Miscellaneous DVB Notes

How to test that a device is working?

Here is one basic way to test a dtv(4) device. The example uses DVB-T. First install the necessary packages

# cd /usr/pkgsrc/multimedia/dvb-apps
# make install package clean

# cd /usr/pkgsrc/multimedia/mplayer
# make install package clean

Scan a basic channels.conf:

$ scan -x 0 /usr/pkg/share/dvb/dvb-t/fi-Turku > ~/.mplayer/channels.conf

Then you should be able to already use mplayer:

$ mplayer dvb://"YLE TV1"

Above "YLE TV1" is a channel present in the configuration file. For more involved testing, one can use for instance tzap (or equivalently, czap or szap). First prepare again the configuration file:

$ mkdir ~/.tzap && cd ~/.tzap
$ ln -s ~/.mplayer/channels.conf .

Then in one terminal set the driver for recording:

$ tzap -r "YLE TV1"

This gives continuous information about the signal strength, signal to noise ratio (SNR), bit error rate (BER), and the number of uncorrected blocks (UNC), respectively. The values typically vary across cards and are often somewhat unreliable. But check for the FE_HAS_LOCK flag; it indicates whether the card has locked onto a signal. If there is a lock, pipe in an another terminal:

$ cat /dev/dvb/adapter0/dvr0 > file.ts

At some point break the pipe. If the output file is empty, something is wrong. Otherwise you can try to play it with mplayer.

Posted Tuesday evening, August 30th, 2011