media: Delete renderer/demuxer splicing code.

media/base/audio_splicer.h

-// Copyright (c) 2012 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_AUDIO_SPLICER_H_
-#define MEDIA_BASE_AUDIO_SPLICER_H_
-
-#include <memory>
-
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/time/time.h"
-#include "media/base/audio_parameters.h"
-#include "media/base/media_export.h"
-#include "media/base/timestamp_constants.h"
-
-namespace media {
-
-class AudioBuffer;
-class AudioBus;
-class AudioStreamSanitizer;
-class MediaLog;
-
-// Helper class that handles filling gaps and resolving overlaps.
-class MEDIA_EXPORT AudioSplicer {
- public:
-  AudioSplicer(int samples_per_second,
-               const scoped_refptr<MediaLog>& media_log);
-  ~AudioSplicer();
-
-  enum {
-    // The number of ms to crossfade before trimming when buffers overlap.
-    kCrossfadeDurationInMilliseconds = 5,
-
-    // Largest gap or overlap allowed between buffers.  Anything larger than
-    // this will trigger an error.  This is an arbitrary value, but the initial
-    // selection of 50ms roughly represents the duration of 2 compressed AAC or
-    // MP3 frames.
-    kMaxTimeDeltaInMilliseconds = 50,
-  };
-
-  // Resets the splicer state by clearing the output buffers queue and resetting
-  // the timestamp helper.
-  void Reset();
-
-  // Adds a new buffer full of samples or end of stream buffer to the splicer.
-  // Returns true if the buffer was accepted.  False is returned if an error
-  // occurred.
-  bool AddInput(const scoped_refptr<AudioBuffer>& input);
-
-  // Returns true if the splicer has a buffer to return.
-  bool HasNextBuffer() const;
-
-  // Removes the next buffer from the output buffer queue and returns it; this
-  // should only be called if HasNextBuffer() returns true.
-  scoped_refptr<AudioBuffer> GetNextBuffer();
-
-  // Indicates an upcoming splice point.  All buffers overlapping or after the
-  // |splice_timestamp| will be considered as "before the splice."  Clients must
-  // then call SetSpliceTimestamp(kNoTimestamp) to signal that future buffers
-  // should be considered as "after the splice."
-  //
-  // Once |kCrossfadeDurationInMilliseconds| of buffers "after the splice" or
-  // end of stream has been received, the "after" buffers will be crossfaded
-  // with all "before" buffers which overlap them.  "before" buffers outside
-  // of the overlap range will be discarded.
-  void SetSpliceTimestamp(base::TimeDelta splice_timestamp);
-
- private:
-  friend class AudioSplicerTest;
-
-  // Extracts frames to be crossfaded from |pre_splice_sanitizer_|.  Transfers
-  // all frames before |splice_timestamp_| into |output_sanitizer_| and drops
-  // frames outside of the crossfade duration.
-  //
-  // The size of the returned AudioBus is the crossfade duration in frames.
-  // Crossfade duration is calculated based on the number of frames available
-  // after |splice_timestamp_| in each sanitizer and capped by
-  // |max_crossfade_duration_|.
-  //
-  // |pre_splice_sanitizer_| will be empty after this operation.
-  std::unique_ptr<AudioBus> ExtractCrossfadeFromPreSplice(
-      scoped_refptr<AudioBuffer>* crossfade_buffer);
-
-  // Crossfades |pre_splice_bus->frames()| frames from
-  // |post_splice_sanitizer_|
-  // with those from |pre_splice_bus|.  Adds the crossfaded buffer to
-  // |output_sanitizer_| along with all buffers in |post_splice_sanitizer_|.
-  //
-  // |post_splice_sanitizer_| will be empty after this operation.
-  void CrossfadePostSplice(std::unique_ptr<AudioBus> pre_splice_bus,
-                           const scoped_refptr<AudioBuffer>& crossfade_buffer);
-
-  // Reset the splice and splice end timestamps.
-  void reset_splice_timestamps() {
-    splice_timestamp_ = max_splice_end_timestamp_ = kNoTimestamp;
-  }
-
-  const base::TimeDelta max_crossfade_duration_;
-  base::TimeDelta splice_timestamp_;
-  base::TimeDelta max_splice_end_timestamp_;
-
-  // The various sanitizers for each stage of the crossfade process.  Buffers in
-  // |output_sanitizer_| are immediately available for consumption by external
-  // callers.
-  //
-  // Overlapped buffers go into the |pre_splice_sanitizer_| while overlapping
-  // buffers go into the |post_splice_sanitizer_|.  Once enough buffers for
-  // crossfading are received the pre and post sanitizers are drained into
-  // |output_sanitizer_| by the two ExtractCrossfadeFromXXX methods above.
-  //
-  // |pre_splice_sanitizer_| is not constructed until the first splice frame is
-  // encountered.  At which point it is constructed based on the timestamp state
-  // of |output_sanitizer_|.  It is destructed once the splice is finished.
-  std::unique_ptr<AudioStreamSanitizer> output_sanitizer_;
-  std::unique_ptr<AudioStreamSanitizer> pre_splice_sanitizer_;
-  std::unique_ptr<AudioStreamSanitizer> post_splice_sanitizer_;
-
-  // Whether all buffers which should go into |pre_splice_sanitizer_| have been
-  // received.  If true, buffers should now be put in |post_splice_sanitizer_|.
-  bool have_all_pre_splice_buffers_;
-
-  DISALLOW_IMPLICIT_CONSTRUCTORS(AudioSplicer);
-};
-
-}  // namespace media
-
-#endif  // MEDIA_BASE_AUDIO_SPLICER_H_