Derive current layer from TL frame config.

webrtc/modules/video_coding/codecs/vp8/default_temporal_layers.cc

 /* Copyright (c) 2013 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/codecs/vp8/default_temporal_layers.h"
 
 #include <stdlib.h>
 #include <string.h>
 
 #include <algorithm>
 #include <vector>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/modules/video_coding/include/video_codec_interface.h"
 #include "webrtc/modules/video_coding/codecs/vp8/include/vp8_common_types.h"
 
 #include "vpx/vpx_encoder.h"
 #include "vpx/vp8cx.h"
 
 namespace webrtc {
 
-TemporalReferences::TemporalReferences(TemporalBufferFlags last,
-                                       TemporalBufferFlags golden,
-                                       TemporalBufferFlags arf)
-    : TemporalReferences(last, golden, arf, false, false) {}
+TemporalLayers::FrameConfig::FrameConfig() {}
 
-TemporalReferences::TemporalReferences(TemporalBufferFlags last,
-                                       TemporalBufferFlags golden,
-                                       TemporalBufferFlags arf,
-                                       int extra_flags)
-    : TemporalReferences(last,
-                         golden,
-                         arf,
-                         (extra_flags & kLayerSync) != 0,
-                         (extra_flags & kFreezeEntropy) != 0) {}
+TemporalLayers::FrameConfig::FrameConfig(TemporalLayers::BufferFlags last,
+                                         TemporalLayers::BufferFlags golden,
+                                         TemporalLayers::BufferFlags arf)
+    : FrameConfig(last, golden, arf, false, false) {}
 
-TemporalReferences::TemporalReferences(TemporalBufferFlags last,
-                                       TemporalBufferFlags golden,
-                                       TemporalBufferFlags arf,
-                                       bool layer_sync,
-                                       bool freeze_entropy)
-    : drop_frame(last == kNone && golden == kNone && arf == kNone),
+TemporalLayers::FrameConfig::FrameConfig(TemporalLayers::BufferFlags last,
+                                         TemporalLayers::BufferFlags golden,
+                                         TemporalLayers::BufferFlags arf,
+                                         int extra_flags)
+    : FrameConfig(last,
+                  golden,
+                  arf,
+                  (extra_flags & kLayerSync) != 0,
+                  (extra_flags & kFreezeEntropy) != 0) {}
+
+TemporalLayers::FrameConfig::FrameConfig(TemporalLayers::BufferFlags last,
+                                         TemporalLayers::BufferFlags golden,
+                                         TemporalLayers::BufferFlags arf,
+                                         bool layer_sync,
+                                         bool freeze_entropy)
+    : drop_frame(last == TemporalLayers::kNone &&
+                 golden == TemporalLayers::kNone &&
+                 arf == TemporalLayers::kNone),
       last_buffer_flags(last),
       golden_buffer_flags(golden),
       arf_buffer_flags(arf),
       layer_sync(layer_sync),
       freeze_entropy(freeze_entropy) {}
 
 namespace {
 
 std::vector<unsigned int> GetTemporalIds(size_t num_layers) {
   switch (num_layers) {
@@ skipping 20 matching lines @@
       // 0               0               ...
       return {0, 3, 2, 3, 1, 3, 2, 3};
     default:
       RTC_NOTREACHED();
       break;
   }
   RTC_NOTREACHED();
   return {0};
 }
 
-std::vector<TemporalReferences> GetTemporalPattern(
-    size_t num_layers) {
+std::vector<TemporalLayers::FrameConfig> GetTemporalPattern(size_t num_layers) {
   // For indexing in the patterns described below (which temporal layers they
   // belong to), see the diagram above.
   // Layer sync is done similarly for all patterns (except single stream) and
   // happens every 8 frames:
   // TL1 layer syncs by periodically by only referencing TL0 ('last'), but still
   // updating 'golden', so it can be used as a reference by future TL1 frames.
   // TL2 layer syncs just before TL1 by only depending on TL0 (and not depending
   // on TL1's buffer before TL1 has layer synced).
   // TODO(pbos): Consider cyclically updating 'arf' (and 'golden' for 1TL) for
   // the base layer in 1-3TL instead of 'last' periodically on long intervals,
   // so that if scene changes occur (user walks between rooms or rotates webcam)
   // the 'arf' (or 'golden' respectively) is not stuck on a no-longer relevant
   // keyframe.
   switch (num_layers) {
     case 1:
       // All frames reference all buffers and the 'last' buffer is updated.
-      return {TemporalReferences(kReferenceAndUpdate, kReference, kReference)};
+      return {TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kReference,
+                                          TemporalLayers::kReference)};
     case 2:
       // All layers can reference but not update the 'alt' buffer, this means
       // that the 'alt' buffer reference is effectively the last keyframe.
       // TL0 also references and updates the 'last' buffer.
       // TL1 also references 'last' and references and updates 'golden'.
-      return {TemporalReferences(kReferenceAndUpdate, kUpdate, kReference),
-              TemporalReferences(kReference, kUpdate, kReference, kLayerSync),
-              TemporalReferences(kReferenceAndUpdate, kNone, kReference),
-              TemporalReferences(kReference, kReferenceAndUpdate, kReference),
-              TemporalReferences(kReferenceAndUpdate, kNone, kReference),
-              TemporalReferences(kReference, kReferenceAndUpdate, kReference),
-              TemporalReferences(kReferenceAndUpdate, kNone, kReference),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kFreezeEntropy)};
+      return {TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kUpdate,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kUpdate,
+                  TemporalLayers::kReference, kLayerSync),
+              TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kNone,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kNone,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kNone,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kFreezeEntropy)};
     case 3:
       // All layers can reference but not update the 'alt' buffer, this means
       // that the 'alt' buffer reference is effectively the last keyframe.
       // TL0 also references and updates the 'last' buffer.
       // TL1 also references 'last' and references and updates 'golden'.
       // TL2 references both 'last' and 'golden' but updates no buffer.
-      return {TemporalReferences(kReferenceAndUpdate, kUpdate, kReference),
-              TemporalReferences(kReference, kNone, kReference,
-                                 kLayerSync | kFreezeEntropy),
-              TemporalReferences(kReference, kUpdate, kReference, kLayerSync),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kFreezeEntropy),
-              TemporalReferences(kReferenceAndUpdate, kNone, kReference),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kFreezeEntropy),
-              TemporalReferences(kReference, kReferenceAndUpdate, kReference),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kFreezeEntropy)};
+      return {TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kUpdate,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kNone,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kUpdate,
+                  TemporalLayers::kReference, kLayerSync),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kNone,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kReference),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kFreezeEntropy)};
     case 4:
       // TL0 references and updates only the 'last' buffer.
       // TL1 references 'last' and updates and references 'golden'.
       // TL2 references 'last' and 'golden', and references and updates 'arf'.
       // TL3 references all buffers but update none of them.
-      return {TemporalReferences(kReferenceAndUpdate, kNone, kNone),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kLayerSync | kFreezeEntropy),
-              TemporalReferences(kReference, kNone, kUpdate, kLayerSync),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kLayerSync | kFreezeEntropy),
-              TemporalReferences(kReference, kUpdate, kNone, kLayerSync),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kLayerSync | kFreezeEntropy),
-              TemporalReferences(kReference, kReference, kReferenceAndUpdate),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kLayerSync | kFreezeEntropy),
-              TemporalReferences(kReferenceAndUpdate, kNone, kNone),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kLayerSync | kFreezeEntropy),
-              TemporalReferences(kReference, kReference, kReferenceAndUpdate),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kLayerSync | kFreezeEntropy),
-              TemporalReferences(kReference, kReferenceAndUpdate, kNone),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kLayerSync | kFreezeEntropy),
-              TemporalReferences(kReference, kReference, kReferenceAndUpdate),
-              TemporalReferences(kReference, kReference, kReference,
-                                 kLayerSync | kFreezeEntropy)};
+      return {TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kNone,
+                                          TemporalLayers::kNone),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kNone,
+                                          TemporalLayers::kUpdate, kLayerSync),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kUpdate,
+                                          TemporalLayers::kNone, kLayerSync),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kReference,
+                                          TemporalLayers::kReferenceAndUpdate),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kNone,
+                                          TemporalLayers::kNone),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kReference,
+                                          TemporalLayers::kReferenceAndUpdate),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kReferenceAndUpdate,
+                                          TemporalLayers::kNone),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy),
+              TemporalLayers::FrameConfig(TemporalLayers::kReference,
+                                          TemporalLayers::kReference,
+                                          TemporalLayers::kReferenceAndUpdate),
+              TemporalLayers::FrameConfig(
+                  TemporalLayers::kReference, TemporalLayers::kReference,
+                  TemporalLayers::kReference, kLayerSync | kFreezeEntropy)};
     default:
       RTC_NOTREACHED();
       break;
   }
   RTC_NOTREACHED();
-  return {TemporalReferences(kNone, kNone, kNone)};
+  return {TemporalLayers::FrameConfig(
+      TemporalLayers::kNone, TemporalLayers::kNone, TemporalLayers::kNone)};
 }
 
 }  // namespace
 
 DefaultTemporalLayers::DefaultTemporalLayers(int number_of_temporal_layers,
                                              uint8_t initial_tl0_pic_idx)
     : num_layers_(std::max(1, number_of_temporal_layers)),
       temporal_ids_(GetTemporalIds(num_layers_)),
       temporal_pattern_(GetTemporalPattern(num_layers_)),
       tl0_pic_idx_(initial_tl0_pic_idx),
       pattern_idx_(255),
       timestamp_(0),
       last_base_layer_sync_(false) {
   RTC_CHECK_GE(kMaxTemporalStreams, number_of_temporal_layers);
   RTC_CHECK_GE(number_of_temporal_layers, 0);
   RTC_CHECK_LE(number_of_temporal_layers, 4);
 }
 
-int DefaultTemporalLayers::CurrentLayerId() const {
-  return temporal_ids_[pattern_idx_ % temporal_ids_.size()];
+int DefaultTemporalLayers::GetTemporalLayerId(
+    TemporalLayers::FrameConfig tl_config) const {
+  RTC_DCHECK(!tl_config.drop_frame);
+  return temporal_ids_[tl_config.pattern_idx % temporal_ids_.size()];
 }
 
 std::vector<uint32_t> DefaultTemporalLayers::OnRatesUpdated(
     int bitrate_kbps,
     int max_bitrate_kbps,
     int framerate) {
   std::vector<uint32_t> bitrates;
   for (size_t i = 0; i < num_layers_; ++i) {
     float layer_bitrate =
         bitrate_kbps * kVp8LayerRateAlloction[num_layers_ - 1][i];
@@ skipping 32 matching lines @@
   cfg->ts_number_layers = num_layers_;
   cfg->ts_periodicity = temporal_ids_.size();
   memcpy(cfg->ts_layer_id, &temporal_ids_[0],
          sizeof(unsigned int) * temporal_ids_.size());
 
   new_bitrates_kbps_ = rtc::Optional<std::vector<uint32_t>>();
 
   return true;
 }
 
 // TODO(pbos): Name method so that it's obvious that it updates state.

[sprang_webrtc, 2017/05/03 15:18:43]

Remove todo?

[pbos-webrtc, 2017/05/04 10:52:22]

Done.

-TemporalReferences DefaultTemporalLayers::UpdateLayerConfig(
+TemporalLayers::FrameConfig DefaultTemporalLayers::UpdateLayerConfig(
     uint32_t timestamp) {
   RTC_DCHECK_GT(num_layers_, 0);
   RTC_DCHECK_LT(0, temporal_pattern_.size());
-  return temporal_pattern_[++pattern_idx_ % temporal_pattern_.size()];
+  int pattern_idx = ++pattern_idx_;

[sprang_webrtc, 2017/05/03 15:18:43]

Is it intentional that we let pattern_idx_ go up to 255 before overflowing and
wrapping around rather than explicitly wrapping it at temporal_pattern_.size() ?
Right now this looks to me like it works only because temporal_pattern_.size()
always happen to be a divisor of 256..?
If it is desired I think a DCHECK and/or comment somewhere would be in order :)

[pbos-webrtc, 2017/05/04 10:52:22]

Did as suggested (explicitly wrap). I added a DCHECK above since pattern_idx is
also used to index into temporal_ids_, and a comment saying that if
temporal_ids_ is ever larger than temporal_patterns_ it needs to wrap at the
largest one.

+  TemporalLayers::FrameConfig tl_config =
+      temporal_pattern_[pattern_idx_ % temporal_pattern_.size()];
+  tl_config.pattern_idx = pattern_idx;
+  return tl_config;
 }
 
 void DefaultTemporalLayers::PopulateCodecSpecific(
     bool frame_is_keyframe,
+    TemporalLayers::FrameConfig tl_config,
     CodecSpecificInfoVP8* vp8_info,
     uint32_t timestamp) {
   RTC_DCHECK_GT(num_layers_, 0);
 
   if (num_layers_ == 1) {
     vp8_info->temporalIdx = kNoTemporalIdx;
     vp8_info->layerSync = false;
     vp8_info->tl0PicIdx = kNoTl0PicIdx;
   } else {
     if (frame_is_keyframe) {
       vp8_info->temporalIdx = 0;
       vp8_info->layerSync = true;
     } else {
-      vp8_info->temporalIdx = CurrentLayerId();
-      TemporalReferences temporal_reference =
-          temporal_pattern_[pattern_idx_ % temporal_pattern_.size()];
+      vp8_info->temporalIdx = GetTemporalLayerId(tl_config);
 
-      vp8_info->layerSync = temporal_reference.layer_sync;
+      vp8_info->layerSync = tl_config.layer_sync;
     }
     if (last_base_layer_sync_ && vp8_info->temporalIdx != 0) {
       // Regardless of pattern the frame after a base layer sync will always
       // be a layer sync.
       vp8_info->layerSync = true;
     }
     if (vp8_info->temporalIdx == 0 && timestamp != timestamp_) {
       timestamp_ = timestamp;
       tl0_pic_idx_++;
     }
@@ skipping 11 matching lines @@
   if (listener_)
     listener_->OnTemporalLayersCreated(simulcast_id, tl);
   return tl;
 }
 
 void TemporalLayersFactory::SetListener(TemporalLayersListener* listener) {
   listener_ = listener;
 }
 
 }  // namespace webrtc