Can you use hardware decoding on the display adapter for MVP use?

[CollinR]

It appears some of the newer graphics cards have some advanced hardware decoding. I was wondering if that were only applicable to their output ports or if those new streams can be utilized internally.

[omega]

The Hauppauge MediaMVP has a builtin hardware MPEG-2 decoder, so it shouldn't place any significant load on your server CPU for MPEG-2 videos. There would be no advantage to using a video card's MPEG decoder, even if it were possible.

Where you run into CPU load on the server is if you play back any non-MPEG-2 video on the MVP (including HD MPEG-2), because then the SageTV server has to transcode the video into MPEG-2 before streaming it to the MVP.

[CollinR]

No I meant MPEG4 x264 and h.264 that the 8600GTS has hardware support for.

[omega]

Sorry for the misunderstanding. I guess I'm a little behind in my advanced video technologies.

I don't see any way you could use a video card's MPEG-4/H.264 functionality on the MVP, since the MVP only understands MPEG-2 streams. I'm guessing these decoding optimizations are done directly in hardware, so using them as half of a software transcoding process would require that they were designed with that purpose in mind. Even if the decoding is done in firmware executed on the GPU, you'd still have to be able to get at the raw video output from the decoding process and pipe it into an MPEG-2 encoder, and then stream it out to the MVP. To do this would require either a hook in the driver that provides access to the decoded video (unlikely) or the ability to write a custom driver (also unlikely unless you work for nVidia). You'd still run into the encoding process taking up CPU, especially if the source material was HD or better, though it would alleviate a big chunk of the processing requirements.

I'd love to be wrong about this, since it's a great idea, but I'm pretty sure what you're suggesting is not feasible.

[gplasky]

Anything that is NOT mpeg2 and going to the MVP is handled by the Sagetranscoder which is all software. The videocard does decoding, not transcoding. I don't see a way for that to work.


Gerry

[CollinR]

The real probably is it can only decode a single stream, so even if it did work it would only support one. Not too much help in that.


Would be nice to have some kind of hardware devices for these purposes. With the new more capable extenders coming out it should be a non-issue.