[linux-dvb] dvbstream fails to tune QAM-256

David Liontooth lionteeth at cogweb.net
Mon Nov 22 02:59:00 CET 2010

On 11/19/2010 11:51 PM, David Liontooth wrote:
> I'm using Debian's dvbstream 0.6+cvs20090621-1 to capture video and 
> closed captioning to file.
> If I tune with azap, dvbstream works fine, but I can't get it to tune 
> on its own.
> In the Debian source code, I activated DVB_ATSC by adding -DDVB_ATSC 
> to CFLAGS in the Makefile.
> dvbstream -f 645000000 -qam 256 -v 49 a 52 -o > test.ts
> gives me the error "Unknown FE type".
> Suggestions? Is this a problem with an API that has changed since 
> dvbstream's last release?

If I change tune.h to allow DVB API >=3 major instead of just ==3, I get 
this (this is a very lightly patched version to allow 8 cards):

# dvbstream -f 621000 -qam 256 -v 8192 -a 8192 -s 6875 -n 10 -o:test.ts
dvbstream v0.7.01 - (C) Dave Chapman 2001-2004
Released under the GPL.
Latest version available from http://dvbtools.sourceforge.net
Open file test.ts
Tuning to 621000 MHz
Using DVB card "Samsung S5H1411 QAM/8VSB Frontend", freq=621000
tuning ATSC to 621000000, modulation=5
Getting frontend status
Event:  Frequency: 621000000
         Modulation: 5
Bit error rate: 0
Signal strength: 0
SNR: 0
UNC: 0

MAP 0, file test.ts: From -1 secs, To -1 secs, 0 PIDs -
dvbstream will stop after 10 seconds (0 minutes)
Streaming 1 stream
Caught signal 1 - closing cleanly.

So it tries to tune, and succeeds in a manner of speaking -- if I try to 
tune to an unavailable frequency, it will fail; here we can see it 
locks. However, the Signal strength is zero and the file is empty.

What happened with the ATSC QAM-256 tuning in between DVB API 3.1 and 
now? I'm running, with DVB API 5.1.


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