Architect incorrectly applying gamma conversion

Mark Baird wrote on 8/2/2016, 9:29 PM
I just bought Movie Studio platnum to quickly author some BluRays for festival entrys. I imported my first movie, threw it on a time line set it to be the first to play and looked at the preview. The gamma levels are all wrong. It looks like DVD archetect is doing an RGB to Rec 709 conversion. The problem is all my files are already rec 709 compliant. this makes the blacks grey and the whites murky.

How do I make DVD archetect stop doing the unneded Gamma correction on import?

Thanks

MB

Comments

musicvid10 wrote on 8/2/2016, 9:46 PM
DVD Architect makes no colorspace (incorrectly called "gamma") conversion whatsoever. You can take that to the bank.

A file can say REC 709 and have entirely wrong levels! That means it may preview correctly, but play back incorrectly, or vice versa.

Render your files in Vegas, not Architect, to the correct DVDA stream templates, as has been referred to so many times on this forum..Apply the Computer RGB -> Studio RGB levels filter if needed to the output.

If you are making your judgment by viewing the PREVIEW levels, the OUTPUT levels will be different. It's a fact of Sony software.

If you have Vegas Pro, use the histogram to make that determination. If you have Movie Studio, upload a short sample of your ACTUAL source video (not from Youtube!), and we will help you make the proper levels choice. Again, creating correct YUV levels is an entirely manual procedure that you must undertake yourself. Nothing automatic about any of it.

Mark Baird wrote on 8/2/2016, 10:10 PM
I was using the term gamma conversion correctly and was never talking about a color space conversion. I was saying that it appears Archetect is doing what you refer to as a Computer to 'studio" conversion. (changing from full gamma (0-255) to limited gamma (16-235).

The real problem is what you revealed in your fourth paragraph. The preview is just not accurate. a test copy on TV with scopes proves that.

Probably why I don't use sony software much.

FYI the image chain is original CinemaDNG files edited and graded in Resolve Studio and output as DNxHD 220 with 10 bit color. This master file is then converted to distribution formats, taking care to be sure the gamma stays limited since that is what my applications normally need.
Mark Baird wrote on 8/2/2016, 10:35 PM
I do not have, nor would I see a reason to buy Vegas.
musicvid10 wrote on 8/3/2016, 6:34 AM
"

Substitute the word "luminance" for "gamma" and you've got it correct. Did you know that gamma aims to PRESERVE the luminance endpoints? RGB color space is 0-255 luminance, and YUV (709) color space is 16-235 luminance. That is by definition. A properly displayed scene might have a luminance range of 0-255, and a gamma of 2.2 as viewed on a standard monitor. Apples and Oranges.

That's an oversimplified definition, of course, so spare me.

1. Sony's RGB preview space is there by design, so graders can see the full tonal range without clipping. Some complain, others use it to their advantage. Your source luminance is not changed or "converted" by the software without purposeful human intervention; that is the first and most important thing to understand.
2. Your use of the word gamma is incorrect, but common. Gamma does not serve to change luminance directly, which exactly is what you described.
3. Your source would make me wonder why you chose entry level software that doesn't even show a histogram?
4. How are you converting DNxHD 10-bit 422 to "distribution formats?" Please don't tell me you are importing that into Architect {see #6). Your workflow suggests about ten possibilities for color space error, but without that sample I asked for or software scopes, ...?
5. Assuming though that your source levels are at correct yuv levels, they will look flat in the preview and correct in a player. It's a fact of life. To preview playback levels, you can temporarily slap the Computer RGB levels filter on the preview (opposite of above), and remove it prior to rendering. Did you go so far as to actually prepare a Bluray and view it in a player??
6. Never do your render to Bluray format in DVDA. It is a soccer-mom feature the offers you zero control over the results. Again, use the appropriate DVDA stream templates in Vegas, and DVDA will MUX, not recompress, doing so in a few minutes, not hours.
7. I agree, this may not be the best software for you; however, once undertaking the learning curve, many people find it becomes their editing and authoring software of choice..
8. For more information on avoiding recompression in Architect, see Knowledgebase article #84, using the link at the top of this page. Best of luck with your project.
Former user wrote on 8/3/2016, 8:30 PM
You mentioned twice about the distribution formats, but no mention of how these are created. Is this a third party software you are using?
Richard Jones wrote on 8/5/2016, 4:09 AM
I do not have, nor would I see a reason to buy Vegas.

Thank you for that incredibly useful contribution, Mark. I feel so much better knowing that..

Richard