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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/timing.h"
     12 
     13 #include <algorithm>
     14 
     15 #include "webrtc/modules/video_coding/internal_defines.h"
     16 #include "webrtc/modules/video_coding/jitter_buffer_common.h"
     17 #include "webrtc/system_wrappers/include/clock.h"
     18 #include "webrtc/system_wrappers/include/metrics.h"
     19 #include "webrtc/system_wrappers/include/timestamp_extrapolator.h"
     20 
     21 namespace webrtc {
     22 
     23 VCMTiming::VCMTiming(Clock* clock, VCMTiming* master_timing)
     24     : crit_sect_(CriticalSectionWrapper::CreateCriticalSection()),
     25       clock_(clock),
     26       master_(false),
     27       ts_extrapolator_(),
     28       codec_timer_(),
     29       render_delay_ms_(kDefaultRenderDelayMs),
     30       min_playout_delay_ms_(0),
     31       jitter_delay_ms_(0),
     32       current_delay_ms_(0),
     33       last_decode_ms_(0),
     34       prev_frame_timestamp_(0),
     35       num_decoded_frames_(0),
     36       num_delayed_decoded_frames_(0),
     37       first_decoded_frame_ms_(-1),
     38       sum_missed_render_deadline_ms_(0) {
     39   if (master_timing == NULL) {
     40     master_ = true;
     41     ts_extrapolator_ = new TimestampExtrapolator(clock_->TimeInMilliseconds());
     42   } else {
     43     ts_extrapolator_ = master_timing->ts_extrapolator_;
     44   }
     45 }
     46 
     47 VCMTiming::~VCMTiming() {
     48   UpdateHistograms();
     49   if (master_) {
     50     delete ts_extrapolator_;
     51   }
     52   delete crit_sect_;
     53 }
     54 
     55 void VCMTiming::UpdateHistograms() const {
     56   CriticalSectionScoped cs(crit_sect_);
     57   if (num_decoded_frames_ == 0) {
     58     return;
     59   }
     60   int64_t elapsed_sec =
     61       (clock_->TimeInMilliseconds() - first_decoded_frame_ms_) / 1000;
     62   if (elapsed_sec < metrics::kMinRunTimeInSeconds) {
     63     return;
     64   }
     65   RTC_HISTOGRAM_COUNTS_SPARSE_100(
     66       "WebRTC.Video.DecodedFramesPerSecond",
     67       static_cast<int>((num_decoded_frames_ / elapsed_sec) + 0.5f));
     68   RTC_HISTOGRAM_PERCENTAGE_SPARSE(
     69       "WebRTC.Video.DelayedFramesToRenderer",
     70       num_delayed_decoded_frames_ * 100 / num_decoded_frames_);
     71   if (num_delayed_decoded_frames_ > 0) {
     72     RTC_HISTOGRAM_COUNTS_SPARSE_1000(
     73         "WebRTC.Video.DelayedFramesToRenderer_AvgDelayInMs",
     74         sum_missed_render_deadline_ms_ / num_delayed_decoded_frames_);
     75   }
     76 }
     77 
     78 void VCMTiming::Reset() {
     79   CriticalSectionScoped cs(crit_sect_);
     80   ts_extrapolator_->Reset(clock_->TimeInMilliseconds());
     81   codec_timer_.Reset();
     82   render_delay_ms_ = kDefaultRenderDelayMs;
     83   min_playout_delay_ms_ = 0;
     84   jitter_delay_ms_ = 0;
     85   current_delay_ms_ = 0;
     86   prev_frame_timestamp_ = 0;
     87 }
     88 
     89 void VCMTiming::ResetDecodeTime() {
     90   CriticalSectionScoped lock(crit_sect_);
     91   codec_timer_.Reset();
     92 }
     93 
     94 void VCMTiming::set_render_delay(uint32_t render_delay_ms) {
     95   CriticalSectionScoped cs(crit_sect_);
     96   render_delay_ms_ = render_delay_ms;
     97 }
     98 
     99 void VCMTiming::set_min_playout_delay(uint32_t min_playout_delay_ms) {
    100   CriticalSectionScoped cs(crit_sect_);
    101   min_playout_delay_ms_ = min_playout_delay_ms;
    102 }
    103 
    104 void VCMTiming::SetJitterDelay(uint32_t jitter_delay_ms) {
    105   CriticalSectionScoped cs(crit_sect_);
    106   if (jitter_delay_ms != jitter_delay_ms_) {
    107     jitter_delay_ms_ = jitter_delay_ms;
    108     // When in initial state, set current delay to minimum delay.
    109     if (current_delay_ms_ == 0) {
    110       current_delay_ms_ = jitter_delay_ms_;
    111     }
    112   }
    113 }
    114 
    115 void VCMTiming::UpdateCurrentDelay(uint32_t frame_timestamp) {
    116   CriticalSectionScoped cs(crit_sect_);
    117   uint32_t target_delay_ms = TargetDelayInternal();
    118 
    119   if (current_delay_ms_ == 0) {
    120     // Not initialized, set current delay to target.
    121     current_delay_ms_ = target_delay_ms;
    122   } else if (target_delay_ms != current_delay_ms_) {
    123     int64_t delay_diff_ms =
    124         static_cast<int64_t>(target_delay_ms) - current_delay_ms_;
    125     // Never change the delay with more than 100 ms every second. If we're
    126     // changing the delay in too large steps we will get noticeable freezes. By
    127     // limiting the change we can increase the delay in smaller steps, which
    128     // will be experienced as the video is played in slow motion. When lowering
    129     // the delay the video will be played at a faster pace.
    130     int64_t max_change_ms = 0;
    131     if (frame_timestamp < 0x0000ffff && prev_frame_timestamp_ > 0xffff0000) {
    132       // wrap
    133       max_change_ms = kDelayMaxChangeMsPerS *
    134                       (frame_timestamp + (static_cast<int64_t>(1) << 32) -
    135                        prev_frame_timestamp_) /
    136                       90000;
    137     } else {
    138       max_change_ms = kDelayMaxChangeMsPerS *
    139                       (frame_timestamp - prev_frame_timestamp_) / 90000;
    140     }
    141     if (max_change_ms <= 0) {
    142       // Any changes less than 1 ms are truncated and
    143       // will be postponed. Negative change will be due
    144       // to reordering and should be ignored.
    145       return;
    146     }
    147     delay_diff_ms = std::max(delay_diff_ms, -max_change_ms);
    148     delay_diff_ms = std::min(delay_diff_ms, max_change_ms);
    149 
    150     current_delay_ms_ = current_delay_ms_ + static_cast<int32_t>(delay_diff_ms);
    151   }
    152   prev_frame_timestamp_ = frame_timestamp;
    153 }
    154 
    155 void VCMTiming::UpdateCurrentDelay(int64_t render_time_ms,
    156                                    int64_t actual_decode_time_ms) {
    157   CriticalSectionScoped cs(crit_sect_);
    158   uint32_t target_delay_ms = TargetDelayInternal();
    159   int64_t delayed_ms = actual_decode_time_ms -
    160                        (render_time_ms - MaxDecodeTimeMs() - render_delay_ms_);
    161   if (delayed_ms < 0) {
    162     return;
    163   }
    164   if (current_delay_ms_ + delayed_ms <= target_delay_ms) {
    165     current_delay_ms_ += static_cast<uint32_t>(delayed_ms);
    166   } else {
    167     current_delay_ms_ = target_delay_ms;
    168   }
    169 }
    170 
    171 int32_t VCMTiming::StopDecodeTimer(uint32_t time_stamp,
    172                                    int32_t decode_time_ms,
    173                                    int64_t now_ms,
    174                                    int64_t render_time_ms) {
    175   CriticalSectionScoped cs(crit_sect_);
    176   codec_timer_.MaxFilter(decode_time_ms, now_ms);
    177   assert(decode_time_ms >= 0);
    178   last_decode_ms_ = decode_time_ms;
    179 
    180   // Update stats.
    181   ++num_decoded_frames_;
    182   if (num_decoded_frames_ == 1) {
    183     first_decoded_frame_ms_ = now_ms;
    184   }
    185   int time_until_rendering_ms = render_time_ms - render_delay_ms_ - now_ms;
    186   if (time_until_rendering_ms < 0) {
    187     sum_missed_render_deadline_ms_ += -time_until_rendering_ms;
    188     ++num_delayed_decoded_frames_;
    189   }
    190   return 0;
    191 }
    192 
    193 void VCMTiming::IncomingTimestamp(uint32_t time_stamp, int64_t now_ms) {
    194   CriticalSectionScoped cs(crit_sect_);
    195   ts_extrapolator_->Update(now_ms, time_stamp);
    196 }
    197 
    198 int64_t VCMTiming::RenderTimeMs(uint32_t frame_timestamp,
    199                                 int64_t now_ms) const {
    200   CriticalSectionScoped cs(crit_sect_);
    201   const int64_t render_time_ms = RenderTimeMsInternal(frame_timestamp, now_ms);
    202   return render_time_ms;
    203 }
    204 
    205 int64_t VCMTiming::RenderTimeMsInternal(uint32_t frame_timestamp,
    206                                         int64_t now_ms) const {
    207   int64_t estimated_complete_time_ms =
    208       ts_extrapolator_->ExtrapolateLocalTime(frame_timestamp);
    209   if (estimated_complete_time_ms == -1) {
    210     estimated_complete_time_ms = now_ms;
    211   }
    212 
    213   // Make sure that we have at least the playout delay.
    214   uint32_t actual_delay = std::max(current_delay_ms_, min_playout_delay_ms_);
    215   return estimated_complete_time_ms + actual_delay;
    216 }
    217 
    218 // Must be called from inside a critical section.
    219 int32_t VCMTiming::MaxDecodeTimeMs(
    220     FrameType frame_type /*= kVideoFrameDelta*/) const {
    221   const int32_t decode_time_ms = codec_timer_.RequiredDecodeTimeMs(frame_type);
    222   assert(decode_time_ms >= 0);
    223   return decode_time_ms;
    224 }
    225 
    226 uint32_t VCMTiming::MaxWaitingTime(int64_t render_time_ms,
    227                                    int64_t now_ms) const {
    228   CriticalSectionScoped cs(crit_sect_);
    229 
    230   const int64_t max_wait_time_ms =
    231       render_time_ms - now_ms - MaxDecodeTimeMs() - render_delay_ms_;
    232 
    233   if (max_wait_time_ms < 0) {
    234     return 0;
    235   }
    236   return static_cast<uint32_t>(max_wait_time_ms);
    237 }
    238 
    239 bool VCMTiming::EnoughTimeToDecode(
    240     uint32_t available_processing_time_ms) const {
    241   CriticalSectionScoped cs(crit_sect_);
    242   int32_t max_decode_time_ms = MaxDecodeTimeMs();
    243   if (max_decode_time_ms < 0) {
    244     // Haven't decoded any frames yet, try decoding one to get an estimate
    245     // of the decode time.
    246     return true;
    247   } else if (max_decode_time_ms == 0) {
    248     // Decode time is less than 1, set to 1 for now since
    249     // we don't have any better precision. Count ticks later?
    250     max_decode_time_ms = 1;
    251   }
    252   return static_cast<int32_t>(available_processing_time_ms) -
    253              max_decode_time_ms >
    254          0;
    255 }
    256 
    257 uint32_t VCMTiming::TargetVideoDelay() const {
    258   CriticalSectionScoped cs(crit_sect_);
    259   return TargetDelayInternal();
    260 }
    261 
    262 uint32_t VCMTiming::TargetDelayInternal() const {
    263   return std::max(min_playout_delay_ms_,
    264                   jitter_delay_ms_ + MaxDecodeTimeMs() + render_delay_ms_);
    265 }
    266 
    267 void VCMTiming::GetTimings(int* decode_ms,
    268                            int* max_decode_ms,
    269                            int* current_delay_ms,
    270                            int* target_delay_ms,
    271                            int* jitter_buffer_ms,
    272                            int* min_playout_delay_ms,
    273                            int* render_delay_ms) const {
    274   CriticalSectionScoped cs(crit_sect_);
    275   *decode_ms = last_decode_ms_;
    276   *max_decode_ms = MaxDecodeTimeMs();
    277   *current_delay_ms = current_delay_ms_;
    278   *target_delay_ms = TargetDelayInternal();
    279   *jitter_buffer_ms = jitter_delay_ms_;
    280   *min_playout_delay_ms = min_playout_delay_ms_;
    281   *render_delay_ms = render_delay_ms_;
    282 }
    283 
    284 }  // namespace webrtc
    285