Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938782AbcJ2C6V (ORCPT ); Fri, 28 Oct 2016 22:58:21 -0400 Received: from mail-qk0-f180.google.com ([209.85.220.180]:35467 "EHLO mail-qk0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756471AbcJ2C6S (ORCPT ); Fri, 28 Oct 2016 22:58:18 -0400 MIME-Version: 1.0 X-Originating-IP: [73.25.156.150] In-Reply-To: References: From: Matt Ranostay Date: Fri, 28 Oct 2016 19:58:17 -0700 Message-ID: Subject: Re: [RFC] v4l2 support for thermopile devices To: Devin Heitmueller Cc: Linux Media Mailing List , Linux Kernel , Jonathan Cameron , Lars-Peter Clausen , Attila Kinali , Marek Vasut Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1771 Lines: 38 On Fri, Oct 28, 2016 at 1:30 PM, Devin Heitmueller wrote: > Hi Matt, > >> Need some input for the video pixel data types, which the device we >> are using (see datasheet links below) is outputting pixel data in >> little endian 16-bit of which a 12-bits signed value is used. Does it >> make sense to do some basic processing on the data since greyscale is >> going to look weird with temperatures under 0C degrees? Namely a cold >> object is going to be brighter than the hottest object it could read. >> Or should a new V4L2_PIX_FMT_* be defined and processing done in >> software? Another issue is how to report the scaling value of 0.25 C >> for each LSB of the pixels to the respecting recording application. > > Regarding the format for the pixel data: I did some research into > this when doing some driver work for the Seek Thermal (a product > similar to the FLIR Lepton). While it would be nice to be able to use > an existing application like VLC or gStreamer to just take the video > and capture from the V4L2 interface with no additional userland code, > the reality is that how you colorize the data is going to be highly > user specific (e.g. what thermal ranges to show with what colors, > etc). If your goal is really to do a V4L2 driver which returns the > raw data, then you're probably best returning it in the native > greyscale format (whether that be an existing V4L2 PIX_FMT or a new > one needs to be defined), and then in software you can figure out how > to colorize it. > Good point I was leaning to having userspace do it. But didn't think of the color mapping part though so even more reason. > Just my opinion though.... > > Devin > > -- > Devin J. Heitmueller - Kernel Labs > http://www.kernellabs.com