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