shaka-packager/media/formats/mp4/fragmenter.h

107 lines
3.4 KiB
C++

// Copyright 2014 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#ifndef MEDIA_FORMATS_MP4_FRAGMENTER_H_
#define MEDIA_FORMATS_MP4_FRAGMENTER_H_
#include <vector>
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "media/base/status.h"
namespace media {
class AesCtrEncryptor;
class BufferWriter;
class MediaSample;
namespace mp4 {
struct SegmentReference;
struct TrackFragment;
/// Fragmenter is responsible for the generation of MP4 fragments, i.e. traf
/// box and corresponding mdat box. The samples are also encrypted if encryption
/// is requested.
class Fragmenter {
public:
/// @param traf points to a TrackFragment box.
/// @param encryptor handles encryption of the samples. It can be NULL, which
/// indicates no encryption is required.
/// @param clear_time specifies clear lead duration in units of the current
/// track's timescale.
/// @param nalu_length_size NAL unit length size, in bytes, for subsample
/// encryption.
/// @param normalize_presentation_timestamp defines whether PTS should be
/// normalized to start from zero.
Fragmenter(TrackFragment* traf,
scoped_ptr<AesCtrEncryptor> encryptor,
int64 clear_time,
uint8 nalu_length_size,
bool normalize_presentation_timestamp);
~Fragmenter();
/// Add a sample to the fragmenter.
Status AddSample(scoped_refptr<MediaSample> sample);
/// Initialize the fragment with default data.
void InitializeFragment();
/// Finalize and optimize the fragment.
void FinalizeFragment();
/// Fill @a reference with current fragment information.
void GenerateSegmentReference(SegmentReference* reference);
uint64 fragment_duration() const { return fragment_duration_; }
uint64 first_sap_time() const { return first_sap_time_; }
uint64 earliest_presentation_time() const {
return earliest_presentation_time_;
}
bool fragment_finalized() const { return fragment_finalized_; }
BufferWriter* data() { return data_.get(); }
BufferWriter* aux_data() { return aux_data_.get(); }
private:
void EncryptBytes(uint8* data, uint32 size);
Status EncryptSample(scoped_refptr<MediaSample> sample);
// Should we enable encrytion for the current fragment?
bool ShouldEncryptFragment() {
return (encryptor_ != NULL && clear_time_ <= 0);
}
// Should we enable subsample encryption?
bool IsSubsampleEncryptionRequired() { return nalu_length_size_ != 0; }
// Check if the current fragment starts with SAP.
bool StartsWithSAP();
scoped_ptr<AesCtrEncryptor> encryptor_;
// If this stream contains AVC, subsample encryption specifies that the size
// and type of NAL units remain unencrypted. This field specifies the size of
// the size field. Can be 1, 2 or 4 bytes.
uint8 nalu_length_size_;
TrackFragment* traf_;
bool fragment_finalized_;
uint64 fragment_duration_;
bool normalize_presentation_timestamp_;
int64 presentation_start_time_;
int64 earliest_presentation_time_;
int64 first_sap_time_;
int64 clear_time_;
scoped_ptr<BufferWriter> data_;
scoped_ptr<BufferWriter> aux_data_;
DISALLOW_COPY_AND_ASSIGN(Fragmenter);
};
} // namespace mp4
} // namespace media
#endif // MEDIA_FORMATS_MP4_FRAGMENTER_H_