diff options
Diffstat (limited to 'video/out/opengl/oml_sync.c')
| -rw-r--r-- | video/out/opengl/oml_sync.c | 112 |
1 files changed, 0 insertions, 112 deletions
diff --git a/video/out/opengl/oml_sync.c b/video/out/opengl/oml_sync.c deleted file mode 100644 index 6efd4265d7..0000000000 --- a/video/out/opengl/oml_sync.c +++ /dev/null @@ -1,112 +0,0 @@ -#include <time.h> - -#include "osdep/timer.h" -#include "oml_sync.h" -#include "video/out/vo.h" - -// General nonsense about the associated extension. -// -// This extension returns two unrelated values: -// (ust, msc): clock time and incrementing counter of last vsync (this is -// reported continuously, even if we don't swap) -// sbc: swap counter of frame that was last displayed (every swap -// increments the user_sbc, and the reported sbc is the sbc -// of the frame that was just displayed) -// Invariants: -// - ust and msc change in lockstep (no value can change without the other) -// - msc is incremented; if you query it in a loop, and your thread isn't -// frozen or starved by the scheduler, it will usually either not change, or -// be incremented by 1 (while the ust will be incremented by vsync -// duration) -// - sbc is never higher than the user_sbc -// - (ust, msc) are equal to or higher by vsync increments than the display -// time of the frame referenced by the sbc -// Note that (ust, msc) and sbc are not locked to each other. The following -// can easily happen if vsync skips occur: -// - you draw a frame, in the meantime hardware swaps sbc_1 -// - another display vsync happens during drawing -// - you call swap() -// - query (ust, msc) and sbc -// - sbc contains sbc_1, but (ust, msc) contains the vsync after it -// As a consequence, it's hard to detect the latency or vsync skips. - -static void oml_sync_reset(struct oml_sync *oml) -{ - oml->vsync_duration = -1; - oml->last_skipped_vsyncs = -1; - oml->last_queue_display_time = -1; -} - -void oml_sync_swap(struct oml_sync *oml, int64_t ust, int64_t msc, int64_t sbc) -{ - if (!oml->state_ok) - oml_sync_reset(oml); - - oml->last_skipped_vsyncs = 0; - oml->user_sbc += 1; - - if (sbc < 0) - return; - - oml->state_ok = true; - - int64_t ust_passed = oml->last_ust ? ust - oml->last_ust : 0; - oml->last_ust = ust; - - int64_t msc_passed = oml->last_msc ? msc - oml->last_msc : 0; - oml->last_msc = msc; - - int64_t sbc_passed = sbc - oml->last_sbc; - oml->last_sbc = sbc; - - // Display frame duration. This makes assumptions about UST (see below). - if (msc_passed && ust_passed) - oml->vsync_duration = ust_passed / msc_passed; - - // Only if a new frame was displayed (sbc increased) we have sort-of a - // chance that the current (ust, msc) is for the sbc. But this is racy, - // because skipped frames drops could have increased the msc right after the - // display event and before we queried the values. This code hopes for the - // best and ignores this. - if (sbc_passed) { - // The GLX extension spec doesn't define what the UST is (not even its - // unit). Simply assume UST is a simple CLOCK_MONOTONIC usec value. This - // is what Mesa does, and what the Google EGL extension seems to imply - // (they mention CLOCK_MONOTONIC, but not the unit). - // The swap buffer call happened "some" but very small time ago, so we - // can get away with querying the current time. There is also the - // implicit assumption that mpv's timer and the UST use the same clock - // (which it does on POSIX). - struct timespec ts; - if (clock_gettime(CLOCK_MONOTONIC, &ts)) - return; - uint64_t now_monotonic = ts.tv_sec * 1000000LL + ts.tv_nsec / 1000; - uint64_t ust_mp_time = mp_time_us() - (now_monotonic - ust); - - // Assume this is exactly when the actual display event for this sbc - // happened. This is subject to the race mentioned above. - oml->last_sbc_mp_time = ust_mp_time; - } - - // At least one frame needs to be actually displayed before - // oml->last_sbc_mp_time is set. - if (!sbc) - return; - - // Extrapolate from the last sbc time (when a frame was actually displayed), - // and by adding the number of frames that were queued since to it. - // For every unit the sbc is smaller than user_sbc, the actual display - // is one frame ahead (assumes oml_sync_swap() is called for every - // vsync). - oml->last_queue_display_time = - oml->last_sbc_mp_time + (oml->user_sbc - sbc) * oml->vsync_duration; -} - -void oml_sync_get_info(struct oml_sync *oml, struct vo_vsync_info *info) -{ - if (!oml->state_ok) - oml_sync_reset(oml); - info->vsync_duration = oml->vsync_duration; - info->skipped_vsyncs = oml->last_skipped_vsyncs; - info->last_queue_display_time = oml->last_queue_display_time; -} |