View Full Version : High Def to DVD quality losses?


Walt Noon
March 25th, 2008, 01:20 PM
I recently did a two camera shoot with a standard def consumer camera (Optura Xi), and a high def XH-A1.
When I viewed the edit as a high def HDV file, not surprisingly, the high def A1 camera clearly had the richer picture with better colors and contrast.
However, after I rendered the project to DVD, I was amazed to find my fortunes switched! The high def picture looked "washed out" and the low def consumer camera shots actually looked BETTER than the high def shots when rendered to DVD.
I found the exact same thing when rendering to WMV.
Is there any reason a high def image suffers so much when rendered to these other formats?
I'd hate to have my high def camera produce a worse image than my low def when rendered to a DVD (which is where it will usually wind up).
Can I fix it?
I'm using Vegas 6, and the Cineform intermediate.
I'm rendering the Mpeg2 files for the DVD from Vegas as well, and not recoding with DVD Architect.
Thanks!

David Newman
March 25th, 2008, 05:03 PM
This the pain of Vegas using of "studio RGB" (black at 16) instead of computer RGB (black at 0.) "Washed out" tells me you are not handle the RGB ranges correctly. Someone get this wrong every day using Vegas, it is surprizing to me that it is not made easier on users. The quick fix: place the studio RGB to cumpter RGB filter on output for rendering. Users shouldn't have to do that. Search on "washed out" and you will find hundreds discussing discovering the same thing. The weird thing is studio RGB is better then cgRGB, it just shouldn't impact your editing experience like it does. I told Sony of my opinion on this before. The good news is there is nothing wrong with your HD footage, just setup issue.

Mark Williams
March 25th, 2008, 06:20 PM
David,

Your help on this and other items is much appreciated. It is really amazing the amount of help that is available on this site. You are one of the shinning stars.

Paul Kellett
March 25th, 2008, 06:23 PM
This the pain of Vegas using of "studio RGB" (black at 16) instead of computer RGB (black at 0.) "Washed out" tells me you are not handle the RGB ranges correctly. Someone get this wrong every day using Vegas, it is surprizing to me that it is not made easier on users. The quick fix: place the studio RGB to cumpter RGB filter on output for rendering. Users shouldn't have to do that. Search on "washed out" and you will find hundreds discussing discovering the same thing. The weird thing is studio RGB is better then cgRGB, it just shouldn't impact your editing experience like it does. I told Sony of my opinion on this before. The good news is there is nothing wrong with your HD footage, just setup issue.


David,could you explain the above proccess.

Thanks,Paul.

Paul Cascio
March 25th, 2008, 08:32 PM
I just had a similar experience, so I'd love to hear the nuts and bolts of this technique too. Thanks David.

Mike Kujbida
March 25th, 2008, 09:41 PM
To convert from Studio RGB to Computer RGB (or vice versa), click the FX icon and select "Color Corrector (Secondary)".
In the Preset window, select "Studio RGB to Computer RGB" (or "Computer RGB to Studio RGB").
That's it :-)

BTW, Glenn Chan has two excellent articles on color space ("Explanation of Levels and the Different Color Spaces used in Sony Vegas" and "Color Spaces in Vegas 8") on his site (http://glennchan.info/articles/articles.html).
Highly recommended reading!!

Mark Howells
March 26th, 2008, 06:31 AM
For idiots like me what exactly does this mean in a practical sense?

I have just started editing hdv in Vegas. Will this default to Studio RGB in the Vegas preview window and therefore true blacks at zero and whites at 100 using the scopes?

If I render out and downconvert to SD on DVD, do I keep it as Studio RGB. ie apply no preset If I render out to an internet format such as wmv, do I then apply the Studio RGB to Computer RGB preset to ensure the levels are correct. What about H264.

Kevin Janisch
March 26th, 2008, 01:05 PM
Wouldn't this have an adverse affect on color correcting? I just imported some footage into Vegas that looked vivid while capturing with a 3rd party app but was washed out in Vegas. Imported the same clip into Premiere and it looked good. Changed my setup per this thread's recommendation and all looks like it should, but I just finished up a piece yesterday with full CC. When I apply this to my finished project, blacks are crushed and highlights are blown. So if you're doing your thing with CC and then output using the Studio RGB to Computer RGB, how does the end result DVD on a HDTV or CRT compare to what your seeing while color correcting? Shouldn't this be the first thing you do before any CC? Shouldn't this be automatic? Premiere doesn't have this problem.

Kevin

David Newman
March 26th, 2008, 01:24 PM
Sony created this trouble, they should have a white paper on the correct proceedures. I would love to see it.

Paul Cascio
March 26th, 2008, 02:08 PM
Really dissapointing that Sony would allow what would seem to be an easily correctible problem to exist. I love Vegas, but this is a deal killer in my opinion.

Matthew Roddy
March 26th, 2008, 03:31 PM
And from what I understand, it's even wackier in 32bit mode with gamma being this or that or maybe something else.
As mentioned, Glenn Chan tried his best to explain it, but... it's way beyond me at this point.
I do wish there was a one-sheet (is that the same as a white sheet?) that said:
To make a DVD from HDV material in 8 bit mode, do this:
To make a DVD from HDV material in 32 bit mode, do this:
To make a WMV (or similar) from HD... etc...
That, I might understand... maybe...
Better yet, why can't Vegas just behave like other edit programmes like Preimer or even FCP.
But looking through some of the Stickies that have nearly 200 posts each is just mind boggling. Makes trying to gleen info from them very daunting indeed.
Don't get me wrong, I love Vegas - been using it since V4. But now that I'm into HDV and hopefully soon into HD, I'd like an easy, smooth workflow that you don't have to have several workarounds for.

Perrone Ford
March 26th, 2008, 03:31 PM
I love Vegas, but this is a deal killer in my opinion.

Why?

Not that I am a Sony apologist...
I always work in 32bit. Seems to me that if I am planning on going to the web or DVD, I'll lay on a Studio to Computer level and render. If not, turn it off. On projects I don't plan to take to the web or DVD, I just work normally and render out.

I just don't see how that's a deal killer. When I worked with Canopus, ONLY Canopus could read the AVI files! It was like Cineform, but without the open sharing and free decoders that Cineform offers.

[edit]

You know, since I am in the middle of a project right now that is going to render out for web as well as DVD, I just checked my settings. 32 bit, linear (1.000), and my renders to mpeg, mov, and wmv all look very close to what I have in the previews. And yes, I use a calibrated monitor to see what things will actually look like NTSC also. No levels, no trickery, it just works. Maybe life is different for 8-bit folks, but I am VERY pleased with my results and I am not doing anything special at all.

Paul Cascio
March 26th, 2008, 07:11 PM
I see you point Perrone, but unfortunately we don't find out about this flaw until we render. Even then, Sony doesn't tell us why, or how to fix it.

Perrone Ford
March 26th, 2008, 08:28 PM
Do you guys not do test renders? I typically highlight five seconds of video in different places (dark, bright, saturated, etc.) and run those through a quick render to tell me how the codec I am going to use, is going to hold up at the selected bitrate.

When I am happy, I'll run the whole thing. If I am going to DVD, I can tell when I drop the proof into DVD Architect how it's going to look. If my colors are all screwed up, I know about it BEFORE I burn the whole thing.

It takes 5 minutes and can save hours of trouble. But I do this kind of thing daily, so I've built up my confidence. I know mostly how the codecs I use will respond. I've been rechecking a lot lately since I've just gone to a cineform workflow, but so far, so good.

Everything still just "works". The proof DVD that I rendered the other night was spot on with colors. I couldn't have been happier, and I didn't need to change any levels or anything else.

32-bit may be slower, but it's consistent, and I love my results. I wouldn't trade this confidence for the bit of speed I might get back in 8-bit and having to fool with the gamma and levels, etc.

Paul Cascio
March 26th, 2008, 11:31 PM
Pardon these questions, but how do you set for 32 bit, and can it be done at any time?
Also, how much longer do you estimate it takes to render v. 8 bit?

Perrone Ford
March 27th, 2008, 12:10 PM
All this specuation got my mind wandering last night and this morning. And I decided to try something.

Suppose you could generate video that was clean and with known colors, render that video, and pull it BACK into vegas. Then modify it to match colors with what your started with. The corrections that were necessary would be a fixed quantity that you could save as an effects chain, and you could just drop onto any timeline when you were going to render out. This way you could be sure your colors were correct for the medium you were going to.

So, with that in mind, I created a project that had color bars, gradients, pluges, and porches. And I rendered to MOV (mpeg4), mpg (Mainconcept DVD), WMV, and Cineform. I used 32 bit float, and linear gamma, just like I do with all my projects.

What I got back was interesting.

Going to MOV with the mpeg-4 codec, the video shifted dark by .01. That change in brightnes/contrast put the pluges right back on the money. Color levels were unaffected in both the gradients and the bars. (bitrate 4Mb)

Going to WMV the colors were on the MONEY. It was like looking at generated media. But the video shifted bright by .01. So I corrected that and all was right with the world (bitrate 4mb)

Going to Cineform, the brightness was spot on, as were the colors, but the colors bloomed a bit. VERY interesting. (no options on encode)

Going to Mpeg, the colors bloomed a bit. Especially Magenta and Blue. Cyan was affected a bit, but the other colors seemed untouched. Brightness seemed to drop about .005 but I left them alone. There was some waviness on each line of the waveform when looking at the pluges. I don't know what the codec is doing, but it's strange, and none of the other codecs introduced anything that looked like it.


I did see one thing that shocked the HECK out of me. And it will change the way I work in Vegas from now on when doing correcting work. Changing the preview changes the results dramatically on the WFM and the Vectorscope. Using Best Full is of course accurate. Using Best Auto, is tolerable. But anything less and you really can't rely on the scopes. This really surprised me as I had expected the scopes to remain accurate regardless of my "preview", but this was not the case.

I am very pleased I did this little experiement, but it reinforced what I had been seeing in my work. Staying in 32 bit with linear gamma produced accurate, repeatabe results when going out to MOV, WMV, DVD, and Cineform. I can't speak to the 8-bit workflow since I don't use it. Maybe someone else can redo this with those workflows and see what the results are.

-Perrone

Walt Noon
March 30th, 2008, 11:49 PM
Thanks to everyone for your input! SUPER advice!!! I tried it all, and I learned a lot. You guys are awesome!
I just thought I'd leave a comment with regards to my opinion after "trying it all."

Thanks to David Newman for the suggestion of using computer RGB.
He is exactly right on both counts. First, it does improve the contrast, AND it "fixes" the blacks which definitely improved the washed out look I was getting. BUT, he was also right that the "studio RGB" picture is just plain better otherwise. So, going to computer RGB is not an ideal fix if you're finicky. (This stuff MAKES you finicky!)

So, my humble opinion after much play with this is that the best solution is Perrone Ford's suggestion of test rendering a few seconds to your planned codec, and looking at the results so that you can adjust your picture for that codec.

If I really have time on my hands in the future, I thought I might fiddle with trying to make a preset that boosts the right values to give a good picture when rendered to DVD.
I don't know about you, but in general, that's where my work is going to wind up being seen. At least for now....

Thanks again everyone!

Walt