90 lines
3.3 KiB
C++
90 lines
3.3 KiB
C++
// Copyright (c) 2012 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_CODECS_AAC_AUDIO_SPECIFIC_CONFIG_H_
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#define MEDIA_CODECS_AAC_AUDIO_SPECIFIC_CONFIG_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <vector>
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namespace shaka {
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namespace media {
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class BitReader;
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// Methods are virtual for mocking.
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/// This class parses the AAC information from decoder specific information
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/// embedded in the @b esds box in an ISO BMFF file.
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/// Please refer to ISO 14496 Part 3 Table 1.13 - Syntax of AudioSpecificConfig
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/// for more details.
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class AACAudioSpecificConfig {
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public:
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AACAudioSpecificConfig();
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virtual ~AACAudioSpecificConfig();
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/// Parse the AAC config from decoder specific information embedded in an @b
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/// esds box. The function will parse the data and get the
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/// ElementaryStreamDescriptor, then it will parse the
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/// ElementaryStreamDescriptor to get audio stream configurations.
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/// @param data contains decoder specific information from an @b esds box.
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/// @return true if successful, false otherwise.
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virtual bool Parse(const std::vector<uint8_t>& data);
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/// Convert a raw AAC frame into an AAC frame with an ADTS header.
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/// @param[in,out] buffer contains the raw AAC frame on input, and the
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/// converted frame on output if successful; it is untouched
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/// on failure.
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/// @return true on success, false otherwise.
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virtual bool ConvertToADTS(std::vector<uint8_t>* buffer) const;
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/// @param sbr_in_mimetype indicates whether SBR mode is specified in the
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/// mimetype, i.e. codecs parameter contains mp4a.40.5.
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/// @return Output sample rate for the AAC stream.
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uint32_t GetOutputSamplesPerSecond(bool sbr_in_mimetype) const;
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/// @param sbr_in_mimetype indicates whether SBR mode is specified in the
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/// mimetype, i.e. codecs parameter contains mp4a.40.5.
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/// @return Number of channels for the AAC stream.
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uint8_t GetNumChannels(bool sbr_in_mimetype) const;
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/// @return The audio object type for this AAC config.
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uint8_t audio_object_type() const { return audio_object_type_; }
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/// @return The sampling frequency for this AAC config.
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uint32_t frequency() const { return frequency_; }
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/// @return Number of channels for this AAC config.
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uint8_t num_channels() const { return num_channels_; }
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/// Size in bytes of the ADTS header added by ConvertEsdsToADTS().
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static const size_t kADTSHeaderSize = 7;
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private:
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bool SkipDecoderGASpecificConfig(BitReader* bit_reader) const;
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bool SkipErrorSpecificConfig() const;
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bool SkipGASpecificConfig(BitReader* bit_reader) const;
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// The following variables store the AAC specific configuration information
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// that are used to generate the ADTS header.
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uint8_t audio_object_type_;
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uint8_t frequency_index_;
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uint8_t channel_config_;
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// Is Parametric Stereo on?
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bool ps_present_;
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// The following variables store audio configuration information.
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// They are based on the AAC specific configuration but can be overridden
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// by extensions in elementary stream descriptor.
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uint32_t frequency_;
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uint32_t extension_frequency_;
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uint8_t num_channels_;
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};
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} // namespace media
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} // namespace shaka
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#endif // MEDIA_CODECS_AAC_AUDIO_SPECIFIC_CONFIG_H_
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