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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 #include "webrtc/modules/video_coding/main/source/timing.h"
     12 
     13 #include "webrtc/modules/video_coding/main/source/internal_defines.h"
     14 #include "webrtc/modules/video_coding/main/source/jitter_buffer_common.h"
     15 #include "webrtc/system_wrappers/interface/clock.h"
     16 #include "webrtc/system_wrappers/interface/timestamp_extrapolator.h"
     17 
     18 
     19 namespace webrtc {
     20 
     21 VCMTiming::VCMTiming(Clock* clock,
     22                      VCMTiming* master_timing)
     23     : crit_sect_(CriticalSectionWrapper::CreateCriticalSection()),
     24       clock_(clock),
     25       master_(false),
     26       ts_extrapolator_(),
     27       codec_timer_(),
     28       render_delay_ms_(kDefaultRenderDelayMs),
     29       min_playout_delay_ms_(0),
     30       jitter_delay_ms_(0),
     31       current_delay_ms_(0),
     32       last_decode_ms_(0),
     33       prev_frame_timestamp_(0) {
     34   if (master_timing == NULL) {
     35     master_ = true;
     36     ts_extrapolator_ = new TimestampExtrapolator(clock_->TimeInMilliseconds());
     37   } else {
     38     ts_extrapolator_ = master_timing->ts_extrapolator_;
     39   }
     40 }
     41 
     42 VCMTiming::~VCMTiming() {
     43   if (master_) {
     44     delete ts_extrapolator_;
     45   }
     46   delete crit_sect_;
     47 }
     48 
     49 void VCMTiming::Reset() {
     50   CriticalSectionScoped cs(crit_sect_);
     51   ts_extrapolator_->Reset(clock_->TimeInMilliseconds());
     52   codec_timer_.Reset();
     53   render_delay_ms_ = kDefaultRenderDelayMs;
     54   min_playout_delay_ms_ = 0;
     55   jitter_delay_ms_ = 0;
     56   current_delay_ms_ = 0;
     57   prev_frame_timestamp_ = 0;
     58 }
     59 
     60 void VCMTiming::ResetDecodeTime() {
     61   CriticalSectionScoped lock(crit_sect_);
     62   codec_timer_.Reset();
     63 }
     64 
     65 void VCMTiming::set_render_delay(uint32_t render_delay_ms) {
     66   CriticalSectionScoped cs(crit_sect_);
     67   render_delay_ms_ = render_delay_ms;
     68 }
     69 
     70 void VCMTiming::set_min_playout_delay(uint32_t min_playout_delay_ms) {
     71   CriticalSectionScoped cs(crit_sect_);
     72   min_playout_delay_ms_ = min_playout_delay_ms;
     73 }
     74 
     75 void VCMTiming::SetJitterDelay(uint32_t jitter_delay_ms) {
     76   CriticalSectionScoped cs(crit_sect_);
     77   if (jitter_delay_ms != jitter_delay_ms_) {
     78     jitter_delay_ms_ = jitter_delay_ms;
     79     // When in initial state, set current delay to minimum delay.
     80     if (current_delay_ms_ == 0) {
     81       current_delay_ms_ = jitter_delay_ms_;
     82     }
     83   }
     84 }
     85 
     86 void VCMTiming::UpdateCurrentDelay(uint32_t frame_timestamp) {
     87   CriticalSectionScoped cs(crit_sect_);
     88   uint32_t target_delay_ms = TargetDelayInternal();
     89 
     90   if (current_delay_ms_ == 0) {
     91     // Not initialized, set current delay to target.
     92     current_delay_ms_ = target_delay_ms;
     93   } else if (target_delay_ms != current_delay_ms_) {
     94     int64_t delay_diff_ms = static_cast<int64_t>(target_delay_ms) -
     95         current_delay_ms_;
     96     // Never change the delay with more than 100 ms every second. If we're
     97     // changing the delay in too large steps we will get noticeable freezes. By
     98     // limiting the change we can increase the delay in smaller steps, which
     99     // will be experienced as the video is played in slow motion. When lowering
    100     // the delay the video will be played at a faster pace.
    101     int64_t max_change_ms = 0;
    102     if (frame_timestamp < 0x0000ffff && prev_frame_timestamp_ > 0xffff0000) {
    103       // wrap
    104       max_change_ms = kDelayMaxChangeMsPerS * (frame_timestamp +
    105           (static_cast<int64_t>(1) << 32) - prev_frame_timestamp_) / 90000;
    106     } else {
    107       max_change_ms = kDelayMaxChangeMsPerS *
    108           (frame_timestamp - prev_frame_timestamp_) / 90000;
    109     }
    110     if (max_change_ms <= 0) {
    111       // Any changes less than 1 ms are truncated and
    112       // will be postponed. Negative change will be due
    113       // to reordering and should be ignored.
    114       return;
    115     }
    116     delay_diff_ms = std::max(delay_diff_ms, -max_change_ms);
    117     delay_diff_ms = std::min(delay_diff_ms, max_change_ms);
    118 
    119     current_delay_ms_ = current_delay_ms_ + static_cast<int32_t>(delay_diff_ms);
    120   }
    121   prev_frame_timestamp_ = frame_timestamp;
    122 }
    123 
    124 void VCMTiming::UpdateCurrentDelay(int64_t render_time_ms,
    125                                    int64_t actual_decode_time_ms) {
    126   CriticalSectionScoped cs(crit_sect_);
    127   uint32_t target_delay_ms = TargetDelayInternal();
    128   int64_t delayed_ms = actual_decode_time_ms -
    129       (render_time_ms - MaxDecodeTimeMs() - render_delay_ms_);
    130   if (delayed_ms < 0) {
    131     return;
    132   }
    133   if (current_delay_ms_ + delayed_ms <= target_delay_ms) {
    134     current_delay_ms_ += static_cast<uint32_t>(delayed_ms);
    135   } else {
    136     current_delay_ms_ = target_delay_ms;
    137   }
    138 }
    139 
    140 int32_t VCMTiming::StopDecodeTimer(uint32_t time_stamp,
    141                                    int64_t start_time_ms,
    142                                    int64_t now_ms) {
    143   CriticalSectionScoped cs(crit_sect_);
    144   int32_t time_diff_ms = codec_timer_.StopTimer(start_time_ms, now_ms);
    145   assert(time_diff_ms >= 0);
    146   last_decode_ms_ = time_diff_ms;
    147   return 0;
    148 }
    149 
    150 void VCMTiming::IncomingTimestamp(uint32_t time_stamp, int64_t now_ms) {
    151   CriticalSectionScoped cs(crit_sect_);
    152   ts_extrapolator_->Update(now_ms, time_stamp);
    153 }
    154 
    155 int64_t VCMTiming::RenderTimeMs(uint32_t frame_timestamp, int64_t now_ms)
    156     const {
    157   CriticalSectionScoped cs(crit_sect_);
    158   const int64_t render_time_ms = RenderTimeMsInternal(frame_timestamp, now_ms);
    159   return render_time_ms;
    160 }
    161 
    162 int64_t VCMTiming::RenderTimeMsInternal(uint32_t frame_timestamp,
    163                                         int64_t now_ms) const {
    164   int64_t estimated_complete_time_ms =
    165     ts_extrapolator_->ExtrapolateLocalTime(frame_timestamp);
    166   if (estimated_complete_time_ms == -1) {
    167     estimated_complete_time_ms = now_ms;
    168   }
    169 
    170   // Make sure that we have at least the playout delay.
    171   uint32_t actual_delay = std::max(current_delay_ms_, min_playout_delay_ms_);
    172   return estimated_complete_time_ms + actual_delay;
    173 }
    174 
    175 // Must be called from inside a critical section.
    176 int32_t VCMTiming::MaxDecodeTimeMs(FrameType frame_type /*= kVideoFrameDelta*/)
    177     const {
    178   const int32_t decode_time_ms = codec_timer_.RequiredDecodeTimeMs(frame_type);
    179   assert(decode_time_ms >= 0);
    180   return decode_time_ms;
    181 }
    182 
    183 uint32_t VCMTiming::MaxWaitingTime(int64_t render_time_ms, int64_t now_ms)
    184     const {
    185   CriticalSectionScoped cs(crit_sect_);
    186 
    187   const int64_t max_wait_time_ms = render_time_ms - now_ms -
    188       MaxDecodeTimeMs() - render_delay_ms_;
    189 
    190   if (max_wait_time_ms < 0) {
    191     return 0;
    192   }
    193   return static_cast<uint32_t>(max_wait_time_ms);
    194 }
    195 
    196 bool VCMTiming::EnoughTimeToDecode(uint32_t available_processing_time_ms)
    197     const {
    198   CriticalSectionScoped cs(crit_sect_);
    199   int32_t max_decode_time_ms = MaxDecodeTimeMs();
    200   if (max_decode_time_ms < 0) {
    201     // Haven't decoded any frames yet, try decoding one to get an estimate
    202     // of the decode time.
    203     return true;
    204   } else if (max_decode_time_ms == 0) {
    205     // Decode time is less than 1, set to 1 for now since
    206     // we don't have any better precision. Count ticks later?
    207     max_decode_time_ms = 1;
    208   }
    209   return static_cast<int32_t>(available_processing_time_ms) -
    210       max_decode_time_ms > 0;
    211 }
    212 
    213 uint32_t VCMTiming::TargetVideoDelay() const {
    214   CriticalSectionScoped cs(crit_sect_);
    215   return TargetDelayInternal();
    216 }
    217 
    218 uint32_t VCMTiming::TargetDelayInternal() const {
    219   return std::max(min_playout_delay_ms_,
    220       jitter_delay_ms_ + MaxDecodeTimeMs() + render_delay_ms_);
    221 }
    222 
    223 void VCMTiming::GetTimings(int* decode_ms,
    224                            int* max_decode_ms,
    225                            int* current_delay_ms,
    226                            int* target_delay_ms,
    227                            int* jitter_buffer_ms,
    228                            int* min_playout_delay_ms,
    229                            int* render_delay_ms) const {
    230   CriticalSectionScoped cs(crit_sect_);
    231   *decode_ms = last_decode_ms_;
    232   *max_decode_ms = MaxDecodeTimeMs();
    233   *current_delay_ms = current_delay_ms_;
    234   *target_delay_ms = TargetDelayInternal();
    235   *jitter_buffer_ms = jitter_delay_ms_;
    236   *min_playout_delay_ms = min_playout_delay_ms_;
    237   *render_delay_ms = render_delay_ms_;
    238 }
    239 
    240 }  // namespace webrtc
    241