231 lines
8.3 KiB
C++
231 lines
8.3 KiB
C++
// Copyright 2014 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef MEDIA_FORMATS_WEBM_WEBM_CLUSTER_PARSER_H_
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#define MEDIA_FORMATS_WEBM_WEBM_CLUSTER_PARSER_H_
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#include <deque>
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#include <map>
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#include <set>
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#include <string>
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#include "packager/base/memory/scoped_ptr.h"
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#include "packager/media/base/media_parser.h"
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#include "packager/media/base/media_sample.h"
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#include "packager/media/formats/webm/webm_parser.h"
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#include "packager/media/formats/webm/webm_tracks_parser.h"
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namespace edash_packager {
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namespace media {
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class WebMClusterParser : public WebMParserClient {
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public:
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/// Numbers chosen to estimate the duration of a buffer if none is set and
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/// there is not enough information to get a better estimate.
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enum {
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/// Common 1k samples @44.1kHz
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kDefaultAudioBufferDurationInMs = 23,
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/// Chosen to represent 16fps duration, which will prevent MSE stalls in
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/// videos with frame-rates as low as 8fps.
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kDefaultVideoBufferDurationInMs = 63
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};
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/// Opus packets encode the duration and other parameters in the 5 most
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/// significant bits of the first byte. The index in this array corresponds
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/// to the duration of each frame of the packet in microseconds. See
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/// https://tools.ietf.org/html/rfc6716#page-14
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static const uint16_t kOpusFrameDurationsMu[];
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private:
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// Helper class that manages per-track state.
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class Track {
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public:
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Track(int track_num,
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bool is_video,
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int64_t default_duration,
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const MediaParser::NewSampleCB& new_sample_cb);
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~Track();
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int track_num() const { return track_num_; }
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// If |last_added_buffer_missing_duration_| is set, updates its duration
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// relative to |buffer|'s timestamp, and emits it and unsets
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// |last_added_buffer_missing_duration_|. Otherwise, if |buffer| is missing
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// duration, saves |buffer| into |last_added_buffer_missing_duration_|.
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bool EmitBuffer(const scoped_refptr<MediaSample>& buffer);
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// If |last_added_buffer_missing_duration_| is set, updates its duration to
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// be non-kNoTimestamp value of |estimated_next_frame_duration_| or a
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// hard-coded default, then emits it and unsets
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// |last_added_buffer_missing_duration_|. (This method helps stream parser
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// emit all buffers in a media segment before signaling end of segment.)
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void ApplyDurationEstimateIfNeeded();
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// Clears all buffer state, including any possibly held-aside buffer that
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// was missing duration.
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void Reset();
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int64_t default_duration() const { return default_duration_; }
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private:
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// Helper that sanity-checks |buffer| duration, updates
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// |estimated_next_frame_duration_|, and emits |buffer|.
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// Returns false if |buffer| failed sanity check and therefore was not
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// emitted. Returns true otherwise.
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bool EmitBufferHelp(const scoped_refptr<MediaSample>& buffer);
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// Helper that calculates the buffer duration to use in
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// ApplyDurationEstimateIfNeeded().
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int64_t GetDurationEstimate();
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// Counts the number of estimated durations used in this track. Used to
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// prevent log spam for LOG()s about estimated duration.
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int num_duration_estimates_ = 0;
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int track_num_;
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bool is_video_;
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// Parsed track buffers, each with duration and in (decode) timestamp order,
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// that have not yet been emitted. Note that up to one additional buffer
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// missing duration may be tracked by |last_added_buffer_missing_duration_|.
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scoped_refptr<MediaSample> last_added_buffer_missing_duration_;
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// If kNoTimestamp, then |estimated_next_frame_duration_| will be used.
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int64_t default_duration_;
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// If kNoTimestamp, then a default value will be used. This estimate is the
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// maximum duration seen so far for this track, and is used only if
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// |default_duration_| is kNoTimestamp.
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int64_t estimated_next_frame_duration_;
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MediaParser::NewSampleCB new_sample_cb_;
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};
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typedef std::map<int, Track> TextTrackMap;
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public:
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WebMClusterParser(int64_t timecode_scale,
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scoped_refptr<AudioStreamInfo> audio_stream_info,
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scoped_refptr<VideoStreamInfo> video_stream_info,
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int64_t audio_default_duration,
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int64_t video_default_duration,
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const WebMTracksParser::TextTracks& text_tracks,
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const std::set<int64_t>& ignored_tracks,
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const std::string& audio_encryption_key_id,
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const std::string& video_encryption_key_id,
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const MediaParser::NewSampleCB& new_sample_cb,
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const MediaParser::InitCB& init_cb);
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~WebMClusterParser() override;
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/// Resets the parser state so it can accept a new cluster.
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void Reset();
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/// Flush data currently in the parser and reset the parser so it can accept a
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/// new cluster.
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void Flush();
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/// Parses a WebM cluster element in |buf|.
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/// @return -1 if the parse fails.
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/// @return 0 if more data is needed.
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/// @return The number of bytes parsed on success.
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int Parse(const uint8_t* buf, int size);
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int64_t cluster_start_time() const { return cluster_start_time_; }
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/// @return true if the last Parse() call stopped at the end of a cluster.
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bool cluster_ended() const { return cluster_ended_; }
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private:
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// WebMParserClient methods.
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WebMParserClient* OnListStart(int id) override;
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bool OnListEnd(int id) override;
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bool OnUInt(int id, int64_t val) override;
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bool OnBinary(int id, const uint8_t* data, int size) override;
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bool ParseBlock(bool is_simple_block,
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const uint8_t* buf,
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int size,
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const uint8_t* additional,
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int additional_size,
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int duration,
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int64_t discard_padding);
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bool OnBlock(bool is_simple_block,
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int track_num,
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int timecode,
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int duration,
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int flags,
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const uint8_t* data,
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int size,
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const uint8_t* additional,
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int additional_size,
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int64_t discard_padding);
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// Resets the Track objects associated with each text track.
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void ResetTextTracks();
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// Search for the indicated track_num among the text tracks. Returns NULL
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// if that track num is not a text track.
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Track* FindTextTrack(int track_num);
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// Attempts to read the duration from the encoded audio data, returning as
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// kNoTimestamp if duration cannot be retrieved.
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// Avoid calling if encrypted; may produce unexpected output. See
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// implementation for supported codecs.
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int64_t TryGetEncodedAudioDuration(const uint8_t* data, int size);
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// Reads Opus packet header to determine packet duration. Duration returned
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// as kNoTimestamp upon failure to read duration from packet.
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int64_t ReadOpusDuration(const uint8_t* data, int size);
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// Tracks the number of LOGs made in process of reading encoded duration.
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// Useful to prevent log spam.
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int num_duration_errors_ = 0;
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double timecode_multiplier_; // Multiplier used to convert timecodes into
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// microseconds.
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scoped_refptr<AudioStreamInfo> audio_stream_info_;
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scoped_refptr<VideoStreamInfo> video_stream_info_;
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std::set<int64_t> ignored_tracks_;
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std::string audio_encryption_key_id_;
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std::string video_encryption_key_id_;
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WebMListParser parser_;
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// Indicates whether init_cb has been executed. |init_cb| is executed when we
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// have codec configuration of video stream, which is extracted from the first
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// video sample.
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bool initialized_;
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MediaParser::InitCB init_cb_;
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int64_t last_block_timecode_ = -1;
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scoped_ptr<uint8_t[]> block_data_;
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int block_data_size_ = -1;
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int64_t block_duration_ = -1;
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int64_t block_add_id_ = -1;
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scoped_ptr<uint8_t[]> block_additional_data_;
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// Must be 0 if |block_additional_data_| is null. Must be > 0 if
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// |block_additional_data_| is NOT null.
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int block_additional_data_size_ = 0;
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int64_t discard_padding_ = -1;
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bool discard_padding_set_ = false;
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int64_t cluster_timecode_ = -1;
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int64_t cluster_start_time_;
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bool cluster_ended_ = false;
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Track audio_;
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Track video_;
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TextTrackMap text_track_map_;
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DISALLOW_IMPLICIT_CONSTRUCTORS(WebMClusterParser);
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};
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} // namespace media
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} // namespace edash_packager
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#endif // MEDIA_FORMATS_WEBM_WEBM_CLUSTER_PARSER_H_
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