{"id":24892,"url":"https://patchwork.libcamera.org/api/1.1/patches/24892/?format=json","web_url":"https://patchwork.libcamera.org/patch/24892/","project":{"id":1,"url":"https://patchwork.libcamera.org/api/1.1/projects/1/?format=json","name":"libcamera","link_name":"libcamera","list_id":"libcamera_core","list_email":"libcamera-devel@lists.libcamera.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20251029172439.1513907-4-kieran.bingham@ideasonboard.com>","date":"2025-10-29T17:24:28","name":"[v2,03/13] ipa: libipa: Provide fixed point quantized traits","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"b0823d291dbb71c0b8283c007787efc65decb4d4","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/1.1/people/4/?format=json","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"delegate":null,"mbox":"https://patchwork.libcamera.org/patch/24892/mbox/","series":[{"id":5544,"url":"https://patchwork.libcamera.org/api/1.1/series/5544/?format=json","web_url":"https://patchwork.libcamera.org/project/libcamera/list/?series=5544","date":"2025-10-29T17:24:25","name":"libipa: Introduce a Quantized type","version":2,"mbox":"https://patchwork.libcamera.org/series/5544/mbox/"}],"comments":"https://patchwork.libcamera.org/api/patches/24892/comments/","check":"pending","checks":"https://patchwork.libcamera.org/api/patches/24892/checks/","tags":{},"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 D788BC3259\n\tfor ;\n\tWed, 29 Oct 2025 17:24:56 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 846306086F;\n\tWed, 29 Oct 2025 18:24:51 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id F1EB060453\n\tfor ;\n\tWed, 29 Oct 2025 18:24:46 +0100 (CET)","from Monstersaurus.hippo-penny.ts.net\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 99CC24E45;\n\tWed, 29 Oct 2025 18:22:57 +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=\"mZLSs1kD\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1761758577;\n\tbh=3Y/kOlzuCJ7hrtzVfrAbQU2EaCvkj+nsrIr8dJIdtJU=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=mZLSs1kD5mUTGKQH7ZcQblkjLWfoTRiVnAr1kgdMrXo4dovWwW01o7X8VB0unbPwH\n\t9V1qlgo3OwvGiwycGQXhSYxsXV+74gOzgCEj45i3pDhz+3UzKPFQPN/WLXKplDMDYu\n\tVgn+NxWFxRI9ztyFos0K5UVATYGqLhpiSTMo+BJg=","From":"Kieran Bingham ","To":"libcamera devel ","Cc":"Kieran Bingham ","Subject":"[PATCH v2 03/13] ipa: libipa: Provide fixed point quantized traits","Date":"Wed, 29 Oct 2025 17:24:28 +0000","Message-ID":"<20251029172439.1513907-4-kieran.bingham@ideasonboard.com>","X-Mailer":"git-send-email 2.50.1","In-Reply-To":"<20251029172439.1513907-1-kieran.bingham@ideasonboard.com>","References":"<20251029172439.1513907-1-kieran.bingham@ideasonboard.com>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","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\" "},"content":"Extend the new Quantized type infrastructure by providing a\nFixedPointQTraits template.\n\nThis allows construction of fixed point types with a Quantized storage\nthat allows easy reading of both the underlying quantized type value and\na floating point representation of that same value.\n\nSigned-off-by: Kieran Bingham \n---\n src/ipa/libipa/fixedpoint.cpp | 114 ++++++++++++++++++++++++++++++++++\n src/ipa/libipa/fixedpoint.h | 43 +++++++++++++\n 2 files changed, 157 insertions(+)","diff":"diff --git a/src/ipa/libipa/fixedpoint.cpp b/src/ipa/libipa/fixedpoint.cpp\nindex 6b698fc5d680..2568c7921348 100644\n--- a/src/ipa/libipa/fixedpoint.cpp\n+++ b/src/ipa/libipa/fixedpoint.cpp\n@@ -37,6 +37,120 @@ namespace ipa {\n * \\return The converted value\n */\n \n+/**\n+ * \\struct libcamera::ipa::FixedPointQTraits\n+ * \\brief Traits type implementing fixed-point quantisation conversions\n+ *\n+ * The FixedPointQTraits structure defines a policy for mapping floating-point\n+ * values to and from fixed-point integer representations. It is parameterised\n+ * by the number of integer bits \\a I, fractional bits \\a F, and the integral\n+ * storage type \\a T. The traits are used with Quantized to create a\n+ * quantised type that stores both the fixed-point representation and the\n+ * corresponding floating-point value.\n+ *\n+ * The trait exposes compile-time constants describing the bit layout, limits,\n+ * and scaling factors used in the fixed-point representation.\n+ *\n+ * \\tparam I Number of integer bits\n+ * \\tparam F Number of fractional bits\n+ * \\tparam T Integral type used to store the quantised value\n+ */\n+\n+/**\n+ * \\typedef FixedPointQTraits::quantized_type\n+ * \\brief The integral storage type used for the fixed-point representation\n+ */\n+\n+/**\n+ * \\var FixedPointQTraits::Bits\n+ * \\brief Total number of bits used in the fixed-point format (I + F)\n+ */\n+\n+/**\n+ * \\var FixedPointQTraits::BitMask\n+ * \\brief Bit mask selecting all valid bits in the fixed-point representation\n+ */\n+\n+/**\n+ * \\var FixedPointQTraits::qmin\n+ * \\brief Minimum representable quantised integer value\n+ *\n+ * This corresponds to the most negative value for signed formats or zero for\n+ * unsigned formats.\n+ */\n+\n+/**\n+ * \\var FixedPointQTraits::qmax\n+ * \\brief Maximum representable quantised integer value\n+ */\n+\n+/**\n+ * \\var FixedPointQTraits::min\n+ * \\brief Minimum representable floating-point value corresponding to qmin\n+ */\n+\n+/**\n+ * \\var FixedPointQTraits::max\n+ * \\brief Maximum representable floating-point value corresponding to qmax\n+ */\n+\n+/**\n+ * \\fn FixedPointQTraits::fromFloat(float v)\n+ * \\brief Convert a floating-point value to a fixed-point integer\n+ * \\param[in] v The floating-point value to be converted\n+ * \\return The quantised fixed-point integer representation\n+ *\n+ * The conversion rounds the floating-point input \\a v to the nearest integer\n+ * according to the scaling factor defined by the number of fractional bits F.\n+ */\n+\n+/**\n+ * \\fn FixedPointQTraits::toFloat(quantized_type q)\n+ * \\brief Convert a fixed-point integer to a floating-point value\n+ * \\param[in] q The fixed-point integer value to be converted\n+ * \\return The corresponding floating-point value\n+ *\n+ * The conversion sign-extends the integer value if required and divides by the\n+ * scaling factor defined by the number of fractional bits F.\n+ */\n+\n+/**\n+ * \\typedef Q1_7\n+ * \\brief 1.7 signed fixed-point quantizer\n+ *\n+ * A Quantized type using 1 bit for the integer part and 7 bits for the\n+ * fractional part, stored in a signed 8-bit integer (\\c int8_t). Represents\n+ * values approximately in the range [-1.0, 0.992] with a resolution of 1/128.\n+ */\n+\n+/**\n+ * \\typedef UQ1_7\n+ * \\brief 1.7 unsigned fixed-point quantizer\n+ *\n+ * A Quantized type using 1 bit for the integer part and 7 bits for the\n+ * fractional part, stored in an unsigned 8-bit integer (\\c uint8_t). Represents\n+ * values in the range [0.0, 1.992] with a resolution of 1/128.\n+ */\n+\n+/**\n+ * \\typedef Q12_4\n+ * \\brief 12.4 signed fixed-point quantizer\n+ *\n+ * A Quantized type using 12 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 approximately [-2048.0, 2047.9375] with a resolution of\n+ * 1/16.\n+ */\n+\n+/**\n+ * \\typedef UQ12_4\n+ * \\brief 12.4 unsigned fixed-point quantizer\n+ *\n+ * A Quantized type using 12 bits for the integer part and 4 bits for the\n+ * fractional part, stored in an unsigned 16-bit integer (\\c uint16_t).\n+ * Represents values in the range [0.0, 4095.9375] with a resolution of 1/16.\n+ */\n+\n } /* namespace ipa */\n \n } /* namespace libcamera */\ndiff --git a/src/ipa/libipa/fixedpoint.h b/src/ipa/libipa/fixedpoint.h\nindex 709cf50f0fcd..9a7674e528d9 100644\n--- a/src/ipa/libipa/fixedpoint.h\n+++ b/src/ipa/libipa/fixedpoint.h\n@@ -10,6 +10,8 @@\n #include \n #include \n \n+#include \"quantized.h\"\n+\n namespace libcamera {\n \n namespace ipa {\n@@ -60,6 +62,47 @@ constexpr R fixedToFloatingPoint(T number)\n \treturn static_cast(t) / static_cast(1 << F);\n }\n \n+template\n+struct FixedPointQTraits {\n+\tstatic_assert(std::is_integral_v, \"FixedPointQTraits: T must be integral\");\n+\tusing quantized_type = T;\n+\n+\tstatic constexpr unsigned int Bits = I + F;\n+\n+\tstatic constexpr T BitMask = (Bits < sizeof(T) * 8)\n+\t\t\t\t ? (T{1} << Bits) - 1\n+\t\t\t\t : T{-1};\n+\n+\tstatic constexpr T qmin = std::is_signed_v\n+\t\t\t\t? -(T{1} << (Bits - 1))\n+\t\t\t\t: T{0};\n+\n+\tstatic constexpr T qmax = std::is_signed_v\n+\t\t\t\t? ((T{1} << (Bits - 1)) - 1)\n+\t\t\t\t: ((T{1} << Bits) - 1);\n+\n+\tstatic constexpr float min = fixedToFloatingPoint(qmin);\n+\tstatic constexpr float max = fixedToFloatingPoint(qmax);\n+\n+\t/* Conversion functions required by Quantized */\n+\tstatic quantized_type fromFloat(float v)\n+\t{\n+\t\tv = std::clamp(v, min, max);\n+\t\treturn floatingToFixedPoint(v);\n+\t}\n+\n+\tstatic float toFloat(quantized_type q)\n+\t{\n+\t\treturn fixedToFloatingPoint(q);\n+\t}\n+};\n+\n+using Q1_7 = Quantized>;\n+using UQ1_7 = Quantized>;\n+\n+using Q12_4 = Quantized>;\n+using UQ12_4 = Quantized>;\n+\n } /* namespace ipa */\n \n } /* namespace libcamera */\n","prefixes":["v2","03/13"]}