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      1 /*
      2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef WEBRTC_MODULES_VIDEO_CODING_MAIN_SOURCE_TIMING_H_
     12 #define WEBRTC_MODULES_VIDEO_CODING_MAIN_SOURCE_TIMING_H_
     13 
     14 #include "webrtc/base/thread_annotations.h"
     15 #include "webrtc/modules/video_coding/main/source/codec_timer.h"
     16 #include "webrtc/system_wrappers/interface/critical_section_wrapper.h"
     17 #include "webrtc/typedefs.h"
     18 
     19 namespace webrtc {
     20 
     21 class Clock;
     22 class TimestampExtrapolator;
     23 
     24 class VCMTiming {
     25  public:
     26   // The primary timing component should be passed
     27   // if this is the dual timing component.
     28   VCMTiming(Clock* clock,
     29             VCMTiming* master_timing = NULL);
     30   ~VCMTiming();
     31 
     32   // Resets the timing to the initial state.
     33   void Reset();
     34   void ResetDecodeTime();
     35 
     36   // Set the amount of time needed to render an image. Defaults to 10 ms.
     37   void set_render_delay(uint32_t render_delay_ms);
     38 
     39   // Set the minimum time the video must be delayed on the receiver to
     40   // get the desired jitter buffer level.
     41   void SetJitterDelay(uint32_t required_delay_ms);
     42 
     43   // Set the minimum playout delay required to sync video with audio.
     44   void set_min_playout_delay(uint32_t min_playout_delay);
     45 
     46   // Increases or decreases the current delay to get closer to the target delay.
     47   // Calculates how long it has been since the previous call to this function,
     48   // and increases/decreases the delay in proportion to the time difference.
     49   void UpdateCurrentDelay(uint32_t frame_timestamp);
     50 
     51   // Increases or decreases the current delay to get closer to the target delay.
     52   // Given the actual decode time in ms and the render time in ms for a frame,
     53   // this function calculates how late the frame is and increases the delay
     54   // accordingly.
     55   void UpdateCurrentDelay(int64_t render_time_ms,
     56                           int64_t actual_decode_time_ms);
     57 
     58   // Stops the decoder timer, should be called when the decoder returns a frame
     59   // or when the decoded frame callback is called.
     60   int32_t StopDecodeTimer(uint32_t time_stamp,
     61                           int64_t start_time_ms,
     62                           int64_t now_ms);
     63 
     64   // Used to report that a frame is passed to decoding. Updates the timestamp
     65   // filter which is used to map between timestamps and receiver system time.
     66   void IncomingTimestamp(uint32_t time_stamp, int64_t last_packet_time_ms);
     67   // Returns the receiver system time when the frame with timestamp
     68   // frame_timestamp should be rendered, assuming that the system time currently
     69   // is now_ms.
     70   int64_t RenderTimeMs(uint32_t frame_timestamp, int64_t now_ms) const;
     71 
     72   // Returns the maximum time in ms that we can wait for a frame to become
     73   // complete before we must pass it to the decoder.
     74   uint32_t MaxWaitingTime(int64_t render_time_ms, int64_t now_ms) const;
     75 
     76   // Returns the current target delay which is required delay + decode time +
     77   // render delay.
     78   uint32_t TargetVideoDelay() const;
     79 
     80   // Calculates whether or not there is enough time to decode a frame given a
     81   // certain amount of processing time.
     82   bool EnoughTimeToDecode(uint32_t available_processing_time_ms) const;
     83 
     84   // Return current timing information.
     85   void GetTimings(int* decode_ms,
     86                   int* max_decode_ms,
     87                   int* current_delay_ms,
     88                   int* target_delay_ms,
     89                   int* jitter_buffer_ms,
     90                   int* min_playout_delay_ms,
     91                   int* render_delay_ms) const;
     92 
     93   enum { kDefaultRenderDelayMs = 10 };
     94   enum { kDelayMaxChangeMsPerS = 100 };
     95 
     96  protected:
     97   int32_t MaxDecodeTimeMs(FrameType frame_type = kVideoFrameDelta) const
     98       EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
     99   int64_t RenderTimeMsInternal(uint32_t frame_timestamp, int64_t now_ms) const
    100       EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
    101   uint32_t TargetDelayInternal() const EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
    102 
    103  private:
    104   CriticalSectionWrapper* crit_sect_;
    105   Clock* const clock_;
    106   bool master_ GUARDED_BY(crit_sect_);
    107   TimestampExtrapolator* ts_extrapolator_ GUARDED_BY(crit_sect_);
    108   VCMCodecTimer codec_timer_ GUARDED_BY(crit_sect_);
    109   uint32_t render_delay_ms_ GUARDED_BY(crit_sect_);
    110   uint32_t min_playout_delay_ms_ GUARDED_BY(crit_sect_);
    111   uint32_t jitter_delay_ms_ GUARDED_BY(crit_sect_);
    112   uint32_t current_delay_ms_ GUARDED_BY(crit_sect_);
    113   int last_decode_ms_ GUARDED_BY(crit_sect_);
    114   uint32_t prev_frame_timestamp_ GUARDED_BY(crit_sect_);
    115 };
    116 }  // namespace webrtc
    117 
    118 #endif  // WEBRTC_MODULES_VIDEO_CODING_MAIN_SOURCE_TIMING_H_
    119