i4h Workflow — Replay Dataset

Purpose

Replay a recorded HDF5 episode inside Isaac Sim for visual verification. Use when the user asks to replay, play back, or step through an HDF5 recording.

Base Code

These steps drive the i4h-workflows base code (the workflows/agentic/ tree). To reuse an existing checkout, set I4H_WORKFLOWS to its path (no clone happens). Otherwise this resolves the current repo, or clones to ~/i4h-workflows — pick that default without prompting. Run every command below from the resolved root:

# Resolve the i4h-workflows base code (provides workflows/agentic/).
ROOT="${I4H_WORKFLOWS:-$(git rev-parse --show-toplevel 2>/dev/null)}"
if [ ! -d "$ROOT/workflows/agentic" ]; then
  ROOT="${I4H_WORKFLOWS:-$HOME/i4h-workflows}"
  [ -d "$ROOT/workflows/agentic" ] || git clone https://github.com/isaac-for-healthcare/i4h-workflows "$ROOT"
fi
export I4H_WORKFLOWS="$ROOT"; cd "$ROOT"

Basics

• Env config (source of truth): workflows/agentic/config/environments/<env>.yaml — the <env> scene, robot, and cameras Arena replays against.
• Replay runs arena/run.sh --replay against the env that produced the HDF5.
• Use it to verify visual correctness before conversion or training.
• Interpret ordinal wording as zero-based episode indices: "first episode" -> 0, "second episode" -> 1, etc.

Run

Run the steps below in order. Each step is a separate bash call; variables persist in the local agent's tmux session.

Step 1 — setup and resolve HDF5

REPO_ROOT="${I4H_WORKFLOWS:-$(git rev-parse --show-toplevel 2>/dev/null)}"; [ -d "$REPO_ROOT/workflows/agentic" ] || REPO_ROOT="$HOME/i4h-workflows"
ENV_ID=scissor_pick_and_place
RUNS_ROOT="${REPO_ROOT}/workflows/agentic/runs"
EPISODE_INDEX="${EPISODE_INDEX:-0}"  # For "Replay second episode", set EPISODE_INDEX=1.

# Point HDF5_PATH at a real recording (absolute path). Recordings come from teleop, mimic, or
# validate (which writes data/verify.hdf5 under each runs/eval_* dir). List candidates newest-first:
#   find "${RUNS_ROOT}" -name '*.hdf5' -printf '%TY-%Tm-%Td %TH:%TM  %p\n' | sort -r | head
HDF5_PATH="${HDF5_PATH:-}"
if [ ! -f "${HDF5_PATH}" ]; then
  echo "replay: set HDF5_PATH to an existing .hdf5 (got '${HDF5_PATH:-<unset>}'). Candidates:" >&2
  find "${RUNS_ROOT}" -name '*.hdf5' -printf '%TY-%Tm-%Td %TH:%TM  %p\n' 2>/dev/null | sort -r | head
  exit 1
fi

RUN_DIR="${RUNS_ROOT}/replay_${ENV_ID}_$(date +%Y%m%d_%H%M%S)"
mkdir -p "${RUN_DIR}/logs"
ln -sfn "${RUN_DIR}" "${RUNS_ROOT}/.latest"

Step 2 — replay

"${REPO_ROOT}/workflows/agentic/arena/run.sh" \
  --env "${ENV_ID}" \
  --replay "${HDF5_PATH}" \
  --episode-index "${EPISODE_INDEX}" \
  2>&1 | tee "${RUN_DIR}/logs/replay.log"

Notes

• HDF5_PATH must be an absolute path to an existing recording — --replay resolves a relative path against runs/<env>/, not your cwd, so a bare/relative path silently fails to load. The block lists real candidates if it's unset or wrong.
• Recordings come from [[i4h-workflow-dataset-teleop]], [[i4h-workflow-dataset-mimic]], or [[i4h-workflow-validate]] (validate writes data/verify.hdf5 under each runs/eval_* dir). There is no default demo.hdf5.
• --episode-index selects the episode within the HDF5 (zero-based).
• For "Replay second episode", use --episode-index 1.
• Use the same env id as the env that produced the recording.

Prerequisites

• Workflow set up via [[i4h-workflow-setup]] (the .venv must exist).
• An existing HDF5 recording to replay.
• The env id that produced the recording.

Limitations

• Visual verification only; replay does not modify or expand the recording.
• Replays one episode per invocation, selected by --episode-index.
• Runs inside Isaac Sim; the env id must match the one that produced the HDF5.

Troubleshooting

• Error: .venv not found / replay fails to launch - Cause: workflow not set up. Fix: run [[i4h-workflow-setup]] first.
• Error: replay: set HDF5_PATH to an existing .hdf5 (or recording fails to load) - Cause: HDF5_PATH unset or not a real file. Fix: pick an absolute path from the printed candidates (e.g. a verify.hdf5 under runs/eval_*/data/).
• Error: episode index out of range - Cause: --episode-index exceeds the episodes in the HDF5. Fix: use a valid zero-based index.
• Error: mismatched/garbled playback - Cause: --env differs from the env that produced the recording. Fix: use the same env id.

Final Response

Report env, HDF5 path, episode index, launch outcome, visible mismatches.