Choose a video format and a sensible file size
A 1080p label tells you the picture's height, but not how large the file will be or whether a browser can play it. When a recording is too large to share, inspect its duration and bitrate before changing resolution. Keep an original copy for future edits.
Container, codec and resolution
MP4, WebM and Matroska are containers: they package streams and metadata. A codec, such as H.264, VP9 or AV1, determines how the picture is encoded. A container can hold different codecs. The file extension cannot prove which codec is inside.
Resolution describes the decoded picture dimensions. Landscape 1920 × 1080 and portrait 1080 × 1920 contain the same number of pixels. Their aspect ratios are 16:9 and 9:16. Do not stretch a portrait clip into a landscape shape merely to match an export preset.
The SaveVideo inspector uses your browser's media metadata to read duration and dimensions. It reports the browser's MIME type hint as a hint, rather than a verified codec. It does not report stream codec names, color depth or frame rate; use a trusted desktop inspector when you need those details.
Calculate size from bitrate
For a rough estimate using decimal units:
Size in MB ≈ total bitrate in Mbps × duration in seconds ÷ 8
A two-minute clip at a combined video-and-audio bitrate of 8 Mbps is approximately 120 MB before small container differences. Reducing it to 4 Mbps roughly halves that estimate; reducing resolution without changing the encoder's bitrate target does not necessarily halve the file.
Average total bitrate can be calculated in reverse: bytes × 8 ÷ seconds ÷ 1,000,000. Our inspector includes all file bytes, so its number includes audio, subtitles and overhead. It is not the isolated video stream's bitrate.
Worked example: one minute below 25 MB
- Set the calculator's target to 25 MB and duration to 60 seconds.
- Reserve 128 kbps for audio. Enter 0 only if you intend to export without audio.
- The calculator leaves a 3% margin, producing a combined budget of about 3.23 Mbps.
- Subtracting audio leaves about 3.11 Mbps for video. Enter that as your editor's video bitrate target.
- Export a copy and inspect its actual size. If it exceeds the destination's limit, lower the target slightly and export again.
The margin is a planning aid, not a guarantee. Variable bitrate, encoder settings, embedded subtitles and unusual metadata can change the result. The calculator does not compress the file for you.
MB and MiB are different
One MB is 1,000,000 bytes. One MiB is 1,048,576 bytes. The inspector displays both so you can compare upload limits without silently mixing units. SaveVideo's server output cap is 400 MiB, which is about 419.43 MB. A destination that says “25 MB” may apply a different interpretation; check its documentation.
Choose what to change first
- Long clip: trim sections you do not need. Duration has a direct effect on file size.
- Static slides or a screen recording: test a lower bitrate and review small text for legibility.
- Fast movement: reducing bitrate too far can smear detail. Check difficult scenes before sharing.
- Audio-only requirement: an authorized audio export avoids carrying a video stream. Converting already compressed audio to MP3 does not improve its quality.
- Unsupported playback: changing the filename does not change codecs. Export a new copy using settings supported by the receiving device.
Privacy and limitations
Selecting a file in the inspector creates a temporary browser object URL. The file and extracted metadata are not uploaded. Clear the selection to release the preview, or close the page. The downloaded JSON report remains wherever you save it. Regular page analytics are separate from the local file operation.
Technical references
Read MDN's container format reference and the browser duration API reference for the underlying distinctions and metadata limitations.