusing and complex beast. I’ll try to share a little about what I’ve learned so far.

My experience to this point with DVCPRO HD has been limited. I’ve worked with the media in various forms, but have only had a very limited involvement with the decks and cameras.

The main selling points for the AJ-HD1400 over the earlier 1200 are that it supports, natively, framerate conversion and CineGamma gamma settings.

In the PAL world we like to produce things in 25FPS rates – meaning we’d tend to shoot 720p25 with DVCPRO HD – which is really an ‘offspeed’ framerate (specifically it has to be 25p over 60fps).

The HD1400 supports this rate natively with it’s 25HD setting.

About 25HD

What wasn’t immediately clear to me with using the 25HD setting is that it also upconverts. A 720p25 recorded tape, in the AJ-DH1400 in 25HD mode will output, via it’s HD-SDI connections, a 1080i50 signal. So it is upconverting as well as performing the framerate conversion.

As yet I have been unable to capture from the deck in 25HD mode via Firewire. It’s not entirely clear what is being sent via the Firewire in that mode – and neither FCP nor Avid Xpress Pro (on OS X) that I have tested it with seem to be happy to capture 720p25, 1080i50 from it.

Making it work

I have not yet found a way to capture 720p25 via Firewire in FCP, and Avid has not support for 720p25 at all. In FCP the only way has been using a Decklink HD Extreme card, with the deck in 60Hz mode, and the card capturing 25fps from the 720p60 signal. Otherwise, with the deck in 25HD mode, and the card capturing the full1080i50 signal.

In 25HD mode, the timecode from the deck is 25fps and appears accurate. In 60Hz mode, the timecode from the deck is 30fps, and reportedly may not be totally accurate on future playings (so there may be frame drift if recapturing at a later date)

[box color="yellow"]The content in this post has been restored from archives after all the site's content was lost in January 2012. Comments from the original post have been lost[/box]