Choices in Avid's export

S

sean90291

Veteran
Two quick questions about exporting files from Avid:

What is the difference between the RGB color level and the 601/709 color level?

and

What is the difference beween 640 x 480 square pixel vs. 648 x 486? I'm not sure why sometimes there's a choice for an extra 8x6 pixels. Hm...
 
RGB is a 0-255 range while 601/709 are SMPTE digital television levels that are 16-235. If you are roundtripping from a graphics program and back use 601. If exporting for computer streaming video, or a film out, use RGB. These are just basic examples, but you need to look at your workflow to make sure you use the right color space or you will see a shift in your final program.

Depending on video format DV, versus analog video, the NTSC frame size does changes. For example, DV does not support close captioning which is outside active picture. The 486 size includes those lines. Check the online help or user guide for more details.

Michael
 
Thanks MichaelP...Before your response, I had NO idea about either of those topics. I now know where to start investigating these options. Cheers.
 
color export option for Sorensen Squeeze

color export option for Sorensen Squeeze

If I'm going to export a QT Reference from Avid so that I can squeeze an MPEG file for DVD burning, should I export from Avid using the RGB or the 601/709 color option?
 
Depends on the MPEG encoder, DVD Studio Pro expects 0-255, others expect 16-235. Try a short test to see if you get the right black levels for your program.

Michael
 
I believe that internally Avid considers everything to be 601/709.

When you import, you are declaring the color space of the material you are importing. If you tell it RGB, it does a conversion, and if you tell it 601/709 it just imports it as-is.

On exporting, you are declaring the color space of the file you are generating. If you say RGB, it converts the data from the 16-235 range to the 0-255 range. If you say 601/709 it leaves it alone.

I personally would rather avoid any extra conversions or processing, so I'm normally a 601/709 kinda guy. Of course that means I have to set up my MPEG encoder to know what kind of color space to expect in the source files.

Anyhow, this is my current understanding. If anyone knows different I would love to hear about it!

geo.
 
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