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

David Liontooth lionteeth at cogweb.net
Thu Nov 25 18:48:26 CET 2010


On 11/24/2010 03:02 AM, Nico Sabbi wrote:
> David Liontooth ha scritto:
>> 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
>> FE_STATUS: FE_HAS_SIGNAL FE_HAS_LOCK FE_HAS_CARRIER FE_HAS_VITERBI 
>> FE_HAS_SYNC
>>
>> 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 2.6.32.5, with DVB API 5.1.
>>
>> Cheers,
>> Dave
>>
>>
>
> it's the usual debian idiocy to package only "official releases".
> I refuse to release anything, so unless Dave does it you should use a 
> fresh cvs checkout from sourceforge, where the limitation was removed 
> years ago.
Hi Nico,

Glad to hear you're around and thanks for responding! The Debian 
maintainer is actually using dvbstream_0.6+cvs20090621, which looks to 
me like the latest version -- I used

cvs -z3 
-d:pserver:anonymous at dvbtools.cvs.sourceforge.net:/cvsroot/dvbtools co 
-P  dvbstream

cvs tune.h still contains the block that restricts the DVB_API to an 
outdated version,

#undef DVB_ATSC
#if defined(DVB_API_VERSION_MINOR)
#if DVB_API_VERSION == 3 && DVB_API_VERSION_MINOR >= 1
#define DVB_ATSC 1
#endif
#endif

and tune.c is not different from the Debian tune.c.

Where is the working code for ATSC QAM tuning? I'd be happy to work with 
you if you can provide some pointers.

Salve,
Dave






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