[mythtv] Audio-upmixing questions regarding #5900

Yeechang Lee ylee at pobox.com
Tue Nov 18 13:09:21 UTC 2008

foo bar <foobum at gmail.com> says:
> Yes, the upmixer (detailed at
> http://www.hydrogenaudio.org/forums/index.php?showtopic=52235) will
> use Dolby Pro Logic, DTS Neo:6 and other cues to turn stereo into 6
> channels.

Nice! This is quite more than I was expecting.

> > In terms of performance, my Pentium 4 3.0GHz frontend has trouble
> > with upmixing 5.1 audio off HD recordings; the normal 55-70% CPU
> > usage turns into 90-99%.
> Could you clarify? Do you mean upmixing (is the original audio track
> 2 channel or 5.1)?

I was misusing terminology, I guess. I was referring to recreating 5.1
audio from native 5.1 audio when timestretching a HD recording to
>1.0X. Whether Passive or either Active mode, CPU hits >90% usage and
the playback stutters.

Upmixing (turning non-5.1 audio into 5.1 audio) while timestretching
to faster than 1.0X is much easier on the CPU.

Frontend:		P4 3.0GHz, 1.5TB software RAID 5 array
Backend:		Quad-core Xeon 1.6GHz, 6.6TB sw RAID 6
Video inputs:		Four high-definition over FireWire/OTA
Accessories:		47" 1080p LCD, 5.1 digital, and MX-600

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