feat(wan): Add diagnostic scripts and porting guide

This commit is contained in:
Daniel
2026-03-06 20:46:43 +01:00
parent 9bdda9f22e
commit 967218b7c1
3 changed files with 1565 additions and 0 deletions

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#!/usr/bin/env python3
"""Compare two videos frame-by-frame with quality metrics.
Useful for validating MLX ports against reference PyTorch implementations.
Reports PSNR, SSIM, per-frame differences, temporal coherence, and color
fidelity. Optionally saves a side-by-side diff video.
Usage:
# Basic comparison
python scripts/video/compare_videos.py reference.mp4 test.mp4
# Save side-by-side diff visualization
python scripts/video/compare_videos.py ref.mp4 test.mp4 --diff-video diff.mp4
# Compare only first 64 frames
python scripts/video/compare_videos.py ref.mp4 test.mp4 --max-frames 64
# Adjust SSIM window size (default: 7)
python scripts/video/compare_videos.py ref.mp4 test.mp4 --ssim-win 11
"""
import argparse
import sys
import cv2
import numpy as np
def load_video(path, max_frames=None):
"""Load video frames as float32 numpy arrays (0-255 range)."""
cap = cv2.VideoCapture(path)
if not cap.isOpened():
print(f"Error: cannot open {path}")
sys.exit(1)
fps = cap.get(cv2.CAP_PROP_FPS)
frames = []
while True:
ret, frame = cap.read()
if not ret:
break
frames.append(frame.astype(np.float32))
if max_frames and len(frames) >= max_frames:
break
cap.release()
return frames, fps
def compute_psnr(a, b):
"""Peak Signal-to-Noise Ratio between two frames."""
mse = np.mean((a - b) ** 2)
if mse == 0:
return float("inf")
return 10 * np.log10(255.0**2 / mse)
def compute_ssim(a, b, win_size=7):
"""Structural Similarity Index (per-channel, averaged).
Uses the standard SSIM formula with default constants.
"""
C1 = (0.01 * 255) ** 2
C2 = (0.03 * 255) ** 2
kernel = cv2.getGaussianKernel(win_size, 1.5)
window = kernel @ kernel.T
ssim_channels = []
for c in range(a.shape[2]):
ac, bc = a[:, :, c], b[:, :, c]
mu_a = cv2.filter2D(ac, -1, window)
mu_b = cv2.filter2D(bc, -1, window)
mu_a_sq = mu_a**2
mu_b_sq = mu_b**2
mu_ab = mu_a * mu_b
sigma_a_sq = cv2.filter2D(ac**2, -1, window) - mu_a_sq
sigma_b_sq = cv2.filter2D(bc**2, -1, window) - mu_b_sq
sigma_ab = cv2.filter2D(ac * bc, -1, window) - mu_ab
num = (2 * mu_ab + C1) * (2 * sigma_ab + C2)
den = (mu_a_sq + mu_b_sq + C1) * (sigma_a_sq + sigma_b_sq + C2)
ssim_map = num / den
ssim_channels.append(np.mean(ssim_map))
return np.mean(ssim_channels)
def temporal_coherence(frames):
"""Mean frame-to-frame difference (lower = smoother)."""
if len(frames) < 2:
return 0.0
diffs = []
for i in range(1, len(frames)):
diffs.append(np.mean(np.abs(frames[i] - frames[i - 1])))
return np.mean(diffs)
def color_histogram_distance(a, b, bins=64):
"""Chi-squared distance between color histograms."""
dist = 0.0
for c in range(3):
ha, _ = np.histogram(a[:, :, c], bins=bins, range=(0, 256))
hb, _ = np.histogram(b[:, :, c], bins=bins, range=(0, 256))
ha = ha.astype(np.float64) / (ha.sum() + 1e-10)
hb = hb.astype(np.float64) / (hb.sum() + 1e-10)
dist += np.sum((ha - hb) ** 2 / (ha + hb + 1e-10)) / 2
return dist / 3
def make_diff_frame(a, b, scale=5.0):
"""Create a heatmap visualization of the absolute difference."""
diff = np.mean(np.abs(a - b), axis=2)
diff_scaled = np.clip(diff * scale, 0, 255).astype(np.uint8)
heatmap = cv2.applyColorMap(diff_scaled, cv2.COLORMAP_JET)
return heatmap
def analyze(ref_frames, test_frames, ssim_win=7):
"""Compute per-frame and aggregate metrics."""
n = min(len(ref_frames), len(test_frames))
psnrs = []
ssims = []
mean_diffs = []
max_diffs = []
color_dists = []
for i in range(n):
r, t = ref_frames[i], test_frames[i]
psnrs.append(compute_psnr(r, t))
ssims.append(compute_ssim(r, t, ssim_win))
absdiff = np.abs(r - t)
mean_diffs.append(np.mean(absdiff))
max_diffs.append(np.max(absdiff))
color_dists.append(color_histogram_distance(r, t))
ref_tc = temporal_coherence(ref_frames[:n])
test_tc = temporal_coherence(test_frames[:n])
return {
"num_frames": n,
"psnr": np.array(psnrs),
"ssim": np.array(ssims),
"mean_diff": np.array(mean_diffs),
"max_diff": np.array(max_diffs),
"color_dist": np.array(color_dists),
"ref_temporal_coherence": ref_tc,
"test_temporal_coherence": test_tc,
}
def print_report(results, ref_path, test_path):
"""Print a formatted comparison report."""
n = results["num_frames"]
psnr = results["psnr"]
ssim = results["ssim"]
md = results["mean_diff"]
mx = results["max_diff"]
cd = results["color_dist"]
print("=" * 72)
print("VIDEO COMPARISON REPORT")
print("=" * 72)
print(f" Reference: {ref_path}")
print(f" Test: {test_path}")
print(f" Frames compared: {n}")
print()
print("AGGREGATE METRICS")
print("-" * 40)
print(f" PSNR (dB): mean={np.mean(psnr):6.2f} min={np.min(psnr):6.2f} max={np.max(psnr):6.2f}")
print(f" SSIM: mean={np.mean(ssim):.4f} min={np.min(ssim):.4f} max={np.max(ssim):.4f}")
print(f" Mean diff: mean={np.mean(md):6.2f} min={np.min(md):6.2f} max={np.max(md):6.2f}")
print(f" Max diff: mean={np.mean(mx):6.1f} min={np.min(mx):6.1f} max={np.max(mx):6.1f}")
print(f" Color dist: mean={np.mean(cd):.4f} min={np.min(cd):.4f} max={np.max(cd):.4f}")
print()
print("TEMPORAL COHERENCE (mean frame-to-frame diff, lower = smoother)")
print("-" * 40)
print(f" Reference: {results['ref_temporal_coherence']:.2f}")
print(f" Test: {results['test_temporal_coherence']:.2f}")
ratio = results["test_temporal_coherence"] / (results["ref_temporal_coherence"] + 1e-10)
print(f" Ratio: {ratio:.2f}x {'(test is smoother)' if ratio < 1 else '(test is jerkier)' if ratio > 1.05 else '(similar)'}")
print()
# Identify worst frames
print("WORST FRAMES (by PSNR)")
print("-" * 40)
worst_idx = np.argsort(psnr)[:5]
for i in worst_idx:
print(f" Frame {i:4d}: PSNR={psnr[i]:6.2f} dB SSIM={ssim[i]:.4f} mean_diff={md[i]:.2f}")
print()
# Quality assessment
mean_psnr = np.mean(psnr)
mean_ssim = np.mean(ssim)
print("QUALITY ASSESSMENT")
print("-" * 40)
if mean_psnr > 40:
grade = "Excellent"
elif mean_psnr > 35:
grade = "Good"
elif mean_psnr > 30:
grade = "Fair"
elif mean_psnr > 25:
grade = "Poor"
else:
grade = "Very different"
print(f" Overall: {grade} (PSNR={mean_psnr:.1f} dB, SSIM={mean_ssim:.4f})")
if mean_psnr < 30:
print(" ⚠ Videos differ significantly — likely a bug or different generation seed")
print("=" * 72)
def save_diff_video(ref_frames, test_frames, output_path, fps, scale=5.0):
"""Save a side-by-side video: reference | test | diff heatmap."""
n = min(len(ref_frames), len(test_frames))
h, w = ref_frames[0].shape[:2]
fourcc = cv2.VideoWriter_fourcc(*"mp4v")
out = cv2.VideoWriter(output_path, fourcc, fps, (w * 3, h))
for i in range(n):
r = ref_frames[i].astype(np.uint8)
t = test_frames[i].astype(np.uint8)
d = make_diff_frame(ref_frames[i], test_frames[i], scale)
combined = np.hstack([r, t, d])
out.write(combined)
out.release()
print(f"Diff video saved to {output_path}")
def main():
parser = argparse.ArgumentParser(
description="Compare two videos frame-by-frame with quality metrics"
)
parser.add_argument("reference", help="Path to reference video")
parser.add_argument("test", help="Path to test video")
parser.add_argument(
"--diff-video", help="Save side-by-side diff visualization to this path"
)
parser.add_argument(
"--max-frames", type=int, help="Compare only first N frames"
)
parser.add_argument(
"--ssim-win", type=int, default=7, help="SSIM window size (default: 7)"
)
parser.add_argument(
"--diff-scale",
type=float,
default=5.0,
help="Diff heatmap amplification (default: 5.0)",
)
parser.add_argument(
"--csv", help="Export per-frame metrics to CSV file"
)
args = parser.parse_args()
print(f"Loading reference: {args.reference}")
ref_frames, ref_fps = load_video(args.reference, args.max_frames)
print(f"{len(ref_frames)} frames, {ref_fps:.1f} fps, {ref_frames[0].shape[1]}x{ref_frames[0].shape[0]}")
print(f"Loading test: {args.test}")
test_frames, test_fps = load_video(args.test, args.max_frames)
print(f"{len(test_frames)} frames, {test_fps:.1f} fps, {test_frames[0].shape[1]}x{test_frames[0].shape[0]}")
if ref_frames[0].shape != test_frames[0].shape:
print(f"Warning: resolution mismatch {ref_frames[0].shape} vs {test_frames[0].shape}")
print("Resizing test frames to match reference...")
h, w = ref_frames[0].shape[:2]
test_frames = [
cv2.resize(f, (w, h), interpolation=cv2.INTER_LANCZOS4)
for f in test_frames
]
print("Computing metrics...")
results = analyze(ref_frames, test_frames, args.ssim_win)
print()
print_report(results, args.reference, args.test)
if args.diff_video:
save_diff_video(ref_frames, test_frames, args.diff_video, ref_fps, args.diff_scale)
if args.csv:
import csv
with open(args.csv, "w", newline="") as f:
writer = csv.writer(f)
writer.writerow(["frame", "psnr", "ssim", "mean_diff", "max_diff", "color_dist"])
for i in range(results["num_frames"]):
writer.writerow([
i,
f"{results['psnr'][i]:.4f}",
f"{results['ssim'][i]:.6f}",
f"{results['mean_diff'][i]:.4f}",
f"{results['max_diff'][i]:.1f}",
f"{results['color_dist'][i]:.6f}",
])
print(f"Per-frame metrics saved to {args.csv}")
if __name__ == "__main__":
main()

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#!/usr/bin/env python3
"""Analyze quality of a single generated video.
Reports sharpness, temporal stability, color distribution, motion smoothness,
chunk boundary artifacts, and common generation defects. Useful for quick
quality checks during model porting and debugging.
Usage:
# Basic analysis
python scripts/video/video_quality.py output.mp4
# With chunk boundary analysis (e.g., 32 frames/chunk)
python scripts/video/video_quality.py output.mp4 --chunk-size 32
# Detailed per-frame CSV export
python scripts/video/video_quality.py output.mp4 --csv metrics.csv
# Analyze specific frame range
python scripts/video/video_quality.py output.mp4 --start 0 --end 64
"""
import argparse
import sys
import cv2
import numpy as np
def load_video(path, start=0, end=None):
"""Load video frames as float32 numpy arrays (0-255 range)."""
cap = cv2.VideoCapture(path)
if not cap.isOpened():
print(f"Error: cannot open {path}")
sys.exit(1)
fps = cap.get(cv2.CAP_PROP_FPS)
total = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))
if start > 0:
cap.set(cv2.CAP_PROP_POS_FRAMES, start)
frames = []
idx = start
while True:
ret, frame = cap.read()
if not ret:
break
frames.append(frame.astype(np.float32))
idx += 1
if end and idx >= end:
break
cap.release()
return frames, fps, total
def sharpness_laplacian(frame):
"""Laplacian variance — higher means sharper."""
gray = cv2.cvtColor(frame.astype(np.uint8), cv2.COLOR_BGR2GRAY)
return cv2.Laplacian(gray, cv2.CV_64F).var()
def sharpness_gradient(frame):
"""Mean gradient magnitude — higher means more edges/detail."""
gray = cv2.cvtColor(frame.astype(np.uint8), cv2.COLOR_BGR2GRAY).astype(np.float32)
gx = cv2.Sobel(gray, cv2.CV_32F, 1, 0, ksize=3)
gy = cv2.Sobel(gray, cv2.CV_32F, 0, 1, ksize=3)
return np.mean(np.sqrt(gx**2 + gy**2))
def color_stats(frame):
"""Per-channel mean and std in BGR order."""
means = [np.mean(frame[:, :, c]) for c in range(3)]
stds = [np.std(frame[:, :, c]) for c in range(3)]
return means, stds
def detect_uniform_color(frame, std_threshold=15.0):
"""Detect if frame is near-uniform (common failure mode)."""
return np.std(frame) < std_threshold
def detect_noise(frame, threshold=200.0):
"""High Laplacian variance with low gradient can indicate noise."""
lap = sharpness_laplacian(frame)
grad = sharpness_gradient(frame)
# Noise has high variance but less coherent edges
return lap > threshold and grad < 5.0
def frame_difference(a, b):
"""Mean absolute pixel difference between frames."""
return np.mean(np.abs(a - b))
def optical_flow_magnitude(prev, curr):
"""Mean optical flow magnitude (Farneback method)."""
prev_gray = cv2.cvtColor(prev.astype(np.uint8), cv2.COLOR_BGR2GRAY)
curr_gray = cv2.cvtColor(curr.astype(np.uint8), cv2.COLOR_BGR2GRAY)
flow = cv2.calcOpticalFlowFarneback(
prev_gray, curr_gray, None, 0.5, 3, 15, 3, 5, 1.2, 0
)
mag = np.sqrt(flow[..., 0] ** 2 + flow[..., 1] ** 2)
return np.mean(mag), np.max(mag)
def analyze_video(frames, chunk_size=None, compute_flow=False):
"""Compute per-frame and aggregate quality metrics."""
n = len(frames)
metrics = {
"sharpness_lap": [],
"sharpness_grad": [],
"brightness": [],
"contrast": [],
"color_mean_b": [],
"color_mean_g": [],
"color_mean_r": [],
"frame_diff": [],
"is_uniform": [],
"is_noisy": [],
}
if compute_flow:
metrics["flow_mean"] = []
metrics["flow_max"] = []
for i in range(n):
f = frames[i]
metrics["sharpness_lap"].append(sharpness_laplacian(f))
metrics["sharpness_grad"].append(sharpness_gradient(f))
metrics["brightness"].append(np.mean(f))
metrics["contrast"].append(np.std(f))
means, _ = color_stats(f)
metrics["color_mean_b"].append(means[0])
metrics["color_mean_g"].append(means[1])
metrics["color_mean_r"].append(means[2])
metrics["is_uniform"].append(detect_uniform_color(f))
metrics["is_noisy"].append(detect_noise(f))
if i > 0:
metrics["frame_diff"].append(frame_difference(frames[i - 1], f))
if compute_flow:
fm, fmx = optical_flow_magnitude(frames[i - 1], f)
metrics["flow_mean"].append(fm)
metrics["flow_max"].append(fmx)
else:
metrics["frame_diff"].append(0.0)
if compute_flow:
metrics["flow_mean"].append(0.0)
metrics["flow_max"].append(0.0)
# Convert to arrays
for k in metrics:
metrics[k] = np.array(metrics[k])
# Chunk boundary analysis
if chunk_size and n > chunk_size:
boundaries = list(range(chunk_size, n, chunk_size))
boundary_metrics = []
for b in boundaries:
if b < n and b > 0:
pre = metrics["frame_diff"][b - 1] if b > 1 else metrics["frame_diff"][1]
at = metrics["frame_diff"][b]
ratio = at / (pre + 1e-10)
brightness_jump = metrics["brightness"][b] - metrics["brightness"][b - 1]
contrast_jump = (
(metrics["contrast"][b] - metrics["contrast"][b - 1])
/ (metrics["contrast"][b - 1] + 1e-10)
* 100
)
sharpness_jump = (
(metrics["sharpness_lap"][b] - metrics["sharpness_lap"][b - 1])
/ (metrics["sharpness_lap"][b - 1] + 1e-10)
* 100
)
boundary_metrics.append(
{
"frame": b,
"diff_ratio": ratio,
"brightness_jump": brightness_jump,
"contrast_jump_pct": contrast_jump,
"sharpness_jump_pct": sharpness_jump,
}
)
metrics["boundaries"] = boundary_metrics
return metrics
def print_report(metrics, path, fps, total_frames, frames_analyzed):
"""Print a formatted quality report."""
sl = metrics["sharpness_lap"]
sg = metrics["sharpness_grad"]
br = metrics["brightness"]
ct = metrics["contrast"]
fd = metrics["frame_diff"]
print("=" * 72)
print("VIDEO QUALITY REPORT")
print("=" * 72)
print(f" File: {path}")
print(f" Total frames: {total_frames} Analyzed: {frames_analyzed} FPS: {fps:.1f}")
duration = total_frames / fps if fps > 0 else 0
print(f" Duration: {duration:.1f}s")
print()
# Defect detection
n_uniform = int(np.sum(metrics["is_uniform"]))
n_noisy = int(np.sum(metrics["is_noisy"]))
if n_uniform > 0 or n_noisy > 0:
print("⚠ DEFECTS DETECTED")
print("-" * 40)
if n_uniform:
frames_list = np.where(metrics["is_uniform"])[0][:10]
print(f" Uniform/blank frames: {n_uniform} — frames {list(frames_list)}{'...' if n_uniform > 10 else ''}")
if n_noisy:
frames_list = np.where(metrics["is_noisy"])[0][:10]
print(f" Noisy frames: {n_noisy} — frames {list(frames_list)}{'...' if n_noisy > 10 else ''}")
print()
print("SHARPNESS")
print("-" * 40)
print(f" Laplacian var: mean={np.mean(sl):8.1f} min={np.min(sl):8.1f} max={np.max(sl):8.1f} std={np.std(sl):.1f}")
print(f" Gradient mag: mean={np.mean(sg):8.2f} min={np.min(sg):8.2f} max={np.max(sg):8.2f} std={np.std(sg):.2f}")
if np.std(sl) / (np.mean(sl) + 1e-10) > 0.3:
print(" ⚠ High sharpness variation — possible blur artifacts")
print()
print("BRIGHTNESS & CONTRAST")
print("-" * 40)
print(f" Brightness: mean={np.mean(br):6.1f} min={np.min(br):6.1f} max={np.max(br):6.1f} std={np.std(br):.2f}")
print(f" Contrast (std): mean={np.mean(ct):6.1f} min={np.min(ct):6.1f} max={np.max(ct):6.1f} std={np.std(ct):.2f}")
if np.std(br) > 3.0:
print(" ⚠ Brightness instability — may indicate chunk boundary artifacts")
print()
print("COLOR DISTRIBUTION (BGR)")
print("-" * 40)
print(f" Blue: mean={np.mean(metrics['color_mean_b']):6.1f} std={np.std(metrics['color_mean_b']):.2f}")
print(f" Green: mean={np.mean(metrics['color_mean_g']):6.1f} std={np.std(metrics['color_mean_g']):.2f}")
print(f" Red: mean={np.mean(metrics['color_mean_r']):6.1f} std={np.std(metrics['color_mean_r']):.2f}")
print()
print("TEMPORAL STABILITY")
print("-" * 40)
fd_nz = fd[1:] # skip first frame (always 0)
if len(fd_nz) > 0:
print(f" Frame diff: mean={np.mean(fd_nz):6.2f} min={np.min(fd_nz):6.2f} max={np.max(fd_nz):6.2f} std={np.std(fd_nz):.2f}")
if np.std(fd_nz) / (np.mean(fd_nz) + 1e-10) > 0.5:
print(" ⚠ High diff variance — jitter or discontinuities")
if "flow_mean" in metrics:
fm = metrics["flow_mean"][1:]
print(f" Optical flow: mean={np.mean(fm):6.2f} max_frame={np.max(metrics['flow_max'][1:]):.1f}")
print()
# Chunk boundaries
if "boundaries" in metrics and metrics["boundaries"]:
print("CHUNK BOUNDARIES")
print("-" * 40)
print(f" {'Frame':>6} {'Diff ratio':>10} {'Brightness':>10} {'Contrast %':>10} {'Sharpness %':>11}")
for bm in metrics["boundaries"]:
print(
f" {bm['frame']:6d}"
f" {bm['diff_ratio']:10.2f}x"
f" {bm['brightness_jump']:+10.1f}"
f" {bm['contrast_jump_pct']:+10.1f}%"
f" {bm['sharpness_jump_pct']:+11.1f}%"
)
avg_ratio = np.mean([b["diff_ratio"] for b in metrics["boundaries"]])
if avg_ratio > 2.0:
print(f" ⚠ Boundary diff ratio {avg_ratio:.1f}x — visible chunk transitions")
print()
# Overall grade
print("OVERALL ASSESSMENT")
print("-" * 40)
issues = []
if n_uniform > 0:
issues.append("uniform/blank frames")
if n_noisy > 0:
issues.append("noisy frames")
if np.std(br) > 3.0:
issues.append("brightness flicker")
if np.std(sl) / (np.mean(sl) + 1e-10) > 0.3:
issues.append("sharpness variation")
if "boundaries" in metrics and metrics["boundaries"]:
avg_ratio = np.mean([b["diff_ratio"] for b in metrics["boundaries"]])
if avg_ratio > 2.0:
issues.append("chunk boundary artifacts")
if issues:
print(f" Issues found: {', '.join(issues)}")
else:
print(" ✓ No significant quality issues detected")
print("=" * 72)
def main():
parser = argparse.ArgumentParser(
description="Analyze quality of a single generated video"
)
parser.add_argument("video", help="Path to video file")
parser.add_argument(
"--chunk-size",
type=int,
help="Frames per chunk for boundary analysis (e.g., 32)",
)
parser.add_argument(
"--start", type=int, default=0, help="Start frame (default: 0)"
)
parser.add_argument("--end", type=int, help="End frame (default: all)")
parser.add_argument(
"--flow",
action="store_true",
help="Compute optical flow (slower but more detailed)",
)
parser.add_argument("--csv", help="Export per-frame metrics to CSV")
args = parser.parse_args()
print(f"Loading: {args.video}")
frames, fps, total = load_video(args.video, args.start, args.end)
h, w = frames[0].shape[:2]
print(f"{len(frames)} frames, {fps:.1f} fps, {w}x{h}")
print("Analyzing...")
metrics = analyze_video(frames, args.chunk_size, args.flow)
print()
print_report(metrics, args.video, fps, total, len(frames))
if args.csv:
import csv
keys = [
"sharpness_lap", "sharpness_grad", "brightness", "contrast",
"color_mean_b", "color_mean_g", "color_mean_r", "frame_diff",
]
if args.flow:
keys += ["flow_mean", "flow_max"]
with open(args.csv, "w", newline="") as f:
writer = csv.writer(f)
writer.writerow(["frame"] + keys)
for i in range(len(frames)):
row = [i] + [f"{metrics[k][i]:.4f}" for k in keys]
writer.writerow(row)
print(f"Per-frame metrics saved to {args.csv}")
if __name__ == "__main__":
main()