Add max pre-decode queue size threshold for pacing
When pacing is enabled for the low latency rendering path,
frames are sent to the decoder in regular intervals. In case of a
jitter, these frames intervals could add up to create a large latency.
Hence, disable frame pacing if the pre-decode queue grows beyond the
threshold. The threshold for when to disable frame pacing is set
through a field trial. The default value is high enough so that
the behavior is not changed unless the field trial is specified.
Bug: chromium:1237402
Change-Id: I901fd579f68da286eca3d654118f60d3c55e21ce
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/228241
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Johannes Kron <kron@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34705}
diff --git a/modules/video_coding/frame_buffer2.h b/modules/video_coding/frame_buffer2.h
index 9226cc3..d46bb9a 100644
--- a/modules/video_coding/frame_buffer2.h
+++ b/modules/video_coding/frame_buffer2.h
@@ -25,6 +25,7 @@
#include "modules/video_coding/jitter_estimator.h"
#include "modules/video_coding/utility/decoded_frames_history.h"
#include "rtc_base/event.h"
+#include "rtc_base/experiments/field_trial_parser.h"
#include "rtc_base/experiments/rtt_mult_experiment.h"
#include "rtc_base/numerics/sequence_number_util.h"
#include "rtc_base/synchronization/mutex.h"
@@ -188,6 +189,13 @@
// rtt_mult experiment settings.
const absl::optional<RttMultExperiment::Settings> rtt_mult_settings_;
+
+ // Maximum number of frames in the decode queue to allow pacing. If the
+ // queue grows beyond the max limit, pacing will be disabled and frames will
+ // be pushed to the decoder as soon as possible. This only has an effect
+ // when the low-latency rendering path is active, which is indicated by
+ // the frame's render time == 0.
+ FieldTrialParameter<unsigned> zero_playout_delay_max_decode_queue_size_;
};
} // namespace video_coding