From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from ffm.saftware.de ([83.141.3.46]) by www.linuxtv.org with esmtp (Exim 4.63) (envelope-from ) id 1Kg39b-0008N9-E4 for linux-dvb@linuxtv.org; Wed, 17 Sep 2008 21:57:38 +0200 Received: from localhost (localhost [127.0.0.1]) by ffm.saftware.de (Postfix) with ESMTP id D58A1E6E39 for ; Wed, 17 Sep 2008 21:57:31 +0200 (CEST) Received: from ffm.saftware.de ([83.141.3.46]) by localhost (pinky.saftware.org [127.0.0.1]) (amavisd-new, port 10024) with LMTP id BjlHeF2gpesQ for ; Wed, 17 Sep 2008 21:57:30 +0200 (CEST) Received: from [172.22.22.60] (unknown [92.50.81.33]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ffm.saftware.de (Postfix) with ESMTPSA id E2A90E6E32 for ; Wed, 17 Sep 2008 21:57:30 +0200 (CEST) Message-ID: <48D1612B.3000405@linuxtv.org> Date: Wed, 17 Sep 2008 21:57:31 +0200 From: Andreas Oberritter MIME-Version: 1.0 To: linux-dvb@linuxtv.org References: <20080916173121.202250@gmx.net> <48CFF4FC.1000005@linuxtv.org> <48D13BF6.8050500@gmx.de> In-Reply-To: <48D13BF6.8050500@gmx.de> Subject: Re: [linux-dvb] Why Parameter 'INVERSION' is really needed? List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-dvb-bounces@linuxtv.org Errors-To: linux-dvb-bounces+mchehab=infradead.org@linuxtv.org List-ID: wk wrote: > Andreas Oberritter wrote: >> If you find two devices which need different inversion settings in the >> same network, then it's a driver bug, which can easily be corrected. >> >> > How can this be a drivers bug, if in the dvb api documentation no > *default value* for inversion was ever defined? > Seems to be a bug inside API (linux-dvb-api-1.0.0.pdf, see > http://www.linuxtv.org/docs.php). Common sense says that the default value is not inverted. >> Spectral inversion depends on the transmitter, too. It can change >> anytime a broadcaster decides to change it. It happens, although not >> very often. >> >> Specifying the inversion parameter can speed up the tuning process, >> especially for devices which don't support automatic swapping in >> hardware. But I would not recommend to store this parameter in a service >> list. >> >> If we decide to keep the parameter, we should probably use four options: >> INVERSION_OFF, INVERSION_ON, INVERSION_AUTO_OFF_FIRST, >> INVERSION_AUTO_ON_FIRST, which matches the capabilities of most >> demodulators. A typical application would then probably use only the >> last two options, while the first two options would rather be used for >> diagnostics and to read back the detected inversion. >> >> >> > May be. But since the application cannot get any information about > transmitters inversion only AUTO makes sense here, neither ON or OFF. > No information field is reserved for inversion inside terrestrial > delivery system descriptor and cable delivery system descriptor, > so applications are not able to figure out useful settings from NIT. > Please try to see this from the application side, not from hardware > point of view. Well, that's essentially what I wrote: Use AUTO in a typical application. All frontend devices support it, either in software or in hardware. Regards, Andreas _______________________________________________ linux-dvb mailing list linux-dvb@linuxtv.org http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb