Extract coded frame processing from SourceState into LegacyFrameProcessor

media/filters/frame_processor_base.h

Index: media/filters/frame_processor_base.h
diff --git a/media/filters/frame_processor_base.h b/media/filters/frame_processor_base.h
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+++ b/media/filters/frame_processor_base.h
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+// 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_BASE_H_
+#define MEDIA_FILTERS_FRAME_PROCESSOR_BASE_H_
+
+#include <map>
+
+#include "base/basictypes.h"
+#include "base/time/time.h"
+#include "media/base/media_export.h"
+#include "media/base/stream_parser.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 {
+ public:
+  explicit MseTrackBuffer(ChunkDemuxerStream* stream);
+  ~MseTrackBuffer();
+
+  // 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_; }
+
+  // Sets |needs_random_access_point_| to true.
+  // TODO(wolenetz): Add the rest of the new coded frame processing algorithm
+  // track buffer attributes and reset them here. See http://crbug.com/249422.
+  void Reset();
+
+ private:
+  // 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);
+};
+
+// Abstract interface for helper class implementation of Media Source
+// Extension's coded frame processing algorithm.
+// TODO(wolenetz): Once the new FrameProcessor implementation stabilizes, remove
+// LegacyFrameProcessor and fold this interface into FrameProcessor. See
+// http://crbug.com/249422.
+class MEDIA_EXPORT FrameProcessorBase {
+ public:
+  // 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
+  };
+
+  // Callback signature used to notify ChunkDemuxer of timestamps that may cause
+  // the duration to be updated.
+  typedef base::Callback<void(
+      base::TimeDelta, ChunkDemuxerStream*)> IncreaseDurationCB;
+
+  virtual ~FrameProcessorBase();
+
+  // 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_; }
+  virtual void SetSequenceMode(bool sequence_mode) = 0;
+
+  // 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.
+  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) = 0;
+
+  // 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);
+
+  // 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();
+
+ protected:
+  typedef std::map<StreamParser::TrackId, MseTrackBuffer*> TrackBufferMap;
+
+  explicit FrameProcessorBase(const IncreaseDurationCB& increase_duration_cb);
+
+  // If |track_buffers_| contains |id|, returns a pointer to the associated
+  // MseTrackBuffer. Otherwise, returns NULL.
+  MseTrackBuffer* FindTrack(StreamParser::TrackId id);
+
+  // 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_;
+
+  IncreaseDurationCB increase_duration_cb_;
+
+  // TrackId-indexed map of each track's stream.
+  TrackBufferMap track_buffers_;
+};
+
+}  // namespace media
+
+#endif  // MEDIA_FILTERS_FRAME_PROCESSOR_BASE_H_