clapper-app: Support Windows high resolution clock

Windows high resolution clock improves accuracy of various Windows
timer APIs and precision of GstSystemClock during playback

src/bin/clapper-app/clapper-app-utils.c

@@ -23,8 +23,124 @@
 #include "clapper-app-utils.h"
 #include "clapper-app-media-item-box.h"
 
-/* Useful only on Windows */
 #ifdef G_OS_WIN32
+#include <windows.h>
+#ifdef HAVE_WIN_PROCESS_THREADS_API
+#include <processthreadsapi.h>
+#endif
+#ifdef HAVE_WIN_TIME_API
+#include <timeapi.h>
+#endif
+#endif
+
+#define GST_CAT_DEFAULT clapper_app_utils_debug
+GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
+
+void
+clapper_app_utils_debug_init (void)
+{
+  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperapputils", 0,
+      "Clapper App Utils");
+}
+
+/* Windows specific functions */
+#ifdef G_OS_WIN32
+
+/*
+ * clapper_app_utils_win_enforce_hi_res_clock:
+ *
+ * Enforce high resolution clock by explicitly disabling Windows
+ * timer resolution power throttling. When disabled, system remembers
+ * and honors any previous timer resolution request by the process.
+ *
+ * By default, Windows 11 may automatically ignore the timer
+ * resolution requests in certain scenarios.
+ */
+void
+clapper_app_utils_win_enforce_hi_res_clock (void)
+{
+#ifdef HAVE_WIN_PROCESS_THREADS_API
+  PROCESS_POWER_THROTTLING_STATE PowerThrottling;
+  RtlZeroMemory (&PowerThrottling, sizeof (PowerThrottling));
+  gboolean success;
+
+  PowerThrottling.Version = PROCESS_POWER_THROTTLING_CURRENT_VERSION;
+  PowerThrottling.ControlMask = PROCESS_POWER_THROTTLING_IGNORE_TIMER_RESOLUTION;
+  PowerThrottling.StateMask = 0; // Always honor timer resolution requests
+
+  success = (gboolean) SetProcessInformation(
+      GetCurrentProcess (),
+      ProcessPowerThrottling,
+      &PowerThrottling,
+      sizeof (PowerThrottling));
+
+  /* Not an error. Older Windows does not have this functionality, but
+   * also honor hi-res clock by default anyway, so do not print then. */
+  GST_INFO ("Windows hi-res clock support is %senforced",
+      (success) ? "" : "NOT ");
+#endif
+}
+
+/*
+ * clapper_app_utils_win_hi_res_clock_start:
+ *
+ * Start Windows high resolution clock which will improve
+ * accuracy of various Windows timer APIs and precision
+ * of #GstSystemClock during playback.
+ *
+ * On Windows 10 version 2004 (and older), this function affects
+ * a global Windows setting. On any other (newer) version this
+ * will only affect a single process.
+ *
+ * Returns: Timer resolution period value.
+ */
+guint
+clapper_app_utils_win_hi_res_clock_start (void)
+{
+  guint resolution = 0;
+
+#ifdef HAVE_WIN_TIME_API
+  TIMECAPS time_caps;
+  MMRESULT res;
+
+  if ((res = timeGetDevCaps (&time_caps, sizeof (TIMECAPS))) != TIMERR_NOERROR) {
+    GST_WARNING ("Could not query timer resolution, code: %u", res);
+    return 0;
+  }
+
+  resolution = MIN (MAX (time_caps.wPeriodMin, 1), time_caps.wPeriodMax);
+
+  if ((res = timeBeginPeriod (resolution)) != TIMERR_NOERROR) {
+    GST_WARNING ("Could not request timer resolution, code: %u", res);
+    return 0;
+  }
+
+  GST_INFO ("Started Windows hi-res clock, precision: %ums", resolution);
+#endif
+
+  return resolution;
+}
+
+/*
+ * clapper_app_utils_win_hi_res_clock_stop:
+ * @resolution: started resolution value (non-zero)
+ *
+ * Stop previously started Microsoft Windows high resolution clock.
+ */
+void
+clapper_app_utils_win_hi_res_clock_stop (guint resolution)
+{
+#ifdef HAVE_WIN_TIME_API
+  MMRESULT res;
+
+  if ((res = timeEndPeriod (resolution)) == TIMERR_NOERROR)
+    GST_INFO ("Stopped Windows hi-res clock");
+  else
+    GST_ERROR ("Could not stop hi-res clock, code: %u", res);
+#endif
+}
+
+/* Extensions are used only on Windows */
 const gchar *const *
 clapper_app_utils_get_extensions (void)
 {
@@ -45,7 +161,7 @@ clapper_app_utils_get_subtitles_extensions (void)
 
   return subs_extensions;
 }
-#endif
+#endif // G_OS_WIN32
 
 const gchar *const *
 clapper_app_utils_get_mime_types (void)

src/bin/clapper-app/clapper-app-utils.h

@@ -26,7 +26,18 @@ G_BEGIN_DECLS
 
 typedef void (* ClapperAppUtilsIterRanks) (const gchar *feature_name, GstRank rank, gboolean from_env, gpointer user_data);
 
+void clapper_app_utils_debug_init (void);
+
 #ifdef G_OS_WIN32
+G_GNUC_INTERNAL
+void clapper_app_utils_win_enforce_hi_res_clock (void);
+
+G_GNUC_INTERNAL
+guint clapper_app_utils_win_hi_res_clock_start (void);
+
+G_GNUC_INTERNAL
+void clapper_app_utils_win_hi_res_clock_stop (guint resolution);
+
 G_GNUC_INTERNAL
 const gchar *const * clapper_app_utils_get_extensions (void);
 

src/bin/clapper-app/main.c

@@ -26,6 +26,7 @@
 
 #include "clapper-app-application.h"
 #include "clapper-app-types.h"
+#include "clapper-app-utils.h"
 
 gint
 main (gint argc, gchar **argv)
@@ -34,6 +35,10 @@ main (gint argc, gchar **argv)
   GApplication *application;
   gint status;
 
+#ifdef G_OS_WIN32
+  guint resolution = 0;
+#endif
+
   g_setenv ("GSK_RENDERER", "gl", FALSE);
 
   setlocale (LC_ALL, "");
@@ -48,13 +53,24 @@ main (gint argc, gchar **argv)
   adw_init ();
 
   clapper_app_types_init ();
+  clapper_app_utils_debug_init ();
 
   g_set_application_name ("Clapper");
 
+#ifdef G_OS_WIN32
+  clapper_app_utils_win_enforce_hi_res_clock ();
+  resolution = clapper_app_utils_win_hi_res_clock_start ();
+#endif
+
   application = clapper_app_application_new ();
 
   status = g_application_run (application, argc, argv);
   g_object_unref (application);
 
+#ifdef G_OS_WIN32
+  if (resolution > 0)
+    clapper_app_utils_win_hi_res_clock_stop (resolution);
+#endif
+
   return status;
 }

src/bin/clapper-app/meson.build

@@ -80,6 +80,22 @@ clapperapp_c_args = [
   '-DGST_USE_UNSTABLE_API',
 ]
 
+is_windows = ['windows'].contains(host_machine.system())
+
+if is_windows
+  clapperapp_c_args += ['-D_WIN32_WINNT=_WIN32_WINNT_WIN8']
+  kernel32_dep = cc.find_library('kernel32', required: false)
+  if kernel32_dep.found() and cc.has_header('processthreadsapi.h')
+    clapperapp_deps += kernel32_dep
+    clapperapp_c_args += ['-DHAVE_WIN_PROCESS_THREADS_API']
+  endif
+  winmm_dep = cc.find_library('winmm', required: false)
+  if winmm_dep.found() and cc.has_header('timeapi.h')
+    clapperapp_deps += winmm_dep
+    clapperapp_c_args += ['-DHAVE_WIN_TIME_API']
+  endif
+endif
+
 executable(
   meson.project_name(),
   clapperapp_sources,
@@ -90,7 +106,7 @@ executable(
   install_dir: bindir,
   win_subsystem: 'windows',
 )
-if ['windows'].contains(host_machine.system())
+if is_windows
   executable(
     meson.project_name() + '-console',
     clapperapp_sources,