Add sender controlled playout delay limits

webrtc/modules/video_coding/timing.h

Index: webrtc/modules/video_coding/timing.h
diff --git a/webrtc/modules/video_coding/timing.h b/webrtc/modules/video_coding/timing.h
index e593c9acbc35a7a1c3973d36a0274c161e880a84..85a3dd0ca0aa9d50dc1dc2e254a16df941ef4363 100644
--- a/webrtc/modules/video_coding/timing.h
+++ b/webrtc/modules/video_coding/timing.h
@@ -35,14 +35,23 @@ class VCMTiming {
   void ResetDecodeTime();
 
   // Set the amount of time needed to render an image. Defaults to 10 ms.
-  void set_render_delay(uint32_t render_delay_ms);
+  void set_render_delay(int render_delay_ms);
 
   // Set the minimum time the video must be delayed on the receiver to
   // get the desired jitter buffer level.
-  void SetJitterDelay(uint32_t required_delay_ms);
+  void SetJitterDelay(int required_delay_ms);
 
-  // Set the minimum playout delay required to sync video with audio.
-  void set_min_playout_delay(uint32_t min_playout_delay);
+  // Set the minimum playout delay from capture to render in ms.
+  void set_min_playout_delay(int min_playout_delay_ms);
+
+  // Returns the minimum playout delay from capture to render in ms.
+  int min_playout_delay();
+
+  // Set the maximum playout delay from capture to render in ms.
+  void set_max_playout_delay(int max_playout_delay_ms);
+
+  // Returns the maximum playout delay from capture to render in ms.
+  int max_playout_delay();
 
   // Increases or decreases the current delay to get closer to the target delay.
   // Calculates how long it has been since the previous call to this function,
@@ -77,7 +86,7 @@ class VCMTiming {
 
   // Returns the current target delay which is required delay + decode time +
   // render delay.
-  uint32_t TargetVideoDelay() const;
+  int TargetVideoDelay() const;
 
   // Calculates whether or not there is enough time to decode a frame given a
   // certain amount of processing time.
@@ -96,11 +105,10 @@ class VCMTiming {
   enum { kDelayMaxChangeMsPerS = 100 };
 
  protected:
-  int64_t RequiredDecodeTimeMs() const
-      EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  int RequiredDecodeTimeMs() const EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
   int64_t RenderTimeMsInternal(uint32_t frame_timestamp, int64_t now_ms) const
       EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
-  uint32_t TargetDelayInternal() const EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
+  int TargetDelayInternal() const EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
 
  private:
   void UpdateHistograms() const;
@@ -110,10 +118,16 @@ class VCMTiming {
   bool master_ GUARDED_BY(crit_sect_);
   TimestampExtrapolator* ts_extrapolator_ GUARDED_BY(crit_sect_);
   std::unique_ptr<VCMCodecTimer> codec_timer_ GUARDED_BY(crit_sect_);
-  uint32_t render_delay_ms_ GUARDED_BY(crit_sect_);
-  uint32_t min_playout_delay_ms_ GUARDED_BY(crit_sect_);
-  uint32_t jitter_delay_ms_ GUARDED_BY(crit_sect_);
-  uint32_t current_delay_ms_ GUARDED_BY(crit_sect_);
+  int render_delay_ms_ GUARDED_BY(crit_sect_);
+  // Best-effort playout delay range for frames from capture to render.
+  // The receiver tries to keep the delay between |min_playout_delay_ms_|
+  // and |max_playout_delay_ms_| taking the network jitter into account.
+  // A special case is where min_playout_delay_ms_ = max_playout_delay_ms_ = 0,
+  // in which case the receiver tries to play the frames as they arrive.
+  int min_playout_delay_ms_ GUARDED_BY(crit_sect_);
+  int max_playout_delay_ms_ GUARDED_BY(crit_sect_);
+  int jitter_delay_ms_ GUARDED_BY(crit_sect_);
+  int current_delay_ms_ GUARDED_BY(crit_sect_);
   int last_decode_ms_ GUARDED_BY(crit_sect_);
   uint32_t prev_frame_timestamp_ GUARDED_BY(crit_sect_);