Fix three DVD video-attribute bugs surfaced by a PAL disc detected as
NTSC:
- PAL/NTSC: parse video_format from VTS_V_ATR bits 5-4, not bits 1-0
(the old mask read permitted_df, so PAL 576i/25fps was mis-detected
as NTSC 480i/29.97). Named consts replace the magic bit positions.
- Anamorphic aspect: write MKV DisplayWidth/Height from the disc's
display_aspect (16:9 720x576 -> 1024x576) instead of square pixels,
so 16:9 DVDs no longer render as 4:3.
- Colour: stamp SD colorimetry (PAL=BT.470BG, NTSC=SMPTE-170M) instead
of BT.709 (HD).
Adds VideoStream.display_aspect (threaded through every muxer) plus
TvSystem/DvdAspect/ColorSpace plumbing, with regression tests. Removes
the deprecated Disc mux set_halt bridge (use with_halt).
Matthew Jackson
e96528ad5b