[mythtv-users] Commercial Detection during recording

Joseph Fry joe at thefrys.com
Mon Mar 11 17:20:40 UTC 2013


> Does enabling "Auto-commercial-detection jobs when recording starts" add a
> significant amount of overhead to the system?  Right now, I can
> simultaneously record three shows (via HD Prime) onto two physical hard
> drives, while I'm watching a previously recorded show without issue.  I'm
> just wondering if the additional commercial detection (3 max) would be too
> much for the system.
>

Every system is different, however I can do it just fine with the following
specs:

Pentium G540
8GB RAM
3x5400 RPM SATA-II recording drives
  - OS/DB resides in a software raid 1 array spanning all 3 drives, however
only a small small partition of the drives is raided
  - Swap is defined on all 3 drives.

I/O will be your greatest concern, as the backend doesn't really have much
CPU overhead, and the commercial detection runs at a low priority.  With a
absolute maximum of 38.8 Mbits/sec (ATSC spec max) per recording  (you will
never see this), writing 3 streams and reading 2 will result in 194Mb/sec
or 24 MB/sec of I/O; well below the the max of most hard drives.  At this
point its all about your drive's seek times, fragmentation, etc.

Odds are your system can handle it no problem.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.mythtv.org/pipermail/mythtv-users/attachments/20130311/610df40a/attachment.html>


More information about the mythtv-users mailing list