4:2:2 Workflow

[Michael Mann]

How could a 1920x1080 4:2:2 workflow (XDCAM EX HD SDI out-> ... -> Sony Vegas 8.0 in) look like?
Is the EX' 4:2:2 HD SDI output RGB or YUV?
Is the EX' 4:2:2 HD SDI output 10 or 8bit?
What are the data rates?
Which Vegas capture codec would I use?
...
Thanks a lot in advance.

[Andrew Kimery]

I think XDCAM HD and the EX are 4:2:0, not 4:2:2.


-A

[Paul Izbicki]

I can see that this is going to become a major interest point for others as well as myself. The latest review:

http://www.simonwyndham.co.uk/xdcam-pmw-ex1.html

is very specific that the camera outputs HD-SDI in 4:2:2.

My understanding is that the HD-SDI spec requires 4:2:2.

Problem is, all other info specifies the camera recordings as 4:2:0, which the MPEG compressed file certainly is. Does the codec expand/uprez the 4:2:0 back to a full bandwidth, 4:2:2 signal for playout through the SDI port?

Is it perhaps 4:2:2 in live recording only, outputting the pre-compression signal to the SDI encoder, which converts it to 4:2:2? This is the more common practice.

[Bob Grant]

What the codec is doing for recording internally and what the image processor is doing for SDI output need have no connection at all. The same goes for the HDMI outputs.

[Andrew Kimery]

Oops, I over looked the "SDI out" part in Michael's post.

Originally Posted by Paul Izbicki

Is it perhaps 4:2:2 in live recording only, outputting the pre-compression signal to the SDI encoder, which converts it to 4:2:2? This is the more common practice.

That would make sense.


-A

[Tim Polster]

Along the same lines, would one be able to capture the HD-SDI footage to a laptop?

[Andrew Kimery]

Originally Posted by Tim Polster

Along the same lines, would one be able to capture the HD-SDI footage to a laptop?

If you are using something like the AJA Io HD or Motu V3 and a laptop w/an eSATA card connected to sufficiently fast storage I'd assume the answer would be "yes."


-A

[Tim Polster]

How fast of a data rate are we talking?

How fast of storage is needed?

Thanks

[Chris Hurd]

Originally Posted by Tim Polster

How fast of a data rate are we talking?

HD-SDI output is approximately 1.5 gigabits per second. It's a raw, uncompressed feed. Ideally you'll need an encoder on the other end of the pipe to compress it into a manageable, workable format.

[Randy Thompson]

this may be a solution for uncompressed video to compressed video in a laptop.

http://www.magma.com/products/pciexp...ox1/index.html

rand

[Paul Izbicki]

Dunno If I'd want to spend on that solution, since it adds a lot of new potential weak links (connections) to the flow. If I have to be tethered to that much hardware, and I'm thinking studio or indie production here, I'd go to the trouble to bring my G5, get the benefits of having FCP onsite, and use my Kona card to do realtime conversion from SDI to Apple Prores 422, or other edit friendly format, or skip it and go native HD-SDI. Just need a boxcar of RAID storage.

For me, the mantra is still KISS. One thing I do like about the HD-SDI workflow is it's just one BNC connector/line. Only objection to being tethered to even that degree, is not using Steadicam type balanced rigs.

[Bob Grant]

Originally Posted by Tim Polster

Along the same lines, would one be able to capture the HD-SDI footage to a laptop?

You no longer need to lug around a laptop, Convergent Design have a little box that'll record at 50Mb/sec to CF cards from HD-SDI:

http://www.dvinfo.net/conf/showthread.php?t=102312

[Greg Boston]

Originally Posted by Paul Izbicki

My understanding is that the HD-SDI spec requires 4:2:2.

Problem is, all other info specifies the camera recordings as 4:2:0, which the MPEG compressed file certainly is. Does the codec expand/uprez the 4:2:0 back to a full bandwidth, 4:2:2 signal for playout through the SDI port?

Is it perhaps 4:2:2 in live recording only, outputting the pre-compression signal to the SDI encoder, which converts it to 4:2:2? This is the more common practice.

That is exactly how it works. Same with the full size F350, and the Canon XLH1, XHG1.

Live HDSDI before recording is uncompressed 4:2:2. After recording, MPEG compression and chroma subsampling have taken place. Playing back pre-recorded material will be upsampled as you indicated to conform to the HDSDI spec.

-gb-

[Paul Izbicki]

Re the Flash XDR press release:

The reason to go this route would be to gain 4:2:2 HD-SDI capture capability. The next format step down it offers is essentially what the EX records on SxS cards.

So, $5000+CF cards. 26 Min of storage across 2 16Gb cards
(at HD-SDI/160Mb/sec)
2x16GB cards= $400 (High speed CF16Gb=$200ea street)
4 cards x $200 = 52min for $800.
Euro price for two 25min 16Gb SxS-$1930.
2.4lbs. + batttery.

No thanks. Might be attractive to some production houses, but expensive for the indie producer or filmmaker. Might be a good item for rental. I'd sooner do the SxS shuffle, and convert to a lossless codec on capture. Users could add single cards as they can afford, and as price drops. If third parties truly offer compatible SxS, prices will drop drastically.

Have to make the transition someday. Meantime, I could live happily if the stored signal is upconverted to true 4:2:2 for playout from the cam or forthcoming player.

[Paul Izbicki]

Originally Posted by Greg Boston

That is exactly how it works. Same with the full size F350, and the Canon XLH1, XHG1.

Live HDSDI before recording is uncompressed 4:2:2. After recording, MPEG compression and chroma subsampling have taken place. Playing back pre-recorded material will be upsampled as you indicated to conform to the HDSDI spec.

-gb-

Good enough for government work!
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