Video Quality Checker — What's Wrong With This File?
Upload a single video. DiffALL samples it second by second, measures bitrate, focus, noise, compression and clipping, checks whether the frame rate is genuine, and names the weakest one.
Free, no sign-up — your files never leave the comparison.
Drop a video here or click to browse
MP4 · MOV · MKV · WebM · AVI — up to 150 MB
Free, no sign-up — your video is deleted as soon as the check finishes.
Reading the video…
What DiffALL measures
Bitrate vs. the standard
Measured as bits per pixel per frame, so one number covers 720p30 and 4K60 alike, and compared against the published recommended upload bitrates. Free — it comes from the container, nothing is decoded.
Is the frame rate real?
A file can claim 60fps and carry 30 distinct pictures. Consecutive frames are compared, so footage converted up from a slower source is caught — invisible otherwise until you scrub.
Focus
Edge energy per tile, from the sharpest region of each sampled second, so a deliberately blurred background is not read as a focus miss.
Compression
Block structure measured across the 8-pixel grid. Catches a file squeezed too hard, or re-encoded more than once.
The worst second, named
The band is the MEDIAN second, not the worst — one soft second in a whip pan is motion, not a defect. The worst moment is reported beside it, as a place to look.
It says when it cannot tell
A flat title card gets no compression verdict; a near-still frame gets no focus verdict. Silence beats a confident wrong answer.
Supported formats
Use cases
Before you upload
Check an export against the recommended bitrate before a platform re-encodes it and takes the decision away from you.
Is this the master?
Heavy block structure and a thin bitrate are the signature of a file that has been through a platform already.
Check a conversion
Footage converted up to 60fps carries duplicate frames. This finds them without scrubbing.
Triage a shoot
Find which clips are soft or noisy enough to be worth reshooting.
Frequently asked questions
How do you check the quality of a video?
Upload one video. DiffALL samples a frame every second and measures six things: bitrate against the recommended upload rate for that resolution and frame rate, how sharply focused the sharpest part of each frame is, noise in the flat areas, JPEG-style block structure, clipped highlights and shadows, and whether consecutive frames are actually different. Each gets a band from Excellent to Poor, and the weakest is named at the top.
Why is the band the median second and not the worst?
Because one soft second in a whip pan is motion, not a defect, and a rule that took the worst would call almost every real video blurry. The worst second is reported beside the band instead — as a place to look, not as the verdict. Across dimensions the opposite applies: there the worst wins, because a file with one fatal flaw is not mostly fine.
How much of my video gets checked?
The free plan checks the first 10 seconds; Pro checks the whole upload up to 3 minutes. Either way the report says exactly how many seconds it looked at, and nothing outside that window is judged.
What does bits per pixel per frame mean?
Bitrate on its own is meaningless without the resolution and frame rate — 5 Mbps is generous for 720p30 and thin for 4K60. Dividing by pixels and frames gives one number that works for both, and it is what the bands are anchored to.
Is my video stored on your servers?
No. The file is deleted as soon as the check finishes. Nothing is kept and nothing is inspected.
What is the difference between this and comparing two videos?
This needs one file and asks "what is wrong with it". The comparison tool needs two and asks "what changed between them" — SSIM per second, a heatmap, and the exact moment they diverge. If you have the original as well, the comparison tells you precisely what an export cost you.
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