cobalt/dom/source_buffer.cc - cobalt - Git at Google

 /*
  * Copyright (C) 2013 Google Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 // Modifications Copyright 2017 The Cobalt Authors. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 #include "cobalt/dom/source_buffer.h"

 #include <algorithm>
 #include <limits>
 #include <utility>

 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "cobalt/base/polymorphic_downcast.h"
 #include "cobalt/base/tokens.h"
 #include "cobalt/dom/dom_settings.h"
 #include "cobalt/dom/media_source.h"
 #include "cobalt/web/dom_exception.h"
 #include "third_party/chromium/media/base/ranges.h"
 #include "third_party/chromium/media/base/timestamp_constants.h"

 namespace cobalt {
 namespace dom {

 namespace {

 static base::TimeDelta DoubleToTimeDelta(double time) {
   DCHECK(!std::isnan(time));
   DCHECK_NE(time, -std::numeric_limits<double>::infinity());

   if (time == std::numeric_limits<double>::infinity()) {
     return ::media::kInfiniteDuration;
   }

   // Don't use base::TimeDelta::Max() here, as we want the largest finite time
   // delta.
   base::TimeDelta max_time = base::TimeDelta::FromInternalValue(
       std::numeric_limits<int64_t>::max() - 1);
   double max_time_in_seconds = max_time.InSecondsF();

   if (time >= max_time_in_seconds) {
     return max_time;
   }

   return base::TimeDelta::FromSecondsD(time);
 }

 // The return value will be used in `SourceBuffer::EvictCodedFrames()` to allow
 // it to evict extra data from the SourceBuffer, so it can reduce the overall
 // memory used by the underlying Demuxer implementation.
 // The default value is 0, i.e. do not evict extra bytes.
 size_t GetEvictExtraInBytes(script::EnvironmentSettings* settings) {
   DOMSettings* dom_settings =
       base::polymorphic_downcast<DOMSettings*>(settings);
   DCHECK(dom_settings);
   DCHECK(dom_settings->media_source_settings());
   int bytes = dom_settings->media_source_settings()
                   ->GetSourceBufferEvictExtraInBytes()
                   .value_or(0);
   DCHECK_GE(bytes, 0);
   return std::max<int>(bytes, 0);
 }

 }  // namespace

 SourceBuffer::SourceBuffer(script::EnvironmentSettings* settings,
                            const std::string& id, MediaSource* media_source,
                            bool asynchronous_reduction_enabled,
                            ChunkDemuxer* chunk_demuxer, EventQueue* event_queue)
     : web::EventTarget(settings),
       id_(id),
       asynchronous_reduction_enabled_(asynchronous_reduction_enabled),
       evict_extra_in_bytes_(GetEvictExtraInBytes(settings)),
       media_source_(media_source),
       chunk_demuxer_(chunk_demuxer),
       event_queue_(event_queue),
       audio_tracks_(
           new AudioTrackList(settings, media_source->GetMediaElement())),
       video_tracks_(
           new VideoTrackList(settings, media_source->GetMediaElement())),
       metrics_(!media_source_->MediaElementHasMaxVideoCapabilities()) {
   DCHECK(!id_.empty());
   DCHECK(media_source_);
   DCHECK(chunk_demuxer);
   DCHECK(event_queue);

   LOG(INFO) << "Evict extra in bytes is set to " << evict_extra_in_bytes_;

   chunk_demuxer_->SetTracksWatcher(
       id_,
       base::Bind(&SourceBuffer::OnInitSegmentReceived, base::Unretained(this)));
   chunk_demuxer_->SetParseWarningCallback(
       id, base::BindRepeating([](::media::SourceBufferParseWarning warning) {
         LOG(WARNING) << "Encountered SourceBufferParseWarning "
                      << static_cast<int>(warning);
       }));
 }

 void SourceBuffer::set_mode(SourceBufferAppendMode mode,
                             script::ExceptionState* exception_state) {
   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }
   if (updating()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   media_source_->OpenIfInEndedState();

   if (chunk_demuxer_->IsParsingMediaSegment(id_)) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   chunk_demuxer_->SetSequenceMode(id_, mode == kSourceBufferAppendModeSequence);

   mode_ = mode;
 }

 scoped_refptr<TimeRanges> SourceBuffer::buffered(
     script::ExceptionState* exception_state) const {
   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return NULL;
   }

   scoped_refptr<TimeRanges> time_ranges = new TimeRanges;
   ::media::Ranges<base::TimeDelta> ranges =
       chunk_demuxer_->GetBufferedRanges(id_);
   for (size_t i = 0; i < ranges.size(); i++) {
     time_ranges->Add(ranges.start(i).InSecondsF(), ranges.end(i).InSecondsF());
   }
   return time_ranges;
 }

 double SourceBuffer::timestamp_offset(
     script::ExceptionState* exception_state) const {
   starboard::ScopedLock scoped_lock(timestamp_offset_mutex_);
   return timestamp_offset_;
 }

 void SourceBuffer::set_timestamp_offset(
     double offset, script::ExceptionState* exception_state) {
   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }
   if (updating()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   media_source_->OpenIfInEndedState();

   if (chunk_demuxer_->IsParsingMediaSegment(id_)) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   // We don't have to acquire |timestamp_offset_mutex_|, as no algorithms are
   // running asynchronously at this moment, which is guaranteed by the check of
   // updating() above.
   timestamp_offset_ = offset;

   chunk_demuxer_->SetGroupStartTimestampIfInSequenceMode(
       id_, DoubleToTimeDelta(timestamp_offset_));
 }

 void SourceBuffer::set_append_window_start(
     double start, script::ExceptionState* exception_state) {
   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }
   if (updating()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   if (start < 0 || start >= append_window_end_) {
     exception_state->SetSimpleException(script::kSimpleTypeError);
     return;
   }

   append_window_start_ = start;
 }

 void SourceBuffer::set_append_window_end(
     double end, script::ExceptionState* exception_state) {
   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }
   if (updating()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   if (std::isnan(end)) {
     exception_state->SetSimpleException(script::kSimpleTypeError);
     return;
   }
   // 4. If the new value is less than or equal to appendWindowStart then throw a
   //    TypeError exception and abort these steps.
   if (end <= append_window_start_) {
     exception_state->SetSimpleException(script::kSimpleTypeError);
     return;
   }

   append_window_end_ = end;
 }

 void SourceBuffer::AppendBuffer(const script::Handle<script::ArrayBuffer>& data,
                                 script::ExceptionState* exception_state) {
   TRACE_EVENT1("cobalt::dom", "SourceBuffer::AppendBuffer()", "size",
                data->ByteLength());
   AppendBufferInternal(static_cast<const unsigned char*>(data->Data()),
                        data->ByteLength(), exception_state);
 }

 void SourceBuffer::AppendBuffer(
     const script::Handle<script::ArrayBufferView>& data,
     script::ExceptionState* exception_state) {
   TRACE_EVENT1("cobalt::dom", "SourceBuffer::AppendBuffer()", "size",
                data->ByteLength());
   AppendBufferInternal(static_cast<const unsigned char*>(data->RawData()),
                        data->ByteLength(), exception_state);
 }

 void SourceBuffer::Abort(script::ExceptionState* exception_state) {
   TRACE_EVENT0("cobalt::dom", "SourceBuffer::Abort()");

   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }
   if (!media_source_->IsOpen()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   if (active_algorithm_handle_) {
     if (!active_algorithm_handle_->algorithm()->SupportExplicitAbort()) {
       web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                                exception_state);
       return;
     }
     active_algorithm_handle_->Abort();
     active_algorithm_handle_ = nullptr;
   }

   base::TimeDelta timestamp_offset = DoubleToTimeDelta(timestamp_offset_);
   chunk_demuxer_->ResetParserState(id_, DoubleToTimeDelta(append_window_start_),
                                    DoubleToTimeDelta(append_window_end_),
                                    &timestamp_offset);
   UpdateTimestampOffset(timestamp_offset);

   set_append_window_start(0, exception_state);
   set_append_window_end(std::numeric_limits<double>::infinity(),
                         exception_state);
 }

 void SourceBuffer::Remove(double start, double end,
                           script::ExceptionState* exception_state) {
   TRACE_EVENT2("cobalt::dom", "SourceBuffer::Remove()", "start", start, "end",
                end);
   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }
   if (updating()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   if (start < 0 || std::isnan(media_source_->duration(NULL)) ||
       start > media_source_->duration(NULL)) {
     exception_state->SetSimpleException(script::kSimpleTypeError);
     return;
   }

   if (end <= start || std::isnan(end)) {
     exception_state->SetSimpleException(script::kSimpleTypeError);
     return;
   }

   media_source_->OpenIfInEndedState();

   ScheduleEvent(base::Tokens::updatestart());

   DCHECK_GE(start, 0);
   DCHECK_LT(start, end);

   std::unique_ptr<SourceBufferAlgorithm> algorithm(
       new SourceBufferRemoveAlgorithm(
           chunk_demuxer_, id_, DoubleToTimeDelta(start), DoubleToTimeDelta(end),
           base::Bind(asynchronous_reduction_enabled_
                          ? &SourceBuffer::ScheduleAndMaybeDispatchImmediately
                          : &SourceBuffer::ScheduleEvent,
                      base::Unretained(this)),
           base::Bind(&SourceBuffer::OnAlgorithmFinalized,
                      base::Unretained(this))));
   active_algorithm_handle_ =
       new SerializedAlgorithmRunner::Handle<SourceBufferAlgorithm>(
           std::move(algorithm));
   media_source_->GetAlgorithmRunner(std::numeric_limits<int>::max())
       ->Start(active_algorithm_handle_);
 }

 void SourceBuffer::set_track_defaults(
     const scoped_refptr<TrackDefaultList>& track_defaults,
     script::ExceptionState* exception_state) {
   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }
   if (updating()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return;
   }

   track_defaults_ = track_defaults;
 }

 void SourceBuffer::OnRemovedFromMediaSource() {
   if (media_source_ == NULL) {
     return;
   }

   if (active_algorithm_handle_) {
     active_algorithm_handle_->Abort();
     active_algorithm_handle_ = nullptr;
   }

   DCHECK(media_source_);

   // TODO: Implement track support.
   // if (media_source_->GetMediaElement()->audio_tracks().length() > 0 ||
   //     media_source_->GetMediaElement()->audio_tracks().length() > 0) {
   //   RemoveMediaTracks();
   // }

   // TODO: Determine if the source buffer contains an audio or video stream,
   //       maybe by implementing track support and get from the type of the
   //       track, and print the steam type along with the metrics.
   metrics_.PrintCurrentMetricsAndUpdateAccumulatedMetrics();

   chunk_demuxer_->RemoveId(id_);
   if (chunk_demuxer_->GetAllStreams().empty()) {
     metrics_.PrintAccumulatedMetrics();
   }

   chunk_demuxer_ = NULL;
   media_source_ = NULL;
   event_queue_ = NULL;

   pending_append_data_.reset();
   pending_append_data_capacity_ = 0;
 }

 double SourceBuffer::GetHighestPresentationTimestamp() const {
   DCHECK(media_source_ != NULL);

   return chunk_demuxer_->GetHighestPresentationTimestamp(id_).InSecondsF();
 }

 void SourceBuffer::TraceMembers(script::Tracer* tracer) {
   web::EventTarget::TraceMembers(tracer);

   tracer->Trace(event_queue_);
   tracer->Trace(media_source_);
   tracer->Trace(track_defaults_);
   tracer->Trace(audio_tracks_);
   tracer->Trace(video_tracks_);
 }

 void SourceBuffer::OnInitSegmentReceived(std::unique_ptr<MediaTracks> tracks) {
   if (!first_initialization_segment_received_) {
     // This can be called from non-web thread when the append is async.
     if (!web_task_runner_->BelongsToCurrentThread()) {
       web_task_runner_->PostTask(
           FROM_HERE, base::Bind(&SourceBuffer::OnInitSegmentReceived, this,
                                 base::Passed(&tracks)));
       return;
     }
     media_source_->SetSourceBufferActive(this, true);
     first_initialization_segment_received_ = true;
   }

   // TODO: Implement track support.
 }

 void SourceBuffer::ScheduleEvent(base::Token event_name) {
   scoped_refptr<web::Event> event = new web::Event(event_name);
   event->set_target(this);
   event_queue_->Enqueue(event);
 }

 void SourceBuffer::ScheduleAndMaybeDispatchImmediately(base::Token event_name) {
   scoped_refptr<web::Event> event = new web::Event(event_name);
   event->set_target(this);
   event_queue_->EnqueueAndMaybeDispatchImmediately(event);
 }

 bool SourceBuffer::PrepareAppend(size_t new_data_size,
                                  script::ExceptionState* exception_state) {
   TRACE_EVENT1("cobalt::dom", "SourceBuffer::PrepareAppend()", "new_data_size",
                new_data_size);
   if (media_source_ == NULL) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return false;
   }
   if (updating()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return false;
   }

   DCHECK(media_source_->GetMediaElement());
   if (media_source_->GetMediaElement()->error()) {
     web::DOMException::Raise(web::DOMException::kInvalidStateErr,
                              exception_state);
     return false;
   }

   media_source_->OpenIfInEndedState();

   double current_time = media_source_->GetMediaElement()->current_time(NULL);
   if (!chunk_demuxer_->EvictCodedFrames(
           id_, base::TimeDelta::FromSecondsD(current_time),
           new_data_size + evict_extra_in_bytes_)) {
     web::DOMException::Raise(web::DOMException::kQuotaExceededErr,
                              exception_state);
     return false;
   }

   return true;
 }

 void SourceBuffer::AppendBufferInternal(
     const unsigned char* data, size_t size,
     script::ExceptionState* exception_state) {
   TRACE_EVENT1("cobalt::dom", "SourceBuffer::AppendBufferInternal()", "size",
                size);
   metrics_.StartTracking();
   if (!PrepareAppend(size, exception_state)) {
     return;
   }
   metrics_.EndTracking(0);

   DCHECK(data || size == 0);

   if (data) {
     if (pending_append_data_capacity_ < size) {
       pending_append_data_.reset();
       pending_append_data_.reset(new uint8_t[size]);
       pending_append_data_capacity_ = size;
     }
     memcpy(pending_append_data_.get(), data, size);
   }

   ScheduleEvent(base::Tokens::updatestart());

   std::unique_ptr<SourceBufferAlgorithm> algorithm(
       new SourceBufferAppendAlgorithm(
           media_source_, chunk_demuxer_, id_, pending_append_data_.get(), size,
           DoubleToTimeDelta(append_window_start_),
           DoubleToTimeDelta(append_window_end_),
           DoubleToTimeDelta(timestamp_offset_),
           base::Bind(&SourceBuffer::UpdateTimestampOffset,
                      base::Unretained(this)),
           base::Bind(asynchronous_reduction_enabled_
                          ? &SourceBuffer::ScheduleAndMaybeDispatchImmediately
                          : &SourceBuffer::ScheduleEvent,
                      base::Unretained(this)),
           base::Bind(&SourceBuffer::OnAlgorithmFinalized,
                      base::Unretained(this)),
           &metrics_));
   active_algorithm_handle_ =
       new SerializedAlgorithmRunner::Handle<SourceBufferAlgorithm>(
           std::move(algorithm));
   media_source_->GetAlgorithmRunner(size)->Start(active_algorithm_handle_);
 }

 void SourceBuffer::OnAlgorithmFinalized() {
   DCHECK(active_algorithm_handle_);
   active_algorithm_handle_ = nullptr;
 }

 void SourceBuffer::UpdateTimestampOffset(base::TimeDelta timestamp_offset) {
   starboard::ScopedLock scoped_lock(timestamp_offset_mutex_);
   // The check avoids overwriting |timestamp_offset_| when there is a small
   // difference between its float and its int64_t representation .
   if (DoubleToTimeDelta(timestamp_offset_) != timestamp_offset) {
     timestamp_offset_ = timestamp_offset.InSecondsF();
   }
 }

 }  // namespace dom
 }  // namespace cobalt
	/*
	* Copyright (C) 2013 Google Inc. All Rights Reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	// Modifications Copyright 2017 The Cobalt Authors. All Rights Reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	#include "cobalt/dom/source_buffer.h"

	#include <algorithm>
	#include <limits>
	#include <utility>

	#include "base/compiler_specific.h"
	#include "base/logging.h"
	#include "base/message_loop/message_loop.h"
	#include "base/time/time.h"
	#include "base/trace_event/trace_event.h"
	#include "cobalt/base/polymorphic_downcast.h"
	#include "cobalt/base/tokens.h"
	#include "cobalt/dom/dom_settings.h"
	#include "cobalt/dom/media_source.h"
	#include "cobalt/web/dom_exception.h"
	#include "third_party/chromium/media/base/ranges.h"
	#include "third_party/chromium/media/base/timestamp_constants.h"

	namespace cobalt {
	namespace dom {

	namespace {

	static base::TimeDelta DoubleToTimeDelta(double time) {
	DCHECK(!std::isnan(time));
	DCHECK_NE(time, -std::numeric_limits<double>::infinity());

	if (time == std::numeric_limits<double>::infinity()) {
	return ::media::kInfiniteDuration;
	}

	// Don't use base::TimeDelta::Max() here, as we want the largest finite time
	// delta.
	base::TimeDelta max_time = base::TimeDelta::FromInternalValue(
	std::numeric_limits<int64_t>::max() - 1);
	double max_time_in_seconds = max_time.InSecondsF();

	if (time >= max_time_in_seconds) {
	return max_time;
	}

	return base::TimeDelta::FromSecondsD(time);
	}

	// The return value will be used in `SourceBuffer::EvictCodedFrames()` to allow
	// it to evict extra data from the SourceBuffer, so it can reduce the overall
	// memory used by the underlying Demuxer implementation.
	// The default value is 0, i.e. do not evict extra bytes.
	size_t GetEvictExtraInBytes(script::EnvironmentSettings* settings) {
	DOMSettings* dom_settings =
	base::polymorphic_downcast<DOMSettings*>(settings);
	DCHECK(dom_settings);
	DCHECK(dom_settings->media_source_settings());
	int bytes = dom_settings->media_source_settings()
	->GetSourceBufferEvictExtraInBytes()
	.value_or(0);
	DCHECK_GE(bytes, 0);
	return std::max<int>(bytes, 0);
	}

	} // namespace

	SourceBuffer::SourceBuffer(script::EnvironmentSettings* settings,
	const std::string& id, MediaSource* media_source,
	bool asynchronous_reduction_enabled,
	ChunkDemuxer* chunk_demuxer, EventQueue* event_queue)
	: web::EventTarget(settings),
	id_(id),
	asynchronous_reduction_enabled_(asynchronous_reduction_enabled),
	evict_extra_in_bytes_(GetEvictExtraInBytes(settings)),
	media_source_(media_source),
	chunk_demuxer_(chunk_demuxer),
	event_queue_(event_queue),
	audio_tracks_(
	new AudioTrackList(settings, media_source->GetMediaElement())),
	video_tracks_(
	new VideoTrackList(settings, media_source->GetMediaElement())),
	metrics_(!media_source_->MediaElementHasMaxVideoCapabilities()) {
	DCHECK(!id_.empty());
	DCHECK(media_source_);
	DCHECK(chunk_demuxer);
	DCHECK(event_queue);

	LOG(INFO) << "Evict extra in bytes is set to " << evict_extra_in_bytes_;

	chunk_demuxer_->SetTracksWatcher(
	id_,
	base::Bind(&SourceBuffer::OnInitSegmentReceived, base::Unretained(this)));
	chunk_demuxer_->SetParseWarningCallback(
	id, base::BindRepeating([](::media::SourceBufferParseWarning warning) {
	LOG(WARNING) << "Encountered SourceBufferParseWarning "
	<< static_cast<int>(warning);
	}));
	}

	void SourceBuffer::set_mode(SourceBufferAppendMode mode,
	script::ExceptionState* exception_state) {
	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}
	if (updating()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	media_source_->OpenIfInEndedState();

	if (chunk_demuxer_->IsParsingMediaSegment(id_)) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	chunk_demuxer_->SetSequenceMode(id_, mode == kSourceBufferAppendModeSequence);

	mode_ = mode;
	}

	scoped_refptr<TimeRanges> SourceBuffer::buffered(
	script::ExceptionState* exception_state) const {
	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return NULL;
	}

	scoped_refptr<TimeRanges> time_ranges = new TimeRanges;
	::media::Ranges<base::TimeDelta> ranges =
	chunk_demuxer_->GetBufferedRanges(id_);
	for (size_t i = 0; i < ranges.size(); i++) {
	time_ranges->Add(ranges.start(i).InSecondsF(), ranges.end(i).InSecondsF());
	}
	return time_ranges;
	}

	double SourceBuffer::timestamp_offset(
	script::ExceptionState* exception_state) const {
	starboard::ScopedLock scoped_lock(timestamp_offset_mutex_);
	return timestamp_offset_;
	}

	void SourceBuffer::set_timestamp_offset(
	double offset, script::ExceptionState* exception_state) {
	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}
	if (updating()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	media_source_->OpenIfInEndedState();

	if (chunk_demuxer_->IsParsingMediaSegment(id_)) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	// We don't have to acquire \|timestamp_offset_mutex_\|, as no algorithms are
	// running asynchronously at this moment, which is guaranteed by the check of
	// updating() above.
	timestamp_offset_ = offset;

	chunk_demuxer_->SetGroupStartTimestampIfInSequenceMode(
	id_, DoubleToTimeDelta(timestamp_offset_));
	}

	void SourceBuffer::set_append_window_start(
	double start, script::ExceptionState* exception_state) {
	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}
	if (updating()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	if (start < 0 \|\| start >= append_window_end_) {
	exception_state->SetSimpleException(script::kSimpleTypeError);
	return;
	}

	append_window_start_ = start;
	}

	void SourceBuffer::set_append_window_end(
	double end, script::ExceptionState* exception_state) {
	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}
	if (updating()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	if (std::isnan(end)) {
	exception_state->SetSimpleException(script::kSimpleTypeError);
	return;
	}
	// 4. If the new value is less than or equal to appendWindowStart then throw a
	// TypeError exception and abort these steps.
	if (end <= append_window_start_) {
	exception_state->SetSimpleException(script::kSimpleTypeError);
	return;
	}

	append_window_end_ = end;
	}

	void SourceBuffer::AppendBuffer(const script::Handle<script::ArrayBuffer>& data,
	script::ExceptionState* exception_state) {
	TRACE_EVENT1("cobalt::dom", "SourceBuffer::AppendBuffer()", "size",
	data->ByteLength());
	AppendBufferInternal(static_cast<const unsigned char*>(data->Data()),
	data->ByteLength(), exception_state);
	}

	void SourceBuffer::AppendBuffer(
	const script::Handle<script::ArrayBufferView>& data,
	script::ExceptionState* exception_state) {
	TRACE_EVENT1("cobalt::dom", "SourceBuffer::AppendBuffer()", "size",
	data->ByteLength());
	AppendBufferInternal(static_cast<const unsigned char*>(data->RawData()),
	data->ByteLength(), exception_state);
	}

	void SourceBuffer::Abort(script::ExceptionState* exception_state) {
	TRACE_EVENT0("cobalt::dom", "SourceBuffer::Abort()");

	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}
	if (!media_source_->IsOpen()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	if (active_algorithm_handle_) {
	if (!active_algorithm_handle_->algorithm()->SupportExplicitAbort()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}
	active_algorithm_handle_->Abort();
	active_algorithm_handle_ = nullptr;
	}

	base::TimeDelta timestamp_offset = DoubleToTimeDelta(timestamp_offset_);
	chunk_demuxer_->ResetParserState(id_, DoubleToTimeDelta(append_window_start_),
	DoubleToTimeDelta(append_window_end_),
	&timestamp_offset);
	UpdateTimestampOffset(timestamp_offset);

	set_append_window_start(0, exception_state);
	set_append_window_end(std::numeric_limits<double>::infinity(),
	exception_state);
	}

	void SourceBuffer::Remove(double start, double end,
	script::ExceptionState* exception_state) {
	TRACE_EVENT2("cobalt::dom", "SourceBuffer::Remove()", "start", start, "end",
	end);
	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}
	if (updating()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	if (start < 0 \|\| std::isnan(media_source_->duration(NULL)) \|\|
	start > media_source_->duration(NULL)) {
	exception_state->SetSimpleException(script::kSimpleTypeError);
	return;
	}

	if (end <= start \|\| std::isnan(end)) {
	exception_state->SetSimpleException(script::kSimpleTypeError);
	return;
	}

	media_source_->OpenIfInEndedState();

	ScheduleEvent(base::Tokens::updatestart());

	DCHECK_GE(start, 0);
	DCHECK_LT(start, end);

	std::unique_ptr<SourceBufferAlgorithm> algorithm(
	new SourceBufferRemoveAlgorithm(
	chunk_demuxer_, id_, DoubleToTimeDelta(start), DoubleToTimeDelta(end),
	base::Bind(asynchronous_reduction_enabled_
	? &SourceBuffer::ScheduleAndMaybeDispatchImmediately
	: &SourceBuffer::ScheduleEvent,
	base::Unretained(this)),
	base::Bind(&SourceBuffer::OnAlgorithmFinalized,
	base::Unretained(this))));
	active_algorithm_handle_ =
	new SerializedAlgorithmRunner::Handle<SourceBufferAlgorithm>(
	std::move(algorithm));
	media_source_->GetAlgorithmRunner(std::numeric_limits<int>::max())
	->Start(active_algorithm_handle_);
	}

	void SourceBuffer::set_track_defaults(
	const scoped_refptr<TrackDefaultList>& track_defaults,
	script::ExceptionState* exception_state) {
	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}
	if (updating()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return;
	}

	track_defaults_ = track_defaults;
	}

	void SourceBuffer::OnRemovedFromMediaSource() {
	if (media_source_ == NULL) {
	return;
	}

	if (active_algorithm_handle_) {
	active_algorithm_handle_->Abort();
	active_algorithm_handle_ = nullptr;
	}

	DCHECK(media_source_);

	// TODO: Implement track support.
	// if (media_source_->GetMediaElement()->audio_tracks().length() > 0 \|\|
	// media_source_->GetMediaElement()->audio_tracks().length() > 0) {
	// RemoveMediaTracks();
	// }

	// TODO: Determine if the source buffer contains an audio or video stream,
	// maybe by implementing track support and get from the type of the
	// track, and print the steam type along with the metrics.
	metrics_.PrintCurrentMetricsAndUpdateAccumulatedMetrics();

	chunk_demuxer_->RemoveId(id_);
	if (chunk_demuxer_->GetAllStreams().empty()) {
	metrics_.PrintAccumulatedMetrics();
	}

	chunk_demuxer_ = NULL;
	media_source_ = NULL;
	event_queue_ = NULL;

	pending_append_data_.reset();
	pending_append_data_capacity_ = 0;
	}

	double SourceBuffer::GetHighestPresentationTimestamp() const {
	DCHECK(media_source_ != NULL);

	return chunk_demuxer_->GetHighestPresentationTimestamp(id_).InSecondsF();
	}

	void SourceBuffer::TraceMembers(script::Tracer* tracer) {
	web::EventTarget::TraceMembers(tracer);

	tracer->Trace(event_queue_);
	tracer->Trace(media_source_);
	tracer->Trace(track_defaults_);
	tracer->Trace(audio_tracks_);
	tracer->Trace(video_tracks_);
	}

	void SourceBuffer::OnInitSegmentReceived(std::unique_ptr<MediaTracks> tracks) {
	if (!first_initialization_segment_received_) {
	// This can be called from non-web thread when the append is async.
	if (!web_task_runner_->BelongsToCurrentThread()) {
	web_task_runner_->PostTask(
	FROM_HERE, base::Bind(&SourceBuffer::OnInitSegmentReceived, this,
	base::Passed(&tracks)));
	return;
	}
	media_source_->SetSourceBufferActive(this, true);
	first_initialization_segment_received_ = true;
	}

	// TODO: Implement track support.
	}

	void SourceBuffer::ScheduleEvent(base::Token event_name) {
	scoped_refptr<web::Event> event = new web::Event(event_name);
	event->set_target(this);
	event_queue_->Enqueue(event);
	}

	void SourceBuffer::ScheduleAndMaybeDispatchImmediately(base::Token event_name) {
	scoped_refptr<web::Event> event = new web::Event(event_name);
	event->set_target(this);
	event_queue_->EnqueueAndMaybeDispatchImmediately(event);
	}

	bool SourceBuffer::PrepareAppend(size_t new_data_size,
	script::ExceptionState* exception_state) {
	TRACE_EVENT1("cobalt::dom", "SourceBuffer::PrepareAppend()", "new_data_size",
	new_data_size);
	if (media_source_ == NULL) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return false;
	}
	if (updating()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return false;
	}

	DCHECK(media_source_->GetMediaElement());
	if (media_source_->GetMediaElement()->error()) {
	web::DOMException::Raise(web::DOMException::kInvalidStateErr,
	exception_state);
	return false;
	}

	media_source_->OpenIfInEndedState();

	double current_time = media_source_->GetMediaElement()->current_time(NULL);
	if (!chunk_demuxer_->EvictCodedFrames(
	id_, base::TimeDelta::FromSecondsD(current_time),
	new_data_size + evict_extra_in_bytes_)) {
	web::DOMException::Raise(web::DOMException::kQuotaExceededErr,
	exception_state);
	return false;
	}

	return true;
	}

	void SourceBuffer::AppendBufferInternal(
	const unsigned char* data, size_t size,
	script::ExceptionState* exception_state) {
	TRACE_EVENT1("cobalt::dom", "SourceBuffer::AppendBufferInternal()", "size",
	size);
	metrics_.StartTracking();
	if (!PrepareAppend(size, exception_state)) {
	return;
	}
	metrics_.EndTracking(0);

	DCHECK(data \|\| size == 0);

	if (data) {
	if (pending_append_data_capacity_ < size) {
	pending_append_data_.reset();
	pending_append_data_.reset(new uint8_t[size]);
	pending_append_data_capacity_ = size;
	}
	memcpy(pending_append_data_.get(), data, size);
	}

	ScheduleEvent(base::Tokens::updatestart());

	std::unique_ptr<SourceBufferAlgorithm> algorithm(
	new SourceBufferAppendAlgorithm(
	media_source_, chunk_demuxer_, id_, pending_append_data_.get(), size,
	DoubleToTimeDelta(append_window_start_),
	DoubleToTimeDelta(append_window_end_),
	DoubleToTimeDelta(timestamp_offset_),
	base::Bind(&SourceBuffer::UpdateTimestampOffset,
	base::Unretained(this)),
	base::Bind(asynchronous_reduction_enabled_
	? &SourceBuffer::ScheduleAndMaybeDispatchImmediately
	: &SourceBuffer::ScheduleEvent,
	base::Unretained(this)),
	base::Bind(&SourceBuffer::OnAlgorithmFinalized,
	base::Unretained(this)),
	&metrics_));
	active_algorithm_handle_ =
	new SerializedAlgorithmRunner::Handle<SourceBufferAlgorithm>(
	std::move(algorithm));
	media_source_->GetAlgorithmRunner(size)->Start(active_algorithm_handle_);
	}

	void SourceBuffer::OnAlgorithmFinalized() {
	DCHECK(active_algorithm_handle_);
	active_algorithm_handle_ = nullptr;
	}

	void SourceBuffer::UpdateTimestampOffset(base::TimeDelta timestamp_offset) {
	starboard::ScopedLock scoped_lock(timestamp_offset_mutex_);
	// The check avoids overwriting \|timestamp_offset_\| when there is a small
	// difference between its float and its int64_t representation .
	if (DoubleToTimeDelta(timestamp_offset_) != timestamp_offset) {
	timestamp_offset_ = timestamp_offset.InSecondsF();
	}
	}

	} // namespace dom
	} // namespace cobalt