path: root/dom/media/encoder/VP8TrackEncoder.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "VP8TrackEncoder.h"
#include "GeckoProfiler.h"
#include "LayersLogging.h"
#include "libyuv.h"
#include "mozilla/gfx/2D.h"
#include "prsystem.h"
#include "VideoSegment.h"
#include "VideoUtils.h"
#include "vpx/vp8cx.h"
#include "vpx/vpx_encoder.h"
#include "WebMWriter.h"
#include "mozilla/media/MediaUtils.h"

namespace mozilla {

LazyLogModule gVP8TrackEncoderLog("VP8TrackEncoder");
#define VP8LOG(msg, ...) MOZ_LOG(gVP8TrackEncoderLog, mozilla::LogLevel::Debug, \
                                  (msg, ##__VA_ARGS__))
// Debug logging macro with object pointer and class name.

#define DEFAULT_BITRATE_BPS 2500000
#define DEFAULT_ENCODE_FRAMERATE 30

using namespace mozilla::gfx;
using namespace mozilla::layers;

VP8TrackEncoder::VP8TrackEncoder(TrackRate aTrackRate)
  : VideoTrackEncoder(aTrackRate)
  , mEncodedFrameDuration(0)
  , mEncodedTimestamp(0)
  , mRemainingTicks(0)
  , mVPXContext(new vpx_codec_ctx_t())
  , mVPXImageWrapper(new vpx_image_t())
{
  MOZ_COUNT_CTOR(VP8TrackEncoder);
}

VP8TrackEncoder::~VP8TrackEncoder()
{
  if (mInitialized) {
    vpx_codec_destroy(mVPXContext);
  }

  if (mVPXImageWrapper) {
    vpx_img_free(mVPXImageWrapper);
  }
  MOZ_COUNT_DTOR(VP8TrackEncoder);
}

nsresult
VP8TrackEncoder::Init(int32_t aWidth, int32_t aHeight, int32_t aDisplayWidth,
                      int32_t aDisplayHeight)
{
  if (aWidth < 1 || aHeight < 1 || aDisplayWidth < 1 || aDisplayHeight < 1) {
    return NS_ERROR_FAILURE;
  }

  ReentrantMonitorAutoEnter mon(mReentrantMonitor);

  mEncodedFrameRate = DEFAULT_ENCODE_FRAMERATE;
  mEncodedFrameDuration = mTrackRate / mEncodedFrameRate;
  mFrameWidth = aWidth;
  mFrameHeight = aHeight;
  mDisplayWidth = aDisplayWidth;
  mDisplayHeight = aDisplayHeight;

  // Encoder configuration structure.
  vpx_codec_enc_cfg_t config;
  memset(&config, 0, sizeof(vpx_codec_enc_cfg_t));
  if (vpx_codec_enc_config_default(vpx_codec_vp8_cx(), &config, 0)) {
    return NS_ERROR_FAILURE;
  }

  // Creating a wrapper to the image - setting image data to NULL. Actual
  // pointer will be set in encode. Setting align to 1, as it is meaningless
  // (actual memory is not allocated).
  vpx_img_wrap(mVPXImageWrapper, VPX_IMG_FMT_I420,
               mFrameWidth, mFrameHeight, 1, nullptr);

  config.g_w = mFrameWidth;
  config.g_h = mFrameHeight;
  // TODO: Maybe we should have various aFrameRate bitrate pair for each devices?
  // or for different platform

  // rc_target_bitrate needs kbit/s
  config.rc_target_bitrate = (mVideoBitrate != 0 ? mVideoBitrate : DEFAULT_BITRATE_BPS)/1000;

  // Setting the time base of the codec
  config.g_timebase.num = 1;
  config.g_timebase.den = mTrackRate;

  config.g_error_resilient = 0;

  config.g_lag_in_frames = 0; // 0- no frame lagging

  int32_t number_of_cores = PR_GetNumberOfProcessors();
  if (mFrameWidth * mFrameHeight > 1280 * 960 && number_of_cores >= 6) {
    config.g_threads = 3; // 3 threads for 1080p.
  } else if (mFrameWidth * mFrameHeight > 640 * 480 && number_of_cores >= 3) {
    config.g_threads = 2; // 2 threads for qHD/HD.
  } else {
    config.g_threads = 1; // 1 thread for VGA or less
  }

  // rate control settings
  config.rc_dropframe_thresh = 0;
  config.rc_end_usage = VPX_CBR;
  config.g_pass = VPX_RC_ONE_PASS;
  // ffmpeg doesn't currently support streams that use resize.
  // Therefore, for safety, we should turn it off until it does.
  config.rc_resize_allowed = 0;
  config.rc_undershoot_pct = 100;
  config.rc_overshoot_pct = 15;
  config.rc_buf_initial_sz = 500;
  config.rc_buf_optimal_sz = 600;
  config.rc_buf_sz = 1000;

  config.kf_mode = VPX_KF_AUTO;
  // Ensure that we can output one I-frame per second.
  config.kf_max_dist = mEncodedFrameRate;

  vpx_codec_flags_t flags = 0;
  flags |= VPX_CODEC_USE_OUTPUT_PARTITION;
  if (vpx_codec_enc_init(mVPXContext, vpx_codec_vp8_cx(), &config, flags)) {
    return NS_ERROR_FAILURE;
  }

  vpx_codec_control(mVPXContext, VP8E_SET_STATIC_THRESHOLD, 1);
  vpx_codec_control(mVPXContext, VP8E_SET_CPUUSED, -6);
  vpx_codec_control(mVPXContext, VP8E_SET_TOKEN_PARTITIONS,
                    VP8_ONE_TOKENPARTITION);

  mInitialized = true;
  mon.NotifyAll();

  return NS_OK;
}

already_AddRefed<TrackMetadataBase>
VP8TrackEncoder::GetMetadata()
{
  PROFILER_LABEL("VP8TrackEncoder", "GetMetadata",
    js::ProfileEntry::Category::OTHER);
  {
    // Wait if mEncoder is not initialized.
    ReentrantMonitorAutoEnter mon(mReentrantMonitor);
    while (!mCanceled && !mInitialized) {
      mon.Wait();
    }
  }

  if (mCanceled || mEncodingComplete) {
    return nullptr;
  }

  RefPtr<VP8Metadata> meta = new VP8Metadata();
  meta->mWidth = mFrameWidth;
  meta->mHeight = mFrameHeight;
  meta->mDisplayWidth = mDisplayWidth;
  meta->mDisplayHeight = mDisplayHeight;
  meta->mEncodedFrameRate = mEncodedFrameRate;

  return meta.forget();
}

bool
VP8TrackEncoder::GetEncodedPartitions(EncodedFrameContainer& aData)
{
  vpx_codec_iter_t iter = nullptr;
  EncodedFrame::FrameType frameType = EncodedFrame::VP8_P_FRAME;
  nsTArray<uint8_t> frameData;
  const vpx_codec_cx_pkt_t *pkt = nullptr;
  while ((pkt = vpx_codec_get_cx_data(mVPXContext, &iter)) != nullptr) {
    switch (pkt->kind) {
      case VPX_CODEC_CX_FRAME_PKT: {
        // Copy the encoded data from libvpx to frameData
        frameData.AppendElements((uint8_t*)pkt->data.frame.buf,
                                 pkt->data.frame.sz);
        break;
      }
      default: {
        break;
      }
    }
    // End of frame
    if ((pkt->data.frame.flags & VPX_FRAME_IS_FRAGMENT) == 0) {
      if (pkt->data.frame.flags & VPX_FRAME_IS_KEY) {
        frameType = EncodedFrame::VP8_I_FRAME;
      }
      break;
    }
  }

  if (!frameData.IsEmpty()) {
    // Copy the encoded data to aData.
    EncodedFrame* videoData = new EncodedFrame();
    videoData->SetFrameType(frameType);
    // Convert the timestamp and duration to Usecs.
    CheckedInt64 timestamp = FramesToUsecs(pkt->data.frame.pts, mTrackRate);
    if (timestamp.isValid()) {
      videoData->SetTimeStamp((uint64_t)timestamp.value());
    }
    CheckedInt64 duration = FramesToUsecs(pkt->data.frame.duration, mTrackRate);
    if (duration.isValid()) {
      videoData->SetDuration((uint64_t)duration.value());
    }
    videoData->SwapInFrameData(frameData);
    VP8LOG("GetEncodedPartitions TimeStamp %lld Duration %lld\n",
           videoData->GetTimeStamp(), videoData->GetDuration());
    VP8LOG("frameType %d\n", videoData->GetFrameType());
    aData.AppendEncodedFrame(videoData);
  }

  return !!pkt;
}

static bool isYUV420(const PlanarYCbCrImage::Data *aData)
{
  if (aData->mYSize == aData->mCbCrSize * 2) {
    return true;
  }
  return false;
}

static bool isYUV422(const PlanarYCbCrImage::Data *aData)
{
  if ((aData->mYSize.width == aData->mCbCrSize.width * 2) &&
      (aData->mYSize.height == aData->mCbCrSize.height)) {
    return true;
  }
  return false;
}

static bool isYUV444(const PlanarYCbCrImage::Data *aData)
{
  if (aData->mYSize == aData->mCbCrSize) {
    return true;
  }
  return false;
}

nsresult VP8TrackEncoder::PrepareRawFrame(VideoChunk &aChunk)
{
  RefPtr<Image> img;
  if (aChunk.mFrame.GetForceBlack() || aChunk.IsNull()) {
    if (!mMuteFrame) {
      mMuteFrame = VideoFrame::CreateBlackImage(gfx::IntSize(mFrameWidth, mFrameHeight));
      MOZ_ASSERT(mMuteFrame);
    }
    img = mMuteFrame;
  } else {
    img = aChunk.mFrame.GetImage();
  }

  if (img->GetSize() != IntSize(mFrameWidth, mFrameHeight)) {
    VP8LOG("Dynamic resolution changes (was %dx%d, now %dx%d) are unsupported\n",
           mFrameWidth, mFrameHeight, img->GetSize().width, img->GetSize().height);
    return NS_ERROR_FAILURE;
  }

  ImageFormat format = img->GetFormat();
  if (format == ImageFormat::PLANAR_YCBCR) {
    PlanarYCbCrImage* yuv = static_cast<PlanarYCbCrImage *>(img.get());

    MOZ_RELEASE_ASSERT(yuv);
    if (!yuv->IsValid()) {
      NS_WARNING("PlanarYCbCrImage is not valid");
      return NS_ERROR_FAILURE;
    }
    const PlanarYCbCrImage::Data *data = yuv->GetData();

    if (isYUV420(data) && !data->mCbSkip) {
      // 420 planar, no need for conversions
      mVPXImageWrapper->planes[VPX_PLANE_Y] = data->mYChannel;
      mVPXImageWrapper->planes[VPX_PLANE_U] = data->mCbChannel;
      mVPXImageWrapper->planes[VPX_PLANE_V] = data->mCrChannel;
      mVPXImageWrapper->stride[VPX_PLANE_Y] = data->mYStride;
      mVPXImageWrapper->stride[VPX_PLANE_U] = data->mCbCrStride;
      mVPXImageWrapper->stride[VPX_PLANE_V] = data->mCbCrStride;

      return NS_OK;
    }
  }

  // Not 420 planar, have to convert
  uint32_t yPlaneSize = mFrameWidth * mFrameHeight;
  uint32_t halfWidth = (mFrameWidth + 1) / 2;
  uint32_t halfHeight = (mFrameHeight + 1) / 2;
  uint32_t uvPlaneSize = halfWidth * halfHeight;

  if (mI420Frame.IsEmpty()) {
    mI420Frame.SetLength(yPlaneSize + uvPlaneSize * 2);
  }

  uint8_t *y = mI420Frame.Elements();
  uint8_t *cb = mI420Frame.Elements() + yPlaneSize;
  uint8_t *cr = mI420Frame.Elements() + yPlaneSize + uvPlaneSize;

  if (format == ImageFormat::PLANAR_YCBCR) {
    PlanarYCbCrImage* yuv = static_cast<PlanarYCbCrImage *>(img.get());

    MOZ_RELEASE_ASSERT(yuv);
    if (!yuv->IsValid()) {
      NS_WARNING("PlanarYCbCrImage is not valid");
      return NS_ERROR_FAILURE;
    }
    const PlanarYCbCrImage::Data *data = yuv->GetData();

    int rv;
    std::string yuvFormat;
    if (isYUV420(data) && data->mCbSkip) {
      // If mCbSkip is set, we assume it's nv12 or nv21.
      if (data->mCbChannel < data->mCrChannel) { // nv12
        rv = libyuv::NV12ToI420(data->mYChannel, data->mYStride,
                                data->mCbChannel, data->mCbCrStride,
                                y, mFrameWidth,
                                cb, halfWidth,
                                cr, halfWidth,
                                mFrameWidth, mFrameHeight);
        yuvFormat = "NV12";
      } else { // nv21
        rv = libyuv::NV21ToI420(data->mYChannel, data->mYStride,
                                data->mCrChannel, data->mCbCrStride,
                                y, mFrameWidth,
                                cb, halfWidth,
                                cr, halfWidth,
                                mFrameWidth, mFrameHeight);
        yuvFormat = "NV21";
      }
    } else if (isYUV444(data) && !data->mCbSkip) {
      rv = libyuv::I444ToI420(data->mYChannel, data->mYStride,
                              data->mCbChannel, data->mCbCrStride,
                              data->mCrChannel, data->mCbCrStride,
                              y, mFrameWidth,
                              cb, halfWidth,
                              cr, halfWidth,
                              mFrameWidth, mFrameHeight);
      yuvFormat = "I444";
    } else if (isYUV422(data) && !data->mCbSkip) {
      rv = libyuv::I422ToI420(data->mYChannel, data->mYStride,
                              data->mCbChannel, data->mCbCrStride,
                              data->mCrChannel, data->mCbCrStride,
                              y, mFrameWidth,
                              cb, halfWidth,
                              cr, halfWidth,
                              mFrameWidth, mFrameHeight);
      yuvFormat = "I422";
    } else {
      VP8LOG("Unsupported planar format\n");
      NS_ASSERTION(false, "Unsupported planar format");
      return NS_ERROR_NOT_IMPLEMENTED;
    }

    if (rv != 0) {
      VP8LOG("Converting an %s frame to I420 failed\n", yuvFormat.c_str());
      return NS_ERROR_FAILURE;
    }

    VP8LOG("Converted an %s frame to I420\n", yuvFormat.c_str());
  } else {
    // Not YCbCr at all. Try to get access to the raw data and convert.

    RefPtr<SourceSurface> surf = GetSourceSurface(img.forget());
    if (!surf) {
      VP8LOG("Getting surface from %s image failed\n", Stringify(format).c_str());
      return NS_ERROR_FAILURE;
    }

    RefPtr<DataSourceSurface> data = surf->GetDataSurface();
    if (!data) {
      VP8LOG("Getting data surface from %s image with %s (%s) surface failed\n",
             Stringify(format).c_str(), Stringify(surf->GetType()).c_str(),
             Stringify(surf->GetFormat()).c_str());
      return NS_ERROR_FAILURE;
    }

    DataSourceSurface::ScopedMap map(data, DataSourceSurface::READ);
    if (!map.IsMapped()) {
      VP8LOG("Reading DataSourceSurface from %s image with %s (%s) surface failed\n",
             Stringify(format).c_str(), Stringify(surf->GetType()).c_str(),
             Stringify(surf->GetFormat()).c_str());
      return NS_ERROR_FAILURE;
    }

    int rv;
    switch (surf->GetFormat()) {
      case SurfaceFormat::B8G8R8A8:
      case SurfaceFormat::B8G8R8X8:
        rv = libyuv::ARGBToI420(static_cast<uint8*>(map.GetData()),
                                map.GetStride(),
                                y, mFrameWidth,
                                cb, halfWidth,
                                cr, halfWidth,
                                mFrameWidth, mFrameHeight);
        break;
      case SurfaceFormat::R5G6B5_UINT16:
        rv = libyuv::RGB565ToI420(static_cast<uint8*>(map.GetData()),
                                  map.GetStride(),
                                  y, mFrameWidth,
                                  cb, halfWidth,
                                  cr, halfWidth,
                                  mFrameWidth, mFrameHeight);
        break;
      default:
        VP8LOG("Unsupported SourceSurface format %s\n",
               Stringify(surf->GetFormat()).c_str());
        NS_ASSERTION(false, "Unsupported SourceSurface format");
        return NS_ERROR_NOT_IMPLEMENTED;
    }

    if (rv != 0) {
      VP8LOG("%s to I420 conversion failed\n",
             Stringify(surf->GetFormat()).c_str());
      return NS_ERROR_FAILURE;
    }

    VP8LOG("Converted a %s frame to I420\n",
           Stringify(surf->GetFormat()).c_str());
  }

  mVPXImageWrapper->planes[VPX_PLANE_Y] = y;
  mVPXImageWrapper->planes[VPX_PLANE_U] = cb;
  mVPXImageWrapper->planes[VPX_PLANE_V] = cr;
  mVPXImageWrapper->stride[VPX_PLANE_Y] = mFrameWidth;
  mVPXImageWrapper->stride[VPX_PLANE_U] = halfWidth;
  mVPXImageWrapper->stride[VPX_PLANE_V] = halfWidth;

  return NS_OK;
}

void
VP8TrackEncoder::ReplyGetSourceSurface(already_AddRefed<gfx::SourceSurface> aSurf)
{
  mSourceSurface = aSurf;
}

already_AddRefed<gfx::SourceSurface>
VP8TrackEncoder::GetSourceSurface(already_AddRefed<Image> aImg)
{
  RefPtr<Image> img = aImg;
  mSourceSurface = nullptr;
  if (img) {
    if (img->AsGLImage() && !NS_IsMainThread()) {
      // GLImage::GetAsSourceSurface() only support main thread
      RefPtr<Runnable> getsourcesurface_runnable =
        media::NewRunnableFrom([this, img]() -> nsresult {
          // Due to the parameter DISPATCH_SYNC, encoder thread will stock at
          // MediaRecorder::Session::Extract(bool). There is no chance
          // that TrackEncoder will be destroyed during this period. So
          // there is no need to use RefPtr to hold TrackEncoder.
          ReplyGetSourceSurface(img->GetAsSourceSurface());
          return NS_OK;
        });
      NS_DispatchToMainThread(getsourcesurface_runnable, NS_DISPATCH_SYNC);
    } else {
      mSourceSurface = img->GetAsSourceSurface();
    }
  }
  return mSourceSurface.forget();
}

// These two define value used in GetNextEncodeOperation to determine the
// EncodeOperation for next target frame.
#define I_FRAME_RATIO (0.5)
#define SKIP_FRAME_RATIO (0.75)

/**
 * Compares the elapsed time from the beginning of GetEncodedTrack and
 * the processed frame duration in mSourceSegment
 * in order to set the nextEncodeOperation for next target frame.
 */
VP8TrackEncoder::EncodeOperation
VP8TrackEncoder::GetNextEncodeOperation(TimeDuration aTimeElapsed,
                                        StreamTime aProcessedDuration)
{
  int64_t durationInUsec =
    FramesToUsecs(aProcessedDuration + mEncodedFrameDuration,
                  mTrackRate).value();
  if (aTimeElapsed.ToMicroseconds() > (durationInUsec * SKIP_FRAME_RATIO)) {
    // The encoder is too slow.
    // We should skip next frame to consume the mSourceSegment.
    return SKIP_FRAME;
  } else if (aTimeElapsed.ToMicroseconds() > (durationInUsec * I_FRAME_RATIO)) {
    // The encoder is a little slow.
    // We force the encoder to encode an I-frame to accelerate.
    return ENCODE_I_FRAME;
  } else {
    return ENCODE_NORMAL_FRAME;
  }
}

StreamTime
VP8TrackEncoder::CalculateRemainingTicks(StreamTime aDurationCopied,
                                         StreamTime aEncodedDuration)
{
  return mRemainingTicks + aEncodedDuration - aDurationCopied;
}

// Try to extend the encodedDuration as long as possible if the target frame
// has a long duration.
StreamTime
VP8TrackEncoder::CalculateEncodedDuration(StreamTime aDurationCopied)
{
  StreamTime temp64 = aDurationCopied;
  StreamTime encodedDuration = mEncodedFrameDuration;
  temp64 -= mRemainingTicks;
  while (temp64 > mEncodedFrameDuration) {
    temp64 -= mEncodedFrameDuration;
    encodedDuration += mEncodedFrameDuration;
  }
  return encodedDuration;
}

/**
 * Encoding flow in GetEncodedTrack():
 * 1: Check the mInitialized state and the packet duration.
 * 2: Move the data from mRawSegment to mSourceSegment.
 * 3: Encode the video chunks in mSourceSegment in a for-loop.
 * 3.1: Pick the video chunk by mRemainingTicks.
 * 3.2: Calculate the encoding duration for the parameter of vpx_codec_encode().
 *      The encoding duration is a multiple of mEncodedFrameDuration.
 * 3.3: Setup the video chunk to mVPXImageWrapper by PrepareRawFrame().
 * 3.4: Send frame into vp8 encoder by vpx_codec_encode().
 * 3.5: Get the output frame from encoder by calling GetEncodedPartitions().
 * 3.6: Calculate the mRemainingTicks for next target frame.
 * 3.7: Set the nextEncodeOperation for the next target frame.
 *      There is a heuristic: If the frame duration we have processed in
 *      mSourceSegment is 100ms, means that we can't spend more than 100ms to
 *      encode it.
 * 4. Remove the encoded chunks in mSourceSegment after for-loop.
 *
 * Ex1: Input frame rate is 100 => input frame duration is 10ms for each.
 *     mEncodedFrameRate is 30 => output frame duration is 33ms.
 *     In this case, the frame duration in mSourceSegment will be:
 *     1st : 0~10ms
 *     2nd : 10~20ms
 *     3rd : 20~30ms
 *     4th : 30~40ms
 *     ...
 *     The VP8 encoder will take the 1st and 4th frames to encode. At beginning
 *     mRemainingTicks is 0 for 1st frame, then the mRemainingTicks is set
 *     to 23 to pick the 4th frame. (mEncodedFrameDuration - 1st frame duration)
 *
 * Ex2: Input frame rate is 25 => frame duration is 40ms for each.
 *     mEncodedFrameRate is 30 => output frame duration is 33ms.
 *     In this case, the frame duration in mSourceSegment will be:
 *     1st : 0~40ms
 *     2nd : 40~80ms
 *     3rd : 80~120ms
 *     4th : 120~160ms
 *     ...
 *     Because the input frame duration is 40ms larger than 33ms, so the first
 *     encoded frame duration will be 66ms by calling CalculateEncodedDuration.
 *     And the mRemainingTicks will be set to 26
 *     (CalculateRemainingTicks 0+66-40) in order to pick the next frame(2nd)
 *     in mSourceSegment.
 */
nsresult
VP8TrackEncoder::GetEncodedTrack(EncodedFrameContainer& aData)
{
  PROFILER_LABEL("VP8TrackEncoder", "GetEncodedTrack",
    js::ProfileEntry::Category::OTHER);
  bool EOS;
  {
    // Move all the samples from mRawSegment to mSourceSegment. We only hold
    // the monitor in this block.
    ReentrantMonitorAutoEnter mon(mReentrantMonitor);
    // Wait if mEncoder is not initialized, or when not enough raw data, but is
    // not the end of stream nor is being canceled.
    while (!mCanceled && (!mInitialized ||
           (mRawSegment.GetDuration() + mSourceSegment.GetDuration() <
            mEncodedFrameDuration && !mEndOfStream))) {
      mon.Wait();
    }
    if (mCanceled || mEncodingComplete) {
      return NS_ERROR_FAILURE;
    }
    mSourceSegment.AppendFrom(&mRawSegment);
    EOS = mEndOfStream;
  }

  VideoSegment::ChunkIterator iter(mSourceSegment);
  StreamTime durationCopied = 0;
  StreamTime totalProcessedDuration = 0;
  TimeStamp timebase = TimeStamp::Now();
  EncodeOperation nextEncodeOperation = ENCODE_NORMAL_FRAME;

  for (; !iter.IsEnded(); iter.Next()) {
    VideoChunk &chunk = *iter;
    // Accumulate chunk's duration to durationCopied until it reaches
    // mRemainingTicks.
    durationCopied += chunk.GetDuration();
    MOZ_ASSERT(mRemainingTicks <= mEncodedFrameDuration);
    VP8LOG("durationCopied %lld mRemainingTicks %lld\n",
           durationCopied, mRemainingTicks);
    if (durationCopied >= mRemainingTicks) {
      VP8LOG("nextEncodeOperation is %d\n",nextEncodeOperation);
      // Calculate encodedDuration for this target frame.
      StreamTime encodedDuration = CalculateEncodedDuration(durationCopied);

      // Encode frame.
      if (nextEncodeOperation != SKIP_FRAME) {
        nsresult rv = PrepareRawFrame(chunk);
        NS_ENSURE_SUCCESS(rv, NS_ERROR_FAILURE);

        // Encode the data with VP8 encoder
        int flags = (nextEncodeOperation == ENCODE_NORMAL_FRAME) ?
                    0 : VPX_EFLAG_FORCE_KF;
        if (vpx_codec_encode(mVPXContext, mVPXImageWrapper, mEncodedTimestamp,
                             (unsigned long)encodedDuration, flags,
                             VPX_DL_REALTIME)) {
          return NS_ERROR_FAILURE;
        }
        // Get the encoded data from VP8 encoder.
        GetEncodedPartitions(aData);
      } else {
        // SKIP_FRAME
        // Extend the duration of the last encoded data in aData
        // because this frame will be skip.
        RefPtr<EncodedFrame> last = aData.GetEncodedFrames().LastElement();
        if (last) {
          CheckedInt64 skippedDuration = FramesToUsecs(chunk.mDuration, mTrackRate);
          if (skippedDuration.isValid() && skippedDuration.value() > 0) {
            last->SetDuration(last->GetDuration() +
                              (static_cast<uint64_t>(skippedDuration.value())));
          }
        }
      }
      // Move forward the mEncodedTimestamp.
      mEncodedTimestamp += encodedDuration;
      totalProcessedDuration += durationCopied;
      // Calculate mRemainingTicks for next target frame.
      mRemainingTicks = CalculateRemainingTicks(durationCopied,
                                                encodedDuration);

      // Check the remain data is enough for next target frame.
      if (mSourceSegment.GetDuration() - totalProcessedDuration
          >= mEncodedFrameDuration) {
        TimeDuration elapsedTime = TimeStamp::Now() - timebase;
        nextEncodeOperation = GetNextEncodeOperation(elapsedTime,
                                                     totalProcessedDuration);
        // Reset durationCopied for next iteration.
        durationCopied = 0;
      } else {
        // Process done, there is no enough data left for next iteration,
        // break the for-loop.
        break;
      }
    }
  }
  // Remove the chunks we have processed.
  mSourceSegment.RemoveLeading(totalProcessedDuration);
  VP8LOG("RemoveLeading %lld\n",totalProcessedDuration);

  // End of stream, pull the rest frames in encoder.
  if (EOS) {
    VP8LOG("mEndOfStream is true\n");
    mEncodingComplete = true;
    // Bug 1243611, keep calling vpx_codec_encode and vpx_codec_get_cx_data
    // until vpx_codec_get_cx_data return null.

    do {
      if (vpx_codec_encode(mVPXContext, nullptr, mEncodedTimestamp,
                           mEncodedFrameDuration, 0, VPX_DL_REALTIME)) {
        return NS_ERROR_FAILURE;
      }
    } while(GetEncodedPartitions(aData));
  }

  return NS_OK ;
}

} // namespace mozilla