Video compression testing methodology | Video Size Reducer

What a measured case means

The homepage cases are individual runs through the live compressor. Each lists the source, settings, date, input and output size, and measured times. They are not averages, independent reviews, or guarantees for other videos.

A camera-original file, a downloaded copy, and a prepared excerpt are different inputs. Our cases identify which was used. The size before compression always means the file actually uploaded, including any preparation described in the source notes.

Measurements and quality comparison

1. Identify a source that can legally be shared, record its origin and license, and inspect its duration, dimensions, codecs, audio, and dynamic range.
2. Submit it to the live compressor and retain the task's actual settings and result metadata.
3. Download the result, verify its bytes and media properties, and compare them with the task record.
4. Compare source and result frames at the same media time. Publish the settings and limitations with the result.

We calculate size reduction as (1 − result bytes / source bytes) × 100%. MiB uses 1,048,576 bytes; decimal MB uses 1,000,000 bytes. A target is an upper bound, not a requirement to fill every available byte. For sharing, leave room below the receiving service's limit.

Matching still frames help inspect text and fine detail, but do not establish motion or audio quality. Reducing resolution can account for part of the saving. A quality-based run does not prove performance in target-size mode.

Timing and compression credits

Encoding time is the server's encoding measurement. Total task time also includes preparation, waiting, validation, and delivery; download time is excluded. Network conditions and server load affect these values. Where upload time is reported, it is measured separately.

Compression credits depend on the source and chosen settings. A case's recorded consumption applies to that run, not to every video of the same duration. The upload area shows the current estimate before you start.

Public records and source permissions

The September 16, 2026 cases include an original test-page recording, an iPhone 7 recording downloaded from Wikimedia Commons, and a six-minute excerpt of Sintel. Read the measurement data and preparation, timing, and license notes. The longer case uses a lower output resolution; the phone case is not a camera-original file.

We retain failed runs in our test records. A successful shorter excerpt does not establish that a full-length input succeeds. Results and source links on the homepage let you inspect the published successful runs directly.

The September 23, 2026 target-size tests reuse the screen and phone inputs with 2 MiB and 20 MiB targets. The results include verified download sizes, consumed credits, matching frames, and output hashes. Their total task time is measured from server task creation to its completed update; it excludes local checks before task creation and downloading.

Using these results

Choose a case close to your source and settings, then compare your own downloaded result before sharing it. Use pricing for current plans and About for editorial responsibility and corrections.