[mythtv-users] Getting Started with MythTV

Igor Izyumin igor at mlug.missouri.edu
Sun Jul 6 23:41:59 EDT 2003


Isaac Richards wrote:

>On Sunday 06 July 2003 10:59 pm, Igor Izyumin wrote:
>  
>
>>Don't even bother without such a card.  An 800MHz CPU can not encode
>>video in real-time, period.  My 700MHz processor has trouble DECODING
>>video (in Live TV mode).  It works when the quality is cranked down.
>>    
>>
>
>Err, that's really not true at all.  Plenty of people are using slower 
>machines than that.
>
>Additionally, you're using mjpeg, which is really quite cpu intensive to 
>decode.  MPEG-2 from a pvr-[2/3]50, or the software encoded mpeg4 or rtjpeg 
>codecs are much easier to decode.
>  
>
It could probably decode MPEG-2 just fine, I was just pointing out that 
you need some kind of hardware to encode.  I definitely don't think you 
can get a watchable image if you are using real-time Nuppelvideo 
encoding on an 800MHz machine.  If you set the resolution really low, it 
will work, but it will look very bad.

On my machine, if decimation is set to '1' and resolution to 720x480, 
the video jumps about once every two seconds.  Granted, I am using 
mjpeg.  Changing decimation to '2' fixes the problem without affecting 
the quality too much (but it still uses ~80% of the CPU when watching 
live TV -- could it be the ghetto Voodoo 3 videocard?).

Also, does MythTV normally take ~6 seconds to switch channels in live TV 
mode?  I am starting to suspect it's a problem with my machine.

Thanks.

-- Igor



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