well i might be a tad bit late but...this is the expected reaction and its neither the fault of https nor ffmpeg. if you ask ffmpeg to capture a frame at 10 seconds for example, it will have to wait until your slow internet downloads 10s worth of content from your server before it can do what you asked it to...when its on your local machine its directly accessible so the processing time will of course drop significantly.
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well i might be a tad bit late but...this is the expected reaction and its neither the fault of https nor ffmpeg. if you ask ffmpeg to capture a frame at 10 seconds for example, it will have to wait until your slow internet downloads 10s worth of content from your server before it can do what you asked it to...when its on your local machine its directly accessible so the processing time will of course drop significantly.