[{"id":36873,"web_url":"https://patchwork.libcamera.org/comment/36873/","msgid":"<176346953523.880260.4416557132835145605@isaac-ThinkPad-T16-Gen-2>","date":"2025-11-18T12:38:55","subject":"Re: [PATCH v4 07/21] ipa: libipa: Provide Q5.4 FixedPoint support","submitter":{"id":215,"url":"https://patchwork.libcamera.org/api/people/215/","name":"Isaac Scott","email":"isaac.scott@ideasonboard.com"},"content":"Hi Kieran,\n\nThank you for the patch!\n\nReviewed-by: Isaac Scott \n\nQuoting Kieran Bingham (2025-11-14 00:54:11)\n> Provide a FixedPoint Quantized type to support the Q5.4 format\n> representing values in the range [-16.0, 15.9375] with a resolution of\n> 1/16.\n> \n> Signed-off-by: Kieran Bingham \n> \n> ---\n> This format is used by the RKISP1 for Chromatic Abberation Correction\n> handling\n> \n> v4:\n> - Fix grammar in type documentation\n> \n> src/ipa/libipa/fixedpoint.cpp | 9 +++++++++\n> src/ipa/libipa/fixedpoint.h | 2 ++\n> test/ipa/libipa/fixedpoint.cpp | 5 +++++\n> 3 files changed, 16 insertions(+)\n> \n> diff --git a/src/ipa/libipa/fixedpoint.cpp b/src/ipa/libipa/fixedpoint.cpp\n> index 4c3ea33497bf..967b00bcd7c2 100644\n> --- a/src/ipa/libipa/fixedpoint.cpp\n> +++ b/src/ipa/libipa/fixedpoint.cpp\n> @@ -139,6 +139,15 @@ namespace ipa {\n> * values in the range [0.0, 1.992] with a resolution of 1/128.\n> */\n> \n> +/**\n> + * \\typedef Q5_4\n> + * \\brief 5.4 signed fixed-point quantizer\n> + *\n> + * A Quantized type using 5 bits for the integer part and 4 bits for the\n> + * fractional part, stored in a signed 16-bit integer (\\c int16_t). Represents\n> + * values in the range [-16.0, 15.9375] with a resolution of 1/16.\n> + */\n> +\n> /**\n> * \\typedef Q12_4\n> * \\brief 12.4 signed fixed-point quantizer\n> diff --git a/src/ipa/libipa/fixedpoint.h b/src/ipa/libipa/fixedpoint.h\n> index d97e6d6135ad..ce621cb01a5a 100644\n> --- a/src/ipa/libipa/fixedpoint.h\n> +++ b/src/ipa/libipa/fixedpoint.h\n> @@ -105,6 +105,8 @@ struct FixedPointQTraits {\n> using Q1_7 = Quantized>;\n> using UQ1_7 = Quantized>;\n> \n> +using Q5_4 = Quantized>;\n> +\n> using Q12_4 = Quantized>;\n> using UQ12_4 = Quantized>;\n> \n> diff --git a/test/ipa/libipa/fixedpoint.cpp b/test/ipa/libipa/fixedpoint.cpp\n> index 338571e38f68..1d018c0128df 100644\n> --- a/test/ipa/libipa/fixedpoint.cpp\n> +++ b/test/ipa/libipa/fixedpoint.cpp\n> @@ -190,6 +190,11 @@ protected:\n> fails += quantizedCheck(-0.4f, 0b1111'1001101, -0.398438f); /* 0x7cd */\n> fails += quantizedCheck(-1.4f, 0b1110'1001101, -1.39844f); /* 0x74d */\n> \n> + /* Q5_4(-16 .. 15.9375) Min: [0x0100:-16] -- Max: [0x00ff:15.9375] Step:0.0625 */\n> + introduce(\"Q5_4\");\n> + fails += quantizedCheck(-16.00f, 0b10000'0000, -16.00f);\n> + fails += quantizedCheck( 15.94f, 0b01111'1111, 15.9375f);\n> +\n> /* Q12.4(-2048 .. 2047.94) Min: [0x8000:-2048] -- Max: [0x7fff:2047.94] Step:0.0625 */\n> introduce(\"Q12_4\");\n> fails += quantizedCheck(0.0f, 0b000000000000'0000, 0.0f);\n> -- \n> 2.51.1\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 AF013BD80A\n\tfor ;\n\tTue, 18 Nov 2025 12:38:59 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 50CCC60AA0;\n\tTue, 18 Nov 2025 13:38:59 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id E8EE5609D8\n\tfor ;\n\tTue, 18 Nov 2025 13:38:57 +0100 (CET)","from thinkpad.ideasonboard.com\n\t(cpc89244-aztw30-2-0-cust6594.18-1.cable.virginm.net [86.31.185.195])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 3D065D52;\n\tTue, 18 Nov 2025 13:36:54 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"Ev+Xgqw3\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1763469414;\n\tbh=UsLVBDz5L3TsjrSuGyp1haphShdKO5TArEu4L3Ei4I0=;\n\th=In-Reply-To:References:Subject:From:Cc:To:Date:From;\n\tb=Ev+Xgqw3FAol6ZDsemjq7jf5kTa9F9rWjuYvzV0vyp9RvTzwy2V0iYkj65xV/LVSK\n\txg6m8hdTdlA+Tu3yCoHNM4ktQKlCRC7TiIatpa7Dr0GiIFlJJslkQzUsV1AbuXr+TE\n\tCNVN6ud6mJLg5kaQSr4RdLQtgDAolz3hhJGbd2/Q=","Content-Type":"text/plain; charset=\"utf-8\"","MIME-Version":"1.0","Content-Transfer-Encoding":"quoted-printable","In-Reply-To":"<20251114005428.90024-8-kieran.bingham@ideasonboard.com>","References":"<20251114005428.90024-1-kieran.bingham@ideasonboard.com>\n\t<20251114005428.90024-8-kieran.bingham@ideasonboard.com>","Subject":"Re: [PATCH v4 07/21] ipa: libipa: Provide Q5.4 FixedPoint support","From":"Isaac Scott ","Cc":"Kieran Bingham ","To":"Kieran Bingham ,\n\tlibcamera devel ","Date":"Tue, 18 Nov 2025 12:38:55 +0000","Message-ID":"<176346953523.880260.4416557132835145605@isaac-ThinkPad-T16-Gen-2>","User-Agent":"alot/0.10","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","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]