minimodem-mirror/src-tscope/tscope.c

190 lines
4.8 KiB
C

/*
* tscope.c
*
* Author: Kamal Mostafa <kamal@whence.com>
*
* Unpublished work, not licensed for any purpose.
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <alloca.h>
#include <ctype.h>
#include <assert.h>
#include <errno.h>
#include <math.h>
#include <pulse/simple.h>
#include <pulse/error.h>
#include <pulse/gccmacro.h>
#include <fftw3.h>
#include "tscope_print.h"
int
main( int argc, char*argv[] )
{
static const pa_sample_spec ss = {
.format = PA_SAMPLE_FLOAT32,
.rate = 9600, // pulseaudio will resample to this rate
.channels = 2 // 2 channel stereo
//.channels = 1 // downmix (additively) to 1 channel
//.channels = 3 // 2 channel stereo + 1 mixed channel
};
#if 1
static pa_buffer_attr pa_ba = {
.maxlength = (uint32_t)-1,
.fragsize = 0, // filled in at runtime
};
#endif
unsigned int decode_rate = 50;
unsigned int band_width = decode_rate;
int one_line_mode = 1;
int show_maxmag = 1;
if ( ! isatty(1) )
one_line_mode = 0;
int argi = 1;
while ( argi < argc && argv[argi][0] == '-' ) {
/* -s switch enables "scrolling mode" instead of "one line mode" */
if ( argv[argi][1] == 's' ) {
one_line_mode = 0;
} else {
fprintf(stderr,
"usage: tscope [-s] [ analysis_rate [ band_width ] ]\n");
return 1;
}
argi++;
}
if ( argi < argc )
decode_rate = atoi(argv[argi++]);
if ( argi < argc )
band_width = atoi(argv[argi++]);
assert( band_width <= decode_rate );
unsigned int sample_rate = ss.rate;
if ( isatty(1) )
pa_ba.fragsize = sample_rate / decode_rate;
/* Initiate the capture stream */
int error;
pa_simple *s;
s = pa_simple_new(NULL, argv[0], PA_STREAM_RECORD, NULL,
"text spectrum scope",
&ss, NULL, &pa_ba, &error);
// &ss, NULL, NULL, &error);
if ( !s ) {
fprintf(stderr, __FILE__": pa_simple_new() failed: %s\n",
pa_strerror(error));
return 1;
}
int pa_samplesize = pa_sample_size(&ss);
int pa_framesize = pa_frame_size(&ss);
int pa_nchannels = ss.channels;
assert( pa_samplesize == sizeof(float) );
assert( pa_framesize == pa_samplesize * pa_nchannels );
/* Create the FFT plan */
fftwf_plan fftplan;
int fftsize = sample_rate / band_width;
if ( fftsize & 1 )
fprintf(stderr, __FILE__": WARNING: fftsize %u is not even\n", fftsize);
unsigned int nbands = fftsize / 2 + 1;
float *fftin = fftwf_malloc(fftsize * sizeof(float) * pa_nchannels);
fftwf_complex *fftout = fftwf_malloc(nbands *
sizeof(fftwf_complex) * pa_nchannels);
/* basic fftw plan, works for only 1 channel:
fftplan = fftwf_plan_dft_r2c_1d(fftsize, fftin, fftout, FFTW_ESTIMATE);
*/
/* complex fftw plan, works for N channels: */
fftplan = fftwf_plan_many_dft_r2c(
/*rank*/1, &fftsize, /*howmany*/pa_nchannels,
fftin, NULL, /*istride*/pa_nchannels, /*idist*/1,
fftout, NULL, /*ostride*/1, /*odist*/nbands,
FFTW_ESTIMATE);
if ( !fftplan ) {
fprintf(stderr, __FILE__": fftwf_plan_dft_r2c_1d() failed\n");
return 1;
}
/* Calculate the input sample chunk rate */
int nsamples = sample_rate / decode_rate;
size_t nframes = nsamples;
size_t nbytes = nframes * pa_framesize;
/* Calculate the fftw output normalization factor */
float magscalar = 1.0 / (nsamples/2.0);
# if 0
float actual_decode_rate = (float)sample_rate / nsamples;
fprintf(stderr, "### baud=%.2f ###\n", actual_decode_rate);
# endif
/* Prepare the text scope output buffer */
// sadly, COLUMNS is not exported by default (?)
char *columns_env = getenv("COLUMNS");
int columns = columns_env ? atoi(columns_env) : 80;
int show_nbands = ( (columns - 2 - 10) / pa_nchannels ) - 1;
if ( show_nbands > nbands )
show_nbands = nbands;
char *magline = malloc(show_nbands+1);
/*
* Run the main loop
*/
while ( 1 )
{
// for possible future use...
// bzero(fftin, (fftsize * sizeof(float) * pa_nchannels));
/* read a chunk of input sample frames (directly into the
* FFT input buffer) */
if (pa_simple_read(s, fftin, nbytes, &error) < 0) {
fprintf(stderr, __FILE__": pa_simple_read() failed: %s\n",
pa_strerror(error));
return(1);
}
/* run the FFT to compute the spectrum (for all pa_nchannels) */
fftwf_execute(fftplan);
/* display the spectrum magnitudes for each channel */
int n;
for ( n=0; n<pa_nchannels; n++ )
tscope_print(fftout+n*nbands, show_nbands, magscalar,
one_line_mode, show_maxmag);
printf( one_line_mode ? "\r" : "\n" );
fflush(stdout);
}
/* Clean up */
free(magline);
pa_simple_free(s);
fftwf_free(fftin);
fftwf_free(fftout);
fftwf_destroy_plan(fftplan);
return 0;
}