From patchwork Tue Oct 27 14:12:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Plowman X-Patchwork-Id: 10266 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id C4EF6BDB1E for ; Tue, 27 Oct 2020 14:12:54 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 3CC066211B; Tue, 27 Oct 2020 15:12:54 +0100 (CET) Authentication-Results: lancelot.ideasonboard.com; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=raspberrypi.com header.i=@raspberrypi.com header.b="EcPXdKeS"; dkim-atps=neutral Received: from mail-wr1-x436.google.com (mail-wr1-x436.google.com [IPv6:2a00:1450:4864:20::436]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 5659662034 for ; Tue, 27 Oct 2020 15:12:52 +0100 (CET) Received: by mail-wr1-x436.google.com with SMTP id i1so2124541wro.1 for ; Tue, 27 Oct 2020 07:12:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=raspberrypi.com; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=i0lCQ03bxICKTbPiWh/9Nze3roZkY83vPAHr/svmWzA=; b=EcPXdKeSWrvBufc6ABtowVha+zikQKtJVF6hkJi5LMq6/KwB5tcSfnDVj91Wjs3ohW ul5P7sO+gBWkQ8km/Q6CGTeCJEh+kv/PoIlhHuHvH4/dLfZ4Pap5XikPXCL6V+wud9yz X9SdcAFlx45sBupFjaP3f+6uvHhE0/dwu5TNCyNaaOMj7xjHwzSfHAM39iKt4NbOigDa qYNqa5PmfuYoy5B3ReDCneK1Yg6YEdBiGfOit4QrKrdBQ7tdi293Lj5udE11mvHQwj2y zzmteiY8sUHeqd/hpDNQa8yOAJg71n3hGeCnevYSP0Z/MJJdstnGfgL1Si4/Xf8asXXC eJcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=i0lCQ03bxICKTbPiWh/9Nze3roZkY83vPAHr/svmWzA=; b=BR/x8zrB8htnaf6f0G49Xabn1qPwMSySLQYmmxpQMzWToLLKVPVE3/liKrVlhr4SDH 5CieI6UEO4I2XwEdRfxojtRReZYAI1AbK2yHAhBEPl8lfgBugFr4MFY1Sfo1FmlgGn52 uwbrHzstRd8P7fdmqMZftEdmWVcTySLSZWPCTe4meuwwbkcSzUeQ/H5HNYwmYy3DX8RL aYZt9v/iMV2T40SKAQMXns+GzoHES71RhppmbAfBk9/yXFArq/DDRknt9kyRy+BJ7Z3U 3gzxBH/cS7sFgZwdmNGcAXPQ+ZnssHZvtel4UPPXi9jPE/sA8tIL0ZVUh6MP8MUd/5fj 6Fag== X-Gm-Message-State: AOAM533UrOHcx4eLKN0bOEx3nHMueUI0p/n+bmsC0U5agrLcmveug0QW ggZKMLFuJuWi//uAlEMD/zlkUTQgwBmNBw== X-Google-Smtp-Source: ABdhPJyyPdCDSPL1xlpBzC4DLNQ/3pqoy/kDuin5ozc0i9N4r27DkVZFqoldT+jlCNEsrnTD922D0Q== X-Received: by 2002:adf:cd82:: with SMTP id q2mr3354601wrj.118.1603807971699; Tue, 27 Oct 2020 07:12:51 -0700 (PDT) Received: from pi4-davidp.pitowers.org ([2a00:1098:3142:14:1ce1:9965:4328:89c4]) by smtp.gmail.com with ESMTPSA id w1sm2083186wrp.95.2020.10.27.07.12.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2020 07:12:50 -0700 (PDT) From: David Plowman To: libcamera-devel@lists.libcamera.org Date: Tue, 27 Oct 2020 14:12:45 +0000 Message-Id: <20201027141246.4708-1-david.plowman@raspberrypi.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Subject: [libcamera-devel] [PATCH 0/1] DigitalGain control X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" Hi everyone I wanted to raise a topic on which there was already some discussion a few weeks back, prompted by my noticing a gap in the metadata that we provide with images. My observation was that I couldn't correctly set the ISO value in my JPEG files because we don't report how much digital gain has been supplied by the image processing pipeline. To address this problem, it seemed as good a way as any actually to include a proposal for a new DigitalGain control (see the associated patch). Nevertheless, I think there's a discussion to be had first. Notably: * Should we let the pipeline report a single global "digital gain" value or, given that different gains may be applied to the colour channels, should we report three gain values instead? * In the Pi world I'd like this to be a read-only control, i.e. you can't force the pipeline digital gain to a particular value, as our AGC doesn't work like that. But there may be platforms that do allow you to set the digital gain. * You could imagine this being "per-stream". I think it's another case of "practically everyone will just want a single value", though technically you might be able to imagine some platform and use-cases where different outputs might reflect different digital gains. * There's a question about digital gain being applied by the sensor itself, but I'm inclined to view that as a separate topic. The issue at hand, at least for me, is being able to distinguish the gain applied by the sensor, and which we see in the raw frames, from that applied by the ISP, which appears in the JPEGs. You may have other comments too - so everyone's thoughts would be much appreciated. Thanks! David David Plowman (1): libcamera: controls: Add DigitalGain control src/libcamera/control_ids.yaml | 11 +++++++++++ 1 file changed, 11 insertions(+)