raspberry pi hw jpg encoder (nihui#185)

Author: nihui

highgui/CMakeLists.txt

@@ -4,6 +4,7 @@ ocv_add_module(highgui opencv_imgproc)
 option(WITH_CVI "build with cvi" OFF)
 option(WITH_AW "build with aw" OFF)
 option(WITH_RK "build with rk" OFF)
+option(WITH_RPI "build with rpi" OFF)
 
 set(highgui_srcs
     ${CMAKE_CURRENT_LIST_DIR}/src/exif.cpp
@@ -53,6 +54,13 @@ if(WITH_RK)
   message(STATUS "highgui rk enabled")
 endif()
 
+if(WITH_RPI)
+  list(APPEND highgui_srcs
+    ${CMAKE_CURRENT_LIST_DIR}/src/jpeg_encoder_v4l_rpi.cpp)
+  add_definitions(-DCV_WITH_RPI=1)
+  message(STATUS "highgui rpi enabled")
+endif()
+
 file(GLOB highgui_ext_hdrs
      "${CMAKE_CURRENT_LIST_DIR}/include/opencv2/*.hpp"
      "${CMAKE_CURRENT_LIST_DIR}/include/opencv2/${name}/*.hpp"

highgui/src/highgui.cpp

@@ -51,6 +51,9 @@
 #if CV_WITH_RK
 #include "jpeg_encoder_rk_mpp.h"
 #endif
+#if CV_WITH_RPI
+#include "jpeg_encoder_v4l_rpi.h"
+#endif
 #if defined __linux__ && !__ANDROID__
 #include "display_fb.h"
 #endif
@@ -404,6 +407,57 @@ bool imwrite(const String& filename, InputArray _img, const std::vector<int>& pa
             // fallback to stb_image_write
         }
 #endif
+#if CV_WITH_RPI
+        if (jpeg_encoder_v4l_rpi::supported(img.cols, img.rows, c))
+        {
+            // anything to bgr
+            if (!img.isContinuous())
+            {
+                img = img.clone();
+            }
+
+            int quality = 95;
+            for (size_t i = 0; i < params.size(); i += 2)
+            {
+                if (params[i] == IMWRITE_JPEG_QUALITY)
+                {
+                    quality = params[i + 1];
+                    break;
+                }
+            }
+
+            // cache jpeg_encoder_v4l_rpi context
+            static int old_w = 0;
+            static int old_h = 0;
+            static int old_ch = 0;
+            static int old_quality = 0;
+            static jpeg_encoder_v4l_rpi e;
+            if (img.cols == old_w && img.rows == old_h && c == old_ch && quality == old_quality)
+            {
+                int ret = e.encode(img.data, filename.c_str());
+                if (ret == 0)
+                    return true;
+            }
+            else
+            {
+                int ret = e.init(img.cols, img.rows, c, quality);
+                if (ret == 0)
+                {
+                    ret = e.encode(img.data, filename.c_str());
+                    if (ret == 0)
+                    {
+                        old_w = img.cols;
+                        old_h = img.rows;
+                        old_ch = c;
+                        old_quality = quality;
+                        return true;
+                    }
+                }
+            }
+
+            // fallback to stb_image_write
+        }
+#endif
     }
 
     // bgr to rgb
@@ -724,6 +778,40 @@ bool imencode(const String& ext, InputArray _img, std::vector<uchar>& buf, const
             // fallback to stb_image_write
         }
 #endif
+#if CV_WITH_RPI
+        if (jpeg_encoder_v4l_rpi::supported(img.cols, img.rows, c))
+        {
+            // anything to bgr
+            if (!img.isContinuous())
+            {
+                img = img.clone();
+            }
+
+            int quality = 95;
+            for (size_t i = 0; i < params.size(); i += 2)
+            {
+                if (params[i] == IMWRITE_JPEG_QUALITY)
+                {
+                    quality = params[i + 1];
+                    break;
+                }
+            }
+
+            jpeg_encoder_v4l_rpi e;
+            int ret = e.init(img.cols, img.rows, c, quality);
+            if (ret == 0)
+            {
+                ret = e.encode(img.data, buf);
+                if (ret == 0)
+                {
+                    e.deinit();
+                    return true;
+                }
+            }
+
+            // fallback to stb_image_write
+        }
+#endif
     }
 
     // bgr to rgb