Hello.

I've encountered a bug in Chrome on Android where MediaRecorder, using Canvas.captureStream(), fails to encode video from large canvas elements (e.g., 1280x720). While the process works on desktop Chrome, on Android, the recording stops abruptly at unpredictable points, likely due to limitations in the MediaRecorder API's encoding capabilities. A smaller canvas (640x480) works fine, suggesting resolution-based limitations. I've reported this as Chrome bug 897727 and created a demo to illustrate the issue.

I combined FFMPEG.js, a tool compiled with asm.js for video editing in web apps, with Comlink, a library that simplifies web worker interactions. This integration, along with my experiment of exporting FFMPEG to Web Assembly, allows for cleaner video encoding off the main thread. The provided code snippets demonstrate the simplicity of using Comlink to expose the ffmpeg interface within a web worker and then access it from the main thread as a proxy, offering a neat solution for asynchronous video processing.