for hd screencast, should I convert to yuv using rec709 or pc709?

[codemaster]

I have an .avi file. It was exported from Camtasia Studio. The codec Lagarith was chosen. The mode RGB was chosen in Lagarith settings. The avi file has: 1280 x 720 px, and 15 fps.

Before I can encode it with x264, I have to add the function

ConvertToYV12()

in AviSynth.

But now I don't know what value to use for the "matrix" parameter.

I have two options. Option 1 is:

ConvertToYV12(interlaced=false, matrix="Rec709")

Option 2 is:

ConvertToYV12(interlaced=false, matrix="PC.709")

Questions:
1. Which of the above two options do you recommend? Which is the correct one? Are both correct?
2. How do I determine which of the two options to choose? How to I determine which one is correct, why it is not correct, and why I shouldn't use it?

[KarMa]

Rec709 is for TV luma levels, and what is pretty much expected for any 720p/1080p content. It's even commonly used for UHD content still. If you are wanting to share your video with other people then Rec709 is what you want.

[SameSelf]

Interesting question. Since you are likely capping full range RGB images (e.g. white is 255) from your 'puter, I wonder if wantonly applying a Rec.709 conversion will clip the shadows and highlights? Or does it have a soft touch? Maybe someone can confirm? The good news is RGB is fully defined with YUV, so you shouldn't be plagued with out of gamut values. Colorspace conversions are the bane of nitpicky editors.

[raffriff42]

ColorYUV(analyze=true)


This tells you exactly what your YUV values are.
Look for Luma Loose Minimum ~16 (in dark scenes) and Loose Maximum ~235 (in bright scenes).
Try both Rec709 and PC.709 -- one of them should be obviously wrong.