[SGVLUG] Myth TV question!

[Michael Proctor-Smith]

On 11/6/06, Munjal Thakkar <m00njal at gmail.com> wrote:
> another question, *thanks for feedback BTW* what is the difference between
> hardware decoding and encoding, sorry I know I could google, but ......

Well it is just what it sounds like, hardware encoders/decoders do the
work on a dedecated asic/processor/dsp on the card. There work is not
done on the system cpu kind of like 3d accellerators vs. doing 3d on
the system cpu. With a hardware encoder you can basically just cat
/dev/video to a file and it will have encoded video and or video and
audio. Same for decoders in reverse thought most require mpeg stream
to be demuxed before it is fed to driver.

Put it this way I have a system with 3 pvr250 encoders, it is a P4
2.4Ghz and only uses about 6% cpu while capturing three 480x480 mpeg2
streams.

There is also hardware assisted mpeg decoding where some of the more
cpu intensive work is done by the video card(NVIDIA hardware/drivers
do that).