MSE: Move FrameProcessorBase code into FrameProcessor

media/filters/frame_processor.h

 // Copyright 2014 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_FILTERS_FRAME_PROCESSOR_H_
 #define MEDIA_FILTERS_FRAME_PROCESSOR_H_
 
+#include <map>
+
 #include "base/basictypes.h"
 #include "base/callback_forward.h"
 #include "base/time/time.h"
 #include "media/base/media_export.h"
 #include "media/base/stream_parser.h"
-#include "media/filters/frame_processor_base.h"
+#include "media/filters/chunk_demuxer.h"
 
 namespace media {
 
+// Helper class to capture per-track details needed by a frame processor. Some
+// of this information may be duplicated in the short-term in the associated
+// ChunkDemuxerStream and SourceBufferStream for a track.
+// This parallels the MSE spec each of a SourceBuffer's Track Buffers at
+// http://www.w3.org/TR/media-source/#track-buffers.
+class MseTrackBuffer {

[acolwell GONE FROM CHROMIUM, 2014/07/01 17:40:22]

nit: It doesn't look like this class actually needs to be in the header file.
Move to the .cc?

[wolenetz, 2014/07/01 18:16:39]

Good point. Done.

+ public:
+  explicit MseTrackBuffer(ChunkDemuxerStream* stream);
+  ~MseTrackBuffer();
+
+  // Get/set |last_decode_timestamp_|.
+  base::TimeDelta last_decode_timestamp() const {
+    return last_decode_timestamp_;
+  }
+  void set_last_decode_timestamp(base::TimeDelta timestamp) {
+    last_decode_timestamp_ = timestamp;
+  }
+
+  // Get/set |last_frame_duration_|.
+  base::TimeDelta last_frame_duration() const {
+    return last_frame_duration_;
+  }
+  void set_last_frame_duration(base::TimeDelta duration) {
+    last_frame_duration_ = duration;
+  }
+
+  // Gets |highest_presentation_timestamp_|.
+  base::TimeDelta highest_presentation_timestamp() const {
+    return highest_presentation_timestamp_;
+  }
+
+  // Get/set |needs_random_access_point_|.
+  bool needs_random_access_point() const {
+    return needs_random_access_point_;
+  }
+  void set_needs_random_access_point(bool needs_random_access_point) {
+    needs_random_access_point_ = needs_random_access_point;
+  }
+
+  // Gets a pointer to this track's ChunkDemuxerStream.
+  ChunkDemuxerStream* stream() const { return stream_; }
+
+  // Unsets |last_decode_timestamp_|, unsets |last_frame_duration_|,
+  // unsets |highest_presentation_timestamp_|, and sets
+  // |needs_random_access_point_| to true.
+  void Reset();
+
+  // If |highest_presentation_timestamp_| is unset or |timestamp| is greater
+  // than |highest_presentation_timestamp_|, sets
+  // |highest_presentation_timestamp_| to |timestamp|. Note that bidirectional
+  // prediction between coded frames can cause |timestamp| to not be
+  // monotonically increasing even though the decode timestamps are
+  // monotonically increasing.
+  void SetHighestPresentationTimestampIfIncreased(base::TimeDelta timestamp);
+
+ private:
+  // The decode timestamp of the last coded frame appended in the current coded
+  // frame group. Initially kNoTimestamp(), meaning "unset".
+  base::TimeDelta last_decode_timestamp_;
+
+  // The coded frame duration of the last coded frame appended in the current
+  // coded frame group. Initially kNoTimestamp(), meaning "unset".
+  base::TimeDelta last_frame_duration_;
+
+  // The highest presentation timestamp encountered in a coded frame appended
+  // in the current coded frame group. Initially kNoTimestamp(), meaning
+  // "unset".
+  base::TimeDelta highest_presentation_timestamp_;
+
+  // Keeps track of whether the track buffer is waiting for a random access
+  // point coded frame. Initially set to true to indicate that a random access
+  // point coded frame is needed before anything can be added to the track
+  // buffer.
+  bool needs_random_access_point_;
+
+  // Pointer to the stream associated with this track. The stream is not owned
+  // by |this|.
+  ChunkDemuxerStream* const stream_;
+
+  DISALLOW_COPY_AND_ASSIGN(MseTrackBuffer);
+};
+
 // Helper class that implements Media Source Extension's coded frame processing
 // algorithm.
-class MEDIA_EXPORT FrameProcessor : public FrameProcessorBase {
+class MEDIA_EXPORT FrameProcessor {
  public:
   typedef base::Callback<void(base::TimeDelta)> UpdateDurationCB;
+
+  // TODO(wolenetz/acolwell): Ensure that all TrackIds are coherent and unique
+  // for each track buffer. For now, special track identifiers are used for each
+  // of audio and video here, and text TrackIds are assumed to be non-negative.
+  // See http://crbug.com/341581.
+  enum {
+    kAudioTrackId = -2,
+    kVideoTrackId = -3
+  };
+
   explicit FrameProcessor(const UpdateDurationCB& update_duration_cb);
-  virtual ~FrameProcessor();
-
-  // FrameProcessorBase implementation
-  virtual void SetSequenceMode(bool sequence_mode) OVERRIDE;
-  virtual bool ProcessFrames(const StreamParser::BufferQueue& audio_buffers,
-                             const StreamParser::BufferQueue& video_buffers,
-                             const StreamParser::TextBufferQueueMap& text_map,
-                             base::TimeDelta append_window_start,
-                             base::TimeDelta append_window_end,
-                             bool* new_media_segment,
-                             base::TimeDelta* timestamp_offset) OVERRIDE;
+  ~FrameProcessor();
+
+  // Get/set the current append mode, which if true means "sequence" and if
+  // false means "segments".
+  // See http://www.w3.org/TR/media-source/#widl-SourceBuffer-mode.
+  bool sequence_mode() { return sequence_mode_; }
+  void SetSequenceMode(bool sequence_mode);
+
+  // Processes buffers in |audio_buffers|, |video_buffers|, and |text_map|.
+  // Returns true on success or false on failure which indicates decode error.
+  // |append_window_start| and |append_window_end| correspond to the MSE spec's
+  // similarly named source buffer attributes that are used in coded frame
+  // processing.
+  // |*new_media_segment| tracks whether the next buffers processed within the
+  // append window represent the start of a new media segment. This method may
+  // both use and update this flag.
+  // Uses |*timestamp_offset| according to the coded frame processing algorithm,
+  // including updating it as required in 'sequence' mode frame processing.
+  bool ProcessFrames(const StreamParser::BufferQueue& audio_buffers,
+                     const StreamParser::BufferQueue& video_buffers,
+                     const StreamParser::TextBufferQueueMap& text_map,
+                     base::TimeDelta append_window_start,
+                     base::TimeDelta append_window_end,
+                     bool* new_media_segment,
+                     base::TimeDelta* timestamp_offset);
+
+  // Signals the frame processor to update its group start timestamp to be
+  // |timestamp_offset| if it is in sequence append mode.
+  void SetGroupStartTimestampIfInSequenceMode(base::TimeDelta timestamp_offset);
+
+  // Adds a new track with unique track ID |id|.
+  // If |id| has previously been added, returns false to indicate error.
+  // Otherwise, returns true, indicating future ProcessFrames() will emit
+  // frames for the track |id| to |stream|.
+  bool AddTrack(StreamParser::TrackId id, ChunkDemuxerStream* stream);
+
+  // Updates the internal mapping of TrackId to track buffer for the track
+  // buffer formerly associated with |old_id| to be associated with |new_id|.
+  // Returns false to indicate failure due to either no existing track buffer
+  // for |old_id| or collision with previous track buffer already mapped to
+  // |new_id|. Otherwise returns true.
+  bool UpdateTrack(StreamParser::TrackId old_id, StreamParser::TrackId new_id);
+
+  // Sets the need random access point flag on all track buffers to true.
+  void SetAllTrackBuffersNeedRandomAccessPoint();
+
+  // Resets state for the coded frame processing algorithm as described in steps
+  // 2-5 of the MSE Reset Parser State algorithm described at
+  // http://www.w3.org/TR/media-source/#sourcebuffer-reset-parser-state
+  void Reset();
+
+  // Must be called when the audio config is updated.  Used to manage when
+  // the preroll buffer is cleared and the allowed "fudge" factor between
+  // preroll buffers.
+  void OnPossibleAudioConfigUpdate(const AudioDecoderConfig& config);
 
  private:
+  typedef std::map<StreamParser::TrackId, MseTrackBuffer*> TrackBufferMap;
+
+  // If |track_buffers_| contains |id|, returns a pointer to the associated
+  // MseTrackBuffer. Otherwise, returns NULL.
+  MseTrackBuffer* FindTrack(StreamParser::TrackId id);
+
+  // Signals all track buffers' streams that a new media segment is starting
+  // with timestamp |segment_timestamp|.
+  void NotifyNewMediaSegmentStarting(base::TimeDelta segment_timestamp);
+
+  // Handles partial append window trimming of |buffer|.  Returns true if the
+  // given |buffer| can be partially trimmed or have preroll added; otherwise,
+  // returns false.
+  //
+  // If |buffer| overlaps |append_window_start|, the portion of |buffer| before
+  // |append_window_start| will be marked for post-decode discard.  Further, if
+  // |audio_preroll_buffer_| exists and abuts |buffer|, it will be set as
+  // preroll on |buffer| and |audio_preroll_buffer_| will be cleared.  If the
+  // preroll buffer does not abut |buffer|, it will be discarded, but not used.
+  //
+  // If |buffer| lies entirely before |append_window_start|, and thus would
+  // normally be discarded, |audio_preroll_buffer_| will be set to |buffer| and
+  // the method will return false.
+  bool HandlePartialAppendWindowTrimming(
+      base::TimeDelta append_window_start,
+      base::TimeDelta append_window_end,
+      const scoped_refptr<StreamParserBuffer>& buffer);
+
   // Helper that processes one frame with the coded frame processing algorithm.
   // Returns false on error or true on success.
   bool ProcessFrame(const scoped_refptr<StreamParserBuffer>& frame,
                     base::TimeDelta append_window_start,
                     base::TimeDelta append_window_end,
                     base::TimeDelta* timestamp_offset,
                     bool* new_media_segment);
 
+  // TrackId-indexed map of each track's stream.
+  TrackBufferMap track_buffers_;
+
+  // The last audio buffer seen by the frame processor that was removed because
+  // it was entirely before the start of the append window.
+  scoped_refptr<StreamParserBuffer> audio_preroll_buffer_;
+
+  // The AudioDecoderConfig associated with buffers handed to ProcessFrames().
+  AudioDecoderConfig current_audio_config_;
+  base::TimeDelta sample_duration_;
+
+  // The AppendMode of the associated SourceBuffer.
+  // See SetSequenceMode() for interpretation of |sequence_mode_|.
+  // Per http://www.w3.org/TR/media-source/#widl-SourceBuffer-mode:
+  // Controls how a sequence of media segments are handled. This is initially
+  // set to false ("segments").
+  bool sequence_mode_;
+
+  // Tracks the MSE coded frame processing variable of same name.
+  // Initially kNoTimestamp(), meaning "unset".
+  base::TimeDelta group_start_timestamp_;
+
   // Tracks the MSE coded frame processing variable of same name. It stores the
   // highest coded frame end timestamp across all coded frames in the current
   // coded frame group. It is set to 0 when the SourceBuffer object is created
   // and gets updated by ProcessFrames().
   base::TimeDelta group_end_timestamp_;
 
   UpdateDurationCB update_duration_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(FrameProcessor);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_FRAME_PROCESSOR_H_