Video Metadata Viewer
Read duration, resolution, container and average bitrate from MP4, WebM, MOV or MKV files — locally.
Quick answer: Read duration, resolution, container and average bitrate from MP4, WebM, MOV or MKV files — locally.
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Frequently asked questions
- How do I see the resolution and duration of a video file?
- Drop the file onto the upload area; we read it locally and show duration, resolution, container, MIME type, file size, average bitrate and the video/audio codec within a second or two.
- Which formats are supported?
- MP4, MOV, WebM and MKV files. We parse the container header directly, so codec detection works even when your browser refuses to decode the actual video stream.
- Is my video uploaded anywhere?
- No. The file is read locally as a Blob and only the first 256 KB are parsed in JavaScript. Nothing leaves your device.
- How are the codec strings detected?
- For MP4/MOV we walk the moov→trak→mdia→minf→stbl→stsd boxes and read the 4-character codec ID (avc1, hvc1, vp09, av01, mp4a, opus…). For WebM/MKV we read the Matroska CodecID (V_VP9, V_AV1, A_OPUS, A_VORBIS…).
- What's the file size limit?
- 200 MB. The header parser only needs the first chunk, so the limit is mainly to keep memory predictable when the browser also tries to decode for duration/resolution.
- Why is the bitrate just an average?
- We compute size / duration, which gives an accurate overall average. Per-second variations (VBR encodes) require parsing the full bitstream, which is out of scope for a quick browser tool.
- Can I get the exact codec profile / level?
- We surface the FourCC / CodecID, which is enough to know the family (avc1 = H.264, hvc1 = H.265, av01 = AV1, vp09 = VP9). For exact profile/level use a desktop inspector like MediaInfo.
- Does it work with audio files?
- This page is for video files. If you only need audio length and bitrate, almost any audio player will display them.
- Why is my MKV file not loading?
- Browsers historically have patchy MKV support — duration and resolution may be missing if the browser can't decode the stream, but the container/codec readout still works because we parse the header directly.
- Is the metadata viewer free?
- Yes — completely free, no signup, no watermark.