1 files changed, 736 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc b/third_party/libwebrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc
new file mode 100644
index 0000000000..ee69b9befb
--- /dev/null
+++ b/third_party/libwebrtc/modules/video_coding/codecs/h264/h264_encoder_impl.cc
@@ -0,0 +1,736 @@
+/*
+ *  Copyright (c) 2015 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.
+ *
+ */
+
+// Everything declared/defined in this header is only required when WebRTC is
+// build with H264 support, please do not move anything out of the
+// #ifdef unless needed and tested.
+#ifdef WEBRTC_USE_H264
+
+#include "modules/video_coding/codecs/h264/h264_encoder_impl.h"
+
+#include <algorithm>
+#include <limits>
+#include <string>
+
+#include "absl/strings/match.h"
+#include "absl/types/optional.h"
+#include "api/video/video_codec_constants.h"
+#include "api/video_codecs/scalability_mode.h"
+#include "common_video/libyuv/include/webrtc_libyuv.h"
+#include "modules/video_coding/svc/create_scalability_structure.h"
+#include "modules/video_coding/utility/simulcast_rate_allocator.h"
+#include "modules/video_coding/utility/simulcast_utility.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/time_utils.h"
+#include "system_wrappers/include/metrics.h"
+#include "third_party/libyuv/include/libyuv/convert.h"
+#include "third_party/libyuv/include/libyuv/scale.h"
+#include "third_party/openh264/src/codec/api/wels/codec_api.h"
+#include "third_party/openh264/src/codec/api/wels/codec_app_def.h"
+#include "third_party/openh264/src/codec/api/wels/codec_def.h"
+#include "third_party/openh264/src/codec/api/wels/codec_ver.h"
+
+namespace webrtc {
+
+namespace {
+
+const bool kOpenH264EncoderDetailedLogging = false;
+
+// QP scaling thresholds.
+static const int kLowH264QpThreshold = 24;
+static const int kHighH264QpThreshold = 37;
+
+// Used by histograms. Values of entries should not be changed.
+enum H264EncoderImplEvent {
+  kH264EncoderEventInit = 0,
+  kH264EncoderEventError = 1,
+  kH264EncoderEventMax = 16,
+};
+
+int NumberOfThreads(absl::optional<int> encoder_thread_limit,
+                    int width,
+                    int height,
+                    int number_of_cores) {
+  // TODO(hbos): In Chromium, multiple threads do not work with sandbox on Mac,
+  // see crbug.com/583348. Until further investigated, only use one thread.
+  // While this limitation is gone, this changes the bitstream format (see
+  // bugs.webrtc.org/14368) so still guarded by field trial to allow for
+  // experimentation using th experimental
+  // WebRTC-VideoEncoderSettings/encoder_thread_limit trial.
+  if (encoder_thread_limit.has_value()) {
+    int limit = encoder_thread_limit.value();
+    RTC_DCHECK_GE(limit, 1);
+    if (width * height >= 1920 * 1080 && number_of_cores > 8) {
+      return std::min(limit, 8);  // 8 threads for 1080p on high perf machines.
+    } else if (width * height > 1280 * 960 && number_of_cores >= 6) {
+      return std::min(limit, 3);  // 3 threads for 1080p.
+    } else if (width * height > 640 * 480 && number_of_cores >= 3) {
+      return std::min(limit, 2);  // 2 threads for qHD/HD.
+    } else {
+      return 1;  // 1 thread for VGA or less.
+    }
+  }
+  // TODO(sprang): Also check sSliceArgument.uiSliceNum on GetEncoderParams(),
+  //               before enabling multithreading here.
+  return 1;
+}
+
+VideoFrameType ConvertToVideoFrameType(EVideoFrameType type) {
+  switch (type) {
+    case videoFrameTypeIDR:
+      return VideoFrameType::kVideoFrameKey;
+    case videoFrameTypeSkip:
+    case videoFrameTypeI:
+    case videoFrameTypeP:
+    case videoFrameTypeIPMixed:
+      return VideoFrameType::kVideoFrameDelta;
+    case videoFrameTypeInvalid:
+      break;
+  }
+  RTC_DCHECK_NOTREACHED() << "Unexpected/invalid frame type: " << type;
+  return VideoFrameType::kEmptyFrame;
+}
+
+absl::optional<ScalabilityMode> ScalabilityModeFromTemporalLayers(
+    int num_temporal_layers) {
+  switch (num_temporal_layers) {
+    case 0:
+      break;
+    case 1:
+      return ScalabilityMode::kL1T1;
+    case 2:
+      return ScalabilityMode::kL1T2;
+    case 3:
+      return ScalabilityMode::kL1T3;
+    default:
+      RTC_DCHECK_NOTREACHED();
+  }
+  return absl::nullopt;
+}
+
+}  // namespace
+
+// Helper method used by H264EncoderImpl::Encode.
+// Copies the encoded bytes from `info` to `encoded_image`. The
+// `encoded_image->_buffer` may be deleted and reallocated if a bigger buffer is
+// required.
+//
+// After OpenH264 encoding, the encoded bytes are stored in `info` spread out
+// over a number of layers and "NAL units". Each NAL unit is a fragment starting
+// with the four-byte start code {0,0,0,1}. All of this data (including the
+// start codes) is copied to the `encoded_image->_buffer`.
+static void RtpFragmentize(EncodedImage* encoded_image, SFrameBSInfo* info) {
+  // Calculate minimum buffer size required to hold encoded data.
+  size_t required_capacity = 0;
+  size_t fragments_count = 0;
+  for (int layer = 0; layer < info->iLayerNum; ++layer) {
+    const SLayerBSInfo& layerInfo = info->sLayerInfo[layer];
+    for (int nal = 0; nal < layerInfo.iNalCount; ++nal, ++fragments_count) {
+      RTC_CHECK_GE(layerInfo.pNalLengthInByte[nal], 0);
+      // Ensure `required_capacity` will not overflow.
+      RTC_CHECK_LE(layerInfo.pNalLengthInByte[nal],
+                   std::numeric_limits<size_t>::max() - required_capacity);
+      required_capacity += layerInfo.pNalLengthInByte[nal];
+    }
+  }
+  auto buffer = EncodedImageBuffer::Create(required_capacity);
+  encoded_image->SetEncodedData(buffer);
+
+  // Iterate layers and NAL units, note each NAL unit as a fragment and copy
+  // the data to `encoded_image->_buffer`.
+  const uint8_t start_code[4] = {0, 0, 0, 1};
+  size_t frag = 0;
+  encoded_image->set_size(0);
+  for (int layer = 0; layer < info->iLayerNum; ++layer) {
+    const SLayerBSInfo& layerInfo = info->sLayerInfo[layer];
+    // Iterate NAL units making up this layer, noting fragments.
+    size_t layer_len = 0;
+    for (int nal = 0; nal < layerInfo.iNalCount; ++nal, ++frag) {
+      // Because the sum of all layer lengths, `required_capacity`, fits in a
+      // `size_t`, we know that any indices in-between will not overflow.
+      RTC_DCHECK_GE(layerInfo.pNalLengthInByte[nal], 4);
+      RTC_DCHECK_EQ(layerInfo.pBsBuf[layer_len + 0], start_code[0]);
+      RTC_DCHECK_EQ(layerInfo.pBsBuf[layer_len + 1], start_code[1]);
+      RTC_DCHECK_EQ(layerInfo.pBsBuf[layer_len + 2], start_code[2]);
+      RTC_DCHECK_EQ(layerInfo.pBsBuf[layer_len + 3], start_code[3]);
+      layer_len += layerInfo.pNalLengthInByte[nal];
+    }
+    // Copy the entire layer's data (including start codes).
+    memcpy(buffer->data() + encoded_image->size(), layerInfo.pBsBuf, layer_len);
+    encoded_image->set_size(encoded_image->size() + layer_len);
+  }
+}
+
+H264EncoderImpl::H264EncoderImpl(const cricket::VideoCodec& codec)
+    : packetization_mode_(H264PacketizationMode::SingleNalUnit),
+      max_payload_size_(0),
+      number_of_cores_(0),
+      encoded_image_callback_(nullptr),
+      has_reported_init_(false),
+      has_reported_error_(false) {
+  RTC_CHECK(absl::EqualsIgnoreCase(codec.name, cricket::kH264CodecName));
+  std::string packetization_mode_string;
+  if (codec.GetParam(cricket::kH264FmtpPacketizationMode,
+                     &packetization_mode_string) &&
+      packetization_mode_string == "1") {
+    packetization_mode_ = H264PacketizationMode::NonInterleaved;
+  }
+  downscaled_buffers_.reserve(kMaxSimulcastStreams - 1);
+  encoded_images_.reserve(kMaxSimulcastStreams);
+  encoders_.reserve(kMaxSimulcastStreams);
+  configurations_.reserve(kMaxSimulcastStreams);
+  tl0sync_limit_.reserve(kMaxSimulcastStreams);
+  svc_controllers_.reserve(kMaxSimulcastStreams);
+}
+
+H264EncoderImpl::~H264EncoderImpl() {
+  Release();
+}
+
+int32_t H264EncoderImpl::InitEncode(const VideoCodec* inst,
+                                    const VideoEncoder::Settings& settings) {
+  ReportInit();
+  if (!inst || inst->codecType != kVideoCodecH264) {
+    ReportError();
+    return WEBRTC_VIDEO_CODEC_ERR_PARAMETER;
+  }
+  if (inst->maxFramerate == 0) {
+    ReportError();
+    return WEBRTC_VIDEO_CODEC_ERR_PARAMETER;
+  }
+  if (inst->width < 1 || inst->height < 1) {
+    ReportError();
+    return WEBRTC_VIDEO_CODEC_ERR_PARAMETER;
+  }
+
+  int32_t release_ret = Release();
+  if (release_ret != WEBRTC_VIDEO_CODEC_OK) {
+    ReportError();
+    return release_ret;
+  }
+
+  int number_of_streams = SimulcastUtility::NumberOfSimulcastStreams(*inst);
+  bool doing_simulcast = (number_of_streams > 1);
+
+  if (doing_simulcast &&
+      !SimulcastUtility::ValidSimulcastParameters(*inst, number_of_streams)) {
+    return WEBRTC_VIDEO_CODEC_ERR_SIMULCAST_PARAMETERS_NOT_SUPPORTED;
+  }
+  downscaled_buffers_.resize(number_of_streams - 1);
+  encoded_images_.resize(number_of_streams);
+  encoders_.resize(number_of_streams);
+  pictures_.resize(number_of_streams);
+  svc_controllers_.resize(number_of_streams);
+  scalability_modes_.resize(number_of_streams);
+  configurations_.resize(number_of_streams);
+  tl0sync_limit_.resize(number_of_streams);
+
+  max_payload_size_ = settings.max_payload_size;
+  number_of_cores_ = settings.number_of_cores;
+  encoder_thread_limit_ = settings.encoder_thread_limit;
+  codec_ = *inst;
+
+  // Code expects simulcastStream resolutions to be correct, make sure they are
+  // filled even when there are no simulcast layers.
+  if (codec_.numberOfSimulcastStreams == 0) {
+    codec_.simulcastStream[0].width = codec_.width;
+    codec_.simulcastStream[0].height = codec_.height;
+  }
+
+  for (int i = 0, idx = number_of_streams - 1; i < number_of_streams;
+       ++i, --idx) {
+    ISVCEncoder* openh264_encoder;
+    // Create encoder.
+    if (WelsCreateSVCEncoder(&openh264_encoder) != 0) {
+      // Failed to create encoder.
+      RTC_LOG(LS_ERROR) << "Failed to create OpenH264 encoder";
+      RTC_DCHECK(!openh264_encoder);
+      Release();
+      ReportError();
+      return WEBRTC_VIDEO_CODEC_ERROR;
+    }
+    RTC_DCHECK(openh264_encoder);
+    if (kOpenH264EncoderDetailedLogging) {
+      int trace_level = WELS_LOG_DETAIL;
+      openh264_encoder->SetOption(ENCODER_OPTION_TRACE_LEVEL, &trace_level);
+    }
+    // else WELS_LOG_DEFAULT is used by default.
+
+    // Store h264 encoder.
+    encoders_[i] = openh264_encoder;
+
+    // Set internal settings from codec_settings
+    configurations_[i].simulcast_idx = idx;
+    configurations_[i].sending = false;
+    configurations_[i].width = codec_.simulcastStream[idx].width;
+    configurations_[i].height = codec_.simulcastStream[idx].height;
+    configurations_[i].max_frame_rate = static_cast<float>(codec_.maxFramerate);
+    configurations_[i].frame_dropping_on = codec_.GetFrameDropEnabled();
+    configurations_[i].key_frame_interval = codec_.H264()->keyFrameInterval;
+    configurations_[i].num_temporal_layers =
+        std::max(codec_.H264()->numberOfTemporalLayers,
+                 codec_.simulcastStream[idx].numberOfTemporalLayers);
+
+    // Create downscaled image buffers.
+    if (i > 0) {
+      downscaled_buffers_[i - 1] = I420Buffer::Create(
+          configurations_[i].width, configurations_[i].height,
+          configurations_[i].width, configurations_[i].width / 2,
+          configurations_[i].width / 2);
+    }
+
+    // Codec_settings uses kbits/second; encoder uses bits/second.
+    configurations_[i].max_bps = codec_.maxBitrate * 1000;
+    configurations_[i].target_bps = codec_.startBitrate * 1000;
+
+    // Create encoder parameters based on the layer configuration.
+    SEncParamExt encoder_params = CreateEncoderParams(i);
+
+    // Initialize.
+    if (openh264_encoder->InitializeExt(&encoder_params) != 0) {
+      RTC_LOG(LS_ERROR) << "Failed to initialize OpenH264 encoder";
+      Release();
+      ReportError();
+      return WEBRTC_VIDEO_CODEC_ERROR;
+    }
+    // TODO(pbos): Base init params on these values before submitting.
+    int video_format = EVideoFormatType::videoFormatI420;
+    openh264_encoder->SetOption(ENCODER_OPTION_DATAFORMAT, &video_format);
+
+    // Initialize encoded image. Default buffer size: size of unencoded data.
+
+    const size_t new_capacity =
+        CalcBufferSize(VideoType::kI420, codec_.simulcastStream[idx].width,
+                       codec_.simulcastStream[idx].height);
+    encoded_images_[i].SetEncodedData(EncodedImageBuffer::Create(new_capacity));
+    encoded_images_[i]._encodedWidth = codec_.simulcastStream[idx].width;
+    encoded_images_[i]._encodedHeight = codec_.simulcastStream[idx].height;
+    encoded_images_[i].set_size(0);
+
+    tl0sync_limit_[i] = configurations_[i].num_temporal_layers;
+    scalability_modes_[i] = ScalabilityModeFromTemporalLayers(
+        configurations_[i].num_temporal_layers);
+    if (scalability_modes_[i].has_value()) {
+      svc_controllers_[i] = CreateScalabilityStructure(*scalability_modes_[i]);
+      if (svc_controllers_[i] == nullptr) {
+        RTC_LOG(LS_ERROR) << "Failed to create scalability structure";
+        Release();
+        ReportError();
+        return WEBRTC_VIDEO_CODEC_ERROR;
+      }
+    }
+  }
+
+  SimulcastRateAllocator init_allocator(codec_);
+  VideoBitrateAllocation allocation =
+      init_allocator.Allocate(VideoBitrateAllocationParameters(
+          DataRate::KilobitsPerSec(codec_.startBitrate), codec_.maxFramerate));
+  SetRates(RateControlParameters(allocation, codec_.maxFramerate));
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+int32_t H264EncoderImpl::Release() {
+  while (!encoders_.empty()) {
+    ISVCEncoder* openh264_encoder = encoders_.back();
+    if (openh264_encoder) {
+      RTC_CHECK_EQ(0, openh264_encoder->Uninitialize());
+      WelsDestroySVCEncoder(openh264_encoder);
+    }
+    encoders_.pop_back();
+  }
+  downscaled_buffers_.clear();
+  configurations_.clear();
+  encoded_images_.clear();
+  pictures_.clear();
+  tl0sync_limit_.clear();
+  svc_controllers_.clear();
+  scalability_modes_.clear();
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+int32_t H264EncoderImpl::RegisterEncodeCompleteCallback(
+    EncodedImageCallback* callback) {
+  encoded_image_callback_ = callback;
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+void H264EncoderImpl::SetRates(const RateControlParameters& parameters) {
+  if (encoders_.empty()) {
+    RTC_LOG(LS_WARNING) << "SetRates() while uninitialized.";
+    return;
+  }
+
+  if (parameters.framerate_fps < 1.0) {
+    RTC_LOG(LS_WARNING) << "Invalid frame rate: " << parameters.framerate_fps;
+    return;
+  }
+
+  if (parameters.bitrate.get_sum_bps() == 0) {
+    // Encoder paused, turn off all encoding.
+    for (size_t i = 0; i < configurations_.size(); ++i) {
+      configurations_[i].SetStreamState(false);
+    }
+    return;
+  }
+
+  codec_.maxFramerate = static_cast<uint32_t>(parameters.framerate_fps);
+
+  size_t stream_idx = encoders_.size() - 1;
+  for (size_t i = 0; i < encoders_.size(); ++i, --stream_idx) {
+    // Update layer config.
+    configurations_[i].target_bps =
+        parameters.bitrate.GetSpatialLayerSum(stream_idx);
+    configurations_[i].max_frame_rate = parameters.framerate_fps;
+
+    if (configurations_[i].target_bps) {
+      configurations_[i].SetStreamState(true);
+
+      // Update h264 encoder.
+      SBitrateInfo target_bitrate;
+      memset(&target_bitrate, 0, sizeof(SBitrateInfo));
+      target_bitrate.iLayer = SPATIAL_LAYER_ALL,
+      target_bitrate.iBitrate = configurations_[i].target_bps;
+      encoders_[i]->SetOption(ENCODER_OPTION_BITRATE, &target_bitrate);
+      encoders_[i]->SetOption(ENCODER_OPTION_FRAME_RATE,
+                              &configurations_[i].max_frame_rate);
+    } else {
+      configurations_[i].SetStreamState(false);
+    }
+  }
+}
+
+int32_t H264EncoderImpl::Encode(
+    const VideoFrame& input_frame,
+    const std::vector<VideoFrameType>* frame_types) {
+  if (encoders_.empty()) {
+    ReportError();
+    return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
+  }
+  if (!encoded_image_callback_) {
+    RTC_LOG(LS_WARNING)
+        << "InitEncode() has been called, but a callback function "
+           "has not been set with RegisterEncodeCompleteCallback()";
+    ReportError();
+    return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
+  }
+
+  rtc::scoped_refptr<I420BufferInterface> frame_buffer =
+      input_frame.video_frame_buffer()->ToI420();
+  if (!frame_buffer) {
+    RTC_LOG(LS_ERROR) << "Failed to convert "
+                      << VideoFrameBufferTypeToString(
+                             input_frame.video_frame_buffer()->type())
+                      << " image to I420. Can't encode frame.";
+    return WEBRTC_VIDEO_CODEC_ENCODER_FAILURE;
+  }
+  RTC_CHECK(frame_buffer->type() == VideoFrameBuffer::Type::kI420 ||
+            frame_buffer->type() == VideoFrameBuffer::Type::kI420A);
+
+  bool is_keyframe_needed = false;
+  for (size_t i = 0; i < configurations_.size(); ++i) {
+    if (configurations_[i].key_frame_request && configurations_[i].sending) {
+      // This is legacy behavior, generating a keyframe on all layers
+      // when generating one for a layer that became active for the first time
+      // or after being disabled.
+      is_keyframe_needed = true;
+      break;
+    }
+  }
+
+  RTC_DCHECK_EQ(configurations_[0].width, frame_buffer->width());
+  RTC_DCHECK_EQ(configurations_[0].height, frame_buffer->height());
+
+  // Encode image for each layer.
+  for (size_t i = 0; i < encoders_.size(); ++i) {
+    // EncodeFrame input.
+    pictures_[i] = {0};
+    pictures_[i].iPicWidth = configurations_[i].width;
+    pictures_[i].iPicHeight = configurations_[i].height;
+    pictures_[i].iColorFormat = EVideoFormatType::videoFormatI420;
+    pictures_[i].uiTimeStamp = input_frame.ntp_time_ms();
+    // Downscale images on second and ongoing layers.
+    if (i == 0) {
+      pictures_[i].iStride[0] = frame_buffer->StrideY();
+      pictures_[i].iStride[1] = frame_buffer->StrideU();
+      pictures_[i].iStride[2] = frame_buffer->StrideV();
+      pictures_[i].pData[0] = const_cast<uint8_t*>(frame_buffer->DataY());
+      pictures_[i].pData[1] = const_cast<uint8_t*>(frame_buffer->DataU());
+      pictures_[i].pData[2] = const_cast<uint8_t*>(frame_buffer->DataV());
+    } else {
+      pictures_[i].iStride[0] = downscaled_buffers_[i - 1]->StrideY();
+      pictures_[i].iStride[1] = downscaled_buffers_[i - 1]->StrideU();
+      pictures_[i].iStride[2] = downscaled_buffers_[i - 1]->StrideV();
+      pictures_[i].pData[0] =
+          const_cast<uint8_t*>(downscaled_buffers_[i - 1]->DataY());
+      pictures_[i].pData[1] =
+          const_cast<uint8_t*>(downscaled_buffers_[i - 1]->DataU());
+      pictures_[i].pData[2] =
+          const_cast<uint8_t*>(downscaled_buffers_[i - 1]->DataV());
+      // Scale the image down a number of times by downsampling factor.
+      libyuv::I420Scale(pictures_[i - 1].pData[0], pictures_[i - 1].iStride[0],
+                        pictures_[i - 1].pData[1], pictures_[i - 1].iStride[1],
+                        pictures_[i - 1].pData[2], pictures_[i - 1].iStride[2],
+                        configurations_[i - 1].width,
+                        configurations_[i - 1].height, pictures_[i].pData[0],
+                        pictures_[i].iStride[0], pictures_[i].pData[1],
+                        pictures_[i].iStride[1], pictures_[i].pData[2],
+                        pictures_[i].iStride[2], configurations_[i].width,
+                        configurations_[i].height, libyuv::kFilterBox);
+    }
+
+    if (!configurations_[i].sending) {
+      continue;
+    }
+    if (frame_types != nullptr && i < frame_types->size()) {
+      // Skip frame?
+      if ((*frame_types)[i] == VideoFrameType::kEmptyFrame) {
+        continue;
+      }
+    }
+    // Send a key frame either when this layer is configured to require one
+    // or we have explicitly been asked to.
+    const size_t simulcast_idx =
+        static_cast<size_t>(configurations_[i].simulcast_idx);
+    bool send_key_frame =
+        is_keyframe_needed ||
+        (frame_types && simulcast_idx < frame_types->size() &&
+         (*frame_types)[simulcast_idx] == VideoFrameType::kVideoFrameKey);
+    if (send_key_frame) {
+      // API doc says ForceIntraFrame(false) does nothing, but calling this
+      // function forces a key frame regardless of the `bIDR` argument's value.
+      // (If every frame is a key frame we get lag/delays.)
+      encoders_[i]->ForceIntraFrame(true);
+      configurations_[i].key_frame_request = false;
+    }
+    // EncodeFrame output.
+    SFrameBSInfo info;
+    memset(&info, 0, sizeof(SFrameBSInfo));
+
+    std::vector<ScalableVideoController::LayerFrameConfig> layer_frames;
+    if (svc_controllers_[i]) {
+      layer_frames = svc_controllers_[i]->NextFrameConfig(send_key_frame);
+      RTC_CHECK_EQ(layer_frames.size(), 1);
+    }
+
+    // Encode!
+    int enc_ret = encoders_[i]->EncodeFrame(&pictures_[i], &info);
+    if (enc_ret != 0) {
+      RTC_LOG(LS_ERROR)
+          << "OpenH264 frame encoding failed, EncodeFrame returned " << enc_ret
+          << ".";
+      ReportError();
+      return WEBRTC_VIDEO_CODEC_ERROR;
+    }
+
+    encoded_images_[i]._encodedWidth = configurations_[i].width;
+    encoded_images_[i]._encodedHeight = configurations_[i].height;
+    encoded_images_[i].SetRtpTimestamp(input_frame.timestamp());
+    encoded_images_[i].SetColorSpace(input_frame.color_space());
+    encoded_images_[i]._frameType = ConvertToVideoFrameType(info.eFrameType);
+    encoded_images_[i].SetSimulcastIndex(configurations_[i].simulcast_idx);
+
+    // Split encoded image up into fragments. This also updates
+    // `encoded_image_`.
+    RtpFragmentize(&encoded_images_[i], &info);
+
+    // Encoder can skip frames to save bandwidth in which case
+    // `encoded_images_[i]._length` == 0.
+    if (encoded_images_[i].size() > 0) {
+      // Parse QP.
+      h264_bitstream_parser_.ParseBitstream(encoded_images_[i]);
+      encoded_images_[i].qp_ =
+          h264_bitstream_parser_.GetLastSliceQp().value_or(-1);
+
+      // Deliver encoded image.
+      CodecSpecificInfo codec_specific;
+      codec_specific.codecType = kVideoCodecH264;
+      codec_specific.codecSpecific.H264.packetization_mode =
+          packetization_mode_;
+      codec_specific.codecSpecific.H264.temporal_idx = kNoTemporalIdx;
+      codec_specific.codecSpecific.H264.idr_frame =
+          info.eFrameType == videoFrameTypeIDR;
+      codec_specific.codecSpecific.H264.base_layer_sync = false;
+      if (configurations_[i].num_temporal_layers > 1) {
+        const uint8_t tid = info.sLayerInfo[0].uiTemporalId;
+        codec_specific.codecSpecific.H264.temporal_idx = tid;
+        codec_specific.codecSpecific.H264.base_layer_sync =
+            tid > 0 && tid < tl0sync_limit_[i];
+        if (svc_controllers_[i]) {
+          if (encoded_images_[i]._frameType == VideoFrameType::kVideoFrameKey) {
+            // Reset the ScalableVideoController on key frame
+            // to reset the expected dependency structure.
+            layer_frames =
+                svc_controllers_[i]->NextFrameConfig(/* restart= */ true);
+            RTC_CHECK_EQ(layer_frames.size(), 1);
+            RTC_DCHECK_EQ(layer_frames[0].TemporalId(), 0);
+            RTC_DCHECK_EQ(layer_frames[0].IsKeyframe(), true);
+          }
+
+          if (layer_frames[0].TemporalId() != tid) {
+            RTC_LOG(LS_WARNING)
+                << "Encoder produced a frame with temporal id " << tid
+                << ", expected " << layer_frames[0].TemporalId() << ".";
+            continue;
+          }
+          encoded_images_[i].SetTemporalIndex(tid);
+        }
+        if (codec_specific.codecSpecific.H264.base_layer_sync) {
+          tl0sync_limit_[i] = tid;
+        }
+        if (tid == 0) {
+          tl0sync_limit_[i] = configurations_[i].num_temporal_layers;
+        }
+      }
+      if (svc_controllers_[i]) {
+        codec_specific.generic_frame_info =
+            svc_controllers_[i]->OnEncodeDone(layer_frames[0]);
+        if (send_key_frame && codec_specific.generic_frame_info.has_value()) {
+          codec_specific.template_structure =
+              svc_controllers_[i]->DependencyStructure();
+        }
+        codec_specific.scalability_mode = scalability_modes_[i];
+      }
+      encoded_image_callback_->OnEncodedImage(encoded_images_[i],
+                                              &codec_specific);
+    }
+  }
+  return WEBRTC_VIDEO_CODEC_OK;
+}
+
+// Initialization parameters.
+// There are two ways to initialize. There is SEncParamBase (cleared with
+// memset(&p, 0, sizeof(SEncParamBase)) used in Initialize, and SEncParamExt
+// which is a superset of SEncParamBase (cleared with GetDefaultParams) used
+// in InitializeExt.
+SEncParamExt H264EncoderImpl::CreateEncoderParams(size_t i) const {
+  SEncParamExt encoder_params;
+  encoders_[i]->GetDefaultParams(&encoder_params);
+  if (codec_.mode == VideoCodecMode::kRealtimeVideo) {
+    encoder_params.iUsageType = CAMERA_VIDEO_REAL_TIME;
+  } else if (codec_.mode == VideoCodecMode::kScreensharing) {
+    encoder_params.iUsageType = SCREEN_CONTENT_REAL_TIME;
+  } else {
+    RTC_DCHECK_NOTREACHED();
+  }
+  encoder_params.iPicWidth = configurations_[i].width;
+  encoder_params.iPicHeight = configurations_[i].height;
+  encoder_params.iTargetBitrate = configurations_[i].target_bps;
+  // Keep unspecified. WebRTC's max codec bitrate is not the same setting
+  // as OpenH264's iMaxBitrate. More details in https://crbug.com/webrtc/11543
+  encoder_params.iMaxBitrate = UNSPECIFIED_BIT_RATE;
+  // Rate Control mode
+  encoder_params.iRCMode = RC_BITRATE_MODE;
+  encoder_params.fMaxFrameRate = configurations_[i].max_frame_rate;
+
+  // The following parameters are extension parameters (they're in SEncParamExt,
+  // not in SEncParamBase).
+  encoder_params.bEnableFrameSkip = configurations_[i].frame_dropping_on;
+  // `uiIntraPeriod`    - multiple of GOP size
+  // `keyFrameInterval` - number of frames
+  encoder_params.uiIntraPeriod = configurations_[i].key_frame_interval;
+  // Reuse SPS id if possible. This helps to avoid reset of chromium HW decoder
+  // on each key-frame.
+  // Note that WebRTC resets encoder on resolution change which makes all
+  // EParameterSetStrategy modes except INCREASING_ID (default) essentially
+  // equivalent to CONSTANT_ID.
+  encoder_params.eSpsPpsIdStrategy = SPS_LISTING;
+  encoder_params.uiMaxNalSize = 0;
+  // Threading model: use auto.
+  //  0: auto (dynamic imp. internal encoder)
+  //  1: single thread (default value)
+  // >1: number of threads
+  encoder_params.iMultipleThreadIdc =
+      NumberOfThreads(encoder_thread_limit_, encoder_params.iPicWidth,
+                      encoder_params.iPicHeight, number_of_cores_);
+  // The base spatial layer 0 is the only one we use.
+  encoder_params.sSpatialLayers[0].iVideoWidth = encoder_params.iPicWidth;
+  encoder_params.sSpatialLayers[0].iVideoHeight = encoder_params.iPicHeight;
+  encoder_params.sSpatialLayers[0].fFrameRate = encoder_params.fMaxFrameRate;
+  encoder_params.sSpatialLayers[0].iSpatialBitrate =
+      encoder_params.iTargetBitrate;
+  encoder_params.sSpatialLayers[0].iMaxSpatialBitrate =
+      encoder_params.iMaxBitrate;
+  encoder_params.iTemporalLayerNum = configurations_[i].num_temporal_layers;
+  if (encoder_params.iTemporalLayerNum > 1) {
+    // iNumRefFrame specifies total number of reference buffers to allocate.
+    // For N temporal layers we need at least (N - 1) buffers to store last
+    // encoded frames of all reference temporal layers.
+    // Note that there is no API in OpenH264 encoder to specify exact set of
+    // references to be used to prediction of a given frame. Encoder can
+    // theoretically use all available reference buffers.
+    encoder_params.iNumRefFrame = encoder_params.iTemporalLayerNum - 1;
+  }
+  RTC_LOG(LS_INFO) << "OpenH264 version is " << OPENH264_MAJOR << "."
+                   << OPENH264_MINOR;
+  switch (packetization_mode_) {
+    case H264PacketizationMode::SingleNalUnit:
+      // Limit the size of the packets produced.
+      encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceNum = 1;
+      encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceMode =
+          SM_SIZELIMITED_SLICE;
+      encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceSizeConstraint =
+          static_cast<unsigned int>(max_payload_size_);
+      RTC_LOG(LS_INFO) << "Encoder is configured with NALU constraint: "
+                       << max_payload_size_ << " bytes";
+      break;
+    case H264PacketizationMode::NonInterleaved:
+      // When uiSliceMode = SM_FIXEDSLCNUM_SLICE, uiSliceNum = 0 means auto
+      // design it with cpu core number.
+      // TODO(sprang): Set to 0 when we understand why the rate controller borks
+      //               when uiSliceNum > 1.
+      encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceNum = 1;
+      encoder_params.sSpatialLayers[0].sSliceArgument.uiSliceMode =
+          SM_FIXEDSLCNUM_SLICE;
+      break;
+  }
+  return encoder_params;
+}
+
+void H264EncoderImpl::ReportInit() {
+  if (has_reported_init_)
+    return;
+  RTC_HISTOGRAM_ENUMERATION("WebRTC.Video.H264EncoderImpl.Event",
+                            kH264EncoderEventInit, kH264EncoderEventMax);
+  has_reported_init_ = true;
+}
+
+void H264EncoderImpl::ReportError() {
+  if (has_reported_error_)
+    return;
+  RTC_HISTOGRAM_ENUMERATION("WebRTC.Video.H264EncoderImpl.Event",
+                            kH264EncoderEventError, kH264EncoderEventMax);
+  has_reported_error_ = true;
+}
+
+VideoEncoder::EncoderInfo H264EncoderImpl::GetEncoderInfo() const {
+  EncoderInfo info;
+  info.supports_native_handle = false;
+  info.implementation_name = "OpenH264";
+  info.scaling_settings =
+      VideoEncoder::ScalingSettings(kLowH264QpThreshold, kHighH264QpThreshold);
+  info.is_hardware_accelerated = false;
+  info.supports_simulcast = true;
+  info.preferred_pixel_formats = {VideoFrameBuffer::Type::kI420};
+  return info;
+}
+
+void H264EncoderImpl::LayerConfig::SetStreamState(bool send_stream) {
+  if (send_stream && !sending) {
+    // Need a key frame if we have not sent this stream before.
+    key_frame_request = true;
+  }
+  sending = send_stream;
+}
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_USE_H264