[mythtvnz] Best way to reduce CPU use (by ~10%) during software encoding/decoding

[Nick Rout]

On Sun, Feb 22, 2009 at 10:46 AM, Aaron Whitehouse
<lists at whitehouse.org.nz> wrote:
> Hello,
>
> I have just upgraded my HTPC (to one based on the AMD 780G chipset, as
> mentioned in an earlier email). The weakest link in my new machine is
> the CPU, which is a Sempron LE-1200 (instead of the 2.4GHz P4 in the old
> machine). While I thought the Sempron would be faster, it seems to be
> slightly slower at video encoding/decoding than the P4 was, meaning that
> my current settings (512x576, 2200 bitrate, MPEG-4, quality between 2
> and 15, max 3 quality difference between frames, scale bitrate for frame
> size, HQ encoding and 4MV), which worked fine in Live TV (i.e. one
> encoding stream, one decoding stream, no DCT encoding, no interlaced
> motion estimation) on the P4, are slightly too demanding for the new
> CPU. The new CPU is sitting at around 90+% in Top and is the video is
> quite jerky. I am guessing that the CPU is hitting 100% on occasion,
> stalling the playback.
>
> I have two cards in the machine - a bttv software encoder and a
> Hauppauge PVR-150 with MPEG-2 hardware encoding. I will probably switch
> the default card to be the hardware encoder (MPEG-2 takes heaps of room,
> but I have a new HDD), but I will still need to be able to record one
> hardware, one software and play one back. Playing MPEG-2 actually seems
> to take slightly more CPU than playing back MPEG-4, which surprised me.
>
> So here is my question (after all of that background): I only think that
> I need to reduce CPU use by about 10%, but I am not sure which settings
> are the best to change in order to get that. Disabling 4MV or HQ
> encoding saves a lot, but the picture isn't very good. Tweaking the max
> and min quality makes some difference, but I'm not sure which to change.
> What is the best thing for me to change?
>

Why are you using analogue encoders in this day and age?

My guess: either you are recording from a set top box like sky, or you
haven't bothered updating :)

Anyway you can only use one card for the set  top box. Keep the PVR150
and get a satellite card.

Software encoding is sooo last century!