TieBlockHeader parses the block's own 16 bytes, measured over the 922 blocks
where "the next packets offset ends this block" holds, across all 27 levels. A
real-disc test asserts every figure.
+0x00 count multiple of 16 on 922/922; 16..2096; 72 distinct disc-wide
+0x02 zero on 922/922
+0x04 ONE OF FOUR VALUES DISC-WIDE: 0x501, 0xa02, 0xf03, 0x1404
+0x06 15 distinct, 0x0206..0x0512
+0x08 135 distinct, 0x0b05..0x4ee4
+0x0a 45 distinct
+0x0c 94 distinct, 0x010e..0x0553
+0x0e zero on 914/922
+0x04 is packed rather than a magnitude: four values across the whole disc with
the two bytes moving independently, low 1-4 and high 5/10/15/20 in lockstep. That
it is a texture index paired with a scale is a guess; that it is two fields is
not.
The count is not a record count -- block_size minus the header is divisible by it
on 0 of 922, for any record size and any header up to 512 bytes.
On the payload, a control was needed and changed the answer. Reading blocks as
3 x f32 triples, 53-64% of reads land within +/-5000 of origin, against 16% for
a uniform-random control of identical length. So the content is float-shaped and
genuinely not random.
But the rate is flat across every start offset and every stride tried, 53-65%
throughout. A statistic that cannot separate the right stride from the wrong one
cannot identify a stride -- rule 4's exact case. Flatness plus a count that does
not tile means the records are variable length.
That killed two readings. A VIF1 command walk consumes 0 of 88 blocks exactly,
so it is not a VIF1 CPU-format stream. wad::decompress rejects the block at every
start offset, so it is not WAD LZ77.
Scanning every (start, stride) pair from 0x10 to 0x7f for byte positions with a
small distinct-value vocabulary finds none: every position takes all 256 values
at every alignment. For float payload that is expected, so the scan found nothing
rather than confirming anything -- worth saying, because "no fields found" here is
uninformative, not evidence against fields.
Still open: what the payload holds. Established: variable-length, float-shaped,
non-random, not LZ77, not VIF1. Not established: any record boundary.
ReaperOfVeriod
02342de31b