Justin Kwan, Avid Software Engineer, offers insight into his workflow for importing and exporting QuickTime movies to achieve proper brighness levels.
(Reposted from Kwancentral)
There seems to be a decent amount of confusion about which settings should be selected when exporting a video as QuickTime, and then importing the QuickTime movie into an Avid editor. In this article I will describe the proper settings for exporting video out of a third-party application such as Adobe After Effects using the Avid QuickTime DNxHD codec, and then importing the QuickTime DNxHD movie into an editor. Four workflows are shown, one of which is invalid.
This same workflow should hold true for all the Avid QuickTime codecs. It will not apply to non-Avid QuickTime codecs.
Exporting Source Material With RGB Levels
Source media with RGB levels
If you start with source material with RGB levels (0-255), such as the image above, you should select the RGB button in the QuickTime export options shown below. This is because the option in the QuickTime dialog specifies the levels of the source material. However, it isn't a disaster if you don't select the RGB button.
Assume you export two movies. The first has RGB level source material and is exported with the RGB option selected. This is called RGBsource_RGBOption.mov. The second movie has RGB level source material and is exported using the 709 option. This movie is called RGBsource_709Option.mov.
Select the RGB brightness option with RGB source material.
Importing Source Material With RGB Levels
When you import RGBsource_RGBOption.mov into the editor, select the 601/709 option to perform a quick import. Selecting the RGB button will bring the video in at the correct levels, but it will be a slow import. It is OK to select the 601/709 button as the levels within the QuickTime movie were converted to 709 compliant levels when the RGB button was selected on export. Quick import copies the 709 compliant video data from the QuickTime movie to the editor. See the image below for the optimal setting when bringing this movie into the editor.
Select the 601/709 option for import of RGB source material.
If you look at the levels while in color correction mode, you can see that the darkest black is 16 and the brightest white is 235 as shown in the image below. The left side of the color picker represents the darkest black value and the right side of the color picker represents the brightest white value. The levels of the imported media are correct.
RGB source material imported into the editor
When you import RGBsource_709Option.mov, you must select the RGB button in the editor import dialog as shown below. Selecting the 601/709 option will cause the video to come in at RGB levels.
Select the RGB button for import of RGB material exported with 709 option selected.
Exporting Source Material With 709 Levels
Source media with 709 compliant levels.
When you export source material that is already 709 level compliant, as shown above, the 709 button should be selected in the QuickTime dialog options as shown below. The RGB button should never be selected in this scenario, as this will not import into the editor with 709 compliant levels. Assume you export two movies. The first contains 709 level compliant source material and is exported using the 709 option. This movie is called 709Source_709Option.mov. The second movie contains 709 compliant source levels and is exported improperly using the RGB option. This movie is called 709Source_RGBOption.mov.
Select the 709 button for 709 compliant source material.
Importing Source Material With 709 Levels
Import 709Source_709Option.mov using the 601/709 option. This is the only option that can be selected for proper import of this movie.
Now, import 709Source_RGBOption.mov. No matter whether you select the RGB import option or the 601/709 option, the imported levels will be incorrect as shown below.
Media imported into the editor when 709 material is exported using the RGB option.
Post by Justin Kwan