1 files changed, 113 insertions, 0 deletions
diff --git a/llama.cpp/tools/mtmd/mtmd-audio.h b/llama.cpp/tools/mtmd/mtmd-audio.h
new file mode 100644
index 0000000..016c739
--- /dev/null
+++ b/llama.cpp/tools/mtmd/mtmd-audio.h
@@ -0,0 +1,113 @@
+#pragma once
+
+#include "ggml.h"
+#include "clip-model.h"
+
+#include <cstdint>
+#include <vector>
+#include <string>
+
+#define MTMD_INTERNAL_HEADER
+
+struct mtmd_audio_mel {
+    int n_len;
+    int n_len_org;
+    int n_mel;
+
+    std::vector<float> data;
+};
+
+struct mtmd_audio_mel_filters {
+    int32_t n_mel;
+    int32_t n_fft;
+
+    std::vector<float> data;
+};
+
+// cache for audio processing, each processor instance owns its own cache
+struct mtmd_audio_cache {
+    std::vector<float> sin_vals;
+    std::vector<float> cos_vals;
+
+    std::vector<float> hann_window;
+
+    mtmd_audio_mel_filters filters;
+
+    void fill_sin_cos_table(int n);
+
+    void fill_hann_window(int length, bool periodic);
+
+    // Build mel filterbank matrix [n_mel × n_fft_bins] at runtime.
+    // n_fft_bins must be (N_fft / 2 + 1). Example: if N_fft=512 -> n_fft_bins=257.
+    void fill_mel_filterbank_matrix(int   n_mel,
+                                    int   n_fft,
+                                    int   sample_rate,               // e.g. 16000
+                                    float fmin             = 0.0f,   // e.g. 0.0
+                                    float fmax             = -1.0f,  // e.g. sr/2; pass -1 for auto
+                                    bool  slaney_area_norm = true,
+                                    float scale = 1.0f  // optional extra scaling
+    );
+};
+
+struct mtmd_audio_preprocessor {
+    const clip_hparams & hparams;
+
+    mtmd_audio_preprocessor(const clip_ctx * ctx): hparams(*clip_get_hparams(ctx)) {}
+
+    virtual ~mtmd_audio_preprocessor() = default;
+    virtual void initialize() = 0; // NOT thread-safe
+    virtual bool preprocess(const float * samples, size_t n_samples, std::vector<mtmd_audio_mel> & output) = 0;
+};
+
+struct mtmd_audio_preprocessor_whisper : mtmd_audio_preprocessor {
+    mtmd_audio_preprocessor_whisper(const clip_ctx * ctx) : mtmd_audio_preprocessor(ctx) {}
+    void initialize() override;
+    bool preprocess(const float * samples, size_t n_samples, std::vector<mtmd_audio_mel> & output) override;
+
+  private:
+    mtmd_audio_cache cache;
+};
+
+struct mtmd_audio_preprocessor_conformer : mtmd_audio_preprocessor {
+    mtmd_audio_preprocessor_conformer(const clip_ctx * ctx) : mtmd_audio_preprocessor(ctx) {}
+    void initialize() override;
+    bool preprocess(const float * samples, size_t n_samples, std::vector<mtmd_audio_mel> & output) override;
+
+  private:
+    mtmd_audio_cache cache;
+};
+
+//
+// streaming ISTFT - converts spectrogram frames back to audio one frame at a time
+//
+struct mtmd_audio_streaming_istft {
+    mtmd_audio_streaming_istft(int n_fft, int hop_length);
+
+    // reset streaming state
+    void reset();
+
+    // process a single STFT frame (streaming)
+    // frame_spectrum: [n_fft_bins x 2] interleaved real/imag
+    // returns: up to hop_length samples
+    std::vector<float> process_frame(const float * frame_spectrum);
+
+    // flush remaining samples at end of stream
+    std::vector<float> flush();
+
+  private:
+    int n_fft;
+    int hop_length;
+    int n_fft_bins;
+
+    // Own cache for output processing
+    mtmd_audio_cache cache;
+
+    // Streaming state
+    std::vector<float> overlap_buffer;
+    std::vector<float> window_sum_buffer;
+    int                padding_to_remove;
+
+    // Working buffers for IFFT
+    std::vector<float> ifft_in;
+    std::vector<float> ifft_out;
+};