问题
How can I capture the datastream of a JS / Leaflet animation and download it to MP4?
I am looking for output that looks something like the smooth path traced in these demos: https://github.com/IvanSanchez/Leaflet.Polyline.SnakeAnim
Their author appears to have done them in ffcast or some screencasting softare.
However, I am looking for an automated solution that can be run as script, ideally one that works on the data stream itself (not the screen), perhaps with a headless browser.
I have tried puppeteer-gif and puppeteer-gif-cast but the best frame rate is jumpy.
I have tried WebRTC-Experiment but it requires me to set manual permissions. Ditto the Screen Capture API mentioned here, though this at least seems to work on the data stream itself.
回答1:
The canvas captureStream method combined with the MediaRecorder API should do the trick.
Mind you that Chrome only supports webm as a container format (but does record h264) so you might need a postprocessing step with ffmpeg.
来源：https://stackoverflow.com/questions/59726775/capturing-data-stream-of-a-js-leaflet-animation-as-mp4