2009/11/24 Adam Charrett <adam@dvbstreamer.org>
On Sun, November 22, 2009 10:44 pm, Bernard Mentink wrote:
> 2009/11/23 Trevor Michel-Smith <trevor.michelsmith@gmail.com>
>> Hi,
>> I have been experiencing severe macro blocking and audio pops and
>> squeaks
>> when watching TV and recording at the same time.  Recordings always
>> turns
>> out prefect but live TV (via livepause) is afflicted with these errors.
>> The
>> problem can be fix, for a while, by exiting back to the TV guide and
>> then
>> back to the TV channel being watched.
>> I have an Asus M2A-VM motherboard with dual core Athlon 64 X2 4600+
>> processor, two DVB-S receivers (one PCI and one PCIE-1), 2G RAM and
>> Freevo
>> 1.9 (on Arch Linux).
>> Has anyone else experienced these problems and possibly corrected them?
>> Thank you.  Regards, Trevor.
> Just for record, I have had "not quite so severe" macro blocking under the
> same conditions, i.e using livepause/dvbstreamer/mplayer while recording
> ..
> Hope someone can help out ..
> Cheers,
> Bernie

At a guess, your HDDs don't have enough bandwidth to record 2 streams to
disk and playback 1 all at the same time. The reason for the macro blocks
and audio pops is the data isn't being fed fast enough to the decoders

I see you've mention your CPU, RAM, motherboad and cards, but you've
forgotten the major limiting factor your HDD!

I solution, if you have 2 HDDs, is to record onto 1 and livepause onto the
other and see if that makes a difference.

The more expensive option is to buy a consumer grade HDD (Seagate DB35
type) which have better streaming performance and larger temperature

Which reminds me have you checked the temperature of your HDD? When I've
experienced problems like this in the past it has been because the HDD was
v hot (and gotten some bad sectors as a result).

Hope this helps.


Thanks Adam.

I have a Western Digital 320G SATA HDD.  dmesg reports the SATA link is up at 3Gbps.  I am using the EXT4 file system.

The full HDD description is:
WD3200AAKS-75VYA0 Western Digital Caviar Blue 320GB 7200RPM SATA-300 16MB Cache 3.5-Inch Internal Hard Drive

Here is the hdparm output from the read test (not sure how to do a write test):
[root@saturn-tv trevor]# hdparm -tT /dev/sda3

 Timing cached reads:   1946 MB in  2.00 seconds = 973.06 MB/sec
 Timing buffered disk reads:  236 MB in  3.02 seconds =  78.19 MB/sec

The HDD appears to be fast enough to handle two SD video channel write streams and one read stream, but I may be wrong.

Is there a way to disable livepause and stream live TV direct to mplayer?  In my local_conf.py file, I tried removing the activate.plugin('tv.livepause') and leave the tv.mplayer plugin active.  In this case I could still pause live TV so I guess livepause is imbedded somehow.

If I could do this, I could either elliminate or confirm that livepause is or is not the problem.

Thanks, Trevor.