Extract bitrate allocation of spatial/temporal layers out of codec impl.

webrtc/modules/video_coding/video_codec_initializer.cc

Index: webrtc/modules/video_coding/video_codec_initializer.cc
diff --git a/webrtc/modules/video_coding/video_codec_initializer.cc b/webrtc/modules/video_coding/video_codec_initializer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e0f9311d6ac58b828772b6c73a063af8e7920b5d
--- /dev/null
+++ b/webrtc/modules/video_coding/video_codec_initializer.cc
@@ -0,0 +1,229 @@
+/*
+ *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/modules/video_coding/include/video_codec_initializer.h"
+
+#include "webrtc/base/basictypes.h"
+#include "webrtc/common_video/include/video_bitrate_allocator.h"
+#include "webrtc/common_types.h"
+#include "webrtc/modules/video_coding/codecs/vp8/screenshare_layers.h"
+#include "webrtc/modules/video_coding/codecs/vp8/temporal_layers.h"
+#include "webrtc/modules/video_coding/utility/simulcast_rate_allocator.h"
+#include "webrtc/modules/video_coding/utility/default_video_bitrate_allocator.h"
+#include "webrtc/system_wrappers/include/clock.h"
+
+namespace webrtc {
+
+struct ScreenshareTemporalLayersFactory : webrtc::TemporalLayersFactory {
+  ScreenshareTemporalLayersFactory() {}
+  virtual ~ScreenshareTemporalLayersFactory() {}
+
+  virtual webrtc::TemporalLayers* Create(int simulcast_id,
+                                         int num_temporal_layers,
+                                         uint8_t initial_tl0_pic_idx) const {
+    webrtc::TemporalLayers* tl = new webrtc::ScreenshareLayers(
+        num_temporal_layers, rand(), webrtc::Clock::GetRealTimeClock());
+    if (listener_)
+      listener_->OnTemporalLayersCreated(simulcast_id, tl);
+    return tl;
+  }
+};
+
+bool VideoCodecInitializer::SetupCodec(
+    const VideoEncoderConfig& config,
+    const VideoSendStream::Config::EncoderSettings settings,
+    const std::vector<VideoStream>& streams,
+    VideoCodec* codec,
+    std::unique_ptr<VideoBitrateAllocator>* bitrate_allocator) {
+  *codec = VideoEncoderConfigToVideoCodec(
+      config, streams, settings.payload_name, settings.payload_type);
+
+  std::unique_ptr<TemporalLayersFactory> tl_factory;
+  switch (codec->codecType) {
+    case kVideoCodecVP8: {
+      if (!codec->VP8()->tl_factory) {
+        if (codec->mode == kScreensharing &&
+            codec->numberOfSimulcastStreams == 1 &&
+            codec->VP8()->numberOfTemporalLayers == 2) {
+          // Conference mode temporal layering for screen content.
+          tl_factory.reset(new ScreenshareTemporalLayersFactory());
+        } else {
+          // Standard video temporal layers.
+          tl_factory.reset(new TemporalLayersFactory());
+        }
+        codec->VP8()->tl_factory = tl_factory.get();
+      }
+      break;
+    }
+    default: {
+      // TODO(sprang): Warn, once we have specific allocators for all supported
+      //               codec types.

[stefan-webrtc, 2016/11/02 10:26:36]

Why not warn now? Are we expected to get here?

[sprang_webrtc, 2016/11/02 13:28:33]

My thinking is that once we have some form of TL allocation support for VP9 and
H264(?), we should initialize that here. 
Right now we only care about VP8 however, and leave the other ones to handle
that internally if at all.
At least VP9 should follow in another CL, unless you prefer this one to grow?

[stefan-webrtc, 2016/11/03 13:34:58]

Acknowledged.

+      break;
+    }
+  }
+  *bitrate_allocator = GetBitrateAllocator(*codec, std::move(tl_factory));
+
+  return true;
+}
+
+std::unique_ptr<VideoBitrateAllocator>
+VideoCodecInitializer::GetBitrateAllocator(
+    const VideoCodec& codec,
+    std::unique_ptr<TemporalLayersFactory> tl_factory) {
+  std::unique_ptr<VideoBitrateAllocator> rate_allocator;
+
+  switch (codec.codecType) {
+    case kVideoCodecVP8: {
+      // Set up default VP8 temporal layer factory, if not provided.
+      rate_allocator.reset(
+          new SimulcastRateAllocator(codec, std::move(tl_factory)));
+    } break;
+    default:
+      rate_allocator.reset(new DefaultVideoBitrateAllocator(codec));
+  }
+
+  return rate_allocator;
+}
+
+// TODO(sprang): Split this up and separate the codec specific parts.
+VideoCodec VideoCodecInitializer::VideoEncoderConfigToVideoCodec(
+    const VideoEncoderConfig& config,
+    const std::vector<VideoStream>& streams,
+    const std::string& payload_name,
+    int payload_type) {
+  static const int kEncoderMinBitrateKbps = 30;
+  RTC_DCHECK(!streams.empty());
+  RTC_DCHECK_GE(config.min_transmit_bitrate_bps, 0);
+
+  VideoCodec video_codec;
+  memset(&video_codec, 0, sizeof(video_codec));
+  video_codec.codecType = PayloadNameToCodecType(payload_name)
+                              .value_or(VideoCodecType::kVideoCodecGeneric);
+
+  switch (config.content_type) {
+    case VideoEncoderConfig::ContentType::kRealtimeVideo:
+      video_codec.mode = kRealtimeVideo;
+      break;
+    case VideoEncoderConfig::ContentType::kScreen:
+      video_codec.mode = kScreensharing;
+      if (streams.size() == 1 &&
+          streams[0].temporal_layer_thresholds_bps.size() == 1) {
+        video_codec.targetBitrate =
+            streams[0].temporal_layer_thresholds_bps[0] / 1000;
+      }
+      break;
+  }
+
+  if (config.encoder_specific_settings)
+    config.encoder_specific_settings->FillEncoderSpecificSettings(&video_codec);
+
+  switch (video_codec.codecType) {
+    case kVideoCodecVP8: {
+      if (!config.encoder_specific_settings)
+        video_codec.codecSpecific.VP8 = VideoEncoder::GetDefaultVp8Settings();
+      video_codec.codecSpecific.VP8.numberOfTemporalLayers =
+          static_cast<unsigned char>(
+              streams.back().temporal_layer_thresholds_bps.size() + 1);
+      break;
+    }
+    case kVideoCodecVP9: {
+      if (!config.encoder_specific_settings)
+        video_codec.codecSpecific.VP9 = VideoEncoder::GetDefaultVp9Settings();
+      if (video_codec.mode == kScreensharing &&
+          config.encoder_specific_settings) {
+        video_codec.codecSpecific.VP9.flexibleMode = true;
+        // For now VP9 screensharing use 1 temporal and 2 spatial layers.
+        RTC_DCHECK_EQ(1, video_codec.codecSpecific.VP9.numberOfTemporalLayers);
+        RTC_DCHECK_EQ(2, video_codec.codecSpecific.VP9.numberOfSpatialLayers);
+      }
+      video_codec.codecSpecific.VP9.numberOfTemporalLayers =
+          static_cast<unsigned char>(
+              streams.back().temporal_layer_thresholds_bps.size() + 1);
+      break;
+    }
+    case kVideoCodecH264: {
+      if (!config.encoder_specific_settings)
+        video_codec.codecSpecific.H264 = VideoEncoder::GetDefaultH264Settings();
+      break;
+    }
+    default:
+      // TODO(pbos): Support encoder_settings codec-agnostically.
+      RTC_DCHECK(!config.encoder_specific_settings)
+          << "Encoder-specific settings for codec type not wired up.";
+      break;
+  }
+
+  strncpy(video_codec.plName, payload_name.c_str(), kPayloadNameSize - 1);
+  video_codec.plName[kPayloadNameSize - 1] = '\0';
+  video_codec.plType = payload_type;
+  video_codec.numberOfSimulcastStreams =
+      static_cast<unsigned char>(streams.size());
+  video_codec.minBitrate = streams[0].min_bitrate_bps / 1000;
+  if (video_codec.minBitrate < kEncoderMinBitrateKbps)
+    video_codec.minBitrate = kEncoderMinBitrateKbps;
+  RTC_DCHECK_LE(streams.size(), static_cast<size_t>(kMaxSimulcastStreams));
+  if (video_codec.codecType == kVideoCodecVP9) {
+    // If the vector is empty, bitrates will be configured automatically.
+    RTC_DCHECK(config.spatial_layers.empty() ||
+               config.spatial_layers.size() ==
+                   video_codec.codecSpecific.VP9.numberOfSpatialLayers);
+    RTC_DCHECK_LE(video_codec.codecSpecific.VP9.numberOfSpatialLayers,
+                  kMaxSimulcastStreams);
+    for (size_t i = 0; i < config.spatial_layers.size(); ++i)
+      video_codec.spatialLayers[i] = config.spatial_layers[i];
+  }
+  for (size_t i = 0; i < streams.size(); ++i) {
+    SimulcastStream* sim_stream = &video_codec.simulcastStream[i];
+    RTC_DCHECK_GT(streams[i].width, 0u);
+    RTC_DCHECK_GT(streams[i].height, 0u);
+    RTC_DCHECK_GT(streams[i].max_framerate, 0);
+    // Different framerates not supported per stream at the moment.
+    RTC_DCHECK_EQ(streams[i].max_framerate, streams[0].max_framerate);
+    RTC_DCHECK_GE(streams[i].min_bitrate_bps, 0);
+    RTC_DCHECK_GE(streams[i].target_bitrate_bps, streams[i].min_bitrate_bps);
+    RTC_DCHECK_GE(streams[i].max_bitrate_bps, streams[i].target_bitrate_bps);
+    RTC_DCHECK_GE(streams[i].max_qp, 0);
+
+    sim_stream->width = static_cast<uint16_t>(streams[i].width);
+    sim_stream->height = static_cast<uint16_t>(streams[i].height);
+    sim_stream->minBitrate = streams[i].min_bitrate_bps / 1000;
+    sim_stream->targetBitrate = streams[i].target_bitrate_bps / 1000;
+    sim_stream->maxBitrate = streams[i].max_bitrate_bps / 1000;
+    sim_stream->qpMax = streams[i].max_qp;
+    sim_stream->numberOfTemporalLayers = static_cast<unsigned char>(
+        streams[i].temporal_layer_thresholds_bps.size() + 1);
+
+    video_codec.width =
+        std::max(video_codec.width, static_cast<uint16_t>(streams[i].width));
+    video_codec.height =
+        std::max(video_codec.height, static_cast<uint16_t>(streams[i].height));
+    video_codec.minBitrate =
+        std::min(static_cast<uint16_t>(video_codec.minBitrate),
+                 static_cast<uint16_t>(streams[i].min_bitrate_bps / 1000));
+    video_codec.maxBitrate += streams[i].max_bitrate_bps / 1000;
+    video_codec.qpMax = std::max(video_codec.qpMax,
+                                 static_cast<unsigned int>(streams[i].max_qp));
+  }
+
+  if (video_codec.maxBitrate == 0) {
+    // Unset max bitrate -> cap to one bit per pixel.
+    video_codec.maxBitrate =
+        (video_codec.width * video_codec.height * video_codec.maxFramerate) /
+        1000;
+  }
+  if (video_codec.maxBitrate < kEncoderMinBitrateKbps)
+    video_codec.maxBitrate = kEncoderMinBitrateKbps;
+
+  RTC_DCHECK_GT(streams[0].max_framerate, 0);
+  video_codec.maxFramerate = streams[0].max_framerate;
+  return video_codec;
+}
+
+}  // namespace webrtc