path: root/tools/spectool.cc

// This file is part of the 64k demo project.
// It implements the spectool for analyzing audio into spectrograms.
// Provides both 'analyze' and 'play' modes for spectral data.

#include "audio/audio.h"
#include "audio/dct.h"
#include "audio/gen.h"
#include "audio/synth.h"
#include "audio/window.h"
#include "platform.h"
#include <stdio.h>
#include <string.h>

#include "miniaudio.h"

#include <math.h>
#include <stdlib.h>
#include <time.h>
#include <vector>

// Simple .spec file format:
// char[4] magic = "SPEC"
// int32_t version = 1
// int32_t dct_size
// int32_t num_frames
// float[num_frames * dct_size] data
// struct SpecHeader { ... } -> now in audio.h

int analyze_audio(const char* in_path, const char* out_path, bool normalize,
                  float target_rms) {
  printf("Analyzing %s -> %s", in_path, out_path);
  if (normalize) {
    printf(" (normalizing to RMS=%.3f)", target_rms);
  }
  printf("\n");

  // Use higher quality resampling for better audio quality
  // Source files are typically 44.1kHz or 96kHz, 16/24-bit, mono/stereo
  ma_decoder_config config = ma_decoder_config_init(ma_format_f32, 1, 32000);

  // CRITICAL: Use highest quality low-pass filter to preserve audio quality
  // Default lpfOrder is very low, causing audible aliasing when downsampling
  // Maximum lpfOrder is implementation-dependent, but 8 is reasonable for
  // quality
  config.resampling.linear.lpfOrder =
      8; // Higher = better anti-aliasing (default is likely 1-2)

  ma_decoder decoder;
  if (ma_decoder_init_file(in_path, &config, &decoder) != MA_SUCCESS) {
    printf("Error: Failed to open or decode audio file: %s\n", in_path);
    return 1;
  }

  // First pass: Load all PCM data (needed for normalization)
  std::vector<float> pcm_data;
  float pcm_chunk[DCT_SIZE];
  ma_uint64 frames_read;
  while (ma_decoder_read_pcm_frames(&decoder, pcm_chunk, DCT_SIZE,
                                    &frames_read) == MA_SUCCESS &&
         frames_read > 0) {
    pcm_data.insert(pcm_data.end(), pcm_chunk, pcm_chunk + frames_read);
  }
  ma_decoder_uninit(&decoder);

  if (pcm_data.empty()) {
    printf("Error: No audio data read from file.\n");
    return 1;
  }

  // Calculate RMS and peak
  float rms_sum = 0.0f;
  float peak = 0.0f;
  for (size_t i = 0; i < pcm_data.size(); ++i) {
    const float abs_val = fabsf(pcm_data[i]);
    if (abs_val > peak) {
      peak = abs_val;
    }
    rms_sum += pcm_data[i] * pcm_data[i];
  }
  const float original_rms = sqrtf(rms_sum / pcm_data.size());
  printf("Original: Peak=%.3f, RMS=%.3f\n", peak, original_rms);

  // Normalize if requested
  float scale_factor = 1.0f;
  if (normalize && original_rms > 1e-6f) {
    // Calculate scale factor to reach target RMS
    scale_factor = target_rms / original_rms;

    // Check if this would cause clipping (peak > 1.0 after synthesis)
    // Peak amplification varies by sample (windowing + IDCT effects)
    // Use conservative limit: input peak ≤ 1.0 to guarantee output peak ≤ 1.0
    const float max_safe_peak = 1.0f;
    const float predicted_peak = peak * scale_factor;

    if (predicted_peak > max_safe_peak) {
      // Reduce scale factor to prevent clipping
      const float peak_scale = max_safe_peak / peak;
      printf("Warning: RMS normalization would cause clipping (peak=%.3f)\n",
             predicted_peak);
      printf("         Reducing scale to prevent clipping.\n");
      scale_factor = peak_scale;
    }

    printf("Normalizing: scale factor = %.3f\n", scale_factor);
    printf("  RMS: %.3f -> %.3f\n", original_rms, original_rms * scale_factor);
    printf("  Peak: %.3f -> %.3f\n", peak, peak * scale_factor);

    for (size_t i = 0; i < pcm_data.size(); ++i) {
      pcm_data[i] *= scale_factor;
    }
  }

  // Second pass: Windowing + DCT
  std::vector<float> spec_data;
  float window[WINDOW_SIZE];
  hamming_window_512(window);

  // Process PCM data in DCT_SIZE chunks
  const size_t num_chunks = (pcm_data.size() + DCT_SIZE - 1) / DCT_SIZE;
  for (size_t chunk_idx = 0; chunk_idx < num_chunks; ++chunk_idx) {
    const size_t chunk_start = chunk_idx * DCT_SIZE;
    const size_t chunk_end =
        (chunk_start + DCT_SIZE < pcm_data.size()) ? chunk_start + DCT_SIZE
                                                    : pcm_data.size();
    const size_t chunk_size = chunk_end - chunk_start;

    // Copy chunk (with zero-padding if needed)
    memcpy(pcm_chunk, pcm_data.data() + chunk_start,
           chunk_size * sizeof(float));
    if (chunk_size < DCT_SIZE) {
      memset(pcm_chunk + chunk_size, 0, (DCT_SIZE - chunk_size) * sizeof(float));
    }

    // Apply window
    for (int i = 0; i < DCT_SIZE; ++i) {
      pcm_chunk[i] *= window[i];
    }

    // Apply FDCT
    float dct_chunk[DCT_SIZE];
    fdct_512(pcm_chunk, dct_chunk);

    // Add to spectrogram data
    spec_data.insert(spec_data.end(), dct_chunk, dct_chunk + DCT_SIZE);
  }

  // --- Trim Silent Frames ---
  const float epsilon = 1e-6f;
  int num_frames = spec_data.size() / DCT_SIZE;
  int first_frame = 0;
  int last_frame = num_frames;

  // Trim leading silent frames
  for (int i = 0; i < num_frames; ++i) {
    bool all_zeros = true;
    for (int j = 0; j < DCT_SIZE; ++j) {
      if (fabsf(spec_data[i * DCT_SIZE + j]) > epsilon) {
        all_zeros = false;
        break;
      }
    }
    if (all_zeros) {
      first_frame = i + 1;
    } else {
      break;
    }
  }

  // Trim trailing silent frames
  for (int i = num_frames - 1; i >= first_frame; --i) {
    bool all_zeros = true;
    for (int j = 0; j < DCT_SIZE; ++j) {
      if (fabsf(spec_data[i * DCT_SIZE + j]) > epsilon) {
        all_zeros = false;
        break;
      }
    }
    if (all_zeros) {
      last_frame = i;
    } else {
      break;
    }
  }

  // Create a new vector with the trimmed data
  std::vector<float> trimmed_data;
  if (first_frame < last_frame) {
    trimmed_data.assign(spec_data.begin() + first_frame * DCT_SIZE,
                        spec_data.begin() + last_frame * DCT_SIZE);
  }

  printf("Trimming: Original frames: %d -> Trimmed frames: %zu\n", num_frames,
         trimmed_data.size() / DCT_SIZE);

  // Write to .spec file
  FILE* f_out = fopen(out_path, "wb");
  if (!f_out) {
    printf("Error: Failed to open output file: %s\n", out_path);
    return 1;
  }

  SpecHeader header;
  memcpy(header.magic, "SPEC", 4);
  header.version = 1;
  header.dct_size = DCT_SIZE;
  header.num_frames = trimmed_data.size() / DCT_SIZE;

  fwrite(&header, sizeof(SpecHeader), 1, f_out);
  fwrite(trimmed_data.data(), sizeof(float), trimmed_data.size(), f_out);
  fclose(f_out);

  printf("Analysis complete. Wrote %d spectral frames.\n", header.num_frames);
  return 0;
}

int play_spec(const char* in_path) {
  printf("Playing %s\n", in_path);

  FILE* f_in = fopen(in_path, "rb");
  if (!f_in) {
    printf("Error: Failed to open input file: %s\n", in_path);
    return 1;
  }

  SpecHeader header;
  if (fread(&header, sizeof(SpecHeader), 1, f_in) != 1 ||
      strncmp(header.magic, "SPEC", 4) != 0) {
    printf("Error: Invalid spectrogram file format.\n");
    fclose(f_in);
    return 1;
  }

  std::vector<float> spec_data(header.num_frames * header.dct_size);
  fread(spec_data.data(), sizeof(float), spec_data.size(), f_in);
  fclose(f_in);

  PlatformState platform_state = platform_init(false, 100, 100);
  audio_init();
  audio_start();
  Spectrogram spec;
  spec.spectral_data_a = spec_data.data();
  spec.spectral_data_b =
      spec_data.data(); // Point both to the same buffer for playback
  spec.num_frames = header.num_frames;

  int spec_id = synth_register_spectrogram(&spec);
  synth_trigger_voice(spec_id, 0.7f, 0.0f);

  printf("Playing... Press Ctrl+C to exit.\n");
  while (synth_get_active_voice_count() > 0 &&
         !platform_should_close(&platform_state)) {
    platform_poll(&platform_state);
  }

  audio_shutdown();
  platform_shutdown(&platform_state);

  return 0;
}

int test_gen(const char* out_path) {
  printf("Generating test spectrogram -> %s\n", out_path);

  std::vector<float> track_data;
  int track_frames = 0;

  // Generate a simple C Major scale
  float freqs[] = {261.63f, 293.66f, 329.63f, 349.23f,
                   392.00f, 440.00f, 493.88f, 523.25f};

  srand(time(NULL));

  for (int i = 0; i < 8; ++i) {
    NoteParams params;
    params.base_freq = freqs[i];
    params.duration_sec = 0.5f;
    params.amplitude = 0.5f;
    params.attack_sec = 0.05f;
    params.decay_sec = 0.1f;
    params.vibrato_rate = 5.0f;
    params.vibrato_depth = 2.0f;
    params.num_harmonics = 5;
    params.harmonic_decay = 0.5f;
    params.pitch_randomness = 1.0f;
    params.amp_randomness = 0.05f;

    int note_frames = 0;
    std::vector<float> note_data =
        generate_note_spectrogram(params, &note_frames);

    // Paste at 0.4s intervals (overlap)
    int offset = (int)(i * 0.4f * 32000.0f / DCT_SIZE);
    paste_spectrogram(track_data, &track_frames, note_data, note_frames,
                      offset);
  }

  // Write to file (Duplicate logic, but fine for now)
  FILE* f_out = fopen(out_path, "wb");
  if (!f_out) {
    printf("Error: Failed to open output file: %s\n", out_path);
    return 1;
  }

  SpecHeader header;
  memcpy(header.magic, "SPEC", 4);
  header.version = 1;
  header.dct_size = DCT_SIZE;
  header.num_frames = track_frames;

  fwrite(&header, sizeof(SpecHeader), 1, f_out);
  fwrite(track_data.data(), sizeof(float), track_data.size(), f_out);
  fclose(f_out);

  printf("Generated %d frames.\n", track_frames);
  return 0;
}

void print_usage() {
  printf("Usage: spectool <command> <input> [output] [options]\n");
  printf("Commands:\n");
  printf(
      "  analyze <input.wav|.mp3> <output.spec>   Analyze an audio file and "
      "save as a spectrogram.\n");
  printf(
      "  play    <input.spec>                     Play a spectrogram file.\n");
  printf(
      "  test_gen <output.spec>                   Generate a test "
      "spectrogram.\n");
  printf("\nOptions for 'analyze':\n");
  printf("  --normalize [rms]   Normalize audio to target RMS level (default: "
         "0.15)\n");
  printf(
      "                      Ensures consistent loudness across all samples.\n");
}

int main(int argc, char** argv) {
  if (argc < 2) {
    print_usage();
    return 1;
  }

  const char* command = argv[1];

  if (strcmp(command, "analyze") == 0) {
    if (argc < 4) {
      printf("Error: 'analyze' command requires input and output files.\n");
      print_usage();
      return 1;
    }

    // Parse optional flags
    bool normalize = false;
    float target_rms = 0.15f; // Default target RMS

    for (int i = 4; i < argc; ++i) {
      if (strcmp(argv[i], "--normalize") == 0) {
        normalize = true;
        // Check if next arg is a number (custom target RMS)
        if (i + 1 < argc) {
          char* endptr;
          float custom_rms = strtof(argv[i + 1], &endptr);
          if (endptr != argv[i + 1] && custom_rms > 0.0f && custom_rms < 1.0f) {
            target_rms = custom_rms;
            ++i; // Consume the RMS value
          }
        }
      }
    }

    return analyze_audio(argv[2], argv[3], normalize, target_rms);
  } else if (strcmp(command, "play") == 0) {
    if (argc < 3) {
      printf("Error: 'play' command requires an input file.\n");
      print_usage();
      return 1;
    }
    return play_spec(argv[2]);
  } else if (strcmp(command, "test_gen") == 0) {
    if (argc < 3) {
      printf("Error: 'test_gen' command requires an output file.\n");
      print_usage();
      return 1;
    }
    return test_gen(argv[2]);
  } else {
    printf("Error: Unknown command '%s'\n", command);
    print_usage();
    return 1;
  }

  return 0;
}