[mythtv-users] Re: Hardware Recommendations?

Michael T. Dean mtdean at thirdcontact.com
Fri Jun 3 21:18:05 UTC 2005


Todd Bowman wrote:

> Michael T. Dean wrote:
>
>> b) I highly recommend the PVR-x50's (and, personally, wouldn't touch 
>> a frame grabber).  If you've got experience with IvyTV, you could 
>> probably get PVR-150 up and running and it's not much more expensive 
>> than "dumb" frame grabbers.  If not, there are still some really good 
>> deals on PVR-250MCE's (which are easier to set up).
>
> I've looked at the HW MPEG2 encoders but MPEG2 seems to take up too 
> much room.  I tried using the SW MPEG2 encoding in MythTV and within 
> one day my 160GB disk was filled.  Even though I turned on automatic 
> transcoding to MPEG4, the recordings just seemed to get ahead of the 
> transcoding.  Once the disk was full, it couldn't transcode any more.  
> Do the HW encoders produce smaller video files?  I don't remember the 
> exact file size but I think a 2.5 hour program was something like 
> 26GB! (640x480)

2.5hrs at 26GB would be a 25Mbps bitrate.  DVD specification limits 
total bitrate (audio, video, and subtitles) to 10.08Mbps and no DVD has 
a sustained 10.08Mbps (instead, they would use variable bitrate).  The 
10.08Mbps limit on DVD's is appropriate as DVD's have a max resolution 
of 720x480, and above this bitrate, you've definitely crossed the point 
of diminishing returns.  So, this would only happen with bad recording 
settings (or, if the 26GB was the transcoded version, bad transcode 
settings).

http://mythtv.info/moin.cgi/UserManual_2fTechnicalDetailsAppendix_2fRecordingParameters

My settings are shown on there--720x480 at about 1.15GiB/hr.

Mike


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