The guts of the video renderer logic that relate to timing and queuing of fra...

chrome/renderer/media/video_renderer_impl.cc

 // Copyright (c) 2009 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 "chrome/renderer/media/video_renderer_impl.h"
-#include "media/base/buffers.h"
-#include "media/base/filter_host.h"
-#include "media/base/pipeline.h"
-
-using media::MediaFormat;
-using media::VideoFrame;
-
-
-// The amount of time allowed to pre-submit a frame.  If UpdateQueue is called
-// with a time within this limit, it will skip to the next frame in the queue
-// even though the value for time it is called with is not yet at the frame's
-// timestamp.  Time is specified in microseconds.
-static const int64 kFrameSkipAheadLimit = 5000;
-
-// If there are no frames in the queue, then this value is used for the
-// amount of time to sleep until the next time update callback.  Time is
-// specified in microseconds.
-static const int64 kSleepIfNoFrame = 15000;
-
-// Number of reads to have pending.
-// TODO(ralph): Re-examine the pull model -- perhaps I was wrong.  I think
-// that perhaps the demuxer is the point where pull becomes push.
-static const size_t kDefaultNumberOfFrames = 4;
-
-// Value used for the current_frame_timestamp_ to indicate that the
-// |current_frame_| member should be treated as invalid.
-static const int64 kNoCurrentFrame = -1;
-
-//------------------------------------------------------------------------------
 
 VideoRendererImpl::VideoRendererImpl(WebMediaPlayerDelegateImpl* delegate)
     : delegate_(delegate),
-      submit_reads_task_(NULL),
-      number_of_reads_needed_(kDefaultNumberOfFrames),
-      current_frame_timestamp_(
-          base::TimeDelta::FromMicroseconds(kNoCurrentFrame)),
-      preroll_complete_(false) {
+      last_converted_frame_(NULL) {
 }
 
-VideoRendererImpl::~VideoRendererImpl() {
-  Stop();
+bool VideoRendererImpl::OnInitialize(size_t width, size_t height) {
+  video_size_.SetSize(width, height);
+  bitmap_.setConfig(SkBitmap::kARGB_8888_Config, width, height);
+  if (bitmap_.allocPixels(NULL, NULL)) {
+    bitmap_.eraseRGB(0x00, 0x00, 0x00);
+    return true;
+  }
+  NOTREACHED();
+  return false;
 }
 
-// static
-bool VideoRendererImpl::IsMediaFormatSupported(
-    const media::MediaFormat* media_format) {
-  int width;
-  int height;
-  return ParseMediaFormat(media_format, &width, &height);
+void VideoRendererImpl::OnPaintNeeded() {
+  delegate_->PostRepaintTask();
 }
 
-// static
-bool VideoRendererImpl::ParseMediaFormat(const media::MediaFormat* media_format,
-                                         int* width_out,
-                                         int* height_out) {
-  DCHECK(media_format && width_out && height_out);
-  std::string mime_type;
-  return (media_format->GetAsString(MediaFormat::kMimeType, &mime_type) &&
-          mime_type.compare(media::mime_type::kUncompressedVideo) == 0 &&
-          media_format->GetAsInteger(MediaFormat::kWidth, width_out) &&
-          media_format->GetAsInteger(MediaFormat::kHeight, height_out));
+// This method is always called on the renderer's thread.
+void VideoRendererImpl::Paint(skia::PlatformCanvas *canvas,

[scherkus (not reviewing), 2009/02/24 21:00:19]

pointer goes with the type

+                              const gfx::Rect& dest_rect) {
+  scoped_refptr<media::VideoFrame> video_frame;
+  GetCurrentFrame(&video_frame);
+  if (video_frame.get()) {
+    CopyToCurrentFrame(video_frame);
+    video_frame = NULL;

[scherkus (not reviewing), 2009/02/24 21:00:19]

This line isn't really needed due to scoped_refptr unless you explicitly want to
release your reference here

+  }
+  SkMatrix matrix;
+  matrix.setTranslate(static_cast<SkScalar>(dest_rect.x()),
+                      static_cast<SkScalar>(dest_rect.y()));
+  if (dest_rect.width()  != video_size_.width() ||
+      dest_rect.height() != video_size_.height()) {
+    matrix.preScale(
+        static_cast<SkScalar>(dest_rect.width()  / video_size_.width()),
+        static_cast<SkScalar>(dest_rect.height() / video_size_.height()));
+  }
+  canvas->drawBitmapMatrix(bitmap_, matrix, NULL);
 }
 
-void VideoRendererImpl::Stop() {
-  AutoLock auto_lock(lock_);
-  DiscardAllFrames();
-  if (submit_reads_task_) {
-    // The task is owned by the message loop, so we don't delete it here.  We
-    // know the task won't call us because we canceled it, and we know we are
-    // on the pipeline thread, since we're in the filer's Stop method, so there
-    // is no threading problem.  Just let the task be run by the message loop
-    // and then be killed
-    submit_reads_task_->Cancel();
-    submit_reads_task_ = NULL;
-  }
-  delegate_ = NULL;  // This indicates we're no longer running
-  decoder_ = NULL;   // Release reference to the decoder
-}
-
-bool VideoRendererImpl::Initialize(media::VideoDecoder* decoder) {
-  int width;
-  int height;
-  if (!ParseMediaFormat(decoder_->GetMediaFormat(), &width, &height)) {
-    return false;
-  }
-  current_frame_.setConfig(SkBitmap::kARGB_8888_Config, width, height);
-  if (!current_frame_.allocPixels(NULL, NULL)) {
-    NOTREACHED();
-    return false;
-  }
-  rect_.SetRect(0, 0, width, height);
-  delegate_->SetVideoRenderer(this);
-  host_->SetVideoSize(width, height);
-  host_->SetTimeUpdateCallback(
-      NewCallback(this, &VideoRendererImpl::TimeUpdateCallback));
-  SubmitReads();
-  return true;
-}
-
-void VideoRendererImpl::SubmitReads() {
-  int number_to_read;
-  {
-    AutoLock auto_lock(lock_);
-    submit_reads_task_ = NULL;
-    number_to_read = number_of_reads_needed_;
-    number_of_reads_needed_ = 0;
-  }
-  while (number_to_read > 0) {
-    decoder_->Read(new media::AssignableBuffer<VideoRendererImpl,
-                                               media::VideoFrame>(this));
-    --number_to_read;
+void VideoRendererImpl::CopyToCurrentFrame(media::VideoFrame* video_frame) {
+  base::TimeDelta timestamp = video_frame->GetTimestamp();
+  if (video_frame != last_converted_frame_ ||
+      timestamp != last_converted_timestamp_) {
+    last_converted_frame_ = video_frame;
+    last_converted_timestamp_ = timestamp;
+    media::VideoSurface frame_in;
+    if (video_frame->Lock(&frame_in)) {
+      // TODO(ralphl):  Actually do the color space conversion here!
+      // This is temporary code to set the bits of the current_frame_ to
+      // blue.
+      bitmap_.eraseRGB(0x00, 0x00, 0xFF);
+      video_frame->Unlock();
+    } else {
+      NOTREACHED();
+    }
   }
 }
-
-void VideoRendererImpl::SetRect(const gfx::Rect& rect) {
-  rect_ = rect;
-  // TODO(ralphl) What are all these rects???
-}
-
-// This method is always called on the renderer's thread, so it will not be
-// reentered.  However, it does maniuplate the queue and the current frame
-// timestamp, so those manipulations need to happen with the lock held.
-void VideoRendererImpl::Paint(skia::PlatformCanvas *canvas,
-                              const gfx::Rect& rect) {
-  VideoFrame* video_frame;
-  base::TimeDelta time_of_next_frame;
-  bool need_to_convert_frame = false;
-  {
-    AutoLock auto_lock(lock_);
-    UpdateQueue(host_->GetPipelineStatus()->GetTime(), NULL, &video_frame,
-                &time_of_next_frame);
-    if (video_frame) {
-      // if the |current_frame_| bitmap already has the RGB image of the
-      // front video_frame then there's on no need to call CopyToCurentFrame
-      // to convert the video_frame to RBG.  If we do need to convert a new
-      // frame, then remember the time of the frame so we might be able to skip
-      // this step if asked to repaint multiple times.  Note that the
-      // |current_frame_timestamp_| member needs to only be accessed with the
-      // |lock_| acquired, so we set the timestamp here even though the
-      // conversion won't take place until we call CopyToCurrentFrame.  It's
-      // not a problem because this method is the only place where the current
-      // frame is updated, and it is always called on the renderer's thread.
-      const base::TimeDelta frame_timestamp = video_frame->GetTimestamp();
-      need_to_convert_frame = (current_frame_timestamp_ != frame_timestamp);
-      if (need_to_convert_frame) {
-        current_frame_timestamp_ = frame_timestamp;
-      }
-    }
-  }
-
-  // We no longer hold the |lock_|. Don't access members other than |host_| and
-  // |current_frame_|.
-  if (video_frame) {
-    if (need_to_convert_frame) {
-      CopyToCurrentFrame(video_frame);
-    }
-    video_frame->Release();
-    SkMatrix matrix;
-    matrix.setTranslate(static_cast<SkScalar>(rect.x()),
-                        static_cast<SkScalar>(rect.y()));
-    // TODO(ralphl): I have no idea what's going on here.  How are these
-    // rects related to eachother?  What does SetRect() mean?
-    matrix.preScale(static_cast<SkScalar>(rect.width() / rect_.width()),
-                    static_cast<SkScalar>(rect.height() / rect_.height()));
-    canvas->drawBitmapMatrix(current_frame_, matrix, NULL);
-  }
-  host_->ScheduleTimeUpdateCallback(time_of_next_frame);
-}
-
-void VideoRendererImpl::CopyToCurrentFrame(VideoFrame* video_frame) {
-  media::VideoSurface frame_in;
-  if (video_frame->Lock(&frame_in)) {
-    // TODO(ralphl):  Actually do the color space conversion here!
-    // This is temporary code to set the bits of the current_frame_ to
-    // blue.
-    current_frame_.eraseRGB(0x00, 0x00, 0xFF);
-    video_frame->Unlock();
-  } else {
-    NOTREACHED();
-  }
-}
-
-// Assumes |lock_| has been acquired!
-bool VideoRendererImpl::UpdateQueue(base::TimeDelta time,
-                                    VideoFrame* new_frame,
-                                    VideoFrame** front_frame_out,
-                                    base::TimeDelta* time_of_next_frame) {
-  bool updated_front = false;
-
-  // If a new frame is passed in then put it at the back of the queue.  If the
-  // queue was empty, then we've updated the front too.
-  if (new_frame) {
-    updated_front = queue_.empty();
-    new_frame->AddRef();
-    queue_.push_back(new_frame);
-  }
-
-  // Now make sure that the front of the queue is the correct frame to display
-  // right now.  Discard any frames that are past the current time.  If any
-  // frames are discarded then increment the |number_of_reads_needed_| member.
-  while (queue_.size() > 1 &&
-         queue_.front()->GetTimestamp() +
-         base::TimeDelta::FromMicroseconds(kFrameSkipAheadLimit) >= time) {
-    queue_.front()->Release();
-    queue_.pop_front();
-    updated_front = true;
-    ++number_of_reads_needed_;
-  }
-
-  // If the caller wants the front frame then return it, with the reference
-  // count incremented.  The caller must call Release() on the returned frame.
-  if (front_frame_out) {
-    if (queue_.empty()) {
-      *front_frame_out = NULL;
-    } else {
-      *front_frame_out = queue_.front();
-      (*front_frame_out)->AddRef();
-    }
-  }
-
-  // If the caller wants the time of the next frame, return our best guess:
-  //   If no frame, then wait for a while
-  //   If only one frame, then use the duration of the front frame
-  //   If there is more than one frame, return the time of the next frame.
-  if (time_of_next_frame) {
-    if (queue_.empty()) {
-      *time_of_next_frame = host_->GetPipelineStatus()->GetInterpolatedTime() +
-                            base::TimeDelta::FromMicroseconds(kSleepIfNoFrame);
-    } else {
-      if (queue_.size() == 1) {
-        *time_of_next_frame = queue_.front()->GetTimestamp() +
-                              queue_.front()->GetDuration();
-      } else {
-        *time_of_next_frame = queue_[1]->GetTimestamp();
-      }
-    }
-  }
-
-  // If any frames have been removed we need to call the decoder again.  Note
-  // that the PostSubmitReadsTask method will only post the task if there are
-  // pending reads.
-  PostSubmitReadsTask();
-
-  // True if the front of the queue is a new frame.
-  return updated_front;
-}
-
-// Assumes |lock_| has been acquired!
-void VideoRendererImpl::DiscardAllFrames() {
-  while (!queue_.empty()) {
-    queue_.front()->Release();
-    queue_.pop_front();
-    ++number_of_reads_needed_;
-  }
-  current_frame_timestamp_ = base::TimeDelta::FromMicroseconds(kNoCurrentFrame);
-}
-
-// Assumes |lock_| has been acquired!
-void VideoRendererImpl::PostSubmitReadsTask() {
-  if (number_of_reads_needed_ > 0 && !submit_reads_task_) {
-    submit_reads_task_ = NewRunnableMethod(this,
-                                           &VideoRendererImpl::SubmitReads);
-    host_->PostTask(submit_reads_task_);
-  }
-}
-
-void VideoRendererImpl::TimeUpdateCallback(base::TimeDelta time) {
-  AutoLock auto_lock(lock_);
-  if (IsRunning() && UpdateQueue(time, NULL, NULL, NULL)) {
-    delegate_->PostRepaintTask();
-  }
-}
-
-void VideoRendererImpl::OnAssignment(VideoFrame* video_frame) {
-  bool call_initialized = false;
-  {
-    AutoLock auto_lock(lock_);
-    if (IsRunning()) {
-      // TODO(ralphl): if (!preroll_complete_ && EndOfStream) call_init = true
-      // and preroll_complete_ = true.
-      // TODO(ralphl): If(Seek()) then discard but we don't have SeekFrame().
-      if (false) {
-        // TODO(ralphl): this is the seek() logic.
-        DiscardAllFrames();
-        ++number_of_reads_needed_;
-        PostSubmitReadsTask();
-      } else {
-        if (UpdateQueue(host_->GetPipelineStatus()->GetInterpolatedTime(),
-                        video_frame, NULL, NULL)) {
-          delegate_->PostRepaintTask();
-        }
-        if (!preroll_complete_ && queue_.size() == kDefaultNumberOfFrames) {
-          preroll_complete_ = true;
-          call_initialized = true;
-        }
-      }
-    }
-  }
-  // |lock_| no longer held.  Call the pipeline if we've just entered a
-  // completed preroll state.
-  if (call_initialized) {
-    host_->InitializationComplete();
-  }
-}
-