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Predicted R7 = 0.5-0.9 YELLOW/GREEN. Closely analogous to cycle 1 (VP9 IDCT 8x8 R=0.92 GREEN): same block size, same lane geometry, same data shape. H.264 8x8 IT uses integer butterfly with 3 sub-stages (vs cycle 1's Q14 trig single butterfly) — more compute per pass but simpler operations. Phase 1 documents: - Spec butterfly (e/f/g stages per H.264 §8.5.13) - 30fps@1080p floor = 0.972 Mblock/s (same as cycle 1 since same block density) - NEON ref = ff_h264_idct8_add_neon (already vendored in cycle 6's h264idct_neon.S) - Cycle 8-10 preview: chroma MC, luma qpel MC, in-loop deblock Phase 3 next session: write column-major C ref + bench, capture M1 + M3. Then Phase 4 plan (likely cycle-1 v3d_idct8.comp adapted to integer butterfly), Phase 5 review, Phase 6 implement, Phase 7 measure. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>