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From: Andreas Oberritter <obi@linuxtv.org>
To: Christophe Thommeret <hftom@free.fr>
Cc: linux-dvb@linuxtv.org
Subject: Re: [linux-dvb] [PATCH] cx24116 DVB-S modulation fix
Date: Tue, 14 Oct 2008 23:05:45 +0200	[thread overview]
Message-ID: <48F509A9.1030103@linuxtv.org> (raw)
In-Reply-To: <200810141451.02941.hftom@free.fr>

Christophe Thommeret wrote:
> dvbscan initial tuning data files for DVB-S don't have an entry for 
> modulation. So an app like kaffeine simply set modulation to QAM_AUTO.
> Why not QPSK, you ask? Simply because DVB-S standard allows QPSK and 16QAM. 
> Maybe there is not a single 16QAM TP all over the world, but it's still a 
> valid modulation for DVB-S.
> So, we set modulation to QAM_AUTO when it's unknown/unspecified, like in 
> dvbscan files (those being also used by kaffeine). And it works pretty well, 
> just because most dvb-s can only do QPSK and so force modulation to QPSK 
> instead of returning a notsup.
> See this as software QAM_AUTO :)

It simply doesn't make sense to specify QAM_AUTO if dvb_frontend_info.caps
doesn't contain FE_CAN_QAM_AUTO (or FE_CAN_QAM_16 for that matter).

Regards,
Andreas

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      parent reply	other threads:[~2008-10-14 21:05 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-14  9:33 [linux-dvb] [PATCH] cx24116 DVB-S modulation fix Christophe Thommeret
2008-10-14 10:29 ` Darron Broad
2008-10-14 12:51   ` Christophe Thommeret
2008-10-14 15:10     ` Steven Toth
2008-10-14 17:02     ` Darron Broad
2008-10-15 16:46       ` Christophe Thommeret
2008-10-15 17:22         ` Darron Broad
2008-10-15 18:59           ` Christophe Thommeret
2008-10-14 21:05     ` Andreas Oberritter [this message]

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