BrowserTools

Video Metadata Viewer

Inspect codecs, duration, resolution, bitrate

By Guga — BrowserTools maintainer, Tbilisi, Georgia Updated 2026-08-15
Free Private No uploads

The first inspection pulls a ~30 MB FFmpeg build from unpkg.com so that codec, frame-rate and audio details can be read; duration and resolution come back instantly from the browser's own demuxer, before that download finishes.

What is Video Metadata Viewer?

Six fields appear for each file: size, duration, resolution, video codec, frame rate and audio codec. They come from two different parsers, which is worth understanding because they fail differently. Duration and resolution are read by the browser's own demuxer and appear in well under a second — but a browser can only report on a container it can parse, so an unusual codec leaves those two as dashes. Codec, frame rate and audio details come from the WebAssembly FFmpeg build, and only the first 8 MB of your file is read to get them. That works because most MP4s put their index at the front, but a file written without faststart keeps that index at the end, and on those the second parser can come back empty too.

Drop a video file and instantly see its duration, resolution, codecs, bitrate and frame rate — parsed locally, which makes it safe for confidential footage.

Private Video Metadata Viewer In Your Browser

Video Metadata Viewer is processed locally with client-side JavaScript. Your files never touch a server, and there is no queue to wait in.

Step-by-Step

How to use Video Metadata Viewer

1

Drop a video or audio file onto the panel; the name and size are read straight from the file handle.

2

Wait a moment — duration and resolution resolve from the browser's demuxer, usually before you have finished reading this sentence.

3

Let the engine download and finish parsing, which reads at most the first 8 MB of the file for stream details.

4

Read the six stat tiles; any field marked with a dash was not resolvable by either parser, and the file itself never left the page.

Key Capabilities
  • Reports video codec, frame rate, audio codec, resolution, duration and file size in one view.
  • Uses the browser's native demuxer for duration and resolution, so those values appear without any download.
  • Reads only the first 8 MB of the source to extract stream information, keeping inspection fast on large files.
  • Never modifies the file; the object is only ever read.
Common Use Cases
  • A video editor checking the true codec and frame rate of a client's file before choosing an export preset.
  • A developer confirming whether a shared video is a supported H.264/AAC pair or something a browser will refuse to play.
  • A support engineer verifying that an uploaded file is within a service's duration limit without opening a heavier tool.
Clear Answers

Frequently Asked Questions

Why are some fields showing a dash?
Because one of the two parsers could not read them. Dash in the Duration or Resolution tiles means the browser could not demux the file. Dashes in the codec, frame rate and audio tiles mean FFmpeg's scan of the first 8 MB did not find a usable header — which is what happens with MP4 files whose index sits at the end instead of the front.
Does this read my entire video?
No. The stream details come from a scan capped at the first 8 MB, and duration and resolution come from container metadata near the start of the file. A 4 GB movie is not copied into memory to be inspected.
Where is the bitrate?
Not on screen. The page derives a bitrate value internally while parsing, but the six tiles that render are size, duration, resolution, video codec, frame rate and audio codec. If you need an average bitrate figure, the container's own metadata view is the place to read it.
Is it safe for confidential footage?
Yes. The file is opened through a local object URL and parsed in the tab; no bytes are transmitted. Be aware that the first inspection does pull a ~30 MB FFmpeg build from unpkg.com to do the codec half of the job.