V4L2 and ALSA: Kernel SPI or User API?

Posted by pnongrata on Super User See other posts from Super User or by pnongrata
Published on 2012-12-10T14:42:29Z Indexed on 2012/12/10 17:08 UTC
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Filed under:

linux

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kernel

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alsa

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api

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v4l2

I'm trying to understand what Video for linux and ALSA are (exactly), and I can't discern whether they're APIs for Linux application to use (the userspace) or if they are backend services that are only available to the Linux kernel (sort of a kernalspace SPI). Or, if they are something entirely different.

On one hand, those articles make it sound like its an API for applications to use. However, on the V4L2 page it has a section title Software supporting Video4Linux...

So is V4L2 a library that applications use, or is it a module that "snaps into" the kernel? I'm so coonfused, thanks in advance.

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