What colour transfer function to use for a QuickTime file without NCLC atom?

Question

I have various 1080P QuickTimes files using H.264 and MPEG-4 codecs created via QuickTime and Handbrake. They don't seem to have the NCLC atom. I want to know which transfer function to use to generate RGB video.

Under the Finder inspector, some of the files are HD(1-1-1), others don't have any info. In TN2227 Table 1 shows that HD video should use ITU-R709 and SD video ITU-R601. How can I find out if QuickTime decides it's 1-1-1 or considers the file HD ?

Is there a function to find out or do I have to use something like if((number_of_rows > 576) and (aspect > 3:2)) then HD = true ?

Answer 1

According to TN2227,

Important: Media without a ‘nclc’ tag will be color managed by QuickTime X as if it were created in the SMPTE-C color space.