Index: media/base/download_rate_monitor.cc |
diff --git a/media/base/download_rate_monitor.cc b/media/base/download_rate_monitor.cc |
deleted file mode 100644 |
index f27b2e8059223c6425ba1f3b5c0651e5e19e59d5..0000000000000000000000000000000000000000 |
--- a/media/base/download_rate_monitor.cc |
+++ /dev/null |
@@ -1,262 +0,0 @@ |
-// Copyright (c) 2011 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 "media/base/download_rate_monitor.h" |
- |
-#include "base/bind.h" |
-#include "base/time.h" |
- |
-namespace media { |
- |
-// Number of samples to use to collect and average for each measurement of |
-// download rate. |
-static const size_t kNumberOfSamples = 5; |
- |
-// Minimum number of seconds represented in a sample period. |
-static const float kSamplePeriod = 1.0; |
- |
-DownloadRateMonitor::Sample::Sample() { |
- Reset(); |
-} |
- |
-DownloadRateMonitor::Sample::~Sample() { } |
- |
-DownloadRateMonitor::Sample::Sample( |
- const BufferingPoint& start, const BufferingPoint& end) { |
- Reset(); |
- start_ = start; |
- set_end(end); |
-} |
- |
-void DownloadRateMonitor::Sample::set_end(const BufferingPoint& new_end) { |
- DCHECK(!start_.timestamp.is_null()); |
- DCHECK(new_end.buffered_bytes >= start_.buffered_bytes); |
- DCHECK(new_end.timestamp >= start_.timestamp); |
- end_ = new_end; |
-} |
- |
-float DownloadRateMonitor::Sample::bytes_per_second() const { |
- if (seconds_elapsed() > 0.0 && bytes_downloaded() >= 0) |
- return bytes_downloaded() / seconds_elapsed(); |
- return -1.0; |
-} |
- |
-float DownloadRateMonitor::Sample::seconds_elapsed() const { |
- if (start_.timestamp.is_null() || end_.timestamp.is_null()) |
- return -1.0; |
- return (end_.timestamp - start_.timestamp).InSecondsF(); |
-} |
- |
-int64 DownloadRateMonitor::Sample::bytes_downloaded() const { |
- if (start_.timestamp.is_null() || end_.timestamp.is_null()) |
- return -1.0; |
- return end_.buffered_bytes - start_.buffered_bytes; |
-} |
- |
-bool DownloadRateMonitor::Sample::is_null() const { |
- return start_.timestamp.is_null() && end_.timestamp.is_null(); |
-} |
- |
-void DownloadRateMonitor::Sample::Reset() { |
- start_ = BufferingPoint(); |
- end_ = BufferingPoint(); |
-} |
- |
-void DownloadRateMonitor::Sample::RestartAtEndBufferingPoint() { |
- start_ = end_; |
- end_ = BufferingPoint(); |
-} |
- |
-DownloadRateMonitor::DownloadRateMonitor() { |
- Reset(); |
-} |
- |
-void DownloadRateMonitor::Start( |
- const base::Closure& canplaythrough_cb, int media_bitrate, |
- bool streaming, bool local_source) { |
- canplaythrough_cb_ = canplaythrough_cb; |
- streaming_ = streaming; |
- local_source_ = local_source; |
- stopped_ = false; |
- bitrate_ = media_bitrate; |
- current_sample_.Reset(); |
- buffered_bytes_ = 0; |
- |
- NotifyCanPlayThroughIfNeeded(); |
-} |
- |
-void DownloadRateMonitor::SetBufferedBytes( |
- int64 buffered_bytes, const base::Time& timestamp) { |
- if (stopped_) |
- return; |
- |
- is_downloading_data_ = true; |
- |
- // Check monotonically nondecreasing constraint. |
- base::Time previous_time; |
- if (!current_sample_.is_null()) |
- previous_time = current_sample_.end().timestamp; |
- else if (!sample_window_.empty()) |
- previous_time = sample_window_.back().end().timestamp; |
- |
- // If we go backward in time, dismiss the sample. |
- if (!previous_time.is_null() && timestamp < previous_time) |
- return; |
- |
- // If the buffer level has dropped, invalidate current sample. |
- if (buffered_bytes < buffered_bytes_) |
- current_sample_.Reset(); |
- buffered_bytes_ = buffered_bytes; |
- |
- BufferingPoint latest_point = { buffered_bytes, timestamp }; |
- if (current_sample_.is_null()) |
- current_sample_ = Sample(latest_point, latest_point); |
- else |
- current_sample_.set_end(latest_point); |
- |
- UpdateSampleWindow(); |
- NotifyCanPlayThroughIfNeeded(); |
-} |
- |
-void DownloadRateMonitor::SetNetworkActivity(bool is_downloading_data) { |
- if (is_downloading_data == is_downloading_data_) |
- return; |
- // Invalidate the current sample if downloading is going from start to stopped |
- // or vice versa. |
- current_sample_.Reset(); |
- is_downloading_data_ = is_downloading_data; |
-} |
- |
-void DownloadRateMonitor::Stop() { |
- stopped_ = true; |
- current_sample_.Reset(); |
- buffered_bytes_ = 0; |
-} |
- |
-void DownloadRateMonitor::Reset() { |
- canplaythrough_cb_.Reset(); |
- has_notified_can_play_through_ = false; |
- current_sample_.Reset(); |
- sample_window_.clear(); |
- is_downloading_data_ = false; |
- total_bytes_ = -1; |
- buffered_bytes_ = 0; |
- local_source_ = false; |
- bitrate_ = 0; |
- stopped_ = true; |
- streaming_ = false; |
-} |
- |
-DownloadRateMonitor::~DownloadRateMonitor() { } |
- |
-int64 DownloadRateMonitor::bytes_downloaded_in_window() const { |
- // There are max |kNumberOfSamples| so we might as well recompute each time. |
- int64 total = 0; |
- for (size_t i = 0; i < sample_window_.size(); ++i) |
- total += sample_window_[i].bytes_downloaded(); |
- return total; |
-} |
- |
-float DownloadRateMonitor::seconds_elapsed_in_window() const { |
- // There are max |kNumberOfSamples| so we might as well recompute each time. |
- float total = 0.0; |
- for (size_t i = 0; i < sample_window_.size(); ++i) |
- total += sample_window_[i].seconds_elapsed(); |
- return total; |
-} |
- |
-void DownloadRateMonitor::UpdateSampleWindow() { |
- if (current_sample_.seconds_elapsed() < kSamplePeriod) |
- return; |
- |
- // Add latest sample and remove oldest sample. |
- sample_window_.push_back(current_sample_); |
- if (sample_window_.size() > kNumberOfSamples) |
- sample_window_.pop_front(); |
- |
- // Prepare for next measurement. |
- current_sample_.RestartAtEndBufferingPoint(); |
-} |
- |
-float DownloadRateMonitor::ApproximateDownloadByteRate() const { |
- // Compute and return the average download byte rate from within the sample |
- // window. |
- // NOTE: In the unlikely case where the data is arriving really bursty-ly, |
- // say getting a big chunk of data every 5 seconds, then with this |
- // implementation it will take 25 seconds until bitrate is calculated. |
- if (sample_window_.size() >= kNumberOfSamples && |
- seconds_elapsed_in_window() > 0.0) { |
- return bytes_downloaded_in_window() / seconds_elapsed_in_window(); |
- } |
- |
- // Could not determine approximate download byte rate. |
- return -1.0; |
-} |
- |
-bool DownloadRateMonitor::ShouldNotifyCanPlayThrough() { |
- if (stopped_) |
- return false; |
- |
- // Only notify CanPlayThrough once for now. |
- if (has_notified_can_play_through_) |
- return false; |
- |
- // Fire CanPlayThrough immediately if the source is local or streaming. |
- // |
- // NOTE: It is a requirement for CanPlayThrough to fire immediately if the |
- // source is local, but the choice to optimistically fire the event for any |
- // streaming media element is a design decision that may need to be tweaked. |
- if (local_source_ || streaming_) |
- return true; |
- |
- // If all bytes are buffered, fire CanPlayThrough. |
- if (buffered_bytes_ == total_bytes_) |
- return true; |
- |
- // If bitrate is unknown, optimistically fire CanPlayThrough immediately. |
- // This is so a video with an unknown bitrate with the "autoplay" attribute |
- // will not wait until the entire file is downloaded before playback begins. |
- if (bitrate_ <= 0) |
- return true; |
- |
- float bytes_needed_per_second = bitrate_ / 8; |
- float download_rate = ApproximateDownloadByteRate(); |
- |
- // If we are downloading at or faster than the media's bitrate, then we can |
- // play through to the end of the media without stopping to buffer. |
- if (download_rate > 0) |
- return download_rate >= bytes_needed_per_second; |
- |
- // If download rate is unknown, it may be because the media is being |
- // downloaded so fast that it cannot collect an adequate number of samples |
- // before the download gets deferred. |
- // |
- // To catch this case, we also look at how much data is being downloaded |
- // immediately after the download begins. |
- if (sample_window_.size() < kNumberOfSamples) { |
- int64 bytes_downloaded_since_start = |
- bytes_downloaded_in_window() + current_sample_.bytes_downloaded(); |
- float seconds_elapsed_since_start = |
- seconds_elapsed_in_window() + current_sample_.seconds_elapsed(); |
- |
- // If we download 4 seconds of data in less than 2 seconds of time, we're |
- // probably downloading at a fast enough rate that we can play through. |
- // This is an arbitrary metric that will likely need tweaking. |
- if (seconds_elapsed_since_start < 2.0 && |
- bytes_downloaded_since_start > 4.0 * bytes_needed_per_second) { |
- return true; |
- } |
- } |
- |
- return false; |
-} |
- |
-void DownloadRateMonitor::NotifyCanPlayThroughIfNeeded() { |
- if (ShouldNotifyCanPlayThrough() && !canplaythrough_cb_.is_null()) { |
- canplaythrough_cb_.Run(); |
- has_notified_can_play_through_ = true; |
- } |
-} |
- |
-} // namespace media |