[mythtv-users] Re: Hardware Recommendations?

Todd Bowman tbowman75 at yahoo.com
Sat Jun 4 03:32:58 UTC 2005


Michael T. Dean wrote:

> 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.

Thanks for all of the great information!  I guess I'll just spend a 
little extra money and get a PVR-250.  As a side note, the size of my 
2.5hr program turned out to be 51GB.  At least I'll be able to record it 
again later.



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