waveform.c File Reference

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Functions
char *	audio_visualization_render_waveform (unsigned int width, unsigned int height, audio_visualization_source_t source, bool use_color, int color_mode, bool flip_x, bool flip_y)

Function Documentation

audio_visualization_render_waveform()

char * audio_visualization_render_waveform	(	unsigned int	width,
		unsigned int	height,
		audio_visualization_source_t	source,
		bool	use_color,
		int	color_mode,
		bool	flip_x,
		bool	flip_y )

Definition at line 39 of file waveform.c.

                                                                                                    {
  if (width < 8 || height < 4 || width > MAX_TERMINAL_WIDTH || height > MAX_TERMINAL_HEIGHT ||
      source < AUDIO_VISUALIZATION_SOURCE_MIC || source > AUDIO_VISUALIZATION_SOURCE_MIX)
    return NULL;
 
  /* Keep a fixed one-second view so new audio enters on the right smoothly. */
  const size_t sample_count = VISUALIZATION_HISTORY;
  float *samples = SAFE_MALLOC(sample_count * sizeof(float), float *);
  if (!samples)
    return NULL;
  audio_visualization_read(source, samples, sample_count);
 
  const unsigned int grid_height = GET_OPTION(render_mode) == RENDER_MODE_HALF_BLOCK ? height * 2 : height;
  const unsigned int center = grid_height / 2;
  const unsigned int half_height = grid_height - 1 - center;
  const size_t cell_count = (size_t)width * grid_height;
  char *cells = SAFE_MALLOC(cell_count, char *);
  if (!cells) {
    SAFE_FREE(samples);
    return NULL;
  }
  memset(cells, ' ', cell_count);
  unsigned char palette[MAX_TERMINAL_WIDTH][3] = {{0}};
 
  float positive_peak = 0.0f;
  float negative_peak = 0.0f;
  size_t x = 0;
 
  for (size_t i = 0; i < sample_count; i++) {
    float sample = samples[i];
    positive_peak = fmaxf(positive_peak, sample);
    negative_peak = fmaxf(negative_peak, -sample);
 
    size_t next_bucket = ((i + 1) * width) / sample_count;
    if (next_bucket != x || i + 1 == sample_count) {
      size_t begin = x * sample_count / width;
      size_t end = (x + 1) * sample_count / width;
      size_t bucket_center = begin + (end - begin) / 2;
      float centroid = waveform_spectral_centroid(samples, sample_count, bucket_center);
      /* A gentle square-root scale keeps speech visible without flattening loud peaks. */
      float level = sqrtf(fminf(fmaxf(positive_peak, negative_peak), 1.0f));
      visualization_color_for_level(centroid, level, color_mode, &palette[x][0], &palette[x][1], &palette[x][2]);
      unsigned int positive_amplitude = (unsigned int)lrintf(sqrtf(fminf(positive_peak, 1.0f)) * (float)half_height);
      unsigned int negative_amplitude = (unsigned int)lrintf(sqrtf(fminf(negative_peak, 1.0f)) * (float)half_height);
      if (positive_amplitude > half_height)
        positive_amplitude = half_height;
      if (negative_amplitude > half_height)
        negative_amplitude = half_height;
      unsigned int top = center - positive_amplitude;
      unsigned int bottom = center + negative_amplitude;
      for (unsigned int y = top; y <= bottom; y++) {
        char ch = (y == top || y == bottom) ? '+' : '#';
        cells[(size_t)y * width + x] = ch;
      }
 
      /* Advance to the next time slice in the left-to-right history. */
      positive_peak = 0.0f;
      negative_peak = 0.0f;
      x = next_bucket;
    }
  }
 
  char *frame = visualization_encode(cells, &palette[0][0], true, width, grid_height, use_color, flip_x, flip_y);
  SAFE_FREE(cells);
  SAFE_FREE(samples);
  return frame;
}

References audio_visualization_read(), AUDIO_VISUALIZATION_SOURCE_MIX, cells, color_mode, GET_OPTION, height, MAX_TERMINAL_HEIGHT, MAX_TERMINAL_WIDTH, SAFE_FREE, SAFE_MALLOC, source, visualization_color_for_level(), visualization_encode(), VISUALIZATION_HISTORY, and width.

Referenced by mirror_render_audio_visualization().