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1 /* | 1 /* |
2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. | 2 * Copyright (c) 2014 The WebRTC project authors. All Rights Reserved. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license | 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 | 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 | 6 * tree. An additional intellectual property rights grant can be found |
7 * in the file PATENTS. All contributing project authors may | 7 * in the file PATENTS. All contributing project authors may |
8 * be found in the AUTHORS file in the root of the source tree. | 8 * be found in the AUTHORS file in the root of the source tree. |
9 */ | 9 */ |
10 | 10 |
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169 | 169 |
170 std::vector<webrtc::VideoStream> GetSimulcastConfig(size_t max_streams, | 170 std::vector<webrtc::VideoStream> GetSimulcastConfig(size_t max_streams, |
171 int width, | 171 int width, |
172 int height, | 172 int height, |
173 int max_bitrate_bps, | 173 int max_bitrate_bps, |
174 int max_qp, | 174 int max_qp, |
175 int max_framerate, | 175 int max_framerate, |
176 bool is_screencast) { | 176 bool is_screencast) { |
177 size_t num_simulcast_layers; | 177 size_t num_simulcast_layers; |
178 if (is_screencast) { | 178 if (is_screencast) { |
179 num_simulcast_layers = | 179 if (UseSimulcastScreenshare()) { |
180 UseSimulcastScreenshare() ? kDefaultScreenshareSimulcastStreams : 1; | 180 num_simulcast_layers = |
181 std::min<int>(max_streams, kDefaultScreenshareSimulcastStreams); | |
stefan-webrtc
2017/04/05 15:06:48
kDefaultScreenshareSimulcastStreams should maybe b
sprang_webrtc
2017/05/08 08:50:53
Sure.
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182 } else { | |
183 num_simulcast_layers = 1; | |
184 } | |
181 } else { | 185 } else { |
182 num_simulcast_layers = FindSimulcastMaxLayers(width, height); | 186 num_simulcast_layers = FindSimulcastMaxLayers(width, height); |
183 } | 187 } |
184 | 188 |
185 if (num_simulcast_layers > max_streams) { | 189 if (num_simulcast_layers > max_streams) { |
186 // If the number of SSRCs in the group differs from our target | 190 // If the number of SSRCs in the group differs from our target |
187 // number of simulcast streams for current resolution, switch down | 191 // number of simulcast streams for current resolution, switch down |
188 // to a resolution that matches our number of SSRCs. | 192 // to a resolution that matches our number of SSRCs. |
189 if (!SlotSimulcastMaxResolution(max_streams, &width, &height)) { | 193 if (!SlotSimulcastMaxResolution(max_streams, &width, &height)) { |
190 return std::vector<webrtc::VideoStream>(); | 194 return std::vector<webrtc::VideoStream>(); |
191 } | 195 } |
192 num_simulcast_layers = max_streams; | 196 num_simulcast_layers = max_streams; |
193 } | 197 } |
194 std::vector<webrtc::VideoStream> streams; | 198 std::vector<webrtc::VideoStream> streams; |
195 streams.resize(num_simulcast_layers); | 199 streams.resize(num_simulcast_layers); |
196 | 200 |
197 if (!is_screencast) { | 201 if (is_screencast) { |
stefan-webrtc
2017/04/05 15:06:48
I think it would be good to have a general comment
sprang_webrtc
2017/05/08 08:50:53
Added comments.
In both cases we use the legacy sc
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202 ScreenshareLayerConfig config = ScreenshareLayerConfig::GetDefault(); | |
203 // For legacy screenshare in conference mode, tl0 and tl1 bitrates are | |
204 // piggybacked on the VideoCodec struct as target and max bitrates, | |
205 // respectively. See eg. webrtc::VP8EncoderImpl::SetRates(). | |
206 streams[0].width = width; | |
207 streams[0].height = height; | |
208 streams[0].max_qp = max_qp; | |
209 streams[0].max_framerate = 5; | |
210 streams[0].min_bitrate_bps = kMinVideoBitrateKbps * 1000; | |
211 streams[0].target_bitrate_bps = config.tl0_bitrate_kbps * 1000; | |
212 streams[0].max_bitrate_bps = config.tl1_bitrate_kbps * 1000; | |
213 streams[0].temporal_layer_thresholds_bps.clear(); | |
214 streams[0].temporal_layer_thresholds_bps.push_back(config.tl0_bitrate_kbps * | |
215 1000); | |
stefan-webrtc
2017/04/05 15:06:48
Looks like we're doing 2 temporal layers here, and
sprang_webrtc
2017/05/08 08:50:53
Yes, that's the idea.
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216 | |
217 if (num_simulcast_layers == 2) { | |
stefan-webrtc
2017/04/05 15:06:48
Should this be kDefaultScreenshareSimulcastStreams
sprang_webrtc
2017/05/08 08:50:53
Done.
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218 // Add optional upper simulcast layer. | |
219 // Lowest temporal layers of a 3 layer setup will have 40% of the total | |
220 // bitrate allocation for that stream. Make sure the gap between the | |
221 // target of the lower stream and first temporal layer of the higher one | |
222 // is at most 2x the bitrate, so that upswitching is not hampered by | |
223 // stalled bitrate estimates. | |
stefan-webrtc
2017/04/05 15:06:48
I don't fully understand this. Why would the bitra
sprang_webrtc
2017/05/08 08:50:53
We do at the source, yes. But there is no guarante
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224 int max_bitrate_bps = 2 * ((streams[0].target_bitrate_bps * 10) / 4); | |
225 // Cap max bitrate so it isn't overly high for the given resolution. | |
226 max_bitrate_bps = std::min<int>( | |
227 max_bitrate_bps, FindSimulcastMaxBitrateBps(width, height)); | |
228 | |
229 streams[1].width = width; | |
230 streams[1].height = height; | |
231 streams[1].max_qp = max_qp; | |
232 streams[1].max_framerate = max_framerate; | |
233 // Three temporal layers means two thresholds. | |
234 streams[1].temporal_layer_thresholds_bps.resize(2); | |
235 streams[1].min_bitrate_bps = streams[0].target_bitrate_bps * 2; | |
236 streams[1].target_bitrate_bps = max_bitrate_bps; | |
237 streams[1].max_bitrate_bps = max_bitrate_bps; | |
238 } | |
239 } else { | |
198 // Format width and height has to be divisible by |2 ^ number_streams - 1|. | 240 // Format width and height has to be divisible by |2 ^ number_streams - 1|. |
199 width = NormalizeSimulcastSize(width, num_simulcast_layers); | 241 width = NormalizeSimulcastSize(width, num_simulcast_layers); |
200 height = NormalizeSimulcastSize(height, num_simulcast_layers); | 242 height = NormalizeSimulcastSize(height, num_simulcast_layers); |
201 } | |
202 | 243 |
203 // Add simulcast sub-streams from lower resolution to higher resolutions. | 244 // Add simulcast sub-streams from lower resolution to higher resolutions. |
204 // Add simulcast streams, from highest resolution (|s| = number_streams -1) | 245 // Add simulcast streams, from highest resolution (|s| = number_streams -1) |
205 // to lowest resolution at |s| = 0. | 246 // to lowest resolution at |s| = 0. |
206 for (size_t s = num_simulcast_layers - 1;; --s) { | 247 for (size_t s = num_simulcast_layers - 1;; --s) { |
207 streams[s].width = width; | 248 streams[s].width = width; |
208 streams[s].height = height; | 249 streams[s].height = height; |
209 // TODO(pbos): Fill actual temporal-layer bitrate thresholds. | 250 // TODO(pbos): Fill actual temporal-layer bitrate thresholds. |
210 streams[s].max_qp = max_qp; | 251 streams[s].max_qp = max_qp; |
211 if (is_screencast && s == 0) { | |
212 ScreenshareLayerConfig config = ScreenshareLayerConfig::GetDefault(); | |
213 // For legacy screenshare in conference mode, tl0 and tl1 bitrates are | |
214 // piggybacked on the VideoCodec struct as target and max bitrates, | |
215 // respectively. See eg. webrtc::VP8EncoderImpl::SetRates(). | |
216 streams[s].min_bitrate_bps = kMinVideoBitrateKbps * 1000; | |
217 streams[s].target_bitrate_bps = config.tl0_bitrate_kbps * 1000; | |
218 streams[s].max_bitrate_bps = config.tl1_bitrate_kbps * 1000; | |
219 streams[s].temporal_layer_thresholds_bps.clear(); | |
220 streams[s].temporal_layer_thresholds_bps.push_back( | |
221 config.tl0_bitrate_kbps * 1000); | |
222 streams[s].max_framerate = 5; | |
223 } else { | |
224 streams[s].temporal_layer_thresholds_bps.resize( | 252 streams[s].temporal_layer_thresholds_bps.resize( |
225 kDefaultConferenceNumberOfTemporalLayers[s] - 1); | 253 kDefaultConferenceNumberOfTemporalLayers[s] - 1); |
226 streams[s].max_bitrate_bps = FindSimulcastMaxBitrateBps(width, height); | 254 streams[s].max_bitrate_bps = FindSimulcastMaxBitrateBps(width, height); |
227 streams[s].target_bitrate_bps = | 255 streams[s].target_bitrate_bps = |
228 FindSimulcastTargetBitrateBps(width, height); | 256 FindSimulcastTargetBitrateBps(width, height); |
229 streams[s].min_bitrate_bps = FindSimulcastMinBitrateBps(width, height); | 257 streams[s].min_bitrate_bps = FindSimulcastMinBitrateBps(width, height); |
230 streams[s].max_framerate = max_framerate; | 258 streams[s].max_framerate = max_framerate; |
259 | |
260 if (!is_screencast) { | |
stefan-webrtc
2017/04/05 15:06:48
This is always true AFAICT?
sprang_webrtc
2017/05/08 08:50:53
Done.
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261 width /= 2; | |
262 height /= 2; | |
263 } | |
264 if (s == 0) | |
265 break; | |
231 } | 266 } |
232 | 267 |
233 if (!is_screencast) { | 268 // Spend additional bits to boost the max stream. |
234 width /= 2; | 269 int bitrate_left_bps = max_bitrate_bps - GetTotalMaxBitrateBps(streams); |
235 height /= 2; | 270 if (bitrate_left_bps > 0) { |
271 streams.back().max_bitrate_bps += bitrate_left_bps; | |
236 } | 272 } |
237 if (s == 0) | |
238 break; | |
239 } | |
240 | |
241 // Spend additional bits to boost the max stream. | |
242 int bitrate_left_bps = max_bitrate_bps - GetTotalMaxBitrateBps(streams); | |
243 if (bitrate_left_bps > 0) { | |
244 streams.back().max_bitrate_bps += bitrate_left_bps; | |
245 } | 273 } |
246 | 274 |
247 return streams; | 275 return streams; |
248 } | 276 } |
249 | 277 |
250 static const int kScreenshareMinBitrateKbps = 50; | 278 static const int kScreenshareMinBitrateKbps = 50; |
251 static const int kScreenshareMaxBitrateKbps = 6000; | 279 static const int kScreenshareMaxBitrateKbps = 6000; |
252 static const int kScreenshareDefaultTl0BitrateKbps = 200; | 280 static const int kScreenshareDefaultTl0BitrateKbps = 200; |
253 static const int kScreenshareDefaultTl1BitrateKbps = 1000; | 281 static const int kScreenshareDefaultTl1BitrateKbps = 1000; |
254 | 282 |
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296 config->tl1_bitrate_kbps = tl1_bitrate; | 324 config->tl1_bitrate_kbps = tl1_bitrate; |
297 | 325 |
298 return true; | 326 return true; |
299 } | 327 } |
300 | 328 |
301 bool UseSimulcastScreenshare() { | 329 bool UseSimulcastScreenshare() { |
302 return webrtc::field_trial::IsEnabled(kSimulcastScreenshareFieldTrialName); | 330 return webrtc::field_trial::IsEnabled(kSimulcastScreenshareFieldTrialName); |
303 } | 331 } |
304 | 332 |
305 } // namespace cricket | 333 } // namespace cricket |
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