Re: [PATCH RESEND 7/9] spectrogram: remove arbitrary limit on height of spectrogram

["Måns Rullgård" <mans@mansr.com>]

Eric Wong <normalperson@yhbt.net> writes:

> From: Martin Guy <martinwguy@gmail.com>
>
> Sox had an arbitrary limit of 8193 on the vertical axis size
> based on MAX_FFT_SIZE=4096 and had fixed-size arrays for its data.
> This is both wasteful of memory for smaller FFTs and stops us producing
> more detailed output for no obvious reason.
>
> This patch removes the size limit on Y-axis-height by making array
> allocation dynamic. In practice, you can't remove the limit as getopt
> insists on minimum and maximum values for numeric arguments, so we
> copy the similarly arbitrary limit of 200000 from MAX_X_SIZE.
>
> Tested-by: Eric Wong <normalperson@yhbt.net>
> ---
>  src/spectrogram.c | 37 +++++++++++++++++++++++++++----------
>  1 file changed, 27 insertions(+), 10 deletions(-)
>
> diff --git a/src/spectrogram.c b/src/spectrogram.c
> index afb0b0e8..b38d2124 100644
> --- a/src/spectrogram.c
> +++ b/src/spectrogram.c
> @@ -36,10 +36,13 @@
>    #include <io.h>
>  #endif
>
> -#define MAX_FFT_SIZE 4096
>  #define is_p2(x) !(x & (x - 1))
>
> +/* These are arbitrary as there is no upper limit, but
> + * sox's getopt() needs an upper limit for each option, so...
> + */
>  #define MAX_X_SIZE 200000
> +#define MAX_Y_SIZE 200000
>
>  typedef enum {Window_Hann, Window_Hamming, Window_Bartlett, Window_Rectangular, Window_Kaiser, Window_Dolph} win_type_t;
>  static lsx_enum_item const window_options[] = {
> @@ -71,8 +74,11 @@ typedef struct {
>    int        dft_size, step_size, block_steps, block_num, rows, cols, read;
>    int        x_size, end, end_min, last_end;
>    sox_bool   truncated;
> -  double     buf[MAX_FFT_SIZE], dft_buf[MAX_FFT_SIZE], window[MAX_FFT_SIZE+1];
> -  double     block_norm, max, magnitudes[(MAX_FFT_SIZE>>1) + 1];
> +  double     * buf;		/* [dft_size] */
> +  double     * dft_buf;		/* [dft_size] */
> +  double     * window;		/* [dft_size + 1] */
> +  double     block_norm, max;
> +  double     * magnitudes;	/* [(dft_size / 2) + 1] */
>    float      * dBfs;
>  } priv_t;
>
> @@ -114,9 +120,9 @@ static int getopts(sox_effect_t * effp, int argc, char **argv)
>
>    while ((c = lsx_getopt(&optstate)) != -1) switch (c) {
>      GETOPT_NUMERIC(optstate, 'x', x_size0       , 100, MAX_X_SIZE)
> -    GETOPT_NUMERIC(optstate, 'X', pixels_per_sec,  1 , 5000)
> -    GETOPT_NUMERIC(optstate, 'y', y_size        , 64 , 1200)
> -    GETOPT_NUMERIC(optstate, 'Y', Y_size        , 130, MAX_FFT_SIZE / 2 + 2)
> +    GETOPT_NUMERIC(optstate, 'X', pixels_per_sec,  1 , MAX_X_SIZE)
> +    GETOPT_NUMERIC(optstate, 'y', y_size        , 64 , MAX_Y_SIZE)
> +    GETOPT_NUMERIC(optstate, 'Y', Y_size        , 130, MAX_Y_SIZE)
>      GETOPT_NUMERIC(optstate, 'z', dB_range      , 20 , 180)
>      GETOPT_NUMERIC(optstate, 'Z', gain          ,-100, 100)
>      GETOPT_NUMERIC(optstate, 'q', spectrum_points, 0 , p->spectrum_points)
> @@ -172,7 +178,7 @@ static double make_window(priv_t * p, int end)
>    double sum = 0, * w = end < 0? p->window : p->window + end;
>    int i, n = 1 + p->dft_size - abs(end);
>
> -  if (end) memset(p->window, 0, sizeof(p->window));
> +  if (end) memset(p->window, 0, sizeof(*(p->window)) * p->dft_size);

This memset is short by one element.

>    for (i = 0; i < n; ++i) w[i] = 1;
>    switch (p->win_type) {
>      case Window_Hann: lsx_apply_hann(w, n); break;
> @@ -190,10 +196,10 @@ static double make_window(priv_t * p, int end)
>    return sum;
>  }
>
> -static double * rdft_init(int n)
> +static double * rdft_init(size_t n)
>  {
>    double * q = lsx_malloc(2 * (n / 2 + 1) * n * sizeof(*q)), * p = q;
> -  int i, j;
> +  size_t i, j;
>    for (j = 0; j <= n / 2; ++j) for (i = 0; i < n; ++i)
>      *p++ = cos(2 * M_PI * j * i / n), *p++ = sin(2 * M_PI * j * i / n);
>    return q;
> @@ -260,11 +266,18 @@ static int start(sox_effect_t * effp)
>    if (p->y_size) {
>      p->dft_size = 2 * (p->y_size - 1);
>      if (!is_p2(p->dft_size) && !effp->flow)
> -      p->shared = rdft_init(p->dft_size);
> +      p->shared = rdft_init((size_t)(p->dft_size));
>    } else {
>     int y = max(32, (p->Y_size? p->Y_size : 550) / effp->in_signal.channels - 2);
>     for (p->dft_size = 128; p->dft_size <= y; p->dft_size <<= 1);
>    }
> +
> +  /* Now that dft_size is set, allocate variable-sized elements of priv_t */
> +  p->buf	= lsx_calloc(p->dft_size, sizeof(*(p->buf)));
> +  p->dft_buf	= lsx_calloc(p->dft_size, sizeof(*(p->dft_buf)));
> +  p->window	= lsx_calloc(p->dft_size + 1, sizeof(*(p->window)));
> +  p->magnitudes = lsx_calloc((p->dft_size / 2) + 1, sizeof(*(p->magnitudes)));
> +
>    if (is_p2(p->dft_size) && !effp->flow)
>      lsx_safe_rdft(p->dft_size, 1, p->dft_buf);
>    lsx_debug("duration=%g x_size=%i pixels_per_sec=%g dft_size=%i", duration, p->x_size, pixels_per_sec, p->dft_size);
> @@ -651,6 +664,10 @@ error: png_destroy_write_struct(&png, &png_info);
>    free(png_rows);
>    free(pixels);
>    free(p->dBfs);
> +  free(p->buf);
> +  free(p->dft_buf);
> +  free(p->window);
> +  free(p->magnitudes);
>    return SOX_SUCCESS;
>  }

-- 
Måns Rullgård


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