89 lines
3.1 KiB
C++
89 lines
3.1 KiB
C++
// Copyright 2017 Google Inc. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#ifndef PACKAGER_MEDIA_FORMATS_MP2T_AUDIO_HEADER_H_
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#define PACKAGER_MEDIA_FORMATS_MP2T_AUDIO_HEADER_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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namespace mp2t {
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class AudioHeader {
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public:
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AudioHeader() = default;
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virtual ~AudioHeader() = default;
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/// Check if the leading word (2 bytes) is sync signal.
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/// @param buf points to the buffer to be checked. Must be at least 2 bytes.
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/// @return true if corresponds to a syncword.
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virtual bool IsSyncWord(const uint8_t* buf) const = 0;
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/// @return The minium frame size.
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virtual size_t GetMinFrameSize() const = 0;
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/// @return Number of audio samples per frame.
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virtual size_t GetSamplesPerFrame() const = 0;
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/// Parse a partial audio frame, extracting the fields within. Only audio
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/// frame header / metadata is parsed. The audio_frame_size must contain the
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/// full header / metadata.
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/// @param audio_frame is an input parameter pointing to an audio frame.
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/// @param audio_frame_size is the size, in bytes of the input data. It can be
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/// smaller than the actual frame size, but it should not be smaller
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/// than the header size.
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/// @return true if successful, false otherwise.
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virtual bool Parse(const uint8_t* audio_frame, size_t audio_frame_size) = 0;
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/// Should only be called after a successful Parse.
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/// @return The size of audio header.
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virtual size_t GetHeaderSize() const = 0;
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/// Should only be called after a successful Parse.
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/// @return the size of frame (header + payload).
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virtual size_t GetFrameSize() const = 0;
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/// Obtain the size of the frame from the header data without doing a full
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/// Parse.
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/// @return the size of the frame (header + payload).
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virtual size_t GetFrameSizeWithoutParsing(const uint8_t* data,
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size_t num_bytes) const = 0;
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/// Synthesize an AudioSpecificConfig record from the fields within the audio
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/// header.
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/// Should only be called after a successful Parse.
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/// @param [out] buffer is a pointer to a vector to contain the
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/// AudioSpecificConfig.
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/// @return true if successful, false otherwise.
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virtual void GetAudioSpecificConfig(std::vector<uint8_t>* buffer) const = 0;
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/// Should only be called after a successful Parse.
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/// @return The audio profile for this frame. Only meaningful for AAC.
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virtual uint8_t GetObjectType() const = 0;
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/// Should only be called after a successful Parse.
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/// @return The sampling frequency for this frame.
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virtual uint32_t GetSamplingFrequency() const = 0;
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/// Should only be called after a successful Parse.
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/// @return Number of channels for this frame.
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virtual uint8_t GetNumChannels() const = 0;
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private:
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AudioHeader(const AudioHeader&) = delete;
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AudioHeader& operator=(const AudioHeader&) = delete;
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};
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} // namespace mp2t
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} // namespace media
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} // namespace shaka
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#endif // PACKAGER_MEDIA_FORMATS_MP2T_AUDIO_HEADER_H_
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