lightweight C jpeg header - copy from origin/raj/jpeg-optimizations

source/application/jpeg_header/Makefile

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+#
+# Authored by: Robert Metchev / Chips & Scripts (rmetchev@ieee.org)
+#
+# CERN Open Hardware Licence Version 2 - Permissive
+#
+# Copyright (C) 2024 Robert Metchev
+#
+
+HEIGHT ?= 200
+WIDTH ?= 200
+QF ?= 50
+
+all: header.bin
+header.bin: jhdr.exe
+	$(<) $(HEIGHT) $(WIDTH) $(QF)
+jhdr.exe: jhdr.c main.c
+	gcc -o $(@) $(^)
+
+clean:
+	rm -f jhdr.exe jhdr.o header.bin

source/application/jpeg_header/footer.bin

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+��

source/application/jpeg_header/jhdr.c

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+/*
+Authored by: Robert Metchev / Chips & Scripts (rmetchev@ieee.org)
+CERN Open Hardware Licence Version 2 - Permissive
+Copyright (C) 2024 Robert Metchev
+
+Pre-compiled JPEG header template (incl. quantization and Huffman tables).
+QF = 50, height = 0, width = 0
+Positions:  QT0 25..88, QT1 93..156, height 163..164, width 165..166
+Total length = 623
+*/
+#include "jhdr.h"
+
+int scale_mult (int q, float scale) {
+    float t = (scale*q + 50)/100;   // Round
+    if (t < 1)                      // Prevent divide by 0 error 
+        t = 1;                      
+    else if (t > 255)               // Prevent overflow
+        t = 255;
+    return (int)t;
+}
+
+void hdr(int height, int width, int qf, char header_file_name[]) {
+    char header[] = { 255, 216, 255, 224, 0, 16, 74, 70, 73, 70, 0, 1, 2, 0, 0, 100, 0, 100, 0, 0, 255, 219, 0, 67, 0, 16, 11, 12, 14, 12, 10, 16, 14, 13, 14, 18, 17, 16, 19, 24, 40, 26, 24, 22, 22, 24, 49, 35, 37, 29, 40, 58, 51, 61, 60, 57, 51, 56, 55, 64, 72, 92, 78, 64, 68, 87, 69, 55, 56, 80, 109, 81, 87, 95, 98, 103, 104, 103, 62, 77, 113, 121, 112, 100, 120, 92, 101, 103, 99, 255, 219, 0, 67, 1, 17, 18, 18, 24, 21, 24, 47, 26, 26, 47, 99, 66, 56, 66, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 255, 192, 0, 17, 8, 0, 0, 0, 0, 3, 1, 34, 0, 2, 17, 1, 3, 17, 1, 255, 196, 0, 31, 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 255, 196, 0, 31, 1, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 255, 196, 0, 181, 16, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 125, 1, 2, 3, 0, 4, 17, 5, 18, 33, 49, 65, 6, 19, 81, 97, 7, 34, 113, 20, 50, 129, 145, 161, 8, 35, 66, 177, 193, 21, 82, 209, 240, 36, 51, 98, 114, 130, 9, 10, 22, 23, 24, 25, 26, 37, 38, 39, 40, 41, 42, 52, 53, 54, 55, 56, 57, 58, 67, 68, 69, 70, 71, 72, 73, 74, 83, 84, 85, 86, 87, 88, 89, 90, 99, 100, 101, 102, 103, 104, 105, 106, 115, 116, 117, 118, 119, 120, 121, 122, 131, 132, 133, 134, 135, 136, 137, 138, 146, 147, 148, 149, 150, 151, 152, 153, 154, 162, 163, 164, 165, 166, 167, 168, 169, 170, 178, 179, 180, 181, 182, 183, 184, 185, 186, 194, 195, 196, 197, 198, 199, 200, 201, 202, 210, 211, 212, 213, 214, 215, 216, 217, 218, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 255, 196, 0, 181, 17, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 119, 0, 1, 2, 3, 17, 4, 5, 33, 49, 6, 18, 65, 81, 7, 97, 113, 19, 34, 50, 129, 8, 20, 66, 145, 161, 177, 193, 9, 35, 51, 82, 240, 21, 98, 114, 209, 10, 22, 36, 52, 225, 37, 241, 23, 24, 25, 26, 38, 39, 40, 41, 42, 53, 54, 55, 56, 57, 58, 67, 68, 69, 70, 71, 72, 73, 74, 83, 84, 85, 86, 87, 88, 89, 90, 99, 100, 101, 102, 103, 104, 105, 106, 115, 116, 117, 118, 119, 120, 121, 122, 130, 131, 132, 133, 134, 135, 136, 137, 138, 146, 147, 148, 149, 150, 151, 152, 153, 154, 162, 163, 164, 165, 166, 167, 168, 169, 170, 178, 179, 180, 181, 182, 183, 184, 185, 186, 194, 195, 196, 197, 198, 199, 200, 201, 202, 210, 211, 212, 213, 214, 215, 216, 217, 218, 226, 227, 228, 229, 230, 231, 232, 233, 234, 242, 243, 244, 245, 246, 247, 248, 249, 250, 255, 218, 0, 12, 3, 1, 0, 2, 17, 3, 17, 0, 63, 0};
+    float scale;
+
+    if (qf < 50) 
+        scale = 5000/qf;
+    else 
+        scale = 200 - 2*qf;
+
+    for (int i=25; i<=88; i++) 
+        header[i] = scale_mult(header[i], scale);
+    for (int i=93; i<=156; i++) 
+        header[i] = scale_mult(header[i], scale);
+
+    header[163] = (height >> 8) & 0xff;
+    header[164] = height & 0xff;
+    header[165] = (width >> 8) & 0xff;
+    header[166] = width & 0xff;
+
+    FILE *f = fopen(header_file_name, "wb");
+    fwrite(header, 1, 623, f);
+    fclose(f);
+}

source/application/jpeg_header/jhdr.h

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+/*
+Authored by: Robert Metchev / Chips & Scripts (rmetchev@ieee.org)
+CERN Open Hardware Licence Version 2 - Permissive
+Copyright (C) 2024 Robert Metchev
+
+Pre-compiled JPEG header template (incl. quantization and Huffman tables).
+QF = 50, height = 0, width = 0
+Positions:  QT0 25..88, QT1 93..156, height 163..164, width 165..166
+Total length = 623
+*/
+#include <stdlib.h>
+#include <stdio.h>
+void hdr(int height, int width, int qf, char header_file_name[]);

source/application/jpeg_header/main.c

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+/*
+Authored by: Robert Metchev / Chips & Scripts (rmetchev@ieee.org)
+CERN Open Hardware Licence Version 2 - Permissive
+Copyright (C) 2024 Robert Metchev
+*/
+#include "jhdr.h"
+int main(int argc, char *argv[]) {
+    if(argc <= 2) 
+        exit(1);
+    // call hdr, write header to "header.bin"
+    hdr(atoi(argv[1]), atoi(argv[2]), argc > 3 ? atoi(argv[3]) :  50 , argc > 4 ? argv[4] :  "header.bin");
+    return 0;
+}
+