Video White? What is it?

[Peter Van Lancker]

Hi,

I need to create a Flash animation on a white background for a client and export it for use as an intro for a DVD. He requests it to be "video white". How do I do that? Is it the broadcast-safe option? Or can I do it with notching up the white a bit with grey?

Thanks!

-- PVL

[Dale Stoltzfus]

I'm no pro, by any means, but as far as I know, all pure white is the same in any imaging application (unless you are dealing with HDR): RGB 255 255 255, or Hexadecimal #ffffff.

[Russ Holland]

I too am no expert but video white, or so i read somewhere, is not pure white with 3x 255 values, because on a monitor this would be too blown out. white on video should be represented with three off white values but don't use pure white.

Then again I could be wrong...i'll do some digging.

[Greg Boston]

Originally Posted by Dale Stoltzfus

I'm no pro, by any means, but as far as I know, all pure white is the same in any imaging application (unless you are dealing with HDR): RGB 255 255 255, or Hexadecimal #ffffff.

No, it depends on the colorspace being used, whether it's sRGB, RGB, or YUV.

What he's probably looking for is the 17-235 range used in sRGB (studio RGB).

-gb-

[Russ Holland]

Typically, RGB for digital video is not full range. Instead, video RGB uses a convention with scaling and offsets such that (16, 16, 16) is black, (235, 235, 235) is white, etc

(From Wikipedia)


Sorry Greg - You replied as I was researching :)

[Bill Ravens]

For video under ITU Rec601, that would be standard NTSC broadcast video, RGB is defined as RGB16-RGB235.

For video under ITU Rec709, that would be web display, RGB is defined as RGB0-RGB255.

Any Rec709 compliant video that is played on standard NTSC television will clip all values below RGB16 or above RGB235. The results will be less than satisfactory, being both washed out and muddy. Various codecs expect/produce different I/O standards. The only way to be absolutely sure of what you're generating is to bring along some NTSC pluge bars to view on the final display.

[Glenn Chan]

No, it depends on the colorspace being used, whether it's sRGB, RGB, or YUV.

What he's probably looking for is the 17-235 range used in sRGB (studio RGB).

sRGB is not the same as studio RGB. sRGB refers to a specific color space with its own primaries, transfer function, etc.

studio RGB refers to "RGB" with particular levels. (Where RGB may be ambiguous as to what color space it refers to / you're not sure what transfer function is necessarily being used.)

For video under ITU Rec601, that would be standard NTSC broadcast video, RGB is defined as RGB16-RGB235.

For video under ITU Rec709, that would be web display, RGB is defined as RGB0-RGB255.

Neither standard defines values in RGB. They both define values standard Y'CbCr levels, with black at 16' (Y') and white at 235 (Y'), assuming you're working in 8-bit. The conversion to and from RGB is unspecified.

Both standards are for the video world, not the computing or web world. Rec. 601 is for SD formats, Rec. 709 is for HD formats (and not web display).

Don't get confused with what Vegas 8 does.

2- Peter... to answer your question...

Flash has no way of specifying a video white directly since you can't pick+output Y'CbCr values. Flash can only output RGB values, which get converted into Y'CbCr.

You need to know what RGB-->Y'CbCr conversion/mapping is being used. This depends on the codec. It will either be:
16 16 16 RGB maps to 16 Y'. or...
0 0 0 RGB maps to 16 Y'.
(And similarly for white, 235 RGB or 255 RGB will map to 235 Y'.)
Without knowing what codec is going to be used, you either have to ask him or guess the codec. You could put your blacks at 16 16 16 RGB and whites at 235 235 235 RGB and presume this is what he wanted.

2b- Or if he were smarter, you would give him normal Flash output (black at 0, white at 255) and he would convert the levels appropriately if needed.

3- Broadcast safe is another issue on top of this. Certain highly saturated colors can be somewhat problematic.

4- Do check that all your text is within title safe.

[Dale Stoltzfus]

Ah, yes. Duh - I knew that!

Sorry for any confusion. :)

[Greg Boston]

The length and complexity of Glenn's post just goes to show what a mess we have created for ourselves!

I certainly believed that the small 's' designation referred to studio RGB. There is way too much ambiguity in all of this.

What I was mainly harkening back to, and Bill confirmed, was the ITU Rec 601 standard that I pulled from my memory of reading about color broadcast standards in the Liquid Edition manuals.

-gb-

[Emre Safak]

I'm glad we have someone with Glenn's patience and knowledge to correct mistakes.

[Dmitry Sokayev]

sRGB - Standard (Standardized) color space.
Designed specially for computer/printing/internet/etc needs.

Peter here is a easier way to make sure you do it right.
Finish your animation in Flash within standard RGB color space, then export it to AE, and use Levels to adjust black/white input/output level to 16/235.