A filename extension such as `.mp4` or `.mov` does not tell you which video and audio codecs are inside. Two MP4 files can behave very differently: one may use widely supported H.264 while another uses a codec that a particular browser or device cannot play.
Before recompressing a video, inspect its container, codecs, resolution, frame rate, bitrate, HDR and color information, and audio channels. Media Inspector uses a bundled FFmpeg build in the browser to expose these details and help narrow down the next step.
MP4 and MOV are containers, not codec names
MP4, MOV, MKV, and WebM are containers that can hold video, audio, subtitles, and metadata. Inside them you may find video streams such as H.264, HEVC, AV1, or VP9 and audio streams such as AAC, Opus, or MP3.
That is why an MP4 file can still fail to play on a particular device. The extension alone is not enough; inspect the Video and Audio streams separately to see the actual codecs.
Check resolution, frame rate, bitrate, and color details
For video streams, inspect width, height, frame rate, and bitrate along with pixel format, color space, HDR information, and rotation. A portrait video may appear to have landscape dimensions when rotation metadata is responsible for the displayed orientation.
Compression choices also depend on the source. A 4K 60 fps video should not automatically be treated the same as a 1080p 30 fps clip. Inspect the source first, then choose appropriate settings in a compressor instead of reducing quality blindly.
- Resolution
- Frame rate
- Bitrate
- Pixel format, color, and HDR
- Rotation
Inspect audio, subtitles, and chapters too
A media file can contain more than one video stream. Audio codec, sample rate, and channel count are useful, but subtitles, data streams, attachments, and chapters can matter as well. Knowing what exists before conversion helps explain why a later output lost an audio track or subtitle stream.
For files with multiple audio or subtitle tracks, decide which streams matter before converting. A simple video converter does not necessarily preserve every stream from the source.
Separate media inspection from browser playback support
Even when the browser cannot play a video natively, the bundled FFmpeg build may still be able to parse it and report technical details. Media Doctor combines those inspection results with capability signals from the current browser to organize likely playback issues.
Media Doctor does not repair or automatically convert the video. After identifying likely causes, choose the next step that fits the goal, such as compression, conversion, or a lossless cut.
Review metadata before sharing
Video and audio files can contain metadata such as titles, comments, or encoder information. For supported MP4, MOV, M4V, M4A, MP3, FLAC, and WAV files, Media Inspector can create a new copy with supported metadata removed without re-encoding the media payload.
This does not guarantee removal of information embedded in chapters, codec bitstreams, or specialized data streams. For sensitive files, inspect the cleaned copy again and verify that the information you care about is gone.
Step by step
- Open Media Inspector and select the video or audio file you want to inspect.
- Review the basic information for container, duration, bitrate, and stream count.
- In Video, check codec, resolution, frame rate, color/HDR, and rotation; in Audio, check codec and channels.
- Review subtitles, other streams, metadata, and chapters when they matter.
- If you are troubleshooting playback, review Media Doctor and then choose an appropriate next step such as compression, conversion, or cutting.
Media Inspector
Inspect codecs, bitrate, FPS, HDR, metadata, and more for video and audio files locally.
Tips and limitations
- Check the source resolution and frame rate before compressing so you do not reduce them more than necessary.
- A browser playback failure does not automatically mean the file itself is corrupt. Inspect the container and codecs first.
- After cleaning metadata, load the output back into Media Inspector and verify the result.
Frequently asked questions
Will every MP4 file play on every device?
No. MP4 is a container, and playback support depends on the video and audio codecs inside it. Two `.mp4` files can have different compatibility.
Can I inspect a video that the browser cannot play?
Often yes. If the bundled FFmpeg build can parse the container, it may report details even when the browser cannot play the file natively.
Does Media Doctor repair the video?
No. It organizes likely playback issues from inspection results and browser capability signals; it does not repair or convert the file.
Are inspected video or audio files uploaded to a server?
No. Selected media is not uploaded to a Browser Kitty backend; it is inspected by the bundled FFmpeg running in the browser.