media: recycle buffers/direct rendering etc. (third patch)

media/filters/ffmpeg_video_decoder.cc

 // Copyright (c) 2010 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/filters/ffmpeg_video_decoder.h"
 
 #include <deque>
 
 #include "base/task.h"
 #include "media/base/callback.h"
 #include "media/base/filters.h"
 #include "media/base/filter_host.h"
 #include "media/base/limits.h"
 #include "media/base/media_format.h"
 #include "media/base/video_frame.h"
 #include "media/ffmpeg/ffmpeg_common.h"
 #include "media/ffmpeg/ffmpeg_util.h"
 #include "media/filters/ffmpeg_interfaces.h"
 #include "media/filters/ffmpeg_video_decode_engine.h"
 #include "media/filters/video_decode_engine.h"
 
 namespace media {
 
 FFmpegVideoDecoder::FFmpegVideoDecoder(VideoDecodeEngine* engine)
     : width_(0),
       height_(0),
       time_base_(new AVRational()),
       state_(kUnInitialized),
-      decode_engine_(engine),
-      pending_reads_(0),
-      pending_requests_(0) {
+      decode_engine_(engine) {
   memset(&info_, 0, sizeof(info_));
 }
 
 FFmpegVideoDecoder::~FFmpegVideoDecoder() {
 }
 
 void FFmpegVideoDecoder::Initialize(DemuxerStream* demuxer_stream,
                                     FilterCallback* callback) {
   if (MessageLoop::current() != message_loop()) {
     message_loop()->PostTask(FROM_HERE,
@@ skipping 101 matching lines @@
 }
 
 void FFmpegVideoDecoder::OnUninitializeComplete() {
   DCHECK_EQ(MessageLoop::current(), message_loop());
   DCHECK(uninitialize_callback_.get());
 
   AutoCallbackRunner done_runner(uninitialize_callback_.release());
   state_ = kStopped;
 }
 
+void FFmpegVideoDecoder::Pause(FilterCallback* callback) {
+  if (MessageLoop::current() != message_loop()) {
+    message_loop()->PostTask(FROM_HERE,
+                             NewRunnableMethod(this,
+                                               &FFmpegVideoDecoder::Pause,
+                                               callback));
+    return;
+  }
+
+  AutoCallbackRunner done_runner(callback);
+  state_ = kPausing;
+}
+
 void FFmpegVideoDecoder::Flush(FilterCallback* callback) {
   if (MessageLoop::current() != message_loop()) {
     message_loop()->PostTask(FROM_HERE,
                              NewRunnableMethod(this,
                                                &FFmpegVideoDecoder::Flush,
                                                callback));
     return;
   }
 
   DCHECK_EQ(MessageLoop::current(), message_loop());
   DCHECK(!flush_callback_.get());
 
+  state_ = kFlushing;
+
+  FlushBuffers();
+
   flush_callback_.reset(callback);
 
-  // Everything in the presentation time queue is invalid, clear the queue.
-  while (!pts_heap_.IsEmpty())
-    pts_heap_.Pop();
-
   decode_engine_->Flush();
 }
 
 void FFmpegVideoDecoder::OnFlushComplete() {
   DCHECK_EQ(MessageLoop::current(), message_loop());
   DCHECK(flush_callback_.get());
 
   AutoCallbackRunner done_runner(flush_callback_.release());
+
+  // Everything in the presentation time queue is invalid, clear the queue.
+  while (!pts_heap_.IsEmpty())
+    pts_heap_.Pop();
+
+  // Mark flush operation had been done.
+  state_ = kNormal;
 }
 
 void FFmpegVideoDecoder::Seek(base::TimeDelta time,
                               FilterCallback* callback) {
   if (MessageLoop::current() != message_loop()) {
      message_loop()->PostTask(FROM_HERE,
                               NewRunnableMethod(this,
                                                 &FFmpegVideoDecoder::Seek,
                                                 time,
                                                 callback));
      return;
   }
 
   DCHECK_EQ(MessageLoop::current(), message_loop());
   DCHECK(!seek_callback_.get());
 
-  // TODO(jiesun): when we move to parallel Flush, we should remove this.
-  DCHECK_EQ(0u, pending_reads_) << "Pending reads should have completed";
-  DCHECK_EQ(0u, pending_requests_) << "Pending requests should be empty";
-
   seek_callback_.reset(callback);
   decode_engine_->Seek();
 }
 
 void FFmpegVideoDecoder::OnSeekComplete() {
   DCHECK_EQ(MessageLoop::current(), message_loop());
   DCHECK(seek_callback_.get());
 
   AutoCallbackRunner done_runner(seek_callback_.release());
-  state_ = kNormal;
 }
 
 void FFmpegVideoDecoder::OnError() {
   NOTIMPLEMENTED();
 }
 
 void FFmpegVideoDecoder::OnFormatChange(VideoStreamInfo stream_info) {
   NOTIMPLEMENTED();
 }
 
 void FFmpegVideoDecoder::OnReadComplete(Buffer* buffer_in) {
   scoped_refptr<Buffer> buffer = buffer_in;
   message_loop()->PostTask(
       FROM_HERE,
       NewRunnableMethod(this,
                         &FFmpegVideoDecoder::OnReadCompleteTask,
                         buffer));
 }
 
 void FFmpegVideoDecoder::OnReadCompleteTask(scoped_refptr<Buffer> buffer) {
   DCHECK_EQ(MessageLoop::current(), message_loop());
-  DCHECK_GT(pending_reads_, 0u);
-
-  --pending_reads_;
+  DCHECK_NE(state_, kStopped);  // because of Flush() before Stop().
 
   // During decode, because reads are issued asynchronously, it is possible to
   // receive multiple end of stream buffers since each read is acked. When the
   // first end of stream buffer is read, FFmpeg may still have frames queued
   // up in the decoder so we need to go through the decode loop until it stops
   // giving sensible data.  After that, the decoder should output empty
   // frames.  There are three states the decoder can be in:
   //
   //   kNormal: This is the starting state. Buffers are decoded. Decode errors
   //            are discarded.
   //   kFlushCodec: There isn't any more input data. Call avcodec_decode_video2
   //                until no more data is returned to flush out remaining
   //                frames. The input buffer is ignored at this point.
   //   kDecodeFinished: All calls return empty frames.
   //
   // These are the possible state transitions.
   //
   // kNormal -> kFlushCodec:
   //     When buffer->IsEndOfStream() is first true.
   // kNormal -> kDecodeFinished:
   //     A catastrophic failure occurs, and decoding needs to stop.
   // kFlushCodec -> kDecodeFinished:
   //     When avcodec_decode_video2() returns 0 data or errors out.
   // (any state) -> kNormal:
   //     Any time buffer->IsDiscontinuous() is true.
-  //
-  // If the decoding is finished, we just always return empty frames.
-  if (state_ == kDecodeFinished || state_ == kStopped) {
-    DCHECK(buffer->IsEndOfStream());
-
-    --pending_requests_;
-    // Signal VideoRenderer the end of the stream event.
-    scoped_refptr<VideoFrame> video_frame;
-    VideoFrame::CreateEmptyFrame(&video_frame);
-    fill_buffer_done_callback()->Run(video_frame);
-    return;
-  }
 
   // Transition to kFlushCodec on the first end of stream buffer.
   if (state_ == kNormal && buffer->IsEndOfStream()) {
     state_ = kFlushCodec;
   }
 
   // Push all incoming timestamps into the priority queue as long as we have
   // not yet received an end of stream buffer.  It is important that this line
   // stay below the state transition into kFlushCodec done above.
   //
@@ skipping 15 matching lines @@
         FROM_HERE,
         NewRunnableMethod(this,
                           &FFmpegVideoDecoder::FillThisBuffer,
                           video_frame));
     return;
   }
 
   DCHECK_EQ(MessageLoop::current(), message_loop());
 
   // Synchronized flushing before stop should prevent this.
-  if (state_ == kStopped)
-    return;  // Discard the video frame.
+  DCHECK_NE(state_, kStopped);
+
+  // If the decoding is finished, we just always return empty frames.
+  if (state_ == kDecodeFinished) {
+    // Signal VideoRenderer the end of the stream event.
+    scoped_refptr<VideoFrame> empty_frame;
+    VideoFrame::CreateEmptyFrame(&empty_frame);
+    fill_buffer_done_callback()->Run(empty_frame);
+
+    // Fall through, because we still need to keep record of this frame.
+  }
 
   // Notify decode engine the available of new frame.
-  ++pending_requests_;
   decode_engine_->FillThisBuffer(video_frame);
 }
 
 void FFmpegVideoDecoder::OnFillBufferCallback(
     scoped_refptr<VideoFrame> video_frame) {
   DCHECK_EQ(MessageLoop::current(), message_loop());
-
-  // TODO(jiesun): Flush before stop will prevent this from happening.
-  if (state_ == kStopped)
-    return;  // Discard the video frame.
+  DCHECK_NE(state_, kStopped);
 
   if (video_frame.get()) {
+    if (kPausing == state_ || kFlushing == state_) {
+      frame_queue_flushed_.push_back(video_frame);
+      if (kFlushing == state_)
+        FlushBuffers();
+      return;
+    }
+
     // If we actually got data back, enqueue a frame.
     last_pts_ = FindPtsAndDuration(*time_base_, &pts_heap_, last_pts_,
                                    video_frame.get());
 
     video_frame->SetTimestamp(last_pts_.timestamp);
     video_frame->SetDuration(last_pts_.duration);
 
-    // Deliver this frame to VideoRenderer.
-    --pending_requests_;
     fill_buffer_done_callback()->Run(video_frame);
   } else {
     // When in kFlushCodec, any errored decode, or a 0-lengthed frame,
     // is taken as a signal to stop decoding.
     if (state_ == kFlushCodec) {
       state_ = kDecodeFinished;
 
-      --pending_requests_;
       // Signal VideoRenderer the end of the stream event.
       scoped_refptr<VideoFrame> video_frame;
       VideoFrame::CreateEmptyFrame(&video_frame);
       fill_buffer_done_callback()->Run(video_frame);
     }
   }
 }
 
 void FFmpegVideoDecoder::OnEmptyBufferCallback(
     scoped_refptr<Buffer> buffer) {
   DCHECK_EQ(MessageLoop::current(), message_loop());
-  DCHECK_LE(pending_reads_, pending_requests_);
+  DCHECK_NE(state_, kStopped);
 
   demuxer_stream_->Read(
       NewCallback(this, &FFmpegVideoDecoder::OnReadComplete));
-  ++pending_reads_;
 }
 
 FFmpegVideoDecoder::TimeTuple FFmpegVideoDecoder::FindPtsAndDuration(
     const AVRational& time_base,
     PtsHeap* pts_heap,
     const TimeTuple& last_pts,
     const VideoFrame* frame) {
   TimeTuple pts;
 
   // First search the VideoFrame for the pts. This is the most authoritative.
@@ skipping 36 matching lines @@
   }
 
   return pts;
 }
 
 bool FFmpegVideoDecoder::ProvidesBuffer() {
   DCHECK(info_.success_);
   return info_.provides_buffers_;
 }
 
+void FFmpegVideoDecoder::FlushBuffers() {
+  while (!frame_queue_flushed_.empty()) {
+    scoped_refptr<VideoFrame> video_frame;
+    video_frame = frame_queue_flushed_.front();
+    frame_queue_flushed_.pop_front();
+
+    // Depends on who own the buffers, we either return it to the renderer
+    // or return it to the decode engine.
+    if (ProvidesBuffer())
+      decode_engine_->FillThisBuffer(video_frame);
+    else
+      fill_buffer_done_callback()->Run(video_frame);
+  }
+}
+
 void FFmpegVideoDecoder::SetVideoDecodeEngineForTest(
     VideoDecodeEngine* engine) {
   decode_engine_ = engine;
 }
 
 // static
 FilterFactory* FFmpegVideoDecoder::CreateFactory() {
   return new FilterFactoryImpl1<FFmpegVideoDecoder, FFmpegVideoDecodeEngine*>(
       new FFmpegVideoDecodeEngine());
 }
 
 // static
 bool FFmpegVideoDecoder::IsMediaFormatSupported(const MediaFormat& format) {
   std::string mime_type;
   return format.GetAsString(MediaFormat::kMimeType, &mime_type) &&
       mime_type::kFFmpegVideo == mime_type;
 }
 
 }  // namespace media