pub const VI_PAL_V_TOTAL_THRESHOLD: u32 = 550;Expand description
The encoded VI_V_TOTAL register value above which a field is treated as
PAL rather than NTSC.
The comparison is against the raw register value, which encodes half-lines − 1
(total_halflines() == VI_V_TOTAL + 1): NTSC programs ~524 (525 half-lines), PAL
~624 (625 half-lines), so the encoded > 550 splits them with wide margin.
Shared by Vi::field_hz (the field-rate select) and bus::scanout_scaled (the
geometry ispal select) so cadence and geometry agree on the region. Named after
N64brew Video Interface §Clocks (region field lengths); the register at this
offset is VI_V_SYNC in the wiki’s naming.