shaka-packager/packager/media/formats/webm/webm_cluster_parser.h

233 lines
8.6 KiB
C++

// 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_FORMATS_WEBM_WEBM_CLUSTER_PARSER_H_
#define MEDIA_FORMATS_WEBM_WEBM_CLUSTER_PARSER_H_
#include <deque>
#include <map>
#include <set>
#include <string>
#include "packager/base/compiler_specific.h"
#include "packager/base/memory/scoped_ptr.h"
#include "packager/media/base/decryptor_source.h"
#include "packager/media/base/media_parser.h"
#include "packager/media/base/media_sample.h"
#include "packager/media/formats/webm/webm_parser.h"
#include "packager/media/formats/webm/webm_tracks_parser.h"
namespace shaka {
namespace media {
class WebMClusterParser : public WebMParserClient {
public:
/// Numbers chosen to estimate the duration of a buffer if none is set and
/// there is not enough information to get a better estimate.
enum {
/// Common 1k samples @44.1kHz
kDefaultAudioBufferDurationInMs = 23,
/// Chosen to represent 16fps duration, which will prevent MSE stalls in
/// videos with frame-rates as low as 8fps.
kDefaultVideoBufferDurationInMs = 63
};
private:
// Helper class that manages per-track state.
class Track {
public:
Track(int track_num,
bool is_video,
int64_t default_duration,
const MediaParser::NewSampleCB& new_sample_cb);
~Track();
int track_num() const { return track_num_; }
// If |last_added_buffer_missing_duration_| is set, updates its duration
// relative to |buffer|'s timestamp, and emits it and unsets
// |last_added_buffer_missing_duration_|. Otherwise, if |buffer| is missing
// duration, saves |buffer| into |last_added_buffer_missing_duration_|.
bool EmitBuffer(const scoped_refptr<MediaSample>& buffer);
// If |last_added_buffer_missing_duration_| is set, estimate the duration
// for this buffer using helper function GetDurationEstimate() then emits it
// and unsets |last_added_buffer_missing_duration_| (This method helps
// stream parser emit all buffers in a media segment).
bool ApplyDurationEstimateIfNeeded();
// Clears all buffer state, including any possibly held-aside buffer that
// was missing duration.
void Reset();
private:
// Helper that sanity-checks |buffer| duration, updates
// |estimated_next_frame_duration_|, and emits |buffer|.
// Returns false if |buffer| failed sanity check and therefore was not
// emitted. Returns true otherwise.
bool EmitBufferHelp(const scoped_refptr<MediaSample>& buffer);
// Helper function that calculates the buffer duration to use in
// ApplyDurationEstimateIfNeeded().
int64_t GetDurationEstimate();
int track_num_;
bool is_video_;
// Holding the sample that is missing duration. The duration will be
// computed from the difference in timestamp when next sample arrives; or
// estimated if it is the last sample in this track.
scoped_refptr<MediaSample> last_added_buffer_missing_duration_;
// If kNoTimestamp, then |estimated_next_frame_duration_| will be used.
int64_t default_duration_;
// If kNoTimestamp, then a hardcoded default value will be used. This
// estimate is the maximum duration seen so far for this track, and is used
// only if |default_duration_| is kNoTimestamp.
int64_t estimated_next_frame_duration_;
MediaParser::NewSampleCB new_sample_cb_;
};
typedef std::map<int, Track> TextTrackMap;
public:
/// Create a WebMClusterParser from given parameters.
/// @param timecode_scale indicates timecode scale for the clusters.
/// @param audio_stream_info references audio stream information. It will
/// be NULL if there are no audio tracks available.
/// @param video_stream_info references video stream information. It will
/// be NULL if there are no video tracks available.
/// @param audio_default_duration indicates default duration for audio
/// samples.
/// @param video_default_duration indicates default duration for video
/// samples.
/// @param text_tracks contains text track information.
/// @param ignored_tracks contains a list of ignored track ids.
/// @param audio_encryption_key_id indicates the encryption key id for audio
/// samples if there is an audio stream and the audio stream is
/// encrypted. It is empty otherwise.
/// @param video_encryption_key_id indicates the encryption key id for video
/// samples if there is a video stream and the video stream is
/// encrypted. It is empty otherwise.
/// @param new_sample_cb is the callback to emit new samples.
/// @param init_cb is the callback to initialize streams.
/// @param decryption_key_source points to a decryption key source to fetch
/// decryption keys. Should not be NULL if the tracks are encrypted.
WebMClusterParser(int64_t timecode_scale,
scoped_refptr<AudioStreamInfo> audio_stream_info,
scoped_refptr<VideoStreamInfo> video_stream_info,
int64_t audio_default_duration,
int64_t video_default_duration,
const WebMTracksParser::TextTracks& text_tracks,
const std::set<int64_t>& ignored_tracks,
const std::string& audio_encryption_key_id,
const std::string& video_encryption_key_id,
const MediaParser::NewSampleCB& new_sample_cb,
const MediaParser::InitCB& init_cb,
KeySource* decryption_key_source);
~WebMClusterParser() override;
/// Resets the parser state so it can accept a new cluster.
void Reset();
/// Flush data currently in the parser and reset the parser so it can accept a
/// new cluster.
/// @return true on success, false otherwise.
bool Flush() WARN_UNUSED_RESULT;
/// Parses a WebM cluster element in |buf|.
/// @return -1 if the parse fails.
/// @return 0 if more data is needed.
/// @return The number of bytes parsed on success.
int Parse(const uint8_t* buf, int size);
int64_t cluster_start_time() const { return cluster_start_time_; }
/// @return true if the last Parse() call stopped at the end of a cluster.
bool cluster_ended() const { return cluster_ended_; }
private:
// WebMParserClient methods.
WebMParserClient* OnListStart(int id) override;
bool OnListEnd(int id) override;
bool OnUInt(int id, int64_t val) override;
bool OnBinary(int id, const uint8_t* data, int size) override;
bool ParseBlock(bool is_simple_block,
const uint8_t* buf,
int size,
const uint8_t* additional,
int additional_size,
int duration,
int64_t discard_padding);
bool OnBlock(bool is_simple_block,
int track_num,
int timecode,
int duration,
int flags,
const uint8_t* data,
int size,
const uint8_t* additional,
int additional_size,
int64_t discard_padding);
// Resets the Track objects associated with each text track.
void ResetTextTracks();
// Search for the indicated track_num among the text tracks. Returns NULL
// if that track num is not a text track.
Track* FindTextTrack(int track_num);
// Multiplier used to convert timecodes into microseconds.
double timecode_multiplier_;
scoped_refptr<AudioStreamInfo> audio_stream_info_;
scoped_refptr<VideoStreamInfo> video_stream_info_;
std::set<int64_t> ignored_tracks_;
scoped_ptr<DecryptorSource> decryptor_source_;
std::string audio_encryption_key_id_;
std::string video_encryption_key_id_;
WebMListParser parser_;
// Indicates whether init_cb has been executed. |init_cb| is executed when we
// have codec configuration of video stream, which is extracted from the first
// video sample.
bool initialized_;
MediaParser::InitCB init_cb_;
int64_t last_block_timecode_ = -1;
scoped_ptr<uint8_t[]> block_data_;
int block_data_size_ = -1;
int64_t block_duration_ = -1;
int64_t block_add_id_ = -1;
scoped_ptr<uint8_t[]> block_additional_data_;
// Must be 0 if |block_additional_data_| is null. Must be > 0 if
// |block_additional_data_| is NOT null.
int block_additional_data_size_ = 0;
int64_t discard_padding_ = -1;
bool discard_padding_set_ = false;
int64_t cluster_timecode_ = -1;
int64_t cluster_start_time_;
bool cluster_ended_ = false;
Track audio_;
Track video_;
TextTrackMap text_track_map_;
DISALLOW_COPY_AND_ASSIGN(WebMClusterParser);
};
} // namespace media
} // namespace shaka
#endif // MEDIA_FORMATS_WEBM_WEBM_CLUSTER_PARSER_H_