Sony YUV codec problem.& EX1 good news.

farss wrote on 3/15/2009, 1:29 AM
I just rendered a 720p50 project to the SD 50i SonyYUV 8 bit codec with a PAL Widescreen PAR.

Bought that into a PAL DV Widescreen project.

1) Vegas fails to read the PAR correctly. Not the end of the world, immediately obvious and easily corrected.

2) I glance over at my little external CRT monitor and wonder what has gone wrong. The dancers look like they've got a bad case of St Vitus Dance. I'm wondering if something wierd has happened going from 50p to 50i but no, Vegas has read the wrong field order from the AVI file. Easily fixed but not at all obvious unless you happen to check what you're doing with a CRT.

I know I've many times recommend the SonyYUV codec as a DI. I'd suggest anyone using it checks for field order problems. I haven't noticed this before so maybe it's just rendering from 50p to 50i.

For anyone wondering why I was rendering 50p to 50i.
I tried shooting 720p50 with my EX1 as I'm only delivering SD. Bob like, Bob like this a lot!

I turned Detail down to -20, turned Off Auto Knee and left it at 90. I always find the EX1 gives the best results if slightly underexposed and did that this time. I did a bit of reframing using Event Pan/Crop in a 720p50 project, tweaked levels a bit with curves and rendered to SD SonyYUV. Dropped that into a new project, added Unsharpen Mask at the Ligth Preset and encoded to mepg-2 for DVD. Looks pretty sweet. I think I'm finally happy with shooting with my EX1 for SD delivery, phew. Best of all, no aliasing or line twitter problems. Last time in the same venue shooting 1080p25 I had several horrors with twitter and aliasing, some of the worst I've seen.

Just one thing to watch out for. If you set the shutter to 180deg at 50p what you get is a 90deg shutter at 50i. Next time I'll turn it Off.

Bob.

Comments

megabit wrote on 3/15/2009, 6:22 AM
Bob,

It may be a dumb question, but why not straight from 720/50p to SD widescreen PAL DVD mpeg2 - in other words, what's the advantage of the Sony YUV avi intermediate?

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craftech wrote on 3/15/2009, 9:27 AM
Bob,

If the final result is Lower Field First and you are shooting the EX1 in 720p, can you outline each step in your process in which the field order changes and what it changes to in each step?

John
farss wrote on 3/15/2009, 1:19 PM
"what's the advantage of the Sony YUV avi intermediate? "

Technically nothing. However I was using Pan/crop on the original footage and wanting to apply the Unsharpen Mask after it was downsampled and I needed it done in a hurry. I was also getting tripped up with that differences in AR between HD and 16:9 SD AR.

I'll certainly go back and try to find a way to do it all in one step.

What I don't quite understand is this.
I started with a 16:9 SD project, in Event/Pan crop told it to match output AR. Keyframed my zooms and pans and then switched the project to HD and damn, I had those tiny black bars back again in the rendered output.

Bob.
farss wrote on 3/15/2009, 1:33 PM
I'll need to check this carefully. I've had quite a few issues with Vegas and the YUV codecs coming off DigiBeta. I've never before had an issue (that I know of) using Vegas created YUV AVI files.
My best guess at the moment is when I rendered from 720p50 to YUV but I really want to go back and check this as in the hurry to get the job out the door I wasn't in any mood to diagnose in depth.

Bob.
Coursedesign wrote on 3/15/2009, 8:27 PM
NTSC Digibeta (and SDI!) is 720x486, compared to 720x480 for NTSC DV25/DV50 and MPEG-2 (for DVD) codecs which use groups of 16x16 pixels.

If you're working with 720x486 footage, there are six lines to remove when outputting to DV and DVDs, 2 lines at the top and 4 lines at the bottom.

You can do the stripping as part of your DV/MPEG-2 rendering, but this can be very slow, so a pre-crop has advantages.

On top of that I think the Digibeta format has 8 pixels at the beginning and end of each line that contain no information, so a crop here too may be needed (I shoot mostly D5, not Digibeta, so I can't test this).

farss wrote on 3/16/2009, 12:17 AM
I find the following useful:

http://lipas.uwasa.fi/~f76998/video/conversion/

As you said in NTSC D1 is 720x486. Actual Active Picture is 702.85x486.

In PAL D1, DV, DVD etc is 720x576. Actual Active Picture is 702x576.

I believe it's permissable to have vision in all pixels, even the ones outside active picture and some displays do indeed seem to display them all.

Bob.