From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from perceval.ideasonboard.com ([95.142.166.194]:41869 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752577Ab3DLKRO (ORCPT ); Fri, 12 Apr 2013 06:17:14 -0400 From: Laurent Pinchart To: Guennadi Liakhovetski Cc: Christian Rhodin , linux-media@vger.kernel.org Subject: Re: Pixel Formats Date: Fri, 12 Apr 2013 12:17:15 +0200 Message-ID: <1521576.ES8kTFfaXd@avalon> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: (A bit late, sorry) On Thursday 07 March 2013 22:37:26 Guennadi Liakhovetski wrote: > On Wed, 6 Mar 2013, Christian Rhodin wrote: > > Hi, > > > > I'm looking for some guidance on the correct way to handle a new pixel > > format. What I'm dealing with is a CMOS image sensor that supports > > dynamic switching between linear and iHDR modes. iHDR stands for > > "interlaced High Dynamic Range" and is a mode where odd and even lines > > have different exposure times, typically with an 8:1 ratio. When I > > started implementing a driver for this sensor I used > > "V4L2_MBUS_FMT_SGRBG10_1X10" as the format for the linear mode and > > defined a new format "V4L2_MBUS_FMT_SGRBG10_IHDR_1X10" for the iHDR > > mode. I used the format to control which mode I put the sensor in. But > > now I'm having trouble switching modes without reinitializing the > > sensor. Does anyone (everyone?) have an opinion about the correct way > > to implement this? I'm thinking that the format is overloaded because > > it represents both the size and type of the data. Should I use a single > > format and add a control to switch the mode? > > I would vote for a single format with a control, maybe even somehow > cluster it with the normal exposure, but I'm not an expert in that, not > sure if it would make sense. >>From the above explanation about iHDR I assume that enabling iHDR mode produces an image with the same resolution as linear mode, not an image with 8 times the number of lines compared to the linear mode. Please correct me if I'm wrong. If my understanding of iHDR mode is correct, I agree with Guennadi. I don't think enabling iHDR changes the format, it "just" modifies the exposure time algorithm. A V4L2 control would thus be better than adding an iHDR variant to all existing formats. -- Regards, Laurent Pinchart