[mythtv-users] Some issues with pvr150 cards

[Roger Heflin]

Thomas Fjellstrom wrote:
> On Friday 17 October 2008, Thomas Fjellstrom wrote:
>> I'm getting the following messages from the frontend:
>>
>> 2008-10-17 16:03:06.468 WriteAudio: buffer underrun
>> 2008-10-17 16:03:56.564 WriteAudio: buffer underrun
>> 2008-10-17 16:04:15.065 [mpeg2video @ 0xb6505e88]invalid mb type in P Frame
>> at 35 29
>> 2008-10-17 16:04:31.056 [mpeg2video @ 0xb6505e88]00 motion_type at 27 23
>> 2008-10-17 16:04:31.057 [mpeg2video @ 0xb6505e88]Warning MVs not available
>> 2008-10-17 16:06:09.643 WriteAudio: buffer underrun
>> 2008-10-17 16:11:33.834 [mpeg2video @ 0xb6505e88]ac-tex damaged at 39 13
>> 2008-10-17 16:15:16.846 [mpeg2video @ 0xb6505e88]ac-tex damaged at 44 7
>> 2008-10-17 16:15:16.853 [mpeg2video @ 0xb6505e88]Warning MVs not available
>> 2008-10-17 16:15:21.133 WriteAudio: buffer underrun
>> 2008-10-17 16:16:42.918 DPMS Reactivated.
>> 2008-10-17 16:16:46.524 DPMS Deactivated
>> 2008-10-17 16:16:54.708 [mpeg2video @ 0xb6505e88]skipped MB in I frame at
>> 27 9 2008-10-17 16:17:19.801 [mpeg2video @ 0xb6505e88]00 motion_type at 42
>> 29 2008-10-17 16:17:41.057 [mpeg2video @ 0xb6505e88]invalid cbp at 29 29
>> 2008-10-17 16:18:55.030 [mpeg2video @ 0xb6505e88]00 motion_type at 27 24
>> 2008-10-17 16:19:05.336 [mpeg2video @ 0xb6505e88]ac-tex damaged at 28 5
>> 2008-10-17 16:20:04.395 [mpeg2video @ 0xb6505e88]ac-tex damaged at 30 16
>> 2008-10-17 16:23:28.316 [mpeg2video @ 0xb6505e88]ac-tex damaged at 8 29
>>
>> It doesn't seem to be causing a lot of issues, but I occasionally get
>> stutters or audio corruption. These are brand new pvr150 cards I just got
>> for about $30 each (I love sales). I haven't seen any DMA issues yet, but
>> they seem to have the right chipset for it. lspci says:
>>
>> 00:08.0 Multimedia video controller: Internext Compression Inc iTVC16
>> (CX23416) MPEG-2 Encoder (rev 01)
>> 00:0a.0 Multimedia video controller: Internext Compression Inc iTVC16
>> (CX23416) MPEG-2 Encoder (rev 01)
>>
>> I don't see any errors in dmesg, so I think things are generally ok.. But
>> those mpeg errors, warnings and Audio underruns are curious.
> 
> Anybody at all know what might cause these issues?
> 

Check to make sure you don't have any heavy disk io processes, if a disk process 
is busy enough to make the mythtv process take too long writing data then data 
gets lost because the next bit cannot be grabbed from the card fast enough.

The only other choice is there you are having some sort of PCI issue that is 
also resulting in data being lost.

For both check to see if the backend has messages from the recording time that 
indicates issues.

                                  Roger