[mythtv] Re: [mythtv-users] HDTV recording error: IOBOUND - blocking in ThreadFileWriter::Write()

John Sturgeon john at sturgeonfamily.com
Fri Jul 2 20:18:34 EDT 2004

Chris Pinkham wrote:

>>>>I'm saw somebody mention this error a while back, but I never heard 
>>>>if anybody definitively resolved it.  Occasionally I get the IOBOUND 
>If you compiled your own install of Myth, you could try bumping up the
>recording file writer buffer size from its default of 2 Megs.  Edit
>mytthv/libs/libmythtv/RingBuffer.cpp and change the TFW_BUF_SIZE line
>near the top to 4*1024*1024 instead of 2*1024*1024.  I don't know
>what bitrate the video you're recording is at, but if it's 16Mbit or higher
>then less than 1 second of video will fit in the buffer so if you have
>anything that delays your backend from writing to disk you could easily
>fill the buffer and get the IOBOUND error.
Thanks for the tip Chris.  Unfortunately, I'm not compiling my own.  I'm 
using atrpms CVS bits.  Since this is ATSC, then the bitrate is about 
19.3 megabits per second (yep... 19.3).  I think you've nailed it  This 
seems like an awfully small buffer for HDTV.  You'd think that more 
folks would run into the problem.  Maybe folks aren't looking at their 
log files and their more tolerant of glitches in playback... dunno...

I'm going to crosspost this response over to the dev list and see if 
some of the HDTV developers (John Patrick Poet etc...) think that 
something should be done there.


John Sturgeon <><

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