add night drop feature

SD_ROOT/wz_mini/wz_mini.conf

@@ -84,6 +84,7 @@ ENABLE_CIFS="false"
 DISABLE_FW_UPGRADE="false"
 AUDIO_PROMPT_VOLUME="50"
 ENABLE_MP4_WRITE="false"
+NIGHT_DROP_DISABLE="false"
 
 #####DEBUG#####
 #drops you to a shell via serial, doesn't load app_init.sh

src/libcallback_wz_mod/night_drop.c

@@ -0,0 +1,38 @@
+#define _GNU_SOURCE
+#include <dlfcn.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <fcntl.h>
+
+static uint32_t (*real_local_sdk_video_set_fps)(int encChn);
+
+int local_sdk_video_set_fps(int encChn) {
+
+        const char *nd_enable="/opt/wz_mini/tmp/.nd";
+        const char *product_T31="/opt/wz_mini/tmp/.T31";
+        const char *product_T20="/opt/wz_mini/tmp/.T20";
+
+        if( access( nd_enable, F_OK ) != -1 ) {
+                printf("[command] [night_drop.c] Night Drop Enabled\n");
+        if( encChn == 15 && access( product_T31, F_OK ) != -1 ) {
+                printf("[command] [night_drop.c] T31 detected\n");
+                fprintf(stderr, "[command] [night_drop.c] Night Time Requested FPS Drop Value: %d\n", encChn);
+                printf("[command] [night_drop.c] Night FPS Drop Stopped\n");
+        } else if ( encChn >= 15 && access( product_T20, F_OK ) != -1 ) {
+                printf("[command] [night_drop.c] T20 detected\n");
+                fprintf(stderr, "[command] [night_drop.c] Night Time Requested FPS Drop Value: %d\n", encChn);
+                printf("[command] [night_drop.c] Night FPS Drop Stopped\n");
+        } else {
+                fprintf(stderr, "[command] [night_drop.c] Requested FPS Value: %d\n", encChn);
+                fprintf(stderr, "[command] [night_drop.c] Calling local_sdk_video_set_fps to: %d\n", encChn);
+                real_local_sdk_video_set_fps(encChn);
+        }
+
+        }
+}
+
+
+static void __attribute ((constructor)) nigh_drop_init(void) {
+  real_local_sdk_video_set_fps = dlsym(dlopen("/system/lib/liblocalsdk.so", RTLD_LAZY), "local_sdk_video_set_fps");
+}