w32: use DisplayConfig API to retrieve correct monitor refresh rate

This is based on an older patch by James Ross-Gowan. It was rebased and
cleaned up. Also, the DWM API usage present in the older patch was
removed, because DWM reports nonsense rates at least on Windows 8.1
(they are rounded to integers, just like with the old GDI API - except
the GDI API had a good excuse, as it could report only integers).

Signed-off-by: wm4 <wm4@nowhere>

5 files changed, 303 insertions, 19 deletions

diff --git a/video/out/w32_common.c b/video/out/w32_common.c
index f76384b451..09088df79d 100644
--- a/video/out/w32_common.c
+++ b/video/out/w32_common.c
@@ -34,6 +34,7 @@
 #include "vo.h"
 #include "win_state.h"
 #include "w32_common.h"
+#include "win32/displayconfig.h"
 #include "osdep/io.h"
 #include "osdep/threads.h"
 #include "osdep/w32_keyboard.h"
@@ -59,8 +60,8 @@ struct vo_w32_state {
     HWND window;
     HWND parent; // 0 normally, set in embedding mode
 
-    // Size and virtual position of the current screen.
-    struct mp_rect screenrc;
+    HMONITOR monitor; // Handle of the current screen
+    struct mp_rect screenrc; // Size and virtual position of the current screen
 
     // last non-fullscreen extends (updated only on fullscreen or on initialization)
     int prev_width;
@@ -567,22 +568,17 @@ static void wakeup_gui_thread(void *ctx)
     PostMessage(w32->window, WM_USER, 0, 0);
 }
 
-static double vo_w32_get_display_fps(struct vo_w32_state *w32)
+static double get_refresh_rate_from_gdi(const wchar_t *device)
 {
-    // Get the device name of the monitor containing the window
-    HMONITOR mon = MonitorFromWindow(w32->window, MONITOR_DEFAULTTOPRIMARY);
-    MONITORINFOEXW mi = { .cbSize = sizeof mi };
-    GetMonitorInfoW(mon, (MONITORINFO*)&mi);
-
-    DEVMODE dm = { .dmSize = sizeof dm };
-    if (!EnumDisplaySettingsW(mi.szDevice, ENUM_CURRENT_SETTINGS, &dm))
-        return -1;
+    DEVMODEW dm = { .dmSize = sizeof dm };
+    if (!EnumDisplaySettingsW(device, ENUM_CURRENT_SETTINGS, &dm))
+        return 0.0;
 
     // May return 0 or 1 which "represent the display hardware's default refresh rate"
     // https://msdn.microsoft.com/en-us/library/windows/desktop/dd183565%28v=vs.85%29.aspx
     // mpv validates this value with a threshold of 1, so don't return exactly 1
     if (dm.dmDisplayFrequency == 1)
-        return 0;
+        return 0.0;
 
     // dm.dmDisplayFrequency is an integer which is rounded down, so it's
     // highly likely that 23 represents 24/1.001, 59 represents 60/1.001, etc.
@@ -606,14 +602,37 @@ static double vo_w32_get_display_fps(struct vo_w32_state *w32)
 
 static void update_display_fps(struct vo_w32_state *w32)
 {
-    double fps = vo_w32_get_display_fps(w32);
-    if (fps != w32->display_fps) {
-        w32->display_fps = fps;
+    HMONITOR monitor = MonitorFromWindow(w32->window, MONITOR_DEFAULTTOPRIMARY);
+    if (w32->monitor == monitor)
+        return;
+    w32->monitor = monitor;
+
+    MONITORINFOEXW mi = { .cbSize = sizeof mi };
+    GetMonitorInfoW(monitor, (MONITORINFO*)&mi);
+
+    // Try to get the monitor refresh rate.
+    double freq = 0.0;
+
+    if (freq == 0.0)
+        freq = mp_w32_displayconfig_get_refresh_rate(mi.szDevice);
+    if (freq == 0.0)
+        freq = get_refresh_rate_from_gdi(mi.szDevice);
+
+    if (freq != w32->display_fps) {
+        MP_VERBOSE(w32, "display-fps: %f\n", freq);
+        if (freq == 0.0)
+            MP_WARN(w32, "Couldn't determine monitor refresh rate\n");
+        w32->display_fps = freq;
         signal_events(w32, VO_EVENT_WIN_STATE);
-        MP_VERBOSE(w32, "display-fps: %f\n", fps);
     }
 }
 
+static void force_update_display_fps(struct vo_w32_state *w32)
+{
+    w32->monitor = 0;
+    update_display_fps(w32);
+}
+
 static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
                                 LPARAM lParam)
 {
@@ -648,13 +667,14 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
         if (GetClientRect(w32->window, &r) && r.right > 0 && r.bottom > 0) {
             w32->dw = r.right;
             w32->dh = r.bottom;
-            update_display_fps(w32); // if we moved between monitors
             signal_events(w32, VO_EVENT_RESIZE);
             MP_VERBOSE(w32, "resize window: %d:%d\n", w32->dw, w32->dh);
         }
 
         // Window may have been minimized or restored
         signal_events(w32, VO_EVENT_WIN_STATE);
+
+        update_display_fps(w32);
         break;
     }
     case WM_SIZING:
@@ -799,7 +819,7 @@ static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam,
         mouse_button |= MP_KEY_STATE_UP;
         break;
     case WM_DISPLAYCHANGE:
-        update_display_fps(w32);
+        force_update_display_fps(w32);
         break;
     }
 
diff --git a/video/out/win32/displayconfig.c b/video/out/win32/displayconfig.c
new file mode 100644
index 0000000000..635e8b6b36
--- /dev/null
+++ b/video/out/win32/displayconfig.c
@@ -0,0 +1,236 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <windows.h>
+#include <stdbool.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "displayconfig.h"
+
+#include "talloc.h"
+
+// Some DisplayConfig definitions are broken in mingw-w64 (as of 2015-3-13.) To
+// get the correct struct alignment, it's necessary to define them properly.
+#include <pshpack1.h>
+
+typedef enum {
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_OTHER                 = -1,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_HD15                  = 0,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_SVIDEO                = 1,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_COMPOSITE_VIDEO       = 2,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_COMPONENT_VIDEO       = 3,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_DVI                   = 4,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_HDMI                  = 5,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_LVDS                  = 6,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_D_JPN                 = 8,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_SDI                   = 9,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_DISPLAYPORT_EXTERNAL  = 10,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_DISPLAYPORT_EMBEDDED  = 11,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_UDI_EXTERNAL          = 12,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_UDI_EMBEDDED          = 13,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_SDTVDONGLE            = 14,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_MIRACAST              = 15,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_INTERNAL              = -2147483647 - 1,
+    MP_DISPLAYCONFIG_OUTPUT_TECHNOLOGY_FORCE_UINT32          = 0x7FFFFFFF
+} MP_DISPLAYCONFIG_VIDEO_OUTPUT_TECHNOLOGY;
+
+typedef struct MP_DISPLAYCONFIG_PATH_TARGET_INFO {
+    LUID adapterId;
+    UINT32 id;
+    UINT32 modeInfoIdx;
+    MP_DISPLAYCONFIG_VIDEO_OUTPUT_TECHNOLOGY outputTechnology;
+    DISPLAYCONFIG_ROTATION rotation;
+    DISPLAYCONFIG_SCALING scaling;
+    DISPLAYCONFIG_RATIONAL refreshRate;
+    DISPLAYCONFIG_SCANLINE_ORDERING scanLineOrdering;
+    WINBOOL targetAvailable;
+    UINT32 statusFlags;
+} MP_DISPLAYCONFIG_PATH_TARGET_INFO;
+#define DISPLAYCONFIG_PATH_TARGET_INFO MP_DISPLAYCONFIG_PATH_TARGET_INFO
+
+typedef struct MP_DISPLAYCONFIG_PATH_INFO {
+    DISPLAYCONFIG_PATH_SOURCE_INFO sourceInfo;
+    MP_DISPLAYCONFIG_PATH_TARGET_INFO targetInfo;
+    UINT32 flags;
+} MP_DISPLAYCONFIG_PATH_INFO;
+#define DISPLAYCONFIG_PATH_INFO MP_DISPLAYCONFIG_PATH_INFO
+
+typedef struct MP_DISPLAYCONFIG_TARGET_DEVICE_NAME {
+    DISPLAYCONFIG_DEVICE_INFO_HEADER header;
+    DISPLAYCONFIG_TARGET_DEVICE_NAME_FLAGS flags;
+    MP_DISPLAYCONFIG_VIDEO_OUTPUT_TECHNOLOGY outputTechnology;
+    UINT16 edidManufactureId;
+    UINT16 edidProductCodeId;
+    UINT32 connectorInstance;
+    WCHAR monitorFriendlyDeviceName[64];
+    WCHAR monitorDevicePath[128];
+} MP_DISPLAYCONFIG_TARGET_DEVICE_NAME;
+#define DISPLAYCONFIG_TARGET_DEVICE_NAME MP_DISPLAYCONFIG_TARGET_DEVICE_NAME
+
+#include <poppack.h>
+
+static pthread_once_t displayconfig_load_ran = PTHREAD_ONCE_INIT;
+static bool displayconfig_loaded = false;
+
+static LONG (WINAPI *pDisplayConfigGetDeviceInfo)(
+        DISPLAYCONFIG_DEVICE_INFO_HEADER*);
+static LONG (WINAPI *pGetDisplayConfigBufferSizes)(UINT32, UINT32*, UINT32*);
+static LONG (WINAPI *pQueryDisplayConfig)(UINT32, UINT32*,
+        DISPLAYCONFIG_PATH_INFO*, UINT32*, DISPLAYCONFIG_MODE_INFO*,
+        DISPLAYCONFIG_TOPOLOGY_ID*);
+
+static void displayconfig_load(void)
+{
+    HMODULE user32 = GetModuleHandleW(L"user32.dll");
+    if (!user32)
+        return;
+
+    pDisplayConfigGetDeviceInfo =
+        (LONG (WINAPI*)(DISPLAYCONFIG_DEVICE_INFO_HEADER*))
+        GetProcAddress(user32, "DisplayConfigGetDeviceInfo");
+    if (!pDisplayConfigGetDeviceInfo)
+        return;
+    pGetDisplayConfigBufferSizes =
+        (LONG (WINAPI*)(UINT32, UINT32*, UINT32*))
+        GetProcAddress(user32, "GetDisplayConfigBufferSizes");
+    if (!pGetDisplayConfigBufferSizes)
+        return;
+    pQueryDisplayConfig =
+        (LONG (WINAPI*)(UINT32, UINT32*, DISPLAYCONFIG_PATH_INFO*, UINT32*,
+                        DISPLAYCONFIG_MODE_INFO*, DISPLAYCONFIG_TOPOLOGY_ID*))
+        GetProcAddress(user32, "QueryDisplayConfig");
+    if (!pQueryDisplayConfig)
+        return;
+
+    displayconfig_loaded = true;
+}
+
+static int get_config(void *ctx,
+                      UINT32 *num_paths, DISPLAYCONFIG_PATH_INFO** paths,
+                      UINT32 *num_modes, DISPLAYCONFIG_MODE_INFO** modes)
+{
+    LONG res;
+    *paths = NULL;
+    *modes = NULL;
+
+    // The display configuration could change between the call to
+    // GetDisplayConfigBufferSizes and the call to QueryDisplayConfig, so call
+    // them in a loop until the correct buffer size is chosen
+    do {
+        res = pGetDisplayConfigBufferSizes(QDC_ONLY_ACTIVE_PATHS, num_paths,
+                                           num_modes);
+        if (res != ERROR_SUCCESS)
+            goto fail;
+
+        // Free old buffers if they exist and allocate new ones
+        talloc_free(*paths);
+        talloc_free(*modes);
+        *paths = talloc_array(ctx, DISPLAYCONFIG_PATH_INFO, *num_paths);
+        *modes = talloc_array(ctx, DISPLAYCONFIG_MODE_INFO, *num_modes);
+
+        res = pQueryDisplayConfig(QDC_ONLY_ACTIVE_PATHS, num_paths, *paths,
+                                  num_modes, *modes, NULL);
+    } while (res == ERROR_INSUFFICIENT_BUFFER);
+    if (res != ERROR_SUCCESS)
+        goto fail;
+
+    return 0;
+fail:
+    talloc_free(*paths);
+    talloc_free(*modes);
+    return -1;
+}
+
+static DISPLAYCONFIG_PATH_INFO *get_path(UINT32 num_paths,
+                                         DISPLAYCONFIG_PATH_INFO* paths,
+                                         const wchar_t *device)
+{
+    // Search for a path with a matching device name
+    for (UINT32 i = 0; i < num_paths; i++) {
+        // Send a GET_SOURCE_NAME request
+        DISPLAYCONFIG_SOURCE_DEVICE_NAME source = {
+            .header = {
+                .size = sizeof source,
+                .type = DISPLAYCONFIG_DEVICE_INFO_GET_SOURCE_NAME,
+                .adapterId = paths[i].sourceInfo.adapterId,
+                .id = paths[i].sourceInfo.id,
+            }
+        };
+        if (pDisplayConfigGetDeviceInfo(&source.header) != ERROR_SUCCESS)
+            return NULL;
+
+        // Check if the device name matches
+        if (!wcscmp(device, source.viewGdiDeviceName))
+            return &paths[i];
+    }
+
+    return NULL;
+}
+
+static double get_refresh_rate_from_mode(DISPLAYCONFIG_MODE_INFO *mode)
+{
+    if (mode->infoType != DISPLAYCONFIG_MODE_INFO_TYPE_TARGET)
+        return 0.0;
+
+    DISPLAYCONFIG_VIDEO_SIGNAL_INFO *info =
+        &mode->targetMode.targetVideoSignalInfo;
+    if (info->vSyncFreq.Denominator == 0)
+        return 0.0;
+
+    return ((double)info->vSyncFreq.Numerator) /
+           ((double)info->vSyncFreq.Denominator);
+}
+
+double mp_w32_displayconfig_get_refresh_rate(const wchar_t *device)
+{
+    // Load Windows 7 DisplayConfig API
+    pthread_once(&displayconfig_load_ran, displayconfig_load);
+    if (!displayconfig_loaded)
+        return 0.0;
+
+    void *ctx = talloc_new(NULL);
+    double freq = 0.0;
+
+    // Get the current display configuration
+    UINT32 num_paths;
+    DISPLAYCONFIG_PATH_INFO* paths;
+    UINT32 num_modes;
+    DISPLAYCONFIG_MODE_INFO* modes;
+    if (get_config(ctx, &num_paths, &paths, &num_modes, &modes))
+        goto end;
+
+    // Get the path for the specified monitor
+    DISPLAYCONFIG_PATH_INFO* path;
+    if (!(path = get_path(num_paths, paths, device)))
+        goto end;
+
+    // Try getting the refresh rate from the mode first. The value in the mode
+    // overrides the value in the path.
+    if (path->targetInfo.modeInfoIdx != DISPLAYCONFIG_PATH_MODE_IDX_INVALID)
+        freq = get_refresh_rate_from_mode(&modes[path->targetInfo.modeInfoIdx]);
+
+    // If the mode didn't contain a valid refresh rate, try the path
+    if (freq == 0.0 && path->targetInfo.refreshRate.Denominator != 0) {
+        freq = ((double)path->targetInfo.refreshRate.Numerator) /
+               ((double)path->targetInfo.refreshRate.Denominator);
+    }
+
+end:
+    talloc_free(ctx);
+    return freq;
+}
diff --git a/video/out/win32/displayconfig.h b/video/out/win32/displayconfig.h
new file mode 100644
index 0000000000..ee6cd037f0
--- /dev/null
+++ b/video/out/win32/displayconfig.h
@@ -0,0 +1,27 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef MP_WIN32_DISPLAYCONFIG_H_
+#define MP_WIN32_DISPLAYCONFIG_H_
+
+#include <wchar.h>
+
+// Given a GDI monitor device name, get the precise refresh rate using the
+// Windows 7 DisplayConfig API. Returns 0.0 on failure.
+double mp_w32_displayconfig_get_refresh_rate(const wchar_t *device);
+
+#endif
diff --git a/waftools/detections/compiler.py b/waftools/detections/compiler.py
index d3e6b34455..284a7a5b9e 100644
--- a/waftools/detections/compiler.py
+++ b/waftools/detections/compiler.py
@@ -49,7 +49,7 @@ def __add_clang_flags__(ctx):
                        "-Wno-tautological-constant-out-of-range-compare" ]
 
 def __add_mswin_flags__(ctx):
-    ctx.env.CFLAGS += ['-D_WIN32_WINNT=0x600', '-DUNICODE', '-DCOBJMACROS',
+    ctx.env.CFLAGS += ['-D_WIN32_WINNT=0x0601', '-DUNICODE', '-DCOBJMACROS',
                        '-U__STRICT_ANSI__']
 
 def __add_mingw_flags__(ctx):
diff --git a/wscript_build.py b/wscript_build.py
index 0bb0bc0620..d33c07db68 100644
--- a/wscript_build.py
+++ b/wscript_build.py
@@ -355,6 +355,7 @@ def build(ctx):
         ( "video/out/vo_x11.c" ,                 "x11" ),
         ( "video/out/vo_xv.c",                   "xv" ),
         ( "video/out/w32_common.c",              "win32" ),
+        ( "video/out/win32/displayconfig.c",     "win32" ),
         ( "video/out/wayland_common.c",          "wayland" ),
         ( "video/out/wayland/buffer.c",          "wayland" ),
         ( "video/out/wayland/memfile.c",         "wayland" ),