From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:43134 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753073Ab3ACPfZ (ORCPT ); Thu, 3 Jan 2013 10:35:25 -0500 Message-ID: <50E5A515.4050500@iki.fi> Date: Thu, 03 Jan 2013 17:34:45 +0200 From: Antti Palosaari MIME-Version: 1.0 To: Manu Abraham CC: Mauro Carvalho Chehab , Devin Heitmueller , Linux Media Mailing List , Klaus Schmidinger Subject: Re: [PATCH RFCv3] dvb: Add DVBv5 properties for quality parameters References: <1356739006-22111-1-git-send-email-mchehab@redhat.com> <20130101130041.52dee65f@redhat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 01/01/2013 06:48 PM, Manu Abraham wrote: > On Tue, Jan 1, 2013 at 8:30 PM, Mauro Carvalho Chehab > wrote: > >> [RFCv4] dvb: Add DVBv5 properties for quality parameters >> >> The DVBv3 quality parameters are limited on several ways: >> - Doesn't provide any way to indicate the used measure; >> - Userspace need to guess how to calculate the measure; >> - Only a limited set of stats are supported; >> - Doesn't provide QoS measure for the OFDM TPS/TMCC >> carriers, used to detect the network parameters for >> DVB-T/ISDB-T; >> - Can't be called in a way to require them to be filled >> all at once (atomic reads from the hardware), with may >> cause troubles on interpreting them on userspace; >> - On some OFDM delivery systems, the carriers can be >> independently modulated, having different properties. >> Currently, there's no way to report per-layer stats; > > per layer stats is a mythical bird, nothing of that sort does exist. If some > driver states that it is simply due to lack of knowledge at the coding side. > > ISDB-T uses hierarchial modulation, just like DVB-S2 or DVB-T2 Manu, you confused now two concept (which are aimed to resolve same real life problem) - hierarchical coding and multiple transport stream. Both are quite similar on lower level of radio channel, but differs on upper levels. Hierarchical is a little bit weird baby as it remuxes those lower lever radio channels (called layers in case of ISDB-T) to one single mux! There is only single TS which demodulator is responsible to remux all those 3 physical "layer" channels, which could be modulated differently. So after demodulation you really has a TS which contains stream that has different statistics. That's opposite to compared for multiple TS principle used for DVB-T2/S2. In case of multiple TS you have same statistics for whole TS (but naturally there could be multiple TS after demodulation). regards Antti -- http://palosaari.fi/