Sony AVC to MainConcept MPEG-2 unexpected result

Lou van Wijhe wrote on 9/19/2015, 10:03 AM

I have a series of AVC-files for Blu-ray use (AVCHD footage edited in VP13 and encoded with the Sony AVC encoder). The levels are exactly within the 16-235 range. I tried to convert them to MPEG-2 using the MainConcept encoder for someone wanting a DVD version. The output is crisp but the contrast is higher and the images are a bit darker. The levels appear to go outside the correct range.

I was under the impression that the MainConcept encoder expects and outputs video levels in the 16-235 range only. Can someone give me a tip for getting an output where the levels are unaltered? TIA!

Lou

Comments

Lou van Wijhe wrote on 9/19/2015, 1:29 PM

I think I'm beginning to understand what might be going wrong. In fact, I've been using output files, that were already gamma corrected in the rendering process, as input files in a second process, where they were gamma corrected once more.

I just started a render where in the Project Properties the pixel format was specified as 32-bit floating point and compositing gamma 1,000 (Linear).

Let's see if whether this helps or that I'm doing something silly.

Lou van Wijhe wrote on 9/19/2015, 1:35 PM

I was indeed doing something silly. The output looks ugly (overly vivid) already in the preview.`

P.S.
The output looked ugly because I forgot to set the View transform to Off. Nevertheless, rendering the footage with these settings didn't improve anything. So, problem unsolved...

astar wrote on 9/19/2015, 8:34 PM

One thing I noticed in your workflow is the conversion of AVC 8-bit files to 32-bit full range with a 1.0 gamma. This will change the look of your files significantly.

If your output is to BD or DVD (MC MPEG2) keep your edit workspace in 8-bit mode and render to the various formats and see if that works better for you.

If you feel you need to work in 32-bit mode, work in 32-bit Video Levels. If you apply a monitor correction filter, you will still need to disable this before rendering.

DVD players, flash player / YouTube, and windows media player all transform 16-235 media to 0-255 when playing back.

I find getting another monitor, and setting that device up for external preview, then enabling the adjust sRGB to cRGB setting the preview device setting works to allow a converted view while working in sRGB. The Vegas preview will remain displaying sRGB levels, so you get a look at how both views will look. This also keeps you from forgetting to disable the Vegas preview windows conversion filters.

Lou van Wijhe wrote on 9/19/2015, 10:05 PM

Thanks for your response, Astar, I'll think things over...

Lou