View Full Version : Why use uncompressed 10bit video?


Brian Sargent
December 14th, 2006, 11:52 AM
Hi all,

I am interested in producing the best DVD possible for a 5 min demo reel which was shot in DVCProHD 720 24p. Because I only have a laptop and a crappy old TV, I can't see with enough critical level of detail exactly what it is I'm sending out. The only assumption I am making is that the client/producer has better equipment but does not know how to set it up properly (ie displaying the proper aspect ratio). I have to assume further that this reel will be viewed either on:

1) A regular 4:3 TV monitor
2) A computer monitor.
3) A Wide Screen Plasma

I would want a demo reel to account for all 3 viewing situations, and that all the viewer would have to do is choose the proper one from the menu I create in FCStudio. After I complete my final edit in a DVCProHD timeline, I usually make new Sequences for each of the 3 viewing situations in the timeline, render them, export QT Ref files to compresser and finally run them through a custom a MPEG-2/Dolby 3 setting before exporting to DVD Studio Pro.

My question is, am I squeezing as much out of my HD footage that I possibly can onto DVD? How or Why would I send an uncompressed 10bit file to compresser and does this indeed make for a better DVD? Why, if DVD's can only play MPEG-2 formats,would it matter if I sent a 10bit Uncompressed file, vs a DVCProHD vs DVCPro50 file to DVDStudio Pro to then just make a MPEG-2 file? Wouldn't it just be best to go straight to to MPEG-2 from FCP to Compresser?

( or is uncompressed 10bit is really MPEG2 after all??) UNCLE!!!

Gunleik Groven
December 14th, 2006, 12:03 PM
If you've been doing heavy compositing and color work on your movie, uncompressed could be an option before going to mpeg2 (uncompressed is btw not mpeg2 compressed...)

I would do an a/b test. What I consider VERY important before final render is to change the sequence settings to "Render all YUV material in high precision YUV" and motion to best.

I guess this will get you quite a long way (and if you choose to go uncompressed it's quite silly not to have this setting for final output)

You'll see huge differnces in banding with and without this setting.

Gunleik

Glenn Chan
December 14th, 2006, 02:45 PM
I don't think you'll really see any difference, since banding artifacts are rare and masked by noise.

Other factors would make a bigger difference... content of the shots, packaging of the DVD, aliasing/blurriness/ringing when you resize the image, compression method, etc.

Shane Ross
December 14th, 2006, 08:04 PM
I edit and deliver shows to cable networks edited in the DVCPRO HD format. We simply upconvert the footage to 1080p 23.98 and record onto D5. This doesn't increase the quality, just allows it to be recorded onto tape.

ANYWAY...what I am saying is that the DVCPRO HD codec is a darn good one, and there is no reason to go uncompressed. You gain nothing in quality beyond what you have.

Gunleik Groven
December 15th, 2006, 03:43 AM
Isee quite a difference in banding when doing final render in DVCPRO HD with and without the high prec YUV setting. But that may be only me.

Gunleik

Brian Sargent
December 15th, 2006, 04:03 PM
This helps a lot. I tried them both and thought the 10bit actually looked worse, and started getting confused.

(I rendered my edit in a 10bit uncompressed timeline and exported that to compresser, I too saw some strange banding in the highlights). I'll try the high Prec YUV setting as Gunleik suggests and see if it's any better.

Ultimately, I think I'll probably just stick to the original HD codec as Shane and Glenn recommend.

Glenn Chan
December 15th, 2006, 08:02 PM
Isee quite a difference in banding when doing final render in DVCPRO HD with and without the high prec YUV setting. But that may be only me.

Well sometimes theory does not follow practice. :D

Rendering in 10-bit (i.e. with a 10-bit source; not the intermediate bit depth/format) in Final Cut Pro follows a different route than other modes. So for example, some bugs only crop up when working in 10-bit. This might be a case of that? I haven't tried myself.

2- Not all 8-bit is created equal; better codecs will dither the results, which causes banding to be more invisible.

Gunleik Groven
December 16th, 2006, 03:31 PM
As for DVCPRO HD - I can offer some quite telling screencaps -;)

But I'm generally happy with that format, as that's what I'm shooting, so for upsampling I'm not a big user.

I am from DV, though.

G