Refactor MSE implementation on Android to simplify the logic and improve the performance

media/base/android/media_decoder_job.h

 // Copyright 2013 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.
 
 #ifndef MEDIA_BASE_ANDROID_MEDIA_DECODER_JOB_H_
 #define MEDIA_BASE_ANDROID_MEDIA_DECODER_JOB_H_
 
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "media/base/android/demuxer_stream_player_params.h"
 #include "media/base/android/media_codec_bridge.h"
+#include "ui/gl/android/scoped_java_surface.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace media {
 
+class MediaDrmBridge;
+
 // Class for managing all the decoding tasks. Each decoding task will be posted
 // onto the same thread. The thread will be stopped once Stop() is called.
 // Data is stored in 2 chunks. When new data arrives, it is always stored in
 // an inactive chunk. And when the current active chunk becomes empty, a new
 // data request will be sent to the renderer.
 class MediaDecoderJob {
  public:
   struct Deleter {
     inline void operator()(MediaDecoderJob* ptr) const { ptr->Release(); }
   };
@@ skipping 17 matching lines @@
   // Called by MediaSourcePlayer when more data for this object has arrived.
   void OnDataReceived(const DemuxerData& data);
 
   // Prefetch so we know the decoder job has data when we call Decode().
   // |prefetch_cb| - Run when prefetching has completed.
   void Prefetch(const base::Closure& prefetch_cb);
 
   // Called by MediaSourcePlayer to decode some data.
   // |callback| - Run when decode operation has completed.
   //
-  // Returns a scoped pointer to a DemuxerConfig if a config change is detected,
-  // or an empty scoped pointer otherwise. In the case of requiring further data
-  // before commencing decode, an empty scoped pointer will also be returned
-  // although config change may be the next received access unit. |callback|
-  // will be called when the decode operation is complete. If a config change
-  // is detected, |callback| is ignored and will not be called.
-  scoped_ptr<DemuxerConfigs> Decode(
-      base::TimeTicks start_time_ticks,
-      base::TimeDelta start_presentation_timestamp,
-      const DecoderCallback& callback);
+  // Returns true if the next decode was started and |callback| will be
+  // called when the decode operation is complete.
+  // Returns false if |media_codec_bridge_| cannot be created. |callback| is

[wolenetz, 2014/05/21 00:48:04]

nit: s/./;/

[qinmin, 2014/05/22 00:35:55]

Done.

+  // ignored and will not be called.
+  bool Decode(base::TimeTicks start_time_ticks,
+              base::TimeDelta start_presentation_timestamp,
+              const DecoderCallback& callback);
 
   // Called to stop the last Decode() early.
   // If the decoder is in the process of decoding the next frame, then
   // this method will just allow the decode to complete as normal. If
   // this object is waiting for a data request to complete, then this method
   // will wait for the data to arrive and then call the |callback|
   // passed to Decode() with a status of MEDIA_CODEC_STOPPED. This ensures that
   // the |callback| passed to Decode() is always called and the status
   // reflects whether data was actually decoded or the decode terminated early.
   void StopDecode();
 
-  // Flush the decoder.
+  // Flushes the decoder and abandons all the data that is being decoded.
   void Flush();
 
   // Enter prerolling state. The job must not currently be decoding.
   void BeginPrerolling(base::TimeDelta preroll_timestamp);
 
-  bool prerolling() const { return prerolling_; }
+  // Releases all the decoder resources as the current tab is going background.
+  virtual void ReleaseDecoderResources();
+
+  // Sets the demuxer configs. Returns true if configs has changed, or false
+  // otherwise.
+  virtual bool SetDemuxerConfigs(const DemuxerConfigs& configs);

[wolenetz, 2014/05/21 00:48:04]

Does this need to be virtual? Neither {audio,video}_decoder_job.h have this.

[qinmin, 2014/05/22 00:35:55]

No, removed the virtual keyword.

On 2014/05/21 00:48:04, wolenetz wrote:

+
+  // Returns whether the decoder has finished decoding all the data.
+  bool OutputEOSReached() const;
+
+  // Returns true if the audio/video stream is available, implemented by child
+  // classes.
+  virtual bool HasStream() const = 0;
 
   bool is_decoding() const { return !decode_cb_.is_null(); }
 
-  bool is_requesting_demuxer_data() const {
-    return is_requesting_demuxer_data_;
-  }
+  void set_drm_bridge(MediaDrmBridge* drm_bridge) { drm_bridge_ = drm_bridge; }
+
+  bool is_content_encrypted() const { return is_content_encrypted_; }
 
  protected:
+  // Creates a new MediaDecoderJob instance.
+  // |decoder_task_runner| - Thread on which the decoder task will run.
+  // |request_data_cb| - Callback to request more data for the decoder.
+  // |on_demuxer_config_changed_cb| - Callback to inform the caller that
+  // demuxer config has changed.
   MediaDecoderJob(
       const scoped_refptr<base::SingleThreadTaskRunner>& decoder_task_runner,
-      MediaCodecBridge* media_codec_bridge,
-      const base::Closure& request_data_cb);
+      const base::Closure& request_data_cb,
+      const base::Closure& on_demuxer_config_changed_cb);
 
   // Release the output buffer at index |output_buffer_index| and render it if
   // |render_output| is true. Upon completion, |callback| will be called.
   virtual void ReleaseOutputBuffer(
       int output_buffer_index,
       size_t size,
       bool render_output,
       base::TimeDelta current_presentation_timestamp,
       const ReleaseOutputCompletionCallback& callback) = 0;
 
   // Returns true if the "time to render" needs to be computed for frames in
   // this decoder job.
   virtual bool ComputeTimeToRender() const = 0;
 
+  // Gets MediaCrypto object from |drm_bridge_|.
+  base::android::ScopedJavaLocalRef<jobject> GetMediaCrypto();
+
+  // Releases the |media_codec_bridge_|.
+  void ReleaseMediaCodecBridge();
+
+  MediaDrmBridge* drm_bridge() { return drm_bridge_; }
+
+  void set_is_content_encrypted(bool is_content_encrypted) {
+    is_content_encrypted_ = is_content_encrypted;
+  }
+
+  bool need_to_reconfig_decoder_job_;
+
+  scoped_ptr<MediaCodecBridge> media_codec_bridge_;
+
  private:
   friend class MediaSourcePlayerTest;
 
   // Causes this instance to be deleted on the thread it is bound to.
   void Release();
 
-  MediaCodecStatus QueueInputBuffer(const AccessUnit& unit);
+  // Queues an access unit into |media_codec_bridge_|'s input buffer. If
+  // |drain_decoder| is true,  the access unit is replaced with an EOS unit so
+  // that we can drain the current buffer in |media_codec_bridge_|.
+  MediaCodecStatus QueueInputBuffer(const AccessUnit& unit, bool drain_decoder);
 
   // Returns true if this object has data to decode.
   bool HasData() const;
 
   // Initiates a request for more data.
   // |done_cb| is called when more data is available in |received_data_|.
   void RequestData(const base::Closure& done_cb);
 
   // Posts a task to start decoding the current access unit in |received_data_|.
   void DecodeCurrentAccessUnit(
       base::TimeTicks start_time_ticks,
       base::TimeDelta start_presentation_timestamp);
 
   // Helper function to decoder data on |thread_|. |unit| contains all the data

[wolenetz, 2014/05/21 00:48:04]

nit: s/decoder/decode/ && s/thread_/decoder_task_runner_ (?)

[qinmin, 2014/05/22 00:35:55]

Done.

   // to be decoded. |start_time_ticks| and |start_presentation_timestamp|
   // represent the system time and the presentation timestamp when the first
   // frame is rendered. We use these information to estimate when the current
   // frame should be rendered. If |needs_flush| is true, codec needs to be
   // flushed at the beginning of this call.

[wolenetz, 2014/05/21 00:48:04]

nit: comment drain_decoder to help clarify difference between flush and drain
(abandon current data == flush, decode EOS if drain_decoder).

nit: please also comment w.r.t: Can both needs_flush and drain_decoder be true?
What would expected behavior be?

aside: Is it legal for |stop_decode_pending_| or |release_resources_pending_| to
be true during DecodeInternal? What would expected behavior be?

[qinmin, 2014/05/22 00:35:55]

added comments here.
And added a DCHECK in function definition to verify that needs_flush and
drain_decoder will not both be true.

On 2014/05/21 00:48:04, wolenetz wrote:

   void DecodeInternal(const AccessUnit& unit,
                       base::TimeTicks start_time_ticks,
                       base::TimeDelta start_presentation_timestamp,
                       bool needs_flush,
+                      bool drain_decoder,
                       const DecoderCallback& callback);
 
   // Called on the UI thread to indicate that one decode cycle has completed.
   // Completes any pending job destruction or any pending decode stop. If
   // destruction was not pending, passes its arguments to |decode_cb_|.
   void OnDecodeCompleted(MediaCodecStatus status,
                          base::TimeDelta current_presentation_timestamp,
                          base::TimeDelta max_presentation_timestamp);
 
   // Helper function to get the current access unit that is being decoded.
   const AccessUnit& CurrentAccessUnit() const;
 
   // Helper function to get the current data chunk index that is being decoded.
   size_t CurrentReceivedDataChunkIndex() const;
 
   // Check whether a chunk has no remaining access units to decode. If
   // |is_active_chunk| is true, this function returns whether decoder has
   // consumed all data in |received_data_[current_demuxer_data_index_]|.
   // Otherwise, it returns whether decoder has consumed all data in the inactive
   // chunk.
   bool NoAccessUnitsRemainingInChunk(bool is_active_chunk) const;
 
-  // Clearn all the received data.
-  void ClearData();
-
-  // Request new data for the current chunk if it runs out of data.
+  // Requests new data for the current chunk if it runs out of data.
   void RequestCurrentChunkIfEmpty();
 
-  // Initialize |received_data_| and |access_unit_index_|.
+  // Initializes |received_data_| and |access_unit_index_|.
   void InitializeReceivedData();
 
+  // Called when the decoder is completely drained and is ready to be released.
+  void OnDecoderDrained();
+
+  // Creates |media_codec_bridge_| for decoding purpose.

[wolenetz, 2014/05/21 00:48:04]

nit: doc retval

[qinmin, 2014/05/22 00:35:55]

Done.

+  bool CreateMediaCodecBridge();
+
+  // Called when an access unit is consumed by the decoder. |is_config_change|
+  // indicates whether the current access unit is a config change. If it is
+  // true, the next access unit is guarateed to be an I-frame.
+  virtual void CurrentDataConsumed(bool is_config_change) {}
+
+  // Called when |media_codec_bridge_| is released
+  virtual void OnMediaCodecBridgeReleased() {}
+
+  // Implemented by the child class to create |media_codec_bridge_| for a
+  // particular stream.

[wolenetz, 2014/05/21 00:48:04]

nit: doc retval

[qinmin, 2014/05/22 00:35:55]

Done.

+  virtual bool CreateMediaCodecBridgeInternal() = 0;
+
+  // Returns true if the |configs| doesn't match the current demuxer configs
+  // the decoder job has.
+  virtual bool IsDemuxerConfigChanged(const DemuxerConfigs& configs) const = 0;
+
+  // Update the demuxer configs.
+  virtual void UpdateDemuxerConfigs(const DemuxerConfigs& configs) = 0;
+
   // Return the index to |received_data_| that is not currently being decoded.
   size_t inactive_demuxer_data_index() const {
     return 1 - current_demuxer_data_index_;
   }
 
   // The UI message loop where callbacks should be dispatched.
   scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
 
   // The task runner that decoder job runs on.
   scoped_refptr<base::SingleThreadTaskRunner> decoder_task_runner_;
 
-  // The media codec bridge used for decoding. Owned by derived class.
-  // NOTE: This MUST NOT be accessed in the destructor.
-  MediaCodecBridge* media_codec_bridge_;
-
   // Whether the decoder needs to be flushed.
   bool needs_flush_;
 
   // Whether input EOS is encountered.
   // TODO(wolenetz/qinmin): Protect with a lock. See http://crbug.com/320043.
   bool input_eos_encountered_;
 
   // Whether output EOS is encountered.
   bool output_eos_encountered_;
 
@@ skipping 12 matching lines @@
   // Indicates prerolling state. If true, this job has not yet decoded output
   // that it will render, since the most recent of job construction or
   // BeginPrerolling(). If false, |preroll_timestamp_| has been reached.
   // TODO(qinmin): Comparing access unit's timestamp with |preroll_timestamp_|
   // is not very accurate.
   bool prerolling_;
 
   // Callback used to request more data.
   base::Closure request_data_cb_;
 
+  // Callback to notify the caller config has changed.
+  base::Closure on_demuxer_config_changed_cb_;
+
   // Callback to run when new data has been received.
   base::Closure on_data_received_cb_;
 
   // Callback to run when the current Decode() operation completes.
   DecoderCallback decode_cb_;
 
   // Data received over IPC from last RequestData() operation.
   // We keep 2 chunks at the same time to reduce the IPC latency between chunks.
   // If data inside the current chunk are all decoded, we will request a new
   // chunk from the demuxer and swap the current chunk with the other one.
   // New data will always be stored in the other chunk since the current
   // one may be still in use.
   DemuxerData received_data_[2];
 
   // Index to the current data chunk that is being decoded.
   size_t current_demuxer_data_index_;
 
   // Index to the access unit inside each data chunk that is being decoded.
   size_t access_unit_index_[2];
 
   // The index of input buffer that can be used by QueueInputBuffer().
   // If the index is uninitialized or invalid, it must be -1.
   int input_buf_index_;
 
+  // Indicates whether content is encrypted.
+  bool is_content_encrypted_;
+
+  // Indicates the decoder job should stop after decoding the current access
+  // unit.
   bool stop_decode_pending_;
 
   // Indicates that this object should be destroyed once the current
   // Decode() has completed. This gets set when Release() gets called
   // while there is a decode in progress.
   bool destroy_pending_;
 
   // Indicates whether the decoder is in the middle of requesting new data.
   bool is_requesting_demuxer_data_;
 
   // Indicates whether the incoming data should be ignored.
   bool is_incoming_data_invalid_;
 
-  // Weak pointer passed to media decoder jobs for callbacks. It is bounded to
-  // the decoder thread.
-  // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<MediaDecoderJob> weak_factory_;
+  // Indicates that |media_codec_bridge_| should be released once the current
+  // Decode() has completed. This gets set when ReleaseDecoderResources() gets
+  // called while there is a decode in progress.
+  bool release_resources_pending_;
+
+  // Pointer to a DRM object that will be used for encrypted streams.
+  MediaDrmBridge* drm_bridge_;
+
+  // Indicates whether |media_codec_bridge_| is in the middle of being drained
+  // due to a config change.
+  bool drain_decoder_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(MediaDecoderJob);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_ANDROID_MEDIA_DECODER_JOB_H_