The PlayItem STN (stream-number) table offset was hard-coded to 32, which
is only correct for a single-angle PlayItem. A multi-angle PlayItem inserts
number_of_angles(1) + flags(1) + (number_of_angles-1) angle references (10
bytes each) right after still_time, so its STN begins at 32 + 2 +
(number_of_angles-1)*10. The fixed offset lands inside that angle block and
misreads the stream counts as garbage (e.g. n_video=51 on Spider-Man 3 UHD
00245/00246.mpls, number_of_angles=2 => real offset 44), dropping every
stream including the primary video. That makes DiscTitle::has_video() return
false, which drops a multi-angle/seamless-branch feature from the disc's nav
candidate set and loses it in main-title selection.
Compute the STN offset from is_multi_angle (bit 4 of item[10]) + number_of
_angles. Add a regression test building a 2-angle PlayItem and asserting the
video stream is found past the angle block.
Validated on a 92-disc real UHD/BD corpus (offline scan): 0 main-feature
pick changes vs baseline, 3 multi-angle titles (Spider-Man 3 244/245/246)
recover has_video. Adds examples/corpus_titledump.rs as the regression tool.
dvd_placement_invariant_on_a_real_folder checks, per title set, the sum
ifo.rs relies on: file_start_lba(VTS_nn_0.IFO) + vtstt_vobs must land on
VTS_nn_1.VOB. It reports all 13 sets correct on a real DVD folder, which
is what excluded placement as the cause.
dump_titles_for_an_image prints every title a scan produces with the
numbers canonical_title_order sorts on. It is what showed the real shape:
the same disc scans to 38 titles as a CSS image and 10 once decrypted,
with identical capacity and a byte-complete image.
Both are #[ignore]d and read their target from the environment, so they
cost the gate nothing and are there for whoever picks the defect up.
from_coding_type maps 0x20 (MVC dependent view) to Codec::H264, so the existing
PAT/PMT scan surfaces the SSIF right-eye substream as a second video stream on
its own PID instead of dropping it as Unknown. No new parser: the dependent eye
rides the same demux path as any other TS video stream. Removes the throwaway
3D-structure probes (findings captured in prior commit messages).
Empirical (300, clip 00042): base .m2ts (1567 extents, 25.85 GB) is entirely
inside the SSIF LBA span; dependent = SSIF − base = 1567 ranges, 9.59 GB
(exact vs 35.43−25.85). 200/200 sampled dependent-view units decrypt under the
base UK. => de-interleave needs no SSIF parsing (complement of the base extents
we already resolve), and the dependent eye needs no extra key.
Dev tool for the 3D build: uses the library UDF reader (7z cannot parse these
ISOs) to dump base .m2ts vs SSIF sizes and the MPLS ExtensionData entries
(STN_table_SS + SS sub-path). Not product code.
Stream trait: read() returns PesFrame, write() accepts PesFrame.
A stream is a stream — you read from it or write to it.
No separate Input/Output traits.
API: libfreemkv::input(url) and libfreemkv::output(url, title, codecs)
Returns Box<dyn Stream>.
Matthew Jackson