timer: teach it about nanoseconds

Those changes will alow to change vsync base to more precise time base.
In general there is no reason to truncate values returned by system.

audio/out/ao_audiotrack.c

@@ -372,7 +372,7 @@ static uint32_t AudioTrack_getPlaybackHeadPosition(struct ao *ao)
         return 0;
     JNIEnv *env = MP_JNI_GET_ENV(ao);
     uint32_t pos = 0;
-    int64_t now = mp_raw_time_us() * 1000;
+    int64_t now = mp_raw_time_ns();
     int state = MP_JNI_CALL_INT(p->audiotrack, AudioTrack.getPlayState);
 
     int stable_count = 20;

osdep/timer-darwin.c

@@ -26,18 +26,18 @@
 #include "common/msg.h"
 #include "timer.h"
 
-static double timebase_ratio;
+static double timebase_ratio_ns;
 
 void mp_sleep_us(int64_t us)
 {
-    uint64_t deadline = us / 1e6 / timebase_ratio + mach_absolute_time();
+    uint64_t deadline = us * 1e3 / timebase_ratio_ns + mach_absolute_time();
 
     mach_wait_until(deadline);
 }
 
-uint64_t mp_raw_time_us(void)
+uint64_t mp_raw_time_ns(void)
 {
-    return mach_absolute_time() * timebase_ratio * 1e6;
+    return mach_absolute_time() * timebase_ratio_ns;
 }
 
 void mp_raw_time_init(void)
@@ -45,5 +45,5 @@ void mp_raw_time_init(void)
     struct mach_timebase_info timebase;
 
     mach_timebase_info(&timebase);
-    timebase_ratio = (double)timebase.numer / (double)timebase.denom * 1e-9;
+    timebase_ratio_ns = (double)timebase.numer / (double)timebase.denom;
 }

osdep/timer-linux.c

@@ -18,10 +18,8 @@
  * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <unistd.h>
 #include <stdlib.h>
 #include <time.h>
-#include <sys/time.h>
 #include "timer.h"
 
 void mp_sleep_us(int64_t us)
@@ -34,22 +32,16 @@ void mp_sleep_us(int64_t us)
     nanosleep(&ts, NULL);
 }
 
-#if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0 && defined(CLOCK_MONOTONIC)
-uint64_t mp_raw_time_us(void)
+uint64_t mp_raw_time_ns(void)
 {
-    struct timespec ts;
-    if (clock_gettime(CLOCK_MONOTONIC, &ts))
-        abort();
-    return ts.tv_sec * 1000000LL + ts.tv_nsec / 1000;
-}
+    struct timespec tp = {0};
+#if defined(CLOCK_MONOTONIC_RAW)
+    clock_gettime(CLOCK_MONOTONIC_RAW, &tp);
 #else
-uint64_t mp_raw_time_us(void)
-{
-    struct timeval tv;
-    gettimeofday(&tv,NULL);
-    return tv.tv_sec * 1000000LL + tv.tv_usec;
-}
+    timespec_get(&tp, TIME_UTC);
 #endif
+    return tp.tv_sec * UINT64_C(1000000000) + tp.tv_nsec;
+}
 
 void mp_raw_time_init(void)
 {

osdep/timer-win2.c

@@ -66,16 +66,16 @@ void mp_sleep_us(int64_t us)
     mp_end_hires_timers(hrt);
 }
 
-uint64_t mp_raw_time_us(void)
+uint64_t mp_raw_time_ns(void)
 {
     LARGE_INTEGER perf_count;
     QueryPerformanceCounter(&perf_count);
 
-    // Convert QPC units (1/perf_freq seconds) to microseconds. This will work
+    // Convert QPC units (1/perf_freq seconds) to nanoseconds. This will work
     // without overflow because the QPC value is guaranteed not to roll-over
     // within 100 years, so perf_freq must be less than 2.9*10^9.
-    return perf_count.QuadPart / perf_freq.QuadPart * 1000000 +
-        perf_count.QuadPart % perf_freq.QuadPart * 1000000 / perf_freq.QuadPart;
+    return perf_count.QuadPart / perf_freq.QuadPart * UINT64_C(1000000000) +
+        perf_count.QuadPart % perf_freq.QuadPart * UINT64_C(1000000000) / perf_freq.QuadPart;
 }
 
 void mp_raw_time_init(void)

osdep/timer.c

@@ -34,8 +34,8 @@ static pthread_once_t timer_init_once = PTHREAD_ONCE_INIT;
 static void do_timer_init(void)
 {
     mp_raw_time_init();
-    mp_rand_seed(mp_raw_time_us());
-    raw_time_offset = mp_raw_time_us();
+    mp_rand_seed(mp_raw_time_ns());
+    raw_time_offset = mp_raw_time_ns();
     // Arbitrary additional offset to avoid confusing relative/absolute times.
     // Also,we rule that the timer never returns 0 (so default-initialized
     // time values will be always in the past).
@@ -49,7 +49,12 @@ void mp_time_init(void)
 
 int64_t mp_time_us(void)
 {
-    int64_t r = mp_raw_time_us() - raw_time_offset;
+    return mp_time_ns() / 1000;
+}
+
+int64_t mp_time_ns(void)
+{
+    uint64_t r = mp_raw_time_ns() - raw_time_offset;
     if (r < MP_START_TIME)
         r = MP_START_TIME;
     return r;
@@ -57,13 +62,13 @@ int64_t mp_time_us(void)
 
 double mp_time_sec(void)
 {
-    return mp_time_us() / (double)(1000 * 1000);
+    return mp_time_ns() / 1e9;
 }
 
 int64_t mp_time_us_add(int64_t time_us, double timeout_sec)
 {
     assert(time_us > 0); // mp_time_us() returns strictly positive values
-    double t = MPCLAMP(timeout_sec * (1000 * 1000), -0x1p63, 0x1p63);
+    double t = MPCLAMP(timeout_sec * 1e6, -0x1p63, 0x1p63);
     int64_t ti = t == 0x1p63 ? INT64_MAX : (int64_t)t;
     if (ti > INT64_MAX - time_us)
         return INT64_MAX;
@@ -72,6 +77,18 @@ int64_t mp_time_us_add(int64_t time_us, double timeout_sec)
     return time_us + ti;
 }
 
+int64_t mp_time_ns_add(int64_t time_ns, double timeout_sec)
+{
+    assert(time_ns > 0); // mp_time_ns() returns strictly positive values
+    double t = MPCLAMP(timeout_sec * 1e9, -0x1p63, 0x1p63);
+    int64_t ti = t == 0x1p63 ? INT64_MAX : (int64_t)t;
+    if (ti > INT64_MAX - time_ns)
+        return INT64_MAX;
+    if (ti <= -time_ns)
+        return 1;
+    return time_ns + ti;
+}
+
 static int get_realtime(struct timespec *out_ts)
 {
 #if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
@@ -87,16 +104,18 @@ static int get_realtime(struct timespec *out_ts)
 }
 
 struct timespec mp_time_us_to_realtime(int64_t time_us)
+{
+    return mp_time_ns_to_realtime(MPMIN(INT64_MAX / 1000, time_us) * 1000);
+}
+
+struct timespec mp_time_ns_to_realtime(int64_t time_ns)
 {
     struct timespec ts = {0};
     if (get_realtime(&ts) != 0)
         return ts;
 
-    int64_t time_ns = MPMIN(INT64_MAX / 1000, time_us) * 1000;
-    int64_t time_now = mp_time_us() * 1000;
-
     // clamp to 1000 days in the future
-    int64_t time_rel = MPMIN(time_now - time_ns,
+    int64_t time_rel = MPMIN(mp_time_ns() - time_ns,
                              1000 * 24 * 60 * 60 * INT64_C(1000000000));
     ts.tv_sec += time_rel / INT64_C(1000000000);
     ts.tv_nsec += time_rel % INT64_C(1000000000);
@@ -111,5 +130,5 @@ struct timespec mp_time_us_to_realtime(int64_t time_us)
 
 struct timespec mp_rel_time_to_timespec(double timeout_sec)
 {
-    return mp_time_us_to_realtime(mp_time_us_add(mp_time_us(), timeout_sec));
+    return mp_time_ns_to_realtime(mp_time_ns_add(mp_time_ns(), timeout_sec));
 }

osdep/timer.h

@@ -26,13 +26,16 @@ void mp_time_init(void);
 // Return time in microseconds. Never wraps. Never returns 0 or negative values.
 int64_t mp_time_us(void);
 
+// Return time in nanoseconds. Never wraps. Never returns 0 or negative values.
+int64_t mp_time_ns(void);
+
 // Return time in seconds. Can have down to 1 microsecond resolution, but will
 // be much worse when casted to float.
 double mp_time_sec(void);
 
 // Provided by OS specific functions (timer-linux.c)
 void mp_raw_time_init(void);
-uint64_t mp_raw_time_us(void);
+uint64_t mp_raw_time_ns(void);
 
 // Sleep in microseconds.
 void mp_sleep_us(int64_t us);
@@ -54,9 +57,16 @@ void mp_end_hires_timers(int resolution_ms);
 // Takes care of possible overflows. Never returns a negative or 0 time.
 int64_t mp_time_us_add(int64_t time_us, double timeout_sec);
 
+// Add a time in seconds to the given time in nanoseconds, and return it.
+// Takes care of possible overflows. Never returns a negative or 0 time.
+int64_t mp_time_ns_add(int64_t time_ns, double timeout_sec);
+
 // Convert the mp time in microseconds to a timespec using CLOCK_REALTIME.
 struct timespec mp_time_us_to_realtime(int64_t time_us);
 
+// Convert the mp time in nanoseconds to a timespec using CLOCK_REALTIME.
+struct timespec mp_time_ns_to_realtime(int64_t time_ns);
+
 // Convert the relative timeout in seconds to a timespec.
 // The timespec is absolute, using CLOCK_REALTIME.
 struct timespec mp_rel_time_to_timespec(double timeout_sec);