Downconverting XDCAM HD to SD - problems?

[Peter Newsom]

Originally Posted by Nate Weaver

Paul, people in the film production world have been shooting HD for SD since 2001 or so, when the F900 and Varicam became available en masse.

One other thing, mentioned by Andy above that often doesn't get mentioned (except when I'm rattling on about it). A lot of cameras don't re-introduce edge enhancement to the downscaled image on their downconverts...I have yet to see an HDV camera that does this. The XDHDs do, and you have 3 steps of adjustment. HDCAM and D5 decks have this as well, as well as standalone boxes like a Terenex.

Nate, can you point me towards the edge enhancement setting for down-converting to SD in the HDcam(F350)? I was looking through the manual and couldn't find it.

Thanks Peter

[Tom Alesch]

Originally Posted by Andy Mees

I'd certainly agree that a hardware downconvert, including those available in your camera or deck, is almost always better than anything acheived in software.

In my experience downconverting XDCAM HD with the F70 gives a somewhat poor result compared to DIGIBETA or even DVCAM. To confirm my doubts I captured the F70s SD-SDI (sqeeze mode, high detail gain) to an AVID MediaComposer (uncompressed), exported a frame as TIFF and opened it in Photoshop. Compared to the same frame captured via HD-SDI to a SMOKE-System and scaled down in Photoshop to the exact size of the SD capture I observed on the SD frame:

- an obvious lack of detail in fine textures (skin, hair, trees, fabric, ...)
- a number of white stripes in the first half of the upper line of the frame
- blacked out pixels on both sides of the frame (4 on each side)

When playing around with the menu settings, I found the best result could be achieved with DETAIL GAIN set to HIGH. The CROSS COLOR adjustment didn't make any visible difference.

After mastering to HDCAM there was a conversion done by that recorder to DIGIBETA. The result is very pleasing.

The camera we shot with was the PDW-F350 in progressive scan mode. In the original HD frame (scaled to 1920 x 1080) there are two pixels on the left side and one pixel on the right side that are black. I can't say if it is the camera or the SMOKE-System used for finishing.

Tom

[Peter Newsom]

I shoot NHL hockey news in HD with my 350, and down convert using the camera. As far as I can tell it looks better(quite a bit) than my old BVP90/BVV5 SD combo. I generally use the mid level sharpening. I just wish that I had the SDHDI to output the video in component form.
I have also seen some of my stuff cut together with IMX camera footage, and I thought mine came out looking better. They dubbed my composite out using an IMX machine, and later edited using an Avid system.

[Tim Allison]

Right now, we're planning on shooting EVERYTHING in HD, and if it needs to be down converted to SD, our AJA Io-HD does that quite easily. We're still waiting on delivery of our first XDCAM (F355), so my knowledge is ALL theoretical right now. Are there going to be any problems shooting and editing in native XDCAM (on Final Cut) and then simply dumping a letterbox version to Betacam via the Io-HD to cover any SD distribution needs we may have?