Video compression case studies — 16 September 2026

These samples were uploaded to https://video-size-reducer.com/ and processed
by its production service. The compression results were downloaded and
checked locally. Local FFmpeg was used to prepare the screen and excerpt inputs, inspect files,
and extract comparison frames. Measured outputs were produced by the website.

Measurement
- File sizes are exact file bytes, displayed as MiB (1 MiB = 1,048,576 bytes).
- Reduction = (1 - output bytes / input bytes) x 100.
- Upload time runs from the first upload-part request to the successful upload
  completion response, using browser Resource Timing. It includes transfer,
  multipart completion, and associated network waits.
- Encoding time is the service's encodingWallClockMs, including FFmpeg encoding
  passes in the successful attempt but excluding queueing, earlier failed
  attempts, validation, and result delivery.
- Total task time uses the server's creation and completion timestamps. It
  includes uploading, queueing, retries, encoding, validation, and result
  delivery to storage. Local file selection and the final download are excluded.
  Tasks that needed more than one processing attempt are explicitly marked.
- Each case is one run. Times are not a speed benchmark or an average.
- Comparison PNGs contain unenhanced decoded frames at native resolution.
  Source and output are matched at corresponding media times, accounting for
  frame rate and small container timestamp offsets. WebP previews are resized for page display;
  open the PNGs to inspect native detail. Stills do not establish motion or
  audio quality. The long-video case also reduces resolution.

Phone footage
La rivière Druyes et la rue du capitaine Coignet à Druyes-les-Belles-Fontaines
by Benoît Prieur. The Commons page identifies an iPhone 7 as the capture device.
This test uses the downloaded WebM version, not the camera-original recording.
Source: https://commons.wikimedia.org/wiki/File:La_rivi%C3%A8re_Druyes_et_la_rue_du_capitaine_Coignet_%C3%A0_Druyes-les-Belles-Fontaines.webm
License: CC0 1.0 Universal
https://creativecommons.org/publicdomain/zero/1.0/
Changes for this case: website recompression, extracted frames, resized previews.

Screen recording
Original test webpage with fictional records, small text, search and scrolling.
Prepared specifically for this test; no customer data or third-party imagery.
Real browser frames were captured during automated interaction for 60 seconds.
Frames were assembled according to their capture timestamps as an H.264
CRF 18 / medium / 30 fps / 1920 x 1080 source recording, with no audio.
Repeated frames preserve real static intervals; no bitrate padding was used.
The recording was then uploaded to the same production compressor.

Long video
Sintel (2010), a continuous six-minute excerpt starting at the beginning.
Copyright Blender Foundation | www.sintel.org — Durian Open Movie project.
Source: https://commons.wikimedia.org/wiki/File:Sintel_movie_4K.webm
Official project: https://durian.blender.org/about/
License: Creative Commons Attribution 3.0 Unported
https://creativecommons.org/licenses/by/3.0/
The Commons VP9 download (1920 x 818) was prepared as a 360-second H.264 MP4
at 24 fps, CRF 18 / medium, with AAC 128 kbps stereo, before uploading.
This prepared excerpt is the measured input, not the full film or a lossless
master. No bitrate padding was added. Website output uses a 720p boundary.
Changes: excerpt, format conversion and audio downmix during input preparation;
website recompression and resolution reduction; extracted frames and resized
previews. Attribution does not imply the creators endorse this website.

Additional failed test
The complete 14:48 VP9 WebM was also tested. All three automatic attempts
failed with a source-read HTTP 403 after about 309–311 seconds per attempt;
no completed output is reported for that input. The source link's 300-second
expiry and lack of renewal match this failure. The six-minute MP4 is a
separate test and does not establish that the full-film failure is fixed.

Exact measurements and hashes: measurements.json (in this directory).