| /************************************************************************************************** | |
| * ZipVoice AXERA C++ Port | |
| * | |
| * FBANK: Mel filterbank feature extraction for prompt audio. | |
| * | |
| * Extracts log-mel spectrogram features from audio waveform, matching the | |
| * Python LocalVocosFbank behavior. | |
| **************************************************************************************************/ | |
| class MelFilterBank { | |
| public: | |
| struct Config { | |
| int sampling_rate; | |
| int n_mels; | |
| int n_fft; | |
| int hop_length; | |
| Config() : sampling_rate(24000), n_mels(100), n_fft(1024), hop_length(256) {} | |
| }; | |
| MelFilterBank(); | |
| /** | |
| * Initialize the filterbank with given config. | |
| */ | |
| int Init(const Config& config = Config()); | |
| /** | |
| * Extract log-mel features from float32 audio samples [num_samples]. | |
| * Returns features of shape [num_frames, n_mels]. | |
| */ | |
| std::vector<float> Extract(const std::vector<float>& samples, int sample_rate); | |
| /** | |
| * Get the number of frames for given number of samples. | |
| */ | |
| static int ComputeNumFrames(int num_samples, int hop_length); | |
| const Config& GetConfig() const { return m_config; } | |
| private: | |
| Config m_config; | |
| // Mel filterbank matrix [n_freqs, n_mels] | |
| std::vector<float> m_mel_basis; | |
| int m_n_freqs; | |
| // Hann window | |
| std::vector<float> m_window; | |
| void CreateMelFilterbank(); | |
| void CreateWindow(); | |
| // Simple STFT | |
| void ComputeSTFT(const std::vector<float>& samples, | |
| std::vector<float>& spec_real, | |
| std::vector<float>& spec_imag, | |
| int& num_frames); | |
| }; | |