From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mta4.srv.hcvlny.cv.net ([167.206.4.199]:50916 "EHLO mta4.srv.hcvlny.cv.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751805AbZDBOat (ORCPT ); Thu, 2 Apr 2009 10:30:49 -0400 Received: from steven-toths-macbook-pro.local (ool-45721e5a.dyn.optonline.net [69.114.30.90]) by mta4.srv.hcvlny.cv.net (Sun Java System Messaging Server 6.2-8.04 (built Feb 28 2007)) with ESMTP id <0KHH00CR99NBBBA0@mta4.srv.hcvlny.cv.net> for linux-media@vger.kernel.org; Thu, 02 Apr 2009 10:30:47 -0400 (EDT) Date: Thu, 02 Apr 2009 10:30:46 -0400 From: Steven Toth Subject: Re: API for China DTV standard In-reply-to: <15ed362e0904020309k4b286690u6d4d421e321cd91e@mail.gmail.com> To: David Wong Cc: linux-media@vger.kernel.org Message-id: <49D4CC16.1010309@linuxtv.org> MIME-version: 1.0 Content-type: text/plain; charset=UTF-8; format=flowed Content-transfer-encoding: 7BIT References: <15ed362e0904020309k4b286690u6d4d421e321cd91e@mail.gmail.com> Sender: linux-media-owner@vger.kernel.org List-ID: David Wong wrote: > I would like to initiate a discussion of v4l-dvb API proposal for China DTV. > > Some of you may heard about China DTV standard as DMB-T/H, it is not > totally correctly. > China standard GB20600-2006 is indeed a union of DMB-TH(multi-carrier) > and ADTB-T(single carrier). > > For API inclusion, I just read the standard document for GB20600. I am > not very good in that electronics area, > but I gather the following information of parameters, hope I don't > miss anything: > > Number of Carriers: C=1, C=3780 > Constellations: 4QAM, 4QAM-NR, 16QAM, 32QAM, 64QAM > FEC(LDPC): rate = 0.4, rate = 0.6, rate = 0.8 > Frame body size: always 3780 symbols > Frame header size: 420 symbols (1/10 guard interval), 595 symbols > (0.136 guard interval), 945 symbols (1/5 guard interval) > Time domain symbol interleave: M=240(B=52), M=720(B=52) > > Despite "C=1" and "interleave", I don't know if DVB has such > interleave, I see a chance to extend the current FE_OFDM structure (in > dvb_frontend_parameters). > Or should we create a new structure, like the separation of FE_ATSC > and FE_OFDM? No new structures are required. The existing user facing structures are fine. The S2API will need new properties/types for Constellations, frame header size symbol interleave etc. I suggest: 1) Identify new #defines EG. M_240_52, M_720_52 2) Identify new property types EG. GET/SET_FRAME_BODY_SIZE 3) Update the dvb-core property_cache so dvb-core has a place to store these values. 4) Update dvb-core so that it can interpret you GET/SET_FRAME_BOSY_SIZE and other messages. No user API changes required. - Steve