[mythtv] problem with HDTV in Australia

Berry, David David.Berry at dcita.gov.au
Thu Jul 28 20:07:37 EDT 2005


Disk speed not up to scratch??

I was getting these errors attempting to play back a normal DVB-T
recording on a raid5 setup - once I changed to a LVM setup, the errors
disappeared.

My theory was that it was too much for the bus to handle streaming the
file _and_ reading from all the disks at once - with LVM - it's only
going to be accessing one disk at a time. Now I can also do PIP with no
errors.

Just an idea.

David.

-----Original Message-----
From: mythtv-dev-bounces at mythtv.org
[mailto:mythtv-dev-bounces at mythtv.org] On Behalf Of Hamish Moffatt
Sent: Friday, 29 July 2005 9:25 AM
To: mythtv-dev at mythtv.org
Subject: [mythtv] problem with HDTV in Australia

Hi. I'm attempting to watch HDTV recorded in Australia (on DVB-T).
The backend logs show that a test program was recorded fine (no DVB
errors reported). However when I play back the recording, the frontend
logs MPEG decoder errors continuously.

2005-07-28 23:11:37.252 Changing from None to WatchingPreRecorded
2005-07-28 23:11:37.253 Using realtime priority.
2005-07-28 23:11:37.377 Video timing method: SGI OpenGL
[mpeg2video @ 0xb7765010]ac-tex damaged at 68 21
[mpeg2video @ 0xb7765010]Warning MVs not available
[mpeg2video @ 0xb7765010]invalid cbp at 26 17
[mpeg2video @ 0xb7765010]ac-tex damaged at 51 39
[mpeg2video @ 0xb7765010]ac-tex damaged at 62 53
[mpeg2video @ 0xb7765010]invalid cbp at 58 40
[mpeg2video @ 0xb7765010]invalid cbp at 51 50
[mpeg2video @ 0xb7765010]ac-tex damaged at 54 37
[...]

I get a few of those every second or two. The picture breaks up briefly
every few seconds also. Sound is fine.

I posted two samples of the recording; being 1080i, the data rate is
very high. 5.7Gb for 80 minutes in total.

10Mb version: http://www.risingsoftware.com/~hamish/hdtv/shorthdtv.mpg
30Mb version: http://www.risingsoftware.com/~hamish/hdtv/shorthdtv2.mpg

This is recorded from channel 10 in Melbourne, for any Aussie readers.

The CPU (AthlonXP 2600+) is about 50% idle. (GF4MX440 video, using
Xv but not Xvmc.) Tried libmpeg decoding as well but it was no better.

I remember a discussion a while ago about separate PCR streams in
Australia that weren't recorded or used properly or similar. Is that the
problem here?


Hamish
-- 
Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>


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