piperx-sortletter-20260921-140ep-reverse

140 episodes, 144136 frames, 30 FPS, three 640×480 RGB views. LeRobot v3.0, 14-D action and state.

Selection in output order: reverse episodes 1–140 (1-based). CTR retains two relative-timing samples per original episode (280 total); the 140ep name refers to the 140 source demonstrations.

Source: Takizz/piperx-sortletter-0911-0917-140ep-raw, pinned revision f3d743be7a21e8f9d0c5dd23c910ca50c0134ad1. provenance.json records every output-to-input mapping. Task IDs and the original task text are preserved.

Reverse executes the right segment before the left. Concurrent starts both detected segments at frame zero and holds the shorter arm's final pose. CTR uses two uniform relative-timing samples per source. Retimed main-camera videos use per-episode vertical split compositing; wrists follow their respective arm clocks. This is a video counterfactual, not a certification of physical simultaneous execution or collision safety.

VALIDATION_RECEIPT.json records packaging checks. SHA256SUMS covers payloads. Source clocks and detailed source receipts are retained under meta/.

Training mask

No Idle Mask: observation.arm_active_mask is all ones, supervising every frame of both arms. Only ctr-2x uses pre-task idle masking. NPZ execution intervals and retime.overlap are timing diagnostics, not loss masks.