[chromecast] Adds MediaSinkDefault.

chromecast/media/cma/backend/media_sink_default.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chromecast/media/cma/backend/media_sink_default.h"
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "chromecast/public/media/cast_decoder_buffer.h"
+#include "media/base/timestamp_constants.h"
+
+namespace chromecast {
+namespace media {
+
+MediaSinkDefault::MediaSinkDefault(
+    MediaPipelineBackend::Decoder::Delegate* delegate,
+    base::TimeDelta start_pts)
+    : delegate_(delegate),
+      time_interpolator_(&tick_clock_),
+      playback_rate_(1.0f),
+      last_frame_pts_(start_pts),
+      received_eos_(false) {
+  DCHECK(delegate_);
+  time_interpolator_.SetPlaybackRate(playback_rate_);
+  time_interpolator_.SetBounds(start_pts, start_pts, tick_clock_.NowTicks());
+  time_interpolator_.StartInterpolating();
+}
+
+MediaSinkDefault::~MediaSinkDefault() {}
+
+void MediaSinkDefault::SetPlaybackRate(float rate) {
+  DCHECK_GE(rate, 0.0f);
+  playback_rate_ = rate;
+  time_interpolator_.SetPlaybackRate(playback_rate_);
+
+  // Changing the playback rate affects the delay after which EOS callback
+  // should run. Reschedule the task according to the new delay.
+  if (received_eos_) {
+    eos_task_.Cancel();
+    ScheduleEndOfStreamTask();
+  }
+}
+
+base::TimeDelta MediaSinkDefault::GetCurrentPts() {
+  return time_interpolator_.GetInterpolatedTime();
+}
+
+MediaPipelineBackend::BufferStatus MediaSinkDefault::PushBuffer(
+    CastDecoderBuffer* buffer) {
+  if (buffer->end_of_stream()) {
+    received_eos_ = true;
+    ScheduleEndOfStreamTask();
+    return MediaPipelineBackend::kBufferSuccess;
+  }
+
+  // This is wrong on several levels.
+  // 1. The correct PTS should be buffer->timestamp() + buffer->duration().
+  //    But CastDecoderBuffer does not expose duration unlike
+  //    ::media::DecoderBuffer.
+  // 2. The PTS reported by GetCurrentPts should not move backwards.
+  //    It should be clamped in the range [start_pts, last_frame_pts_].
+  //    But doing so makes several AudioVideoPipelineDeviceTest cases fail.
+  //    Those tests are wrong should be fixed.
+  // TODO(alokp): Fix these issues when the next version of CMA backend is
+  // scheduled to roll out. crbug.com/678394
+  last_frame_pts_ = base::TimeDelta::FromMicroseconds(buffer->timestamp());
+  time_interpolator_.SetUpperBound(last_frame_pts_);
+  return MediaPipelineBackend::kBufferSuccess;
+}
+
+void MediaSinkDefault::ScheduleEndOfStreamTask() {
+  DCHECK(received_eos_);
+  DCHECK(eos_task_.IsCancelled());
+
+  // Do not schedule if playback is paused.
+  if (playback_rate_ == 0.0f)
+    return;
+
+  eos_task_.Reset(
+      base::Bind(&MediaPipelineBackend::Decoder::Delegate::OnEndOfStream,
+                 base::Unretained(delegate_)));
+  base::TimeDelta delay = (last_frame_pts_ - GetCurrentPts()) / playback_rate_;
+  base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+      FROM_HERE, eos_task_.callback(), delay);
+}
+
+}  // namespace media
+}  // namespace chromecast