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Improve async source render timing

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This helps ensure that an asynchronous video source is played as close
to its framerate as possible, reduces the risk of duplication as
much as possible, and helps to ensure that playback is as smooth as
possible.
This commit is contained in:
jp9000 2014-09-12 00:41:56 -07:00
parent 52e08249f1
commit 11b0fe122c
1 changed files with 54 additions and 9 deletions
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63
libobs/obs-source.c
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@ -1501,9 +1501,14 @@ void obs_source_output_audio(obs_source_t source,
static inline bool frame_out_of_bounds(obs_source_t source, uint64_t ts)
{
return ((ts - source->last_frame_ts) > MAX_TIMESTAMP_JUMP);
if (ts < source->last_frame_ts)
return ((source->last_frame_ts - ts) > MAX_TIMESTAMP_JUMP);
else
return ((ts - source->last_frame_ts) > MAX_TIMESTAMP_JUMP);
}
/* #define DEBUG_ASYNC_FRAMES 1 */
static bool ready_async_frame(obs_source_t source, uint64_t sys_time)
{
struct obs_source_frame *next_frame = source->video_frames.array[0];
@ -1512,26 +1517,60 @@ static bool ready_async_frame(obs_source_t source, uint64_t sys_time)
uint64_t frame_time = next_frame->timestamp;
uint64_t frame_offset = 0;
#if DEBUG_ASYNC_FRAMES
blog(LOG_DEBUG, "source->last_frame_ts: %llu, frame_time: %llu, "
"sys_offset: %llu, frame_offset: %llu, "
"number of frames: %lu",
source->last_frame_ts, frame_time, sys_offset,
frame_time - source->last_frame_ts,
(unsigned long)source->video_frames.num);
#endif
/* account for timestamp invalidation */
if (frame_out_of_bounds(source, frame_time)) {
#if DEBUG_ASYNC_FRAMES
blog(LOG_DEBUG, "timing jump");
#endif
source->last_frame_ts = next_frame->timestamp;
return true;
} else {
frame_offset = frame_time - source->last_frame_ts;
source->last_frame_ts += frame_offset;
source->last_frame_ts += sys_offset;
}
while (frame_offset <= sys_offset) {
while (source->last_frame_ts > next_frame->timestamp) {
/* this tries to reduce the needless frame duplication, also
* helps smooth out async rendering to frame boundaries. In
* other words, tries to keep the framerate as smooth as
* possible */
if ((source->last_frame_ts - next_frame->timestamp) < 1000000)
break;
if (frame)
da_erase(source->video_frames, 0);
#if DEBUG_ASYNC_FRAMES
blog(LOG_DEBUG, "new frame, "
"source->last_frame_ts: %llu, "
"next_frame->timestamp: %llu",
source->last_frame_ts,
next_frame->timestamp);
#endif
obs_source_frame_destroy(frame);
if (source->video_frames.num == 1)
return true;
frame = next_frame;
da_erase(source->video_frames, 0);
next_frame = source->video_frames.array[0];
next_frame = source->video_frames.array[1];
/* more timestamp checking and compensating */
if ((next_frame->timestamp - frame_time) > MAX_TIMESTAMP_JUMP) {
#if DEBUG_ASYNC_FRAMES
blog(LOG_DEBUG, "timing jump");
#endif
source->last_frame_ts =
next_frame->timestamp - frame_offset;
}
@ -1540,7 +1579,10 @@ static bool ready_async_frame(obs_source_t source, uint64_t sys_time)
frame_offset = frame_time - source->last_frame_ts;
}
obs_source_frame_destroy(frame);
#if DEBUG_ASYNC_FRAMES
if (!frame)
blog(LOG_DEBUG, "no frame!");
#endif
return frame != NULL;
}
@ -1573,11 +1615,11 @@ struct obs_source_frame *obs_source_get_frame(obs_source_t source)
pthread_mutex_lock(&source->video_mutex);
sys_time = os_gettime_ns();
if (!source->video_frames.num)
goto unlock;
sys_time = os_gettime_ns();
if (!source->last_frame_ts) {
frame = source->video_frames.array[0];
da_erase(source->video_frames, 0);
@ -1589,13 +1631,16 @@ struct obs_source_frame *obs_source_get_frame(obs_source_t source)
/* reset timing to current system time */
if (frame) {
uint64_t min_expected_sys_ts =
frame->timestamp + source->timing_adjust;
source->timing_adjust = sys_time - frame->timestamp;
source->timing_set = true;
}
unlock:
source->last_sys_timestamp = sys_time;
unlock:
pthread_mutex_unlock(&source->video_mutex);
if (frame)