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{ "id": 26266, "url": "https://patchwork.libcamera.org/api/1.1/covers/26266/?format=api", "web_url": "https://patchwork.libcamera.org/cover/26266/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/1.1/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20260306-agc-proportional-v4-0-e87c7e0d837a@jetm.me>", "date": "2026-03-06T18:46:39", "name": "[v4,0/3] Simple pipeline: proportional AGC, AWB stats fix, OV2740 black level", "submitter": { "id": 261, "url": "https://patchwork.libcamera.org/api/1.1/people/261/?format=api", "name": "Javier Tia", "email": "floss@jetm.me" }, "mbox": "https://patchwork.libcamera.org/cover/26266/mbox/", "series": [ { "id": 5824, "url": "https://patchwork.libcamera.org/api/1.1/series/5824/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5824", "date": "2026-03-06T18:46:39", "name": "Simple pipeline: proportional AGC, AWB stats fix, OV2740 black level", "version": 4, "mbox": "https://patchwork.libcamera.org/series/5824/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/covers/26266/comments/", "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "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 7154FBE086\n\tfor <parsemail@patchwork.libcamera.org>;\n\tFri, 6 Mar 2026 18:47:21 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 31C686262B;\n\tFri, 6 Mar 2026 19:47:21 +0100 (CET)", "from fhigh-b6-smtp.messagingengine.com\n\t(fhigh-b6-smtp.messagingengine.com [202.12.124.157])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 3BDC06261B\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tFri, 6 Mar 2026 19:47:19 +0100 (CET)", "from phl-compute-02.internal (phl-compute-02.internal\n\t[10.202.2.42])\n\tby mailfhigh.stl.internal (Postfix) with ESMTP id 165337A017D;\n\tFri, 6 Mar 2026 13:47:18 -0500 (EST)", "from phl-imap-07 ([10.202.2.97])\n\tby phl-compute-02.internal (MEProxy); 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charset=\"utf-8\"", "Content-Transfer-Encoding": "7bit", "X-B4-Tracking": "v=1; b=H4sIAAAAAAAC/x2MQQqAIBAAvxJ7TljMgvpKdNBaayFU1ohA+nvSc\n\tWBmCmQSpgxTU0Do5swxVDBtA+thw06Kt8qgUQ/YYa/svqokMUW5qmpP5axG58feG3RQsyTk+fm\n\tX8/K+H6/2CbViAAAA", "X-Change-ID": "20260305-agc-proportional-ba20bf95f40b", "To": "libcamera-devel@lists.libcamera.org", "Cc": "Javier Tia <floss@jetm.me>, Milan Zamazal <mzamazal@redhat.com>, \n\t=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= <barnabas.pocze@ideasonboard.com>,\n\tRobert Mader <robert.mader@collabora.com>, Kieran Bingham\n\t<kieran.bingham@ideasonboard.com>", "X-Developer-Signature": "v=1; a=openpgp-sha256; l=2541; i=floss@jetm.me;\n\th=from:subject:message-id;\n\tbh=WlJEsjwNWEqS2BvPQLYFYX6sOgyDGxGY5Atx4B3RIz0=; \n\tb=owEB7QES/pANAwAKAbXuwwuoZ3cfAcsmYgBpqyEP1JRZu6xvXNASNWlGfZlrbaOW9h5moThWZ\n\tFBIrB6sM0mJAbMEAAEKAB0WIQSbE7ILzw7eI0VKk8m17sMLqGd3HwUCaashDwAKCRC17sMLqGd3\n\tHzrCDACSerUVQJqshsarS7wFoh0qqhLoIL+YNIb8eZ2hR5mcRw/TzUbwtqTmOxGsCoePQmTAB9P\n\t/c3S3tNV28z+oQ446I8BO7/m2phdCy8jWYnyT46bUkAKjfVMPel7O8k9pFje0voVPfmqSS0Dwxs\n\tPleO7wJo6LL3R92tSVRD8/uz4psLnwsUEQHY0HeUqVspjce3Y1qXdvwqjbR6YY00xgpPGiXV2mj\n\t3y9qngdvwtfZy7ywVlf0y42vMt3JF58niR1svYkVkMTYyVsBEJZ6B0Qjnr6wmQ2QXqQIHdLeJAp\n\tjeTfJDglrm8RLZWTEcRJg/OGy28uHk7zvvWozlxIy2pX/Y5fzgRU/RWcGi7eprvM/1/7/e1Rh8z\n\tpo9FTJaqGDL9sc4R/9tPLYa8cM3pR13mmCU3RwQSr0maN5DZd+auJzBmvx/TT0ANnPbdEQZwbnq\n\td+tgf50GTstTQ4gM7EgecSEcUgocZm8C9BPkSl7gM5i6/5zjOEMS/Amf5Ah3GdAu7naII=", "X-Developer-Key": "i=floss@jetm.me; a=openpgp;\n\tfpr=9B13B20BCF0EDE23454A93C9B5EEC30BA867771F", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "This series fixes AGC oscillation and an AWB statistics bug in the\nSimple pipeline, and adds the OV2740 black level to the sensor helper.\n\nPatch 1 replaces the fixed 10% bang-bang step in the AGC with a\nproportional controller where step size scales with the MSV error.\nThis eliminates the brightness flicker observed on sensors with\nnon-trivial control latency (tested on OV2740 behind Intel\nIPU6/IVSC).\n\nPatch 2 fixes a bit-depth mismatch in the statistics gathering.\nThe SWSTATS_ACCUMULATE_LINE_STATS() macro divides the luminance value\nfor the histogram to normalize it to 8-bit range, but does not apply\nthe same normalization to the RGB sums. For 10-bit and 12-bit\nunpacked Bayer formats, the sums are accumulated at native bit depth\nwhile the AWB subtracts an 8-bit black level, under-correcting by 4x\nor 16x respectively. This skews the AWB grey world gains, producing a\nvisible color cast (~9% green on the OV2740 with BLC=16). The fix\nright-shifts the RGB sums in finishFrame() to normalize them to 8-bit\nscale, matching the histogram and the 8-bit BLC used by AWB.\n\nPatch 3 adds the OV2740 black level (4096, i.e. 0x40 at 10-bit) to\nCameraSensorHelperOv2740, following the established pattern used by\nOV5675, IMX219, and other sensors.\n\nChanges since v3:\n- Patch 1: Removed kExpMaxStep and the std::clamp - the proportional\n gain is applied directly, since the maximum error of ~2.5 already\n bounds the step to ~10%. (Barnabas)\n- Patch 2: Replaced per-case sumShift_ assignments with\n sumShift_ = bayerFormat.bitDepth - 8. (Barnabas)\n- Patch 3: No changes.\n\nChanges since v2:\n- Dropped the OV2740 tuning file patch (identical to uncalibrated.yaml\n without a CCM). A follow-up with calibrated CCMs is planned.\n- Rebased onto current master.\n\nSigned-off-by: Javier Tia <floss@jetm.me>\n---\nJavier Tia (3):\n ipa: simple: agc: Replace bang-bang controller with proportional\n libcamera: software_isp: Normalize statistics sums to 8-bit\n ipa: libipa: camera_sensor_helper: Add OV2740 black level\n\n .../libcamera/internal/software_isp/swstats_cpu.h | 1 +\n src/ipa/libipa/camera_sensor_helper.cpp | 2 +\n src/ipa/simple/algorithms/agc.cpp | 65 ++++++++++++++--------\n src/libcamera/software_isp/swstats_cpu.cpp | 7 +++\n 4 files changed, 51 insertions(+), 24 deletions(-)\n---\nbase-commit: 14ba4d168085dd27aed9bcb043996d6a5f28867e\nchange-id: 20260305-agc-proportional-ba20bf95f40b\n\nBest regards," }