[{"id":13633,"web_url":"https://patchwork.libcamera.org/comment/13633/","msgid":"","date":"2020-11-09T07:53:46","subject":"Re: [libcamera-devel] [PATCH 0/1] DigitalGain control","submitter":{"id":42,"url":"https://patchwork.libcamera.org/api/people/42/","name":"David Plowman","email":"david.plowman@raspberrypi.com"},"content":"Hi everyone\n\nCan I give this patch a little prod, see how folks would like to move\nforward on this one?\n\nThanks!\nDavid\n\nOn Tue, 27 Oct 2020 at 14:12, David Plowman \nwrote:\n\n> Hi everyone\n>\n> I wanted to raise a topic on which there was already some discussion a\n> few weeks back, prompted by my noticing a gap in the metadata that we\n> provide with images.\n>\n> My observation was that I couldn't correctly set the ISO value in my\n> JPEG files because we don't report how much digital gain has been\n> supplied by the image processing pipeline. To address this problem, it\n> seemed as good a way as any actually to include a proposal for a new\n> DigitalGain control (see the associated patch). Nevertheless, I think\n> there's a discussion to be had first. Notably:\n>\n> * Should we let the pipeline report a single global \"digital gain\"\n> value or, given that different gains may be applied to the colour\n> channels, should we report three gain values instead?\n>\n> * In the Pi world I'd like this to be a read-only control, i.e. you\n> can't force the pipeline digital gain to a particular value, as our\n> AGC doesn't work like that. But there may be platforms that do allow\n> you to set the digital gain.\n>\n> * You could imagine this being \"per-stream\". I think it's another case\n> of \"practically everyone will just want a single value\", though\n> technically you might be able to imagine some platform and use-cases\n> where different outputs might reflect different digital gains.\n>\n> * There's a question about digital gain being applied by the sensor\n> itself, but I'm inclined to view that as a separate topic. The issue\n> at hand, at least for me, is being able to distinguish the gain\n> applied by the sensor, and which we see in the raw frames, from that\n> applied by the ISP, which appears in the JPEGs.\n>\n> You may have other comments too - so everyone's thoughts would be much\n> appreciated.\n>\n> Thanks!\n> David\n>\n> David Plowman (1):\n> libcamera: controls: Add DigitalGain control\n>\n> src/libcamera/control_ids.yaml | 11 +++++++++++\n> 1 file changed, 11 insertions(+)\n>\n> --\n> 2.20.1\n>\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 62612BE082\n\tfor ;\n\tMon, 9 Nov 2020 07:54:00 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id D6E6463069;\n\tMon, 9 Nov 2020 08:53:59 +0100 (CET)","from mail-oi1-x22a.google.com (mail-oi1-x22a.google.com\n\t[IPv6:2607:f8b0:4864:20::22a])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id D365E6033F\n\tfor ;\n\tMon, 9 Nov 2020 08:53:58 +0100 (CET)","by mail-oi1-x22a.google.com with SMTP id w188so3790812oib.1\n\tfor ;\n\tSun, 08 Nov 2020 23:53:58 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n\tunprotected) header.d=raspberrypi.com header.i=@raspberrypi.com\n\theader.b=\"bQ+h4v+i\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=raspberrypi.com; s=google;\n\th=mime-version:references:in-reply-to:from:date:message-id:subject:to;\n\tbh=25K7vLbmiZobYlyW895xWy9c0B6pmXcXEPh+IFQYpdk=;\n\tb=bQ+h4v+icUXbvVih+U9Sgo4PgBGZ4O1y4ruHu4Wmn8GMLHC8Sw5l/nmaQPGitkITcc\n\tVViy0CXvL6IXpTL2/Uhjnte0jEDbbgaB2AfsC0LHvpAXD2fuzUygSauq48xK9f3XoS6f\n\tOdD4Y4qzrCpY/s+ZYVQ3w0XO+M7NbjUpN7rrFzPoStl5hAqXm+BJO0tvXgeZuVYE9yXV\n\tfiVdn7YV11byP/TW+JfFPWUEq+9WxEZ+fG96sZMxeQo6lMhMk2e9PuFsF1tT4on6OIa/\n\tWyjC5DSHQ5ZfrvnbBv9zxqL2W2onSlfHtYOg2mo9+Y0ERaL1HerDOoT8sx1UnSD9jd0q\n\ty7ZA==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:mime-version:references:in-reply-to:from:date\n\t:message-id:subject:to;\n\tbh=25K7vLbmiZobYlyW895xWy9c0B6pmXcXEPh+IFQYpdk=;\n\tb=P/L5lbjd3zDKub9uipgfrO2gKFdExyGOrbrOc9ynGpU2JQ9QtR4vbLwSddnsiSKtJl\n\teczj5Oh6F8VC0ixMfKFXz1swyv+WOtAdS3bWm3fXJ2H1A3X5t4gj97Rxavc0sqawzZGM\n\tiRcGOiKZbDhxPO/UB3SQRslLaMrU44M+Tt2g+ULpk9/AJQirPSkGLSH8h93+juUJ4h1S\n\tNt3QlAqhXS6rOdBLI308jqo/8KkX6StWG3LyJBeUpus/c1+LWLoMyzaWCtF+X4x2/uqK\n\tc7BmLFeuLbYajO2t1t/+2lYVyNxMS/ObfQl4ZXjFGbL55H2+QhYfJHV+fSHUobAuRhWC\n\tfxkQ==","X-Gm-Message-State":"AOAM533KSDYb8xryTXwmSFrKfOxR8RzYjaeST74/TKm9hQjG4286Cgn6\n\t0NOnN2urXHYHAzglWACOBbfeXhKFaV9fdkMJby1uL3TvvbY=","X-Google-Smtp-Source":"ABdhPJwsrTZvoEs41bgcQc406SK9hhr+Y4SHHJWTaldUil/js7+cY463RrdZCFgoLBRwjWQea3eMfx34YwiDe3Hzxrc=","X-Received":"by 2002:aca:b606:: with SMTP id g6mr7930334oif.22.1604908437363; \n\tSun, 08 Nov 2020 23:53:57 -0800 (PST)","MIME-Version":"1.0","References":"<20201027141246.4708-1-david.plowman@raspberrypi.com>","In-Reply-To":"<20201027141246.4708-1-david.plowman@raspberrypi.com>","From":"David Plowman ","Date":"Mon, 9 Nov 2020 07:53:46 +0000","Message-ID":"","To":"libcamera devel ","Subject":"Re: [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":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Content-Type":"multipart/mixed;\n\tboundary=\"===============4166087071477503573==\"","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":13716,"web_url":"https://patchwork.libcamera.org/comment/13716/","msgid":"","date":"2020-11-16T10:18:03","subject":"Re: [libcamera-devel] [PATCH 0/1] DigitalGain control","submitter":{"id":42,"url":"https://patchwork.libcamera.org/api/people/42/","name":"David Plowman","email":"david.plowman@raspberrypi.com"},"content":"Hi again\n\nCan I give this discussion another little metaphorical shove, please?\nThanks!\n\nBest regards\nDavid\n\nOn Mon, 9 Nov 2020 at 07:53, David Plowman \nwrote:\n\n> Hi everyone\n>\n> Can I give this patch a little prod, see how folks would like to move\n> forward on this one?\n>\n> Thanks!\n> David\n>\n> On Tue, 27 Oct 2020 at 14:12, David Plowman \n> wrote:\n>\n>> Hi everyone\n>>\n>> I wanted to raise a topic on which there was already some discussion a\n>> few weeks back, prompted by my noticing a gap in the metadata that we\n>> provide with images.\n>>\n>> My observation was that I couldn't correctly set the ISO value in my\n>> JPEG files because we don't report how much digital gain has been\n>> supplied by the image processing pipeline. To address this problem, it\n>> seemed as good a way as any actually to include a proposal for a new\n>> DigitalGain control (see the associated patch). Nevertheless, I think\n>> there's a discussion to be had first. Notably:\n>>\n>> * Should we let the pipeline report a single global \"digital gain\"\n>> value or, given that different gains may be applied to the colour\n>> channels, should we report three gain values instead?\n>>\n>> * In the Pi world I'd like this to be a read-only control, i.e. you\n>> can't force the pipeline digital gain to a particular value, as our\n>> AGC doesn't work like that. But there may be platforms that do allow\n>> you to set the digital gain.\n>>\n>> * You could imagine this being \"per-stream\". I think it's another case\n>> of \"practically everyone will just want a single value\", though\n>> technically you might be able to imagine some platform and use-cases\n>> where different outputs might reflect different digital gains.\n>>\n>> * There's a question about digital gain being applied by the sensor\n>> itself, but I'm inclined to view that as a separate topic. The issue\n>> at hand, at least for me, is being able to distinguish the gain\n>> applied by the sensor, and which we see in the raw frames, from that\n>> applied by the ISP, which appears in the JPEGs.\n>>\n>> You may have other comments too - so everyone's thoughts would be much\n>> appreciated.\n>>\n>> Thanks!\n>> David\n>>\n>> David Plowman (1):\n>> libcamera: controls: Add DigitalGain control\n>>\n>> src/libcamera/control_ids.yaml | 11 +++++++++++\n>> 1 file changed, 11 insertions(+)\n>>\n>> --\n>> 2.20.1\n>>\n>>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 1EE6ABE082\n\tfor ;\n\tMon, 16 Nov 2020 10:18:19 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 70869632B7;\n\tMon, 16 Nov 2020 11:18:18 +0100 (CET)","from mail-ot1-x336.google.com (mail-ot1-x336.google.com\n\t[IPv6:2607:f8b0:4864:20::336])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 421576033B\n\tfor ;\n\tMon, 16 Nov 2020 11:18:15 +0100 (CET)","by mail-ot1-x336.google.com with SMTP id n11so15494189ota.2\n\tfor ;\n\tMon, 16 Nov 2020 02:18:15 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n\tunprotected) header.d=raspberrypi.com header.i=@raspberrypi.com\n\theader.b=\"k49awaDU\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=raspberrypi.com; s=google;\n\th=mime-version:references:in-reply-to:from:date:message-id:subject:to;\n\tbh=0LvplAiqkmnWv7atobzeabu+8wUrbMXIx8xTDQQSjUs=;\n\tb=k49awaDULhcRj+9dHjI9NG1W4rmO0yIe/WS94cbDb0tAVxJ0L8JChhNrROx3x9G1Wf\n\t5t4+TSHt9155TNi3FUhpqjFcvZx23aOfP5Rgd7arc+3g/TyyALL3GbR3wXK96rv6GErr\n\t+WOZ4ssQ0urU4UfNmm8S/muiuhOoyLmSDJj5eiR9YieIKoPP/JyiO4eBquqSz2RiXTo/\n\tHItCL2hvthXHXbTvtrF66RiDAIZtxne3+moXW9jWvF7AeTCl38yWkIqF6hMLPhV5MHqH\n\tPlslQvpK4q8TzSC5VlfTafMRAhTImHm5Hm6mxxe1kEuOp6uICE+6rvsH9m4pyijmjkjZ\n\tBfIg==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:mime-version:references:in-reply-to:from:date\n\t:message-id:subject:to;\n\tbh=0LvplAiqkmnWv7atobzeabu+8wUrbMXIx8xTDQQSjUs=;\n\tb=SfjKrKA6eTU1VeMI7ooo770Y2uxzFdjEFtRrdXpWuZx8ifKdJDyZ2yZ+Rh0ingopes\n\tcq9A1wxlS3brS528/g36OeDydthXP0DyE1h/Qy7BlWpvmvXg3VmsUPPmw3UzFRHFjk+6\n\tWZ5MUqD4RaPOHDtHHqqmO8t4b4eyLL3Q1TstLBfbtv2STpJ1BqitNqyNFPeaSzHtmdHi\n\tQ3rZVxWhZDce2WBfRk0kYNl3aHZ+CjTNgQIa4bj2TXnOep87RTu2gOeZhLhBVkf8m6vw\n\tlH0aLSNOpngIO0QdnUI9FNdGhtMQjk7zNCRh4mp2ZkV14jKq7eqG//IdLJ8I1S94UdQ4\n\tqByw==","X-Gm-Message-State":"AOAM532C6csXNCZyg9rdsvrPuUtv8sfSXS5PEtuKRPCZVLlxsglRIrZR\n\tqSmlvraItRJMmQ4RDROkSvi7yT0KX4IUJrJBGnuUBCQzAow=","X-Google-Smtp-Source":"ABdhPJwvPgfboJXK/+lxG4fAsZ/duLWG+53plg4x4j0ch9wck07CVjdJZPJcmePsFUBn+Mov1wPXtchBDOoxQmTODn0=","X-Received":"by 2002:a05:6830:1ad0:: with SMTP id\n\tr16mr10484686otc.160.1605521893360; \n\tMon, 16 Nov 2020 02:18:13 -0800 (PST)","MIME-Version":"1.0","References":"<20201027141246.4708-1-david.plowman@raspberrypi.com>\n\t","In-Reply-To":"","From":"David Plowman ","Date":"Mon, 16 Nov 2020 10:18:03 +0000","Message-ID":"","To":"libcamera devel ","Subject":"Re: [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":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Content-Type":"multipart/mixed;\n\tboundary=\"===============6463570248505761079==\"","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":13823,"web_url":"https://patchwork.libcamera.org/comment/13823/","msgid":"","date":"2020-11-23T07:40:33","subject":"Re: [libcamera-devel] [PATCH 0/1] DigitalGain control","submitter":{"id":42,"url":"https://patchwork.libcamera.org/api/people/42/","name":"David Plowman","email":"david.plowman@raspberrypi.com"},"content":"Morning all\n\nCan I give this one its little weekly nudge? Thanks :)\n\nBest regards\nDavid\n\nOn Mon, 16 Nov 2020 at 10:18, David Plowman\n wrote:\n>\n> Hi again\n>\n> Can I give this discussion another little metaphorical shove, please? Thanks!\n>\n> Best regards\n> David\n>\n> On Mon, 9 Nov 2020 at 07:53, David Plowman wrote:\n>>\n>> Hi everyone\n>>\n>> Can I give this patch a little prod, see how folks would like to move forward on this one?\n>>\n>> Thanks!\n>> David\n>>\n>> On Tue, 27 Oct 2020 at 14:12, David Plowman wrote:\n>>>\n>>> Hi everyone\n>>>\n>>> I wanted to raise a topic on which there was already some discussion a\n>>> few weeks back, prompted by my noticing a gap in the metadata that we\n>>> provide with images.\n>>>\n>>> My observation was that I couldn't correctly set the ISO value in my\n>>> JPEG files because we don't report how much digital gain has been\n>>> supplied by the image processing pipeline. To address this problem, it\n>>> seemed as good a way as any actually to include a proposal for a new\n>>> DigitalGain control (see the associated patch). Nevertheless, I think\n>>> there's a discussion to be had first. Notably:\n>>>\n>>> * Should we let the pipeline report a single global \"digital gain\"\n>>> value or, given that different gains may be applied to the colour\n>>> channels, should we report three gain values instead?\n>>>\n>>> * In the Pi world I'd like this to be a read-only control, i.e. you\n>>> can't force the pipeline digital gain to a particular value, as our\n>>> AGC doesn't work like that. But there may be platforms that do allow\n>>> you to set the digital gain.\n>>>\n>>> * You could imagine this being \"per-stream\". I think it's another case\n>>> of \"practically everyone will just want a single value\", though\n>>> technically you might be able to imagine some platform and use-cases\n>>> where different outputs might reflect different digital gains.\n>>>\n>>> * There's a question about digital gain being applied by the sensor\n>>> itself, but I'm inclined to view that as a separate topic. The issue\n>>> at hand, at least for me, is being able to distinguish the gain\n>>> applied by the sensor, and which we see in the raw frames, from that\n>>> applied by the ISP, which appears in the JPEGs.\n>>>\n>>> You may have other comments too - so everyone's thoughts would be much\n>>> appreciated.\n>>>\n>>> Thanks!\n>>> David\n>>>\n>>> David Plowman (1):\n>>> libcamera: controls: Add DigitalGain control\n>>>\n>>> src/libcamera/control_ids.yaml | 11 +++++++++++\n>>> 1 file changed, 11 insertions(+)\n>>>\n>>> --\n>>> 2.20.1\n>>>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 183CEBE08A\n\tfor ;\n\tMon, 23 Nov 2020 07:40:48 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 8E17263320;\n\tMon, 23 Nov 2020 08:40:47 +0100 (CET)","from mail-ot1-x344.google.com (mail-ot1-x344.google.com\n\t[IPv6:2607:f8b0:4864:20::344])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 652CF60332\n\tfor ;\n\tMon, 23 Nov 2020 08:40:45 +0100 (CET)","by mail-ot1-x344.google.com with SMTP id f12so3608404oto.10\n\tfor ;\n\tSun, 22 Nov 2020 23:40:45 -0800 (PST)"],"Authentication-Results":"lancelot.ideasonboard.com;\n\tdkim=fail reason=\"signature verification failed\" (2048-bit key;\n\tunprotected) header.d=raspberrypi.com header.i=@raspberrypi.com\n\theader.b=\"fsDxFG5u\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=raspberrypi.com; s=google;\n\th=mime-version:references:in-reply-to:from:date:message-id:subject:to;\n\tbh=wlGXeuTlvhbvplV/0GxIclkw7ac066yWnrwGm87Hkks=;\n\tb=fsDxFG5u/iWdaq1emGCaRlZXQAsQdabieYFmpJWeBoiOidhSS0zLdDDZHL2XEaUNGm\n\teWEXlqeylmEQ6yIiaCo4w8c3KKLtUba3Ru/dTQiKXmrE+2Y8aiZKWKzJMTOvVie5BJXb\n\txuV7E9tV+G4fElvpXediuW8yY64Tf2TAJurIBFxxV+8wR2OSrDQUoDqsg0fkEiAcOdsO\n\tGKx57xMaZyn61i583czRDurAu/xgL0zqagBmbaa2KEVfwl6PQ0hgDtsbpQv92Hy/E6gn\n\t+eaL4G5mgjJLUY4IHHTXWXVcIjzGFWjPUnQZLCuYsaZDa8zht3nfXrnTaJ3+QUSG/AfY\n\tTa/A==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:mime-version:references:in-reply-to:from:date\n\t:message-id:subject:to;\n\tbh=wlGXeuTlvhbvplV/0GxIclkw7ac066yWnrwGm87Hkks=;\n\tb=AmoC1IW1eK2g82FQqlEuGMvzJ8u4m2IeHwIPqWCqV02mKEB2fgZNgjO2SSI0hkaUEf\n\tySq5Vfblip/Srx6d+BIf0wiL9ivpwm8ns+7n9qIcJhL+A3BuNe1MV3DqSUnNhnUbMabS\n\tzp2v9w2JWLxgiy5fbDRvRfstSlgy2fDi7/Rbbn264+ygdRf79h9ZFGS40d1FKE0E1W5f\n\tnW6W62n6fJv7dEQ+jNANlh+Dx49pFYfyVgTFsW10jPJu4GOnIdtjUCOJhA04+LNNIy90\n\t/R1SvNJKzlzKUj7JZMfyR4+hE7NxX+SPlvEaU8EAv1Dzzaqgpd1M8r4Y/UpxNJ+LP0+R\n\tSLBw==","X-Gm-Message-State":"AOAM531OOI2LAgnW9FvQfZQ4bCBAfRFeG/iRA9nmNs0mXQgKOiMW4ES8\n\toWmCTEbWrDWmtVGLqRm6DxP8fyMxje7yvPKdIIP2uDl0GRsEcw==","X-Google-Smtp-Source":"ABdhPJy0khgEa95OUhGDXUYp5V9r1+ZcP1moOAze946aYtViFVbTkLt2g+YnQ0ewtfJ9EdOxGkK0Z7hz9Hyb1/M9O80=","X-Received":"by 2002:a05:6830:18ee:: with SMTP id\n\td14mr8278862otf.317.1606117243912; \n\tSun, 22 Nov 2020 23:40:43 -0800 (PST)","MIME-Version":"1.0","References":"<20201027141246.4708-1-david.plowman@raspberrypi.com>\n\t\n\t","In-Reply-To":"","From":"David Plowman ","Date":"Mon, 23 Nov 2020 07:40:33 +0000","Message-ID":"","To":"libcamera devel ","Subject":"Re: [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":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Content-Type":"text/plain; charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":13825,"web_url":"https://patchwork.libcamera.org/comment/13825/","msgid":"<20201123085547.bnsltxverzbsjzzy@uno.localdomain>","date":"2020-11-23T08:55:47","subject":"Re: [libcamera-devel] [PATCH 0/1] DigitalGain control","submitter":{"id":3,"url":"https://patchwork.libcamera.org/api/people/3/","name":"Jacopo Mondi","email":"jacopo@jmondi.org"},"content":"Hi David,\n\nOn Mon, Nov 23, 2020 at 07:40:33AM +0000, David Plowman wrote:\n> Morning all\n>\n> Can I give this one its little weekly nudge? Thanks :)\n\nSorry for having you nudgin us for three weeks :(\n\nI'll try to provide feedback on the integration with the Control\nframework. I have less valuable comments on the control semantic\nitself, so I'll skip that part.\n\n>\n\n[snip]\n\n> >>>\n> >>> Hi everyone\n> >>>\n> >>> I wanted to raise a topic on which there was already some discussion a\n> >>> few weeks back, prompted by my noticing a gap in the metadata that we\n> >>> provide with images.\n> >>>\n> >>> My observation was that I couldn't correctly set the ISO value in my\n> >>> JPEG files because we don't report how much digital gain has been\n> >>> supplied by the image processing pipeline. To address this problem, it\n> >>> seemed as good a way as any actually to include a proposal for a new\n> >>> DigitalGain control (see the associated patch). Nevertheless, I think\n> >>> there's a discussion to be had first. Notably:\n> >>>\n> >>> * Should we let the pipeline report a single global \"digital gain\"\n> >>> value or, given that different gains may be applied to the colour\n> >>> channels, should we report three gain values instead?\n> >>>\n> >>> * In the Pi world I'd like this to be a read-only control, i.e. you\n> >>> can't force the pipeline digital gain to a particular value, as our\n> >>> AGC doesn't work like that. But there may be platforms that do allow\n> >>> you to set the digital gain.\n\nLibcamera does not enforce (yet) controls being read-only. What I mean\nis that, in example, we don't have a flag in the yaml definition that\nrestrict the control from being written by applications.\n\nBut metadata are read-only by definition and for your case it is\nenough not to advertise digital gain in the Camera's ControlInfoMap\ncontrolInfo_ to prevent application from setting DigitalGain in a\nRequest.\n\nQuestion is now it it is useful to report a ControlInfoMap of\nsupported metadata and their limits. Anyway that should not block you\nfrom reporting DigitalGain like you now report other metadata.\n\n> >>>\n> >>> * You could imagine this being \"per-stream\". I think it's another case\n> >>> of \"practically everyone will just want a single value\", though\n> >>> technically you might be able to imagine some platform and use-cases\n> >>> where different outputs might reflect different digital gains.\n\nI feel the same way as I felt for ScalerCrop: we should be able to\nreport it per stream, but there's no reason to block the definition of\na new control waiting for that feature to eventually land.\n\n> >>>\n> >>> * There's a question about digital gain being applied by the sensor\n> >>> itself, but I'm inclined to view that as a separate topic. The issue\n> >>> at hand, at least for me, is being able to distinguish the gain\n> >>> applied by the sensor, and which we see in the raw frames, from that\n> >>> applied by the ISP, which appears in the JPEGs.\n\nAs long as it is made clear in the Control definition, and we don't\nmake it very hard to find a non-conflicting name for the sensor's\ndigital gain I think it's fine.\n\nThanks\n j\n\n> >>>\n> >>> You may have other comments too - so everyone's thoughts would be much\n> >>> appreciated.\n> >>>\n> >>> Thanks!\n> >>> David\n> >>>\n> >>> David Plowman (1):\n> >>> libcamera: controls: Add DigitalGain control\n> >>>\n> >>> src/libcamera/control_ids.yaml | 11 +++++++++++\n> >>> 1 file changed, 11 insertions(+)\n> >>>\n> >>> --\n> >>> 2.20.1\n> >>>\n> _______________________________________________\n> libcamera-devel mailing list\n> libcamera-devel@lists.libcamera.org\n> https://lists.libcamera.org/listinfo/libcamera-devel","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 65CFEBE08A\n\tfor ;\n\tMon, 23 Nov 2020 08:55:45 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id CABBC63326;\n\tMon, 23 Nov 2020 09:55:44 +0100 (CET)","from relay12.mail.gandi.net (relay12.mail.gandi.net\n\t[217.70.178.232])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id D0421615A0\n\tfor ;\n\tMon, 23 Nov 2020 09:55:43 +0100 (CET)","from uno.localdomain (2-224-242-101.ip172.fastwebnet.it\n\t[2.224.242.101]) (Authenticated sender: jacopo@jmondi.org)\n\tby relay12.mail.gandi.net (Postfix) with ESMTPSA id 2D543200015;\n\tMon, 23 Nov 2020 08:55:42 +0000 (UTC)"],"Date":"Mon, 23 Nov 2020 09:55:47 +0100","From":"Jacopo Mondi ","To":"David Plowman ","Message-ID":"<20201123085547.bnsltxverzbsjzzy@uno.localdomain>","References":"<20201027141246.4708-1-david.plowman@raspberrypi.com>\n\t\n\t\n\t","MIME-Version":"1.0","Content-Disposition":"inline","In-Reply-To":"","Subject":"Re: [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":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera devel ","Content-Type":"text/plain; charset=\"us-ascii\"","Content-Transfer-Encoding":"7bit","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]