shithub: sox

Info  •  Files  •  Log  •  Branches

Allow sending spectrograms to stdout

Send output of the spectrogram effect to standard output, if "-" is
specified as the file name.

--- a/ChangeLog

+++ b/ChangeLog

@@ -29,6 +29,7 @@

   o 'Deemph' can now also be used at 48kHz sample rate.  (robs)

   o 'Rate' now much faster in many cases.  (robs)

+  o Allow sending spectrograms to stdout. (Ulrich Klauer)

 Internal improvements:

--- a/sox.1

+++ b/sox.1

@@ -3242,8 +3242,10 @@

 .IP \fB\-c\ \fItext\fR

 Set (or clear) the image comment\*mtext to display below and to the

 left of the spectrogram.

-.IP \fB\-o\ \fItext\fR

+.IP \fB\-o\ \fIfile\fR

 Name of the spectrogram output PNG file, default `spectrogram.png'.

+If `-' is given, the spectrogram will be sent to standard output

+(stdout).

 .RE

 .TP

 \ 

--- a/src/spectrogram.c

+++ b/src/spectrogram.c

@@ -50,6 +50,7 @@

   sox_bool   raw, alt_palette, truncate;

   win_type_t win_type;

   char const * out_name, * title, * comment;

+  sox_bool   using_stdout; /* output image to stdout */

   /* Shared work area */

   double     * shared, * * shared_ptr;

@@ -145,6 +146,14 @@

   if (p->alt_palette)

     p->spectrum_points = min(p->spectrum_points, (int)alt_palette_len);

   p->shared_ptr = &p->shared;

+  if (!strcmp(p->out_name, "-")) {

+    if (effp->global_info->global_info->stdout_in_use_by) {

+      lsx_fail("stdout already in use by `%s'", effp->global_info->global_info->stdout_in_use_by);

+      return SOX_EOF;

+    }

+    effp->global_info->global_info->stdout_in_use_by = effp->handler.name;

+    p->using_stdout = sox_true;

+  }

   return optstate.ind !=argc || p->win_type == INT_MAX? lsx_usage(effp) : SOX_SUCCESS;

 }

@@ -492,7 +501,7 @@

 static int stop(sox_effect_t * effp)

 {

   priv_t *    p        = (priv_t *) effp->priv;

-  FILE *      file     = fopen(p->out_name, "wb");

+  FILE *      file;

   uLong       font_len = 96 * font_y;

   int         chans    = effp->in_signal.channels;

   int         c_rows   = p->rows * chans + chans - 1;

@@ -508,9 +517,14 @@

   double      limit;

   free(p->shared);

-  if (!file) {

-    lsx_fail("failed to create `%s': %s", p->out_name, strerror(errno));

-    goto error;

+  if (p->using_stdout)

+    file = stdout;

+  else {

+    file = fopen(p->out_name, "wb");

+    if (!file) {

+      lsx_fail("failed to create `%s': %s", p->out_name, strerror(errno));

+      goto error;

+    }

   }

   lsx_debug("signal-max=%g", p->max);

   font = lsx_malloc(font_len);

@@ -601,7 +615,8 @@

   free(font);

   png_set_rows(png, png_info, png_rows);

   png_write_png(png, png_info, PNG_TRANSFORM_IDENTITY, NULL);

-  fclose(file);

+  if (!p->using_stdout)

+    fclose(file);

 error: png_destroy_write_struct(&png, &png_info);

   free(png_rows);

   free(pixels);