[BUG] MKV Advanced Video Signaling Options Have No Effect

[potejan]

ULYO +
Matrix: SMPTE 240M
Range: Bradcast Range
Trasfer Matrix: ITU-R BT.709
Primaries: SMTPE 240M
->
Color range                              : Limited
Color primaries                          : BT.601 NTSC
Transfer characteristics                : BT.709
Matrix coefficients                      : BT.470 System B/G

Primaries: SMTPE 240M != BT.601 NTSC (SMTPE 170M)
Transfer: BT.709 == BT.709
Matrix: SMTPE 240M != BT.470 System B/G

SMTPE 240M primaries are functionally equivalent to BT.601 NTSC (SMTPE 170M) primaries, but they are still different indexes in the H.273 coding (6 vs. 7).
Check https://www.itu.int/rec/T-REC-H.273/en page 5. MKV supports both (https://mkvtoolnix.download/doc/mkvmerge.html) so I don't see a reason it would get changed.

SMTPE 240M matrix and BT.470 System B/G matrix are completely different however, and this is the big problem.

SMTPE 240M matrix:
KR = 0.212; KB = 0.087

BT.470 System B/G matrix:
KR = 0.299; KB = 0.114

The same thing happens if you use SMTPE 170M as matrix (the BT.601 NTSC standard). It gets converted to BT.470 System B/G (the BT.601 PAL standard).

Source: https://www.itu.int/rec/T-REC-H.273/en

Also, may I recommend using ffprobe for this instead of MediaInfo since the former gives the actual codename of the color profile, versus the generic name of the latter (bt.601, bt.601 ntsc, bt.601 pal, etc.)