LZ4 Compression (#79)

Add a new configuration option, "compress_osd", to the air side process.

If this is set to "true", then the entire "frame buffer" will be sent using LZ4 compression at the rate defined in osd_update_rate_hz, instead of sending raw MSP messages over the air.

This should fix INAV delta update related issues as well as provide better link stability.

Makefile.dji

@@ -24,10 +24,14 @@ all: jni/*
 install: all
 	install -d ipk/goggle/build/data/opt/fonts/
 	install fonts/*.bin ipk/goggle/build/data/opt/fonts/
+	install -d ipk/goggle/build/data/opt/mspdictionaries/
+	install dictionaries/*.bin ipk/goggle/build/data/opt/mspdictionaries/
 	install -d ipk/goggle/build/data/opt/etc/preload.d/
 	install libs/armeabi-v7a/libdisplayport_osd_shim.so ipk/goggle/build/data/opt/etc/preload.d/
 	install -d ipk/airunit/build/data/opt/bin/
 	install libs/armeabi-v7a/msp_displayport_mux ipk/airunit/build/data/opt/bin/
+	install -d ipk/airunit/build/data/opt/mspdictionaries/
+	install dictionaries/*.bin ipk/airunit/build/data/opt/mspdictionaries/
 	install -d ipk/airunit/build/data/opt/etc/package-config/msp-osd/
 	install config/airunit/* ipk/airunit/build/data/opt/etc/package-config/msp-osd/
 	install -d ipk/goggle/build/data/opt/etc/package-config/msp-osd/

config/airunit/config.json

@@ -1,4 +1,6 @@
 {
     "fast_serial": false,
-    "cache_serial": false
+    "cache_serial": false,
+    "osd_update_rate_hz": 10,
+    "compress_osd": false
 }

config/airunit/schema.json

@@ -7,6 +7,17 @@
       "cache_serial": {
         "name": "Cache Responses",
         "widget": "checkbox"
+      },
+      "compress_osd": {
+        "name": "Compress OSD",
+        "widget": "checkbox"
+      },
+      "osd_update_rate_hz": {
+        "name": "OSD update rate",
+        "widget": "range",
+        "min": 2,
+        "max": 20,
+        "step":1
       }
     },
     "units": [

config/airunit/schemaV2.json

@@ -24,6 +24,22 @@
                 true,
                 false
             ]
-        }
+        },
+        "compress_osd": {
+            "title": "Compress OSD",
+            "type": "boolean",
+            "description": "Send full frames of compressed data instead of sending MSP to the goggles.",
+            "enum": [
+                true,
+                false
+            ]
+          },
+          "osd_update_rate_hz": {
+            "name": "OSD update rate (for Compressed OSD)",
+            "type": "number",
+            "description": "OSD update rate, used only for compressed OSD.",
+            "minimum": 1,
+            "maximum": 20
+          }
     }
 }

ipk/airunit/control/control

@@ -1,5 +1,5 @@
 Package: msp-osd
-Version: 0.6.11
+Version: 0.7.0
 Maintainer: bri3d
 Description: MSP OSD service for the DJI HD FPV airunit.
 Architecture: pigeon-airside

ipk/goggle/control/control

@@ -1,5 +1,5 @@
 Package: msp-osd
-Version: 0.6.12
+Version: 0.7.0
 Maintainer: bri3d
 Description: MSP OSD service for the DJI HD FPV goggles.
 Architecture: pigeon-glasses

jni/Android.mk

@@ -28,7 +28,8 @@ LOCAL_SRC_FILES := \
 	rec/rec_shim.c \
 	rec/rec.c \
 	util/fs_util.c \
-	toast/toast.c
+	toast/toast.c \
+	lz4/lz4.c
 include $(BUILD_SHARED_LIBRARY)
 
 include $(CLEAR_VARS)
@@ -39,9 +40,11 @@ LOCAL_SRC_FILES:= \
 	json/parson.c \
 	msp_displayport_mux.c \
 	msp/msp.c \
+	msp/msp_displayport.c \
 	net/network.c \
 	net/serial.c \
-	util/fs_util.c
+	util/fs_util.c \
+	lz4/lz4.c
 LOCAL_MODULE := msp_displayport_mux
 include $(BUILD_EXECUTABLE)
 include $(CLEAR_VARS)