1 files changed, 140 insertions, 0 deletions
diff --git a/video/out/win32/displayconfig.c b/video/out/win32/displayconfig.c
new file mode 100644
index 0000000..9844afd
--- /dev/null
+++ b/video/out/win32/displayconfig.c
@@ -0,0 +1,140 @@
+/*
+ * 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 "displayconfig.h"
+
+#include "mpv_talloc.h"
+
+static bool is_valid_refresh_rate(DISPLAYCONFIG_RATIONAL rr)
+{
+    // DisplayConfig sometimes reports a rate of 1 when the rate is not known
+    return rr.Denominator != 0 && rr.Numerator / rr.Denominator > 1;
+}
+
+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 = GetDisplayConfigBufferSizes(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 = QueryDisplayConfig(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 (DisplayConfigGetDeviceInfo(&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 (!is_valid_refresh_rate(info->vSyncFreq))
+        return 0.0;
+
+    return ((double)info->vSyncFreq.Numerator) /
+           ((double)info->vSyncFreq.Denominator);
+}
+
+double mp_w32_displayconfig_get_refresh_rate(const wchar_t *device)
+{
+    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 && is_valid_refresh_rate(path->targetInfo.refreshRate)) {
+        freq = ((double)path->targetInfo.refreshRate.Numerator) /
+               ((double)path->targetInfo.refreshRate.Denominator);
+    }
+
+end:
+    talloc_free(ctx);
+    return freq;
+}