You definitely can, it's just 1) vastly slower, and 2) you have to recompress the decompressed video, which loses quality. It's therefore an option of last resort.

Most people want to be able to download 5 hours of video in the background in 5 minutes. Not wait 5 hours while their computer is unusable.

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netsharc 17 hours ago | parent | next [-]

I wonder if it has to be a real computer, display, and camera, or if doing it with a "headless display" that is nonetheless being fed to a "video recorder" would work...

Funny how it'd be like The Matrix...

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npteljes 16 hours ago | parent | next [-]

I have written software to do this kind of recording on a laptop, running 4 of the stream itself (different episodes of the same show).

It opened DRM enabled browsers side by side, ffmpeg captured the video from the respective parts of the screen, and each browser's audio was piped into a different dummy output, which ffmpeg also captured of course.

The tech stack was linux, bash, PHP, php-webdriver, Selenium, Firefox, ffmpeg. So yes, this idea absolutely works! That is, until they crank up the DRM so that software screen capture doesn't work.

	▲	pabs3 3 hours ago \| parent [-]
		Just move the capturing a layer further away, there is always the analog hole.

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crazygringo 17 hours ago | parent | prev [-]

It depends on a lot of factors. But even if it works in a virtual machine, your CPU is going to be pegged at 100% the whole time to handle the re-encoding. Unless you use a hardware h.264 encoder, but then the quality is pretty terrible since it's explicitly optimized for speed over quality and isn't tunable the way software encoders are.

It's always doable, it's just an option of last resort. You always just want to access the original compressed bitstream if possible.

	▲	tracker1 14 hours ago \| parent [-]
		I think the real key is to only compress enough initially so that you don't blow out your storage in terms of size and throughput... Once you have the stream captured at a higher quality, you can always recompress more optimally. A relatively low compression with hardware h.264 will still take up a lot less space and throughput than mpeg-2 or raw.

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everdrive 17 hours ago | parent | prev [-]

Understood and agreed. I mostly don't even care about keeping videos from Youtube, but some of the most amazing music performances in the world are trapped on Youtube, and in many cases there is no obvious way to purchase or download them elsewhere.

eg: https://www.youtube.com/watch?v=HAi1pn3kBqE