What this video tool does
One local FFmpeg engine performs all six tasks. MP4 output uses H.264 video, AAC audio when present, and yuv420p pixels. Converting and trimming re-encode video; they are not lossless remuxing. WAV extraction is uncompressed 44.1 kHz stereo PCM and can be larger than the original video.
The first run downloads about 31 MiB of processing code from this site. A worker processes the selected file in browser memory. Large clips can exhaust memory or take longer than playback. Keep the tab in the foreground; cancel if needed and retry a smaller file.
Tested input samples: H.264/AAC in MOV and MP4, VP9/Opus in WebM. Container names do not guarantee codec support. HDR, HEVC, ProRes, damaged files, multi-track selection and DRM are not promised. Outputs are SDR-oriented; colour appearance may change. An unsupported or missing stream returns an error, not an empty file.
Desktop Chrome is the primary tested browser. A narrow-screen check does not prove real-phone performance. Mobile has a 25 MiB / 3-minute guard; desktop 100 MiB / 10 minutes. Both cap input at 3840 × 2160, and even files below those limits may exceed device memory.
A practical example
Try the two-second MOV sample, select Trim video, use 0 to 1 seconds and run the tool. Download the resulting MP4. For a smaller frame, select Compress and resize and set a maximum width; the output reports actual bytes and can still be larger than your input.