musicvid10,

Yes, my source is limited to 16-235 levels.
But I should be able to render 0-255 levels with a kind of algorythm (filter, colorspace ...)

Black is black, white is white, unless you can compare your 235 or 16 with a 255 or 0 level.
Contrast is just a bit higher using 0-255 instead of 16-235 levels.

As I wrote, most displays are 0-255 capable today.
By increasing a little bit my contrast this way, I should not loose details in dark shadows or highlights.
I know most people do not calibrate their displays,
But as written into french "Qui peut le plus, peut le moins "

So you helped me to re-write my question :
How can I convert a 16-235 video to a 0-255 rvb levels using Vegas Pro ?

No, the DECODER converts proper 0-235 to 0-255 display levels.
Has nothing to do with displays, bit depth, or anything else you mentioned.

What you want to do, increase contrast by clipping, is quite easy to do in Vegas.
This would be done in an 8 bit workspace with your AVCHD source, using one of the levels or contrast filters.

I use 32-bit full range, 1.0 linear, view transform off.

When you use video levels and want to preview correctly, use 'Video Output FX' and add the 'Levels' plugin, selecting preset, 'Studio RGB to Computer RGB'. Then when you render you'll probably need to disable that plugin.

http://www.glennchan.info/articles/vegas/v8color/vegas-9-levels.htm

I do not want to correct my gamma in the 16-235 range because it's already corrected and Ok.

I would like to expand the range to 0-255 AND to keep the overall contrast on my rendered files written on my blueraydiscs, 23.976fps.

Before


After


Jamon, I had a look to your page : I have to read it very carefully now !

Pay close attention to which video formats and players use 0-255 (computer RGB). If a codec and player use 16-235 (studio RGB), then that's what you have to use. If your video player expects everything to be the studio RGB range, then if you supply it with computer RGB it won't match the original source material. Even on computers, often software and codecs expect everything in the studio RGB range.

The reason to use full range 32-bit in Vegas is usually for quality of mathematical processing for things like special effects, gradients, transitions. By editing in full range, you maximize the possible quality, because you have a wider virtual space of numbers to work with. Then when you render, you usually squash that all back down to 8-bit video levels. But it should look more precise if you edited in the full range to start with.

If you are not using much video processing with effects, and you only are converting whole videos, or splicing some together, then I don't think you'll really benefit from editing in full range, because you render down anyways and not much processing was done on the video.

This is just the weird state of things today. We are using computers for almost everything, but they're artificially restricting themselves to standards of the past. That's why you have to pay attention, because if you find the right combo of inputs and outputs in your chain, then it is possible to produce full range videos that are playable. It's just, unlikely, and not everyone but yourself could easily play them back.

It's a lot like how you can use 10-bit per channel color in a Windows PC today, but most software cannot display that, and most people's video card and monitor won't display that. If you want to go that route, you need to pay close attention to make sure every component along the chain supports that 30-bit color. If you do that, then you can see with your own eyes the better range, and you can edit with that, but once you render for the web you have to convert back down to something most people can see correctly with their hardware and software.

If you expand the native range to 0-255, the values between 0-16 and 235-255 will be clipped on playback, meaning you LOSE dynamic range, not gain something. Last time, the decoder takes care of the conversion to playback levels for you. This is fundamental.

Thank you Jamon and Musicvid10 for your help.

I've finally undrestood.
Our hardwares are able to, but our softwares, no in many cases (it is a pitty). Id did not know that before your answers.

Probably in a near futur, a real expander will be able to expand video ranges to full ranges without clipping the 0-16 and 235-255 levels.

I keep using the 8 bits settings !