Norimasa Okamoto / BaseJpegDecode

huffmancode to decode in real-time for motion-jpeg

Dependents:   BaseJpegDecode_example SimpleJpegDecode_example Dumb_box_rev2

example code:

Import programBaseJpegDecode_example

BaseJpegDeocde exampe program

Last commit 27 Jan 2013 by Norimasa Okamoto

Import programSimpleJpegDecode_example

convert JPEG stream data to bitmap, BaseJpegDecode example program

Last commit 02 Feb 2013 by Norimasa Okamoto

Diff: inverseDCT.cpp

Revision:
3:a7547692071d
Parent:
2:5b1dd4e34857
--- a/inverseDCT.cpp	Tue Oct 30 13:22:08 2012 +0000
+++ b/inverseDCT.cpp	Mon Nov 05 22:47:05 2012 +0000
@@ -1,9 +1,7 @@
 #include "mbed.h"
-#include <math.h>
 #include "inverseDCT.h"
 
-#define PI 3.14159265
-
+#ifdef USE_IDCT_AAN
 const int zigzag[64] =
           {0,
            1, 8,
@@ -21,110 +19,50 @@
           55,62,
           63};
 
-int adjust(int value) {
-    value += 128;
-    if (value < 0) {
-        return 0;
-    } else if (value > 255) {
-        return 255;
-    }
-    return value;
-}
-
-#if DCT_USE_INT
-inverseDCT::inverseDCT()
-{
-    for(int x = 0; x < 8; x++) {
-        for(int u = 0; u < 8; u++) {
-            float value = cos((x*2+1)*u*PI/16);
-            m_cosxu[x*8+u] = value * 32;
-        }
-    }
-    
-    for(int v = 0; v < 8; v++) {
-        for(int u = 0; u < 8; u++) {
-            float value = 1.0 / 4.0;
-            if (v == 0 && u == 0) {
-                value /= 2.0;
-            } else if (v == 0 || u == 0) {
-                value /= sqrt(2.0);
-            }
-            m_cucv[v*8+u] = value * 32;
-        }
-    }
-}
-
-void inverseDCT::inputBLOCK(int mcu, int block, int scan, int value)
-{
-    if (scan == 0) {
-        for(int i = 0; i < 64; i++) {
-            m_sum[i] = 0;
-        }
-    }
-
-    if (value != 0) {
-        int uv = zigzag[scan];
-        int u = uv % 8;
-        int v = uv / 8;
-        for(int y = 0; y < 8; y++) {
-            for(int x = 0; x < 8; x++) {
-                int t = m_cucv[uv] * value * m_cosxu[x*8+u] * m_cosxu[y*8+v] / 32 / 32;
-                m_sum[y*8+x] += t;
-            }
-        }
-    }
-    
-    if (scan == 63) {
-        uint8_t result[64];
-        for(int i = 0; i < 64; i++) {
-            int value = m_sum[i] / 32;
-            result[i] = adjust(value);
-        }
-        outputBLOCK(mcu, block, result);
-    }
-}
-
-#else
-
-inverseDCT::inverseDCT()
-{
-}
-
-void inverseDCT::input(int mcu, int block, int scan, int value) {
+void inverseDCT::inputBLOCK(int mcu, int block, int scan, int value) {
     if (scan == 0) {
         for(int i = 0; i < 64; i++) {
             m_s[i] = 0;
         }
     }
     m_s[zigzag[scan]] = value;
+    if (scan == 63) { // last
+        idct.conv(reinterpret_cast<int8_t*>(m_s), m_s);
+        outputBLOCK(mcu, block, reinterpret_cast<int8_t*>(m_s));
+    }
+};
+#endif //USE_IDCT_AAN
+
+#ifdef USE_IDCT_TABLE
+#include "inverseDCT_table.h"
+void inverseDCT::inputBLOCK(int mcu, int block, int scan, int value)
+{
+    if (scan == 0) {
+        int t = value * 32 / 8;
+        for(int i = 0; i < 64; i++) {
+            m_sum[i] = t;
+        }
+        return;
+    }
+
+    if (value != 0) {
+        for(int xy = 0; xy < 64; xy++) {
+            m_sum[xy] += idct_table[scan*64+xy] * value / 16;
+        }
+    }
+    
     if (scan == 63) {
-        calc(mcu, block, m_s);
+        int8_t* result = reinterpret_cast<int8_t*>(m_sum);
+        for(int i = 0; i < 64; i++) {
+            int t = m_sum[i] / 32;
+            if (t > 127) {
+                t = 127;
+            } else if (t < -128) {
+                t = -128;
+            }
+            result[i] = t;
+        }
+        outputBLOCK(mcu, block, result);
     }
 }
-
-void inverseDCT::calc(int mcu, int block, int s[]) {
-    for(int y = 0; y < 8; y++) {
-        for(int x = 0; x < 8; x++) {
-            float sum = 0.0;
-            for(int v = 0; v < 8; v++) {
-                float cv = 1.0;
-                if (v == 0) {
-                    cv /= sqrt(2.0);
-                }
-                for(int u = 0; u < 8; u++) {
-                    float cu = 1.0;
-                    if (u == 0) {
-                        cu /= sqrt(2.0);
-                    }
-                    int vu = v * 8 + u;
-                    float cosxu = cos((x*2+1) * u * PI / 16);
-                    float cosyv = cos((y*2+1) * v * PI / 16);
-                    sum += cu * cv * s[vu] * cosxu * cosyv;
-                }
-            }    
-            sum /= 4;
-            m_result[y*8+x] = adjust(sum);
-        }
-    }
-}
-#endif
+#endif //USE_IDCT_TABLE