Add synced ZED SVO grid exporter

README.md

@@ -58,6 +58,61 @@ cmake --build build
 ls -la build/{cvmmap_streamer,rtp_receiver_tester,rtmp_stub_tester}
 ```
 
+### ZED SVO/SVO2 To MP4
+
+The repo also includes an offline conversion tool for the left ZED color stream:
+
+```bash
+CUDA_VISIBLE_DEVICES=GPU-9cc7b26e-90d4-0c49-4d4c-060e528ffba6 \
+./build/bin/zed_svo_to_mp4 \
+    --input /workspaces/data/kindergarten/bar/2026-03-18T11-59-41/2026-03-18T11-59-41_zed1.svo2 \
+    --encoder-device auto \
+    --preset balanced \
+    --quality 20 \
+    --start-frame 0 \
+    --end-frame 89
+```
+
+By default the tool writes `foo.mp4` next to `foo.svo` or `foo.svo2`, defaults to `h265`, and shows a tqdm-like progress bar when stderr is attached to a TTY. `--encoder-device auto` tries NVENC first and falls back to software (`libx264` or `libx265`) if the hardware encoder is unavailable or cannot be opened.
+
+### Batch ZED SVO2 To MP4
+
+Python dependencies for the batch wrapper are managed with `uv`:
+
+```bash
+uv sync
+```
+
+Use the wrapper to recurse through a folder, run `zed_svo_to_mp4` on every matched `.svo2`, and show one aggregate tqdm progress bar:
+
+```bash
+uv run python scripts/zed_batch_svo_to_mp4.py \
+    /workspaces/data/kindergarten/bar \
+    --pattern '*.svo2' \
+    --recursive \
+    --jobs 2 \
+    --encoder-device auto \
+    --start-frame 0 \
+    --end-frame 29 \
+    --cuda-visible-devices GPU-9cc7b26e-90d4-0c49-4d4c-060e528ffba6
+```
+
+The batch tool mirrors the common encoder options from `zed_svo_to_mp4`, skips existing sibling `.mp4` outputs by default, and continues after failures while returning a nonzero exit code if any conversion fails.
+
+### ZED SVO Grid To MP4
+
+Use the grid converter to merge four synced ZED recordings into a 2x2 CCTV-style MP4 with a Unix timestamp overlay in the top-left corner:
+
+```bash
+./build/bin/zed_svo_grid_to_mp4 \
+    --segment-dir /workspaces/data/kindergarten/bar/2026-03-18T11-59-41 \
+    --encoder-device auto \
+    --codec h265 \
+    --duration-seconds 2
+```
+
+The tool syncs the four inputs using the same common-start timestamp rule as the ZED multi-camera playback sample, defaults to a 2x2 layout ordered as `zed1 zed2 / zed3 zed4`, and writes `<segment>/<segment>_grid.mp4` unless `--output` is provided. By default each tile is scaled to `0.5x`, so a four-camera 1920x1200 segment produces a 1920x1200 composite. Use repeated `--input` flags instead of `--segment-dir` when you want explicit row-major ordering.
+
 ### Mandatory Acceptance (Standalone)
 
 Run the full mandatory acceptance suite. This executes the complete protocol/codec matrix without requiring external servers.