[FFmpeg-devel] [PATCH] Add Win32 GDI-based screen grabbing

[Eli Kara]

> As far as performance, I actually found that it's pretty good on modern windows computers. The performance issues that I was seeing was solely due to using Windows 8.1 on an laptop with older Intel integrated graphics that didn't > have a fully supported driver.

> Calvin

I just have to mention something with regards to capturing from the screen. As far as modern operating system go, i.e: Win7 with desktop composition and Windows 8 (where desktop composition cannot even be disabled),
the performance will *always* be far from optimal. Copying from video memory back to system memory is an inherently expensive operation, sometimes in the order of tens of milliseconds. Additionally, it will inevitably
stall the entire GPU and WDM pipes. Actually, due to this, capturing this way is even slower than it used to be in Windows XP (this is documented).

Just a point to keep in mind..

Regards,
Eli