zed-playground/py_workspace/svo_playback.py

import sys
import pyzed.sl as sl
import cv2
import argparse
import os
import math
from pathlib import Path


def progress_bar(percent_done, bar_length=50):
    # Display progress bar
    done_length = int(bar_length * percent_done / 100)
    bar = "=" * done_length + "-" * (bar_length - done_length)
    sys.stdout.write("[%s] %i%s\r" % (bar, percent_done, "%"))
    sys.stdout.flush()


def main(opt):
    input_paths = [Path(p) for p in opt.input_svo_files]
    svo_files = []

    for path in input_paths:
        if path.is_dir():
            print(f"Searching for SVO files in {path}...")
            found = sorted(
                [
                    str(f)
                    for f in path.iterdir()
                    if f.is_file() and f.suffix.lower() in (".svo", ".svo2")
                ]
            )
            if found:
                print(f"Found {len(found)} files in {path}")
                svo_files.extend(found)
            else:
                print(f"No .svo or .svo2 files found in {path}")
        elif path.is_file():
            svo_files.append(str(path))
        else:
            print(f"Path not found: {path}")

    if not svo_files:
        print("No valid SVO files provided. Exiting.")
        return

    # Sort files to ensure deterministic order
    svo_files.sort()

    cameras = []

    cam_data = []  # List of dicts to store camera info

    print(f"Opening {len(svo_files)} SVO files...")

    for filepath in svo_files:
        if not os.path.isfile(filepath):
            print(f"File {filepath} does not exist. Skipping.")
            continue

        init = sl.InitParameters()
        init.set_from_svo_file(filepath)
        init.svo_real_time_mode = False
        init.depth_mode = (
            sl.DEPTH_MODE.NONE
        )  # Use NONE for performance with multiple cameras

        cam = sl.Camera()
        status = cam.open(init)
        if status != sl.ERROR_CODE.SUCCESS:
            print(f"Failed to open {filepath}: {status}")
            continue

        cameras.append(cam)

        # Store metadata
        info = cam.get_camera_information()
        cam_data.append(
            {
                "cam": cam,
                "serial": info.serial_number,
                "res": info.camera_configuration.resolution,
                "fps": info.camera_configuration.fps,
                "nb_frames": cam.get_svo_number_of_frames(),
                "start_ts": 0,  # To be filled
            }
        )

    if not cameras:
        print("No cameras opened. Exiting.")
        return

    # SVO Synchronization
    # Since Python API might miss get_svo_position_at_timestamp, we approximate using FPS and start timestamps.
    print("Syncing SVOs...")
    max_start_ts = 0
    runtime = sl.RuntimeParameters()

    # Grab first frame to determine start timestamps
    for data in cam_data:
        cam = data["cam"]
        err = cam.grab(runtime)
        if err == sl.ERROR_CODE.SUCCESS:
            ts = cam.get_timestamp(sl.TIME_REFERENCE.IMAGE).get_nanoseconds()
            data["start_ts"] = ts
            if ts > max_start_ts:
                max_start_ts = ts
        else:
            print(f"Error grabbing first frame from {data['serial']}: {err}")

    # Align cameras
    for data in cam_data:
        cam = data["cam"]
        ts = data["start_ts"]
        if ts < max_start_ts:
            # Calculate frames to skip
            diff_ns = max_start_ts - ts
            fps = data["fps"]
            # frames = seconds * fps
            frames_to_skip = int((diff_ns / 1_000_000_000) * fps)
            print(
                f"Camera {data['serial']} starts {diff_ns / 1e9:.2f}s earlier. Skipping {frames_to_skip} frames."
            )
            cam.set_svo_position(frames_to_skip)
        else:
            # This is the latest camera, just reset to 0 (or stay at 1 since we grabbed one)
            # To be perfectly synced with the skip, we should ideally be at 'frame 0' relative to the sync point.
            # If we simply continue, we are at frame 1.
            # Let's reset to 0 for the "base" cameras to ensure we don't miss the *very* first synced frame if possible,
            # or just accept we are at frame 1.
            # set_svo_position(0) is safer.
            cam.set_svo_position(0)

    print("Starting playback...")
    print(" Press 's' to save SVO image as a PNG")
    print(" Press 'f' to jump forward in the video")
    print(" Press 'b' to jump backward in the video")
    print(" Press 'q' to exit...")

    key = ""
    while key != 113:  # for 'q' key
        frames_displayed = 0

        for data in cam_data:
            cam = data["cam"]
            err = cam.grab(runtime)
            if err == sl.ERROR_CODE.SUCCESS:
                # Resize for display
                res = data["res"]
                w = min(720, res.width)
                h = min(404, res.height)
                # Ensure even dimensions for video
                low_resolution = sl.Resolution(w, h)

                svo_image = sl.Mat()
                cam.retrieve_image(svo_image, sl.VIEW.LEFT, sl.MEM.CPU, low_resolution)

                img = svo_image.get_data()
                cv2.imshow(f"View {data['serial']}", img)
                frames_displayed += 1

                # Update progress bar
                if data == cam_data[0]:
                    pos = cam.get_svo_position()
                    total = data["nb_frames"]
                    if total > 0:
                        progress_bar(int(pos / total * 100), 30)

            elif err == sl.ERROR_CODE.END_OF_SVOFILE_REACHED:
                print(f"\nSVO end reached for {data['serial']}. Looping.")
                cam.set_svo_position(0)
            else:
                pass

        key = cv2.waitKey(10)

        if key == 115:  # 's'
            # Save snapshots
            for data in cam_data:
                cam = data["cam"]
                mat = sl.Mat()
                cam.retrieve_image(mat)
                pos = cam.get_svo_position()
                filename = f"capture_{data['serial']}_{pos}.png"
                mat.write(filename)
                print(f"Saved {filename}")

        if key == 102:  # 'f'
            for data in cam_data:
                cam = data["cam"]
                pos = cam.get_svo_position()
                cam.set_svo_position(pos + int(data["fps"]))

        if key == 98:  # 'b'
            for data in cam_data:
                cam = data["cam"]
                pos = cam.get_svo_position()
                cam.set_svo_position(max(0, pos - int(data["fps"])))

    cv2.destroyAllWindows()
    for cam in cameras:
        cam.close()


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--input_svo_files",
        nargs="+",
        type=str,
        help="Path to .svo/.svo2 files or directories",
        required=True,
    )
    opt = parser.parse_args()

    main(opt)