The trailer opens with two little-endian u32 words. w1 is the leading wave's total sample count -- 282/282 exact, the same number as the last entry of that wave's own seek table. And w0 < w1 with w1-w0 always a whole multiple of 512 (282/282), i.e. a whole number of XMA1 frames, 9 to 91 with a median of 14. What w0 means is left at yellow: trailing the total by a whole number of frames is the shape of a usable-length or loop-end field, but that is a reading of the shape rather than a measurement, and nothing here separates the candidates. Also corrects my own description: I called the region after the seek chunk 'zero padding'. It is not padding -- about 48 non-zero bytes are scattered thinly across the 12 KiB, roughly 17 per KiB in blocks 1, 3 and 7. That is a sparse table, still unidentified, and the distinction matters to anyone skipping it.