Yellow = MPE enabled and no need to pre-render (Pre-render won't start, only plays the clip)
Green = Premiere Pro has made pre-render files, but doesn't make them if the line is yellow.
There's more information about this here:
Thanks for the reply. In the meantime I did some digging and discovered that"Render Entire Work Area" under Sequence will turn the yellow to green which, according to your link, is preferred to yellow.
"Render Entire Work Area" under Sequence will turn the yellow to green which, according to your link, is preferred to yellow.
The first part of this sentence is correct, but the second part is not. Yellow is perfectly OK as long as you have no problems with playing your timeline. All you achieve by forcing a complete render of your sequence is filling your disk with pre-rendered files, that normally are not used for export, and increasing disk activity and thus wear-and-tear on your disk.
A yellow line is normal. You only force sequence renders if the playback is not fluid and you really need fluid playback.
The documentation's a little sketchy on this point, but my impression is that Premiere (via Mercury) only uses (approved) graphics cards for rendering previews, not for exporting/final renders. If that's true, is there any net gain from rendering previews (accelerated by the graphics card) of the entire project before exporting, and then using those previews during the export, which I thought are supposed to speed things up?
Scaling, blending and CUDA enabled effects use the hardware MPE, the rest is done by software. So, no, you won't gain anything from using preview rendered files. All the de-/encoding is done by the CPU.
> my impression is that Premiere (via Mercury) only uses (approved)
graphics cards for rendering previews, not for exporting/final renders.
That is false.
The CUDA acceleration that works for rendering frames for preview files also works for rendering frames for final export.
As Harm mentioned, when these rendered frames are handed off to the encoder to do the encoding step, the encoding/compression is all done on the CPU.