[mythtv-users] Lossless transcoding became really slow

Jim Stichnoth stichnot at gmail.com
Sat Jun 27 15:26:42 UTC 2009

On Sat, Jun 27, 2009 at 8:02 AM, Michael T. Dean<mtdean at thirdcontact.com> wrote:
> On 06/27/2009 10:52 AM, Jim Stichnoth wrote:
>> Lately my lossless (commercial-removing) transcodes have become
>> exceptionally slow.  What used to finish in less than 5 minutes, now
>> takes about 2x realtime -- for example, a 30-minute recording may take
>> about an hour to complete.  During the transcode, the mythtranscode
>> process is consuming 1-2% CPU according to "top".  I don't know how to
>> evaluate disk I/O except by looking at the hard disk LED.  In the old
>> days, the LED would be pretty much solidly on; now it's mostly on but
>> you can see it flashing.  These are HDHR OTA recordings.  Nothing else
>> is going on on the system during the transcode.
>> The problem in diagnosing this is that I made a number of changes over
>> a short period of time, so it's hard to isolate which change led to
>> the slow transcodes.  Before, the system was running MythDora 5.
>> Since then, I upgraded to MythDora 10.21, built my own 0.21-fixes from
>> source (svn 20549), and patched it for VDPAU and HD-PVR.  I also moved
>> the backend from a dual-core 4450e system (GA-MA78GM-S2H, 2.3GHz
>> 4450e) to a faster core 2 duo system (GA-E7AUM-DS2H, 2.5GHz E5200).
>> Any suggestions on what might might have slowed down the transcodes,
>> and how I might get the original speed back?
> Failing hard drive constantly relocating data in bad sectors?

I wouldn't think so (at least I sure hope not).  I get the same
behavior for recordings on both hard drives, which are 1 TB SATA
drives from different manufacturers.  And I haven't noticed any bad
behavior from older recordings, nor from the OS or DB.


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