PDF, video and audio size targets
Download a source or run it here using the same compressor as the homepage. The table reports the bytes from your run; no output size is assumed in advance. One KB here means 1,024 bytes.
| File | Input bytes | Target bytes | Output bytes |
|---|---|---|---|
| VIDEO output | 2,334,407 | 204,800 | 183,848 |
Reference method: the PDF uses the actual PDF processor with a Node canvas adapter; video and audio use native FFmpeg with the same encoding arguments and bitrate search as the browser processor. Browser encoders can return different sizes. See method and measurements.
Three-second video → 200 KB
A silent 1280 × 720 moving test chart. The actual browser encoder aims below 204,800 bytes. Play the output and inspect moving edges; duration and dimensions should remain unchanged.
A target that should be rejected
For this three-second video, a 1 KB target is below the processor's minimum. The expected result is an explanation asking for a larger limit, with no pretend successful output.
Video and audio processing loads the browser encoder on the first run. Keep this page open. A small target can reduce quality, still produce an oversized file, or be rejected; a completed run does not guarantee that the result suits your destination.
Resolution describes the pixel grid of each frame. File size depends much more directly on duration, bitrate, codec efficiency, audio, and scene complexity. That means a 1080p video can be made smaller without becoming 720p—but fewer bits must represent the same number of pixels.
What changes when resolution stays fixed
- Average video bitrate decreases.
- Fine texture is simplified.
- Fast movement can show blocks or smearing sooner.
- Gradients may band.
- Encoder effort and codec choice influence how efficiently the remaining bits are used.
When same-resolution compression works well
Simple scenes are forgiving. Screen recordings with limited movement, talking-head clips, slides, and static backgrounds can often use a lower bitrate while remaining useful. Highly detailed motion—water, trees, crowds, sports, gaming, noise, grain—requires far more information per second.
The quality floor
At a very small target, keeping 1080p can become counterproductive. A cleaner 720p encode may look better than a heavily damaged 1080p encode because each pixel has a larger share of the bitrate budget. There is no rule that ‘more pixels’ always means ‘better video.’
| If you see… | Likely issue | Try… |
|---|---|---|
| Blocks during movement | Bitrate too low for motion | Increase target size or reduce resolution |
| Soft overall picture | Encoder discarding high-frequency detail | Increase bitrate or use a shorter clip |
| Audio dominates quality budget | Audio bitrate too high for tiny target | Use a moderate audio bitrate |
| Encoding takes very long | Large source processed in browser | Use a shorter clip or desktop device |
Use Video Bitrate and File Size Explained to estimate how much bitrate a target leaves for each second. Then use Fitabyte Compress for a concrete target and inspect the output on the device where it will actually be viewed.