I choose PC configuration for multichannel video application: Video surveillance system
which may use video compression/decompression with hardware acceleration via MediaSDK
The newest HD Graphics processors and chipsets have the best performance on computer graphics,
games, CADs etc, and, probably, multimedia compression/decompression.
However, I don't need powerful graphics. I need only compression/decompression.
The question is which of HD graphics generations is sufficient for this task?
Which are other criterias to choose motherboard and processor?
It sounds like you are generally, you are looking for a product that includes Intel Quick Sync Video.
I think you should consider if this is a dedicated usage model (where video encoding/decoding is the only task), or if you desire 'some' bandwidth availability to perform other tasks (like transmitting encoding video thru a network, etc.). I'm not sure from the description if you usage is for a single low-resolution / low-quality / low-framerate video stream, or if you are attempting to support multiple high-resolution / high-quality / high-framerate streams at once.
The video format of your video stream may be one place to start. For example, our new 4th Generation Core products now support acceleration of MJPEG streams used by some cameras.
In general, the newer products support more features (video formats, higher resolution, etc.), and older products may meet the needs of your usage, however, you may want to consider if power-usage is important. Even if system is using AC Power, this can be important to some as it is desirable to have cool/quiet solution that costs less to operate.