100 lines
3.0 KiB
C++
100 lines
3.0 KiB
C++
// 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_MP4_AAC_H_
|
|
#define MEDIA_MP4_AAC_H_
|
|
|
|
#include <vector>
|
|
|
|
#include "base/basictypes.h"
|
|
|
|
namespace media {
|
|
|
|
class BitReader;
|
|
|
|
namespace mp4 {
|
|
|
|
// This class parses the AAC information from decoder specific information
|
|
// embedded in the esds box in an ISO BMFF file.
|
|
// Please refer to ISO 14496 Part 3 Table 1.13 - Syntax of AudioSpecificConfig
|
|
// for more details.
|
|
// TODO(kqyang): the class name is not appropriate, it should be
|
|
// AACAudioSpecificConfig instead.
|
|
class AAC {
|
|
public:
|
|
AAC();
|
|
~AAC();
|
|
|
|
// Parse the AAC config from the raw binary data embedded in esds box.
|
|
// The function will parse the data and get the ElementaryStreamDescriptor,
|
|
// then it will parse the ElementaryStreamDescriptor to get audio stream
|
|
// configurations.
|
|
// |data| is always copied to |codec_specific_data_|.
|
|
bool Parse(const std::vector<uint8>& data);
|
|
|
|
// Gets the output sample rate for the AAC stream.
|
|
// |sbr_in_mimetype| should be set to true if the SBR mode is
|
|
// signalled in the mimetype. (ie mp4a.40.5 in the codecs parameter).
|
|
uint32 GetOutputSamplesPerSecond(bool sbr_in_mimetype) const;
|
|
|
|
// Gets number of channels for the AAC stream.
|
|
// |sbr_in_mimetype| should be set to true if the SBR mode is
|
|
// signalled in the mimetype. (ie mp4a.40.5 in the codecs parameter).
|
|
uint8 GetNumChannels(bool sbr_in_mimetype) const;
|
|
|
|
// This function converts a raw AAC frame into an AAC frame with an ADTS
|
|
// header. On success, the function returns true and stores the converted data
|
|
// in the buffer. The function returns false on failure and leaves the buffer
|
|
// unchanged.
|
|
bool ConvertToADTS(std::vector<uint8>* buffer) const;
|
|
|
|
uint8 audio_object_type() const {
|
|
return audio_object_type_;
|
|
}
|
|
|
|
uint32 frequency() const {
|
|
return frequency_;
|
|
}
|
|
|
|
uint8 num_channels() const {
|
|
return num_channels_;
|
|
}
|
|
|
|
// Returns the codec specific data.
|
|
std::vector<uint8> codec_specific_data() const {
|
|
return codec_specific_data_;
|
|
}
|
|
|
|
// Size in bytes of the ADTS header added by ConvertEsdsToADTS().
|
|
static const size_t kADTSHeaderSize = 7;
|
|
|
|
private:
|
|
bool SkipDecoderGASpecificConfig(BitReader* bit_reader) const;
|
|
bool SkipErrorSpecificConfig() const;
|
|
bool SkipGASpecificConfig(BitReader* bit_reader) const;
|
|
|
|
// The following variables store the AAC specific configuration information
|
|
// that are used to generate the ADTS header.
|
|
uint8 audio_object_type_;
|
|
uint8 frequency_index_;
|
|
uint8 channel_config_;
|
|
// Is Parametric Stereo on?
|
|
bool ps_present_;
|
|
|
|
std::vector<uint8> codec_specific_data_;
|
|
|
|
// The following variables store audio configuration information.
|
|
// They are based on the AAC specific configuration but can be overridden
|
|
// by extensions in elementary stream descriptor.
|
|
uint32 frequency_;
|
|
uint32 extension_frequency_;
|
|
uint8 num_channels_;
|
|
};
|
|
|
|
} // namespace mp4
|
|
|
|
} // namespace media
|
|
|
|
#endif // MEDIA_MP4_AAC_H_
|