Track buffered byte ranges correctly in media::Pipeline.

media/base/pipeline.cc

 // Copyright (c) 2012 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/pipeline.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/callback_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/metrics/histogram.h"
 #include "base/message_loop.h"
 #include "base/stl_util.h"
 #include "base/string_util.h"
 #include "base/synchronization/condition_variable.h"
 #include "media/base/audio_decoder.h"
 #include "media/base/audio_renderer.h"
 #include "media/base/clock.h"
 #include "media/base/composite_filter.h"
 #include "media/base/filter_collection.h"
 #include "media/base/media_log.h"
 #include "media/base/video_decoder.h"
 #include "media/base/video_renderer.h"
 
+using base::TimeDelta;
+
 namespace media {
 
 PipelineStatusNotification::PipelineStatusNotification()
     : cv_(&lock_), status_(PIPELINE_OK), notified_(false) {
 }
 
 PipelineStatusNotification::~PipelineStatusNotification() {
   DCHECK(notified_);
 }
 
@@ skipping 70 matching lines @@
 
 void Pipeline::Stop(const base::Closure& stop_cb) {
   base::AutoLock auto_lock(lock_);
   CHECK(running_) << "Media pipeline isn't running";
 
   // Stop the pipeline, which will set |running_| to false on our behalf.
   message_loop_->PostTask(FROM_HERE, base::Bind(
       &Pipeline::StopTask, this, stop_cb));
 }
 
-void Pipeline::Seek(base::TimeDelta time,
-                    const PipelineStatusCB& seek_cb) {
+void Pipeline::Seek(TimeDelta time, const PipelineStatusCB& seek_cb) {
   base::AutoLock auto_lock(lock_);
   CHECK(running_) << "Media pipeline isn't running";
 
   message_loop_->PostTask(FROM_HERE, base::Bind(
       &Pipeline::SeekTask, this, time, seek_cb));
 }
 
 bool Pipeline::IsRunning() const {
   base::AutoLock auto_lock(lock_);
   return running_;
@@ skipping 54 matching lines @@
     return;
 
   base::AutoLock auto_lock(lock_);
   volume_ = volume;
   if (running_ && !tearing_down_) {
     message_loop_->PostTask(FROM_HERE, base::Bind(
         &Pipeline::VolumeChangedTask, this, volume));
   }
 }
 
-base::TimeDelta Pipeline::GetCurrentTime() const {
+TimeDelta Pipeline::GetCurrentTime() const {
   base::AutoLock auto_lock(lock_);
   return GetCurrentTime_Locked();
 }
 
-base::TimeDelta Pipeline::GetCurrentTime_Locked() const {
+TimeDelta Pipeline::GetCurrentTime_Locked() const {
   lock_.AssertAcquired();
   return clock_->Elapsed();
 }
 
-Ranges<base::TimeDelta> Pipeline::GetBufferedTimeRanges() {
+Ranges<TimeDelta> Pipeline::GetBufferedTimeRanges() {
   base::AutoLock auto_lock(lock_);
   return buffered_time_ranges_;

[scherkus (not reviewing), 2012/05/29 18:13:29]

would it be simpler to compute buffered_time_ranges_ off of
buffered_byte_ranges_ here instead of handling it on the fly in SetDuration() et
al?

[Ami GONE FROM CHROMIUM, 2012/05/29 20:45:44]

Hmm; that does indeed simplify the code.  There is a small cost here in that
this method is called per UI refresh, whereas the others are called only for
network updates (much less frequent), but I don't think that's worth worrying
about.  Done.

 }
 
-base::TimeDelta Pipeline::GetMediaDuration() const {
+TimeDelta Pipeline::GetMediaDuration() const {
   base::AutoLock auto_lock(lock_);
   return clock_->Duration();
 }
 
 int64 Pipeline::GetBufferedBytes() const {
   base::AutoLock auto_lock(lock_);
-  return buffered_bytes_;
+  int64 ret = 0;
+  for (size_t i = 0; i < buffered_byte_ranges_.size(); ++i)
+    ret += buffered_byte_ranges_.end(i) - buffered_byte_ranges_.start(i);
+  return ret;
 }
 
 int64 Pipeline::GetTotalBytes() const {
   base::AutoLock auto_lock(lock_);
   return total_bytes_;
 }
 
 void Pipeline::GetNaturalVideoSize(gfx::Size* out_size) const {
   CHECK(out_size);
   base::AutoLock auto_lock(lock_);
   *out_size = natural_size_;
 }
 
 PipelineStatistics Pipeline::GetStatistics() const {
   base::AutoLock auto_lock(lock_);
   return statistics_;
 }
 
 void Pipeline::SetClockForTesting(Clock* clock) {
   clock_.reset(clock);
 }
 
 void Pipeline::SetCurrentReadPosition(int64 offset) {

[scherkus (not reviewing), 2012/05/29 18:13:29]

AFAIK this is still called by FFDemuxer but I can't remember why or whether it's
still useful.

Do you happen to know?

[Ami GONE FROM CHROMIUM, 2012/05/29 20:45:44]

Hahahahahahahahaha.
current_bytes_ is (was) a write-only variable!

   base::AutoLock auto_lock(lock_);
 
   // The current read position should never be ahead of the buffered byte
   // position but threading issues between BufferedDataSource::DoneRead_Locked()
   // and BufferedDataSource::NetworkEventCallback() can cause them to be
   // temporarily out of sync. The easiest fix for this is to cap both
-  // buffered_bytes_ and current_bytes_ to always be legal values in
-  // SetCurrentReadPosition() and in SetBufferedBytes().
-  if (offset > buffered_bytes_)
-    buffered_bytes_ = offset;
+  // buffered_byte_ranges_ and current_bytes_ to always be legal values in

[scherkus (not reviewing), 2012/05/29 18:13:29]

|var|

[Ami GONE FROM CHROMIUM, 2012/05/29 20:45:44]

Done.

+  // SetCurrentReadPosition() and in AddBufferedByteRange().
   current_bytes_ = offset;
+  if (!buffered_byte_ranges_.size()) {
+    buffered_byte_ranges_.Add(0, offset);
+    return;
+  }
+  int64 start = buffered_byte_ranges_.start(buffered_byte_ranges_.size() - 1);
+  int64 end = buffered_byte_ranges_.end(buffered_byte_ranges_.size() - 1);
+  if (end < offset)
+    buffered_byte_ranges_.Add(start, offset);
 }
 
 void Pipeline::ResetState() {
   base::AutoLock auto_lock(lock_);
-  const base::TimeDelta kZero;
+  const TimeDelta kZero;
   running_          = false;
   stop_pending_     = false;
   seek_pending_     = false;
   tearing_down_     = false;
   error_caused_teardown_ = false;
   playback_rate_change_pending_ = false;
-  buffered_bytes_   = 0;
+  buffered_byte_ranges_.clear();
   buffered_time_ranges_.clear();
   total_bytes_      = 0;
   natural_size_.SetSize(0, 0);
   volume_           = 1.0f;
   playback_rate_    = 0.0f;
   pending_playback_rate_ = 0.0f;
   status_           = PIPELINE_OK;
   has_audio_        = false;
   has_video_        = false;
   waiting_for_clock_update_ = false;
@@ skipping 99 matching lines @@
   DCHECK(IsRunning());
   DCHECK_NE(PIPELINE_OK, error);
   VLOG(1) << "Media pipeline error: " << error;
 
   message_loop_->PostTask(FROM_HERE, base::Bind(
       &Pipeline::ErrorChangedTask, this, error));
 
   media_log_->AddEvent(media_log_->CreatePipelineErrorEvent(error));
 }
 
-base::TimeDelta Pipeline::GetTime() const {
+TimeDelta Pipeline::GetTime() const {
   DCHECK(IsRunning());
   return GetCurrentTime();
 }
 
-base::TimeDelta Pipeline::GetDuration() const {
+TimeDelta Pipeline::GetDuration() const {
   DCHECK(IsRunning());
   return GetMediaDuration();
 }
 
-void Pipeline::OnAudioTimeUpdate(base::TimeDelta time,
-                                 base::TimeDelta max_time) {
+void Pipeline::OnAudioTimeUpdate(TimeDelta time, TimeDelta max_time) {
   DCHECK(time <= max_time);
   DCHECK(IsRunning());
   base::AutoLock auto_lock(lock_);
 
   if (!has_audio_)
     return;
   if (waiting_for_clock_update_ && time < clock_->Elapsed())
     return;
 
   clock_->SetTime(time, max_time);
   StartClockIfWaitingForTimeUpdate_Locked();
 }
 
-void Pipeline::OnVideoTimeUpdate(base::TimeDelta max_time) {
+void Pipeline::OnVideoTimeUpdate(TimeDelta max_time) {
   DCHECK(IsRunning());
   base::AutoLock auto_lock(lock_);
 
   if (has_audio_)
     return;
 
   DCHECK(!waiting_for_clock_update_);
   clock_->SetMaxTime(max_time);
 }
 
-void Pipeline::SetDuration(base::TimeDelta duration) {
+void Pipeline::SetDuration(TimeDelta duration) {
   DCHECK(IsRunning());
   media_log_->AddEvent(
       media_log_->CreateTimeEvent(
           MediaLogEvent::DURATION_SET, "duration", duration));
   UMA_HISTOGRAM_LONG_TIMES("Media.Duration", duration);
 
   base::AutoLock auto_lock(lock_);
   clock_->SetDuration(duration);
-  UpdateBufferedTimeRanges_Locked();
+
+  if (total_bytes_ == 0)
+    return;
+  buffered_time_ranges_.clear();
+  for (size_t i = 0; i < buffered_byte_ranges_.size(); ++i) {
+    TimeDelta start = TimeForByteOffset_Locked(buffered_byte_ranges_.start(i));
+    TimeDelta end = TimeForByteOffset_Locked(buffered_byte_ranges_.end(i));
+    // Cap approximated buffered time at the length of the video.
+    end = std::min(end, clock_->Duration());
+    // Make sure buffered time is at least the current time.
+    end = std::max(end, GetCurrentTime_Locked());
+    buffered_time_ranges_.Add(start, end);
+  }
 }
 
 void Pipeline::SetTotalBytes(int64 total_bytes) {
   DCHECK(IsRunning());
   media_log_->AddEvent(
       media_log_->CreateIntegerEvent(
           MediaLogEvent::TOTAL_BYTES_SET, "total_bytes", total_bytes));
   int64 total_mbytes = total_bytes >> 20;
   if (total_mbytes > kint32max)
     total_mbytes = kint32max;
   UMA_HISTOGRAM_CUSTOM_COUNTS(
       "Media.TotalMBytes", static_cast<int32>(total_mbytes), 1, kint32max, 50);
 
   base::AutoLock auto_lock(lock_);
   total_bytes_ = total_bytes;
 }
 
-void Pipeline::SetBufferedBytes(int64 buffered_bytes) {
+TimeDelta Pipeline::TimeForByteOffset_Locked(int64 byte_offset) const {
+  lock_.AssertAcquired();
+  TimeDelta time_offset = byte_offset * clock_->Duration() / total_bytes_;
+  // Since the byte->time calculation is approximate, fudge the beginning &
+  // ending areas to look better.
+  TimeDelta epsilon = clock_->Duration() / 100;
+  if (time_offset < epsilon)
+    return TimeDelta();
+  if (time_offset + epsilon > clock_->Duration())
+    return clock_->Duration();
+  return time_offset;
+}
+
+void Pipeline::AddBufferedByteRange(int64 start, int64 end) {
   DCHECK(IsRunning());
   base::AutoLock auto_lock(lock_);
   // See comments in SetCurrentReadPosition() about capping.
-  if (buffered_bytes < current_bytes_)
-    current_bytes_ = buffered_bytes;
-  buffered_bytes_ = buffered_bytes;
-  UpdateBufferedTimeRanges_Locked();
-}
+  if (end < current_bytes_)
+    current_bytes_ = end;
+  buffered_byte_ranges_.Add(start, end);
 
-void Pipeline::UpdateBufferedTimeRanges_Locked() {
-  lock_.AssertAcquired();
   if (total_bytes_ == 0)
     return;
-  base::TimeDelta buffered_time =
-      clock_->Duration() * buffered_bytes_ / total_bytes_;
-  // Cap approximated buffered time at the length of the video.
-  buffered_time = std::min(buffered_time, clock_->Duration());
-  // Make sure buffered_time is at least the current time and at least the
-  // current seek target.
-  buffered_time = std::max(buffered_time, GetCurrentTime_Locked());
-  buffered_time = std::max(buffered_time, seek_timestamp_);
-  buffered_time_ranges_.Add(seek_timestamp_, buffered_time);
+  buffered_time_ranges_.Add(TimeForByteOffset_Locked(start),
+                            TimeForByteOffset_Locked(end));
 }
 
 void Pipeline::SetNaturalVideoSize(const gfx::Size& size) {
   DCHECK(IsRunning());
   media_log_->AddEvent(media_log_->CreateVideoSizeSetEvent(
       size.width(), size.height()));
 
   base::AutoLock auto_lock(lock_);
   natural_size_ = size;
 }
@@ skipping 298 matching lines @@
 
 void Pipeline::VolumeChangedTask(float volume) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   if (!running_ || tearing_down_)
     return;
 
   if (audio_renderer_)
     audio_renderer_->SetVolume(volume);
 }
 
-void Pipeline::SeekTask(base::TimeDelta time,
-                        const PipelineStatusCB& seek_cb) {
+void Pipeline::SeekTask(TimeDelta time, const PipelineStatusCB& seek_cb) {
   DCHECK(message_loop_->BelongsToCurrentThread());
   DCHECK(!IsPipelineStopPending());
 
   // Suppress seeking if we're not fully started.
   if (state_ != kStarted && state_ != kEnded) {
     // TODO(scherkus): should we run the callback?  I'm tempted to say the API
     // will only execute the first Seek() request.
     DVLOG(1) << "Media pipeline has not started, ignoring seek to "
              << time.InMicroseconds() << " (current state: " << state_ << ")";
     return;
@@ skipping 456 matching lines @@
   }
 
   if (pipeline_filter_) {
     pipeline_filter_->Stop(callback);
     return;
   }
 
   callback.Run();
 }
 
-void Pipeline::DoSeek(base::TimeDelta seek_timestamp) {
+void Pipeline::DoSeek(TimeDelta seek_timestamp) {
   // TODO(acolwell): We might be able to convert this if (demuxer_) into a
   // DCHECK(). Further investigation is needed to make sure this won't introduce
   // a bug.
   if (demuxer_) {
     demuxer_->Seek(seek_timestamp, base::Bind(
         &Pipeline::OnDemuxerSeekDone, this, seek_timestamp));
     return;
   }
 
   OnDemuxerSeekDone(seek_timestamp, PIPELINE_OK);
 }
 
-void Pipeline::OnDemuxerSeekDone(base::TimeDelta seek_timestamp,
+void Pipeline::OnDemuxerSeekDone(TimeDelta seek_timestamp,
                                  PipelineStatus status) {
   if (!message_loop_->BelongsToCurrentThread()) {
     message_loop_->PostTask(FROM_HERE, base::Bind(
         &Pipeline::OnDemuxerSeekDone, this, seek_timestamp, status));
     return;
   }
 
   PipelineStatusCB done_cb =
       base::Bind(&Pipeline::OnFilterStateTransitionWithStatus, this);
 
@@ skipping 22 matching lines @@
 void Pipeline::StartClockIfWaitingForTimeUpdate_Locked() {
   lock_.AssertAcquired();
   if (!waiting_for_clock_update_)
     return;
 
   waiting_for_clock_update_ = false;
   clock_->Play();
 }
 
 }  // namespace media