Trim
Drag the handles on the timeline, or press I and O at the playhead.
Orientation and speed
Changing the speed re-times every frame and the sound with it, which needs a filter graph.
Sound
Loudness and noise reduction are measured over the whole track by ffmpeg's own filters.
Loudness and noise reduction are measured over the whole track by ffmpeg's own filters.
Silence
Cutting the silences means listening to the whole soundtrack first, then re-timing what is left.
Watermark
Drawing over the picture needs a font and a filter; a browser's encoder takes frames, not text.
Encoded in this browser with WebCodecs. Nothing is uploaded, and the GPU is used where there is one.