From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:43025 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756508Ab2EVJJ1 (ORCPT ); Tue, 22 May 2012 05:09:27 -0400 Message-ID: <4FBB57C4.4040601@iki.fi> Date: Tue, 22 May 2012 12:09:24 +0300 From: Antti Palosaari MIME-Version: 1.0 To: Devin Heitmueller CC: Linux Media Mailing List Subject: Re: SNR status for demods References: <412bdbff0903171945m680218d9xa39982efb1a17728@mail.gmail.com> In-Reply-To: <412bdbff0903171945m680218d9xa39982efb1a17728@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Just ping up old thread since I updated that list. On 18.03.2009 04:45, Devin Heitmueller wrote: > Hello all, > > I have updated my compiled list of the various demods and how they > currently report SNR info (including feedback from people in the last > round). > > http://www.devinheitmueller.com/snr.txt I updated that list up to that day: http://palosaari.fi/linux/v4l-dvb/snr_2012-05-21.txt > Here's how you can help out: > > If you are a maintainer for a device in this list, please let me know > so I can update the document. If you are the maintainer and somebody > else's name is listed by the device, please do not take offense to > this (it's probably just an error on my part [please email and correct > me]). > > If you have specs for a device in this list where the format is > currently "unknown", please let me know as this will be helpful in > identifying which demods we can get accurate information for. > > If you know something about how SNR is currently reported by the > driver, and it is not reflected in this list, please let me know and I > will update the document. > > All of the above information will be helpful once a format has been > decided on, so we can pull together and finally get a consistent > interface. > > Thank you for your time, > > Devin > Basically, but not every case, there seems to be 3 different way: 1) return raw register value without any calculation 2) 0.1 dB 3) scaled to 0-0xffff using some formula Very many drivers seems to do some dB handling even finally scaling it to some value. regards Antti -- http://palosaari.fi/