[mythtv] Random blockiness that probably isn't CPU or PCI bus bandwidth-related

Daniel Thor Kristjansson danielk at mrl.nyu.edu
Mon Jan 10 08:39:27 EST 2005


]recording from one of my ivtv cards, I get intermittent blockiness on
]the HDTV stream.
]Thing is, I get no bttv: buffer overrun errors, except during the
]times I expect them (e.g., another recording starting).  This suggests
]the driver is getting the data correctly, but it is being ditched or
]overwritten before mythtv gets it.  Does this jive with the
]understanding of some of the HDTV developers here?  (Daniel?  John?)

This doesn't really jibe with my experience, unless you are running out 
of CPU, which shouldn't be the case for a P4 3.2Ghz machine. Of course I 
do compile with extra optimizations, even in debug mode. If it is not 
the CPU, do the following:

Make sure there are errors in the stream.
 Yes - If there are is the signal level too low?
   Yes - nothing we can do
   No  - there may be a bug in the ringbuffer 
 No - there may be bug in ffmpeg

-- Daniel


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