If you're downscaling an HD source to SD, I believe you're supposed to indicate that the video is BT.709, so the playback device doesn't incorrectly assume BT.601 or some other SD standard; however, x264 has three related settings:
Code: Select all
--colorprim <string> Specify color primaries ["undef"]
- undef, bt709, bt470m, bt470bg, smpte170m,
smpte240m, film, bt2020, smpte428,
smpte431, smpte432
--transfer <string> Specify transfer characteristics ["undef"]
- undef, bt709, bt470m, bt470bg, smpte170m,
smpte240m, linear, log100, log316,
iec61966-2-4, bt1361e, iec61966-2-1,
bt2020-10, bt2020-12, smpte2084, smpte428,
arib-std-b67
--colormatrix <string> Specify color matrix setting ["???"]
- undef, bt709, fcc, bt470bg, smpte170m,
smpte240m, GBR, YCgCo, bt2020nc, bt2020c,
smpte2085, chroma-derived-nc,
chroma-derived-c, ICtCp