| // Copyright 2023 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef MEDIA_AUDIO_FLAC_AUDIO_HANDLER_H_ |
| #define MEDIA_AUDIO_FLAC_AUDIO_HANDLER_H_ |
| |
| #include <cstddef> |
| #include <memory> |
| #include <string_view> |
| |
| #include "media/audio/audio_handler.h" |
| #include "media/base/media_export.h" |
| #include "third_party/flac/include/FLAC/stream_decoder.h" |
| |
| namespace media { |
| |
| class AudioBus; |
| class AudioFifo; |
| |
| class FlacStreamDecoderDeleter { |
| public: |
| void operator()(FLAC__StreamDecoder* ptr) { |
| FLAC__stream_decoder_delete(ptr); |
| } |
| }; |
| |
| // This class provides the input from flac file format. |
| class MEDIA_EXPORT FlacAudioHandler : public AudioHandler { |
| public: |
| explicit FlacAudioHandler(std::string_view data); |
| FlacAudioHandler(const FlacAudioHandler&) = delete; |
| FlacAudioHandler& operator=(const FlacAudioHandler&) = delete; |
| ~FlacAudioHandler() override; |
| |
| // AudioHandler: |
| bool Initialize() override; |
| int GetNumChannels() const override; |
| int GetSampleRate() const override; |
| base::TimeDelta GetDuration() const override; |
| bool AtEnd() const override; |
| bool CopyTo(AudioBus* bus, size_t* frames_written) override; |
| void Reset() override; |
| |
| int total_frames_for_testing() const { return total_frames_; } |
| |
| private: |
| // Callbacks for the `decoder_`. |
| static FLAC__StreamDecoderReadStatus ReadCallback( |
| const FLAC__StreamDecoder* decoder, |
| FLAC__byte buffer[], |
| size_t* bytes, |
| void* client_data); |
| static FLAC__StreamDecoderWriteStatus WriteCallback( |
| const FLAC__StreamDecoder* decoder, |
| const FLAC__Frame* frame, |
| const FLAC__int32* const buffer[], |
| void* client_data); |
| static void MetaCallback(const FLAC__StreamDecoder* decoder, |
| const FLAC__StreamMetadata* metadata, |
| void* client_data); |
| static void ErrorCallback(const FLAC__StreamDecoder* decoder, |
| FLAC__StreamDecoderErrorStatus status, |
| void* client_data); |
| |
| bool is_initialized() const { return !!fifo_; } |
| |
| // Internal callbacks. |
| FLAC__StreamDecoderReadStatus ReadCallbackInternal(FLAC__byte buffer[], |
| size_t* bytes); |
| FLAC__StreamDecoderWriteStatus WriteCallbackInternal( |
| const FLAC__Frame* frame, |
| const FLAC__int32* const buffer[]); |
| void MetaCallbackInternal(const FLAC__StreamMetadata* metadata); |
| void ErrorCallbackInternal(); |
| |
| // Check if the metadata fecthed in `MetaCallback()` is valid or not. This |
| // function will check the `num_channels_`, `bits_per_sample_`, `sample_rate_` |
| // and `total_frames_`. |
| // Note: We only consider 16 bits per second of audio data currently. |
| bool AreParamsValid() const; |
| |
| const std::string_view flac_data_; |
| const std::unique_ptr<FLAC__StreamDecoder, FlacStreamDecoderDeleter> decoder_; |
| |
| // To transfer decoded PCM samples from `WriteCallback` to `CopyTo`. |
| std::unique_ptr<AudioFifo> fifo_; |
| |
| // The PCM buffer received in `WriteCallback()` is copied into `bus_`. |
| std::unique_ptr<AudioBus> bus_; |
| |
| // Start to read `flac_data_` from `cursor_` position. |
| size_t cursor_ = 0u; |
| |
| int num_channels_ = 0; |
| int sample_rate_ = 0; |
| int bits_per_sample_ = 0; |
| |
| // Equal to the total number of samples per channel. |
| uint64_t total_frames_ = 0u; |
| |
| // Set to true if the error callback is called. |
| bool has_error_ = false; |
| |
| // True if `WriteCallbackInternal` is called in a single call to |
| // `FLAC__stream_decoder_process_single`. |
| bool write_callback_called_ = false; |
| }; |
| |
| } // namespace media |
| |
| #endif // MEDIA_AUDIO_FLAC_AUDIO_HANDLER_H_ |