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minimodem: use sine lookup table of 1024, or --lut={tx_sin_table_len}

This commit is contained in:
Kamal Mostafa 2012-08-13 21:17:03 -07:00
parent e2225d6098
commit a9c2258706
2 changed files with 44 additions and 4 deletions
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5
src/minimodem.1.in
View File

@ -78,6 +78,11 @@ Set the audio sample rate (default rate is 48000 Hz).
Use ALSA as the audio output system instead of the default
PulseAudio (depending on build configuration options).
.TP
.B \-\-lut={tx_sin_table_len}
Minimodem uses a precomputed sine wave lookup table of 1024 elements,
or the size specified here. Use \-\-lut=0 to disable the use of
the sine wave lookup table. (This option applies to \-\-tx mode only).
.TP
.B \-\-float-samples
Generate 32-bit floating-point format audio samples, instead of the
default 16-bit signed integer format (applies to \-\-tx mode only;

39
src/minimodem.c
View File

@ -254,9 +254,13 @@ benchmarks()
simpleaudio *sa_out;
// enable the sine wave LUT
simpleaudio_tone_init(1024);
sa_out = simpleaudio_open_stream(backend, SA_STREAM_PLAYBACK,
SA_SAMPLE_FORMAT_S16, sample_rate, 1,
program_name, "generate-tones-S16-mono");
program_name, "generate-tones-lut1024-S16-mono");
if ( ! sa_out )
return 0;
generate_test_tones(sa_out, 10);
@ -264,12 +268,33 @@ benchmarks()
sa_out = simpleaudio_open_stream(backend, SA_STREAM_PLAYBACK,
SA_SAMPLE_FORMAT_FLOAT, sample_rate, 1,
program_name, "generate-tones-FLOAT-mono");
program_name, "generate-tones-lut1024-FLOAT-mono");
if ( ! sa_out )
return 0;
generate_test_tones(sa_out, 10);
simpleaudio_close(sa_out);
// disable the sine wave LUT
simpleaudio_tone_init(0);
sa_out = simpleaudio_open_stream(backend, SA_STREAM_PLAYBACK,
SA_SAMPLE_FORMAT_S16, sample_rate, 1,
program_name, "generate-tones-nolut-S16-mono");
if ( ! sa_out )
return 0;
generate_test_tones(sa_out, 10);
simpleaudio_close(sa_out);
sa_out = simpleaudio_open_stream(backend, SA_STREAM_PLAYBACK,
SA_SAMPLE_FORMAT_FLOAT, sample_rate, 1,
program_name, "generate-tones-nolut-FLOAT-mono");
if ( ! sa_out )
return 0;
generate_test_tones(sa_out, 10);
simpleaudio_close(sa_out);
return 1;
}
@ -308,6 +333,7 @@ usage()
" -R, --samplerate {rate}\n"
" -V, --version\n"
" -A, --alsa\n"
" --lut={tx_sin_table_len}\n"
" --float-samples\n"
" --benchmarks\n"
" {baudmode}\n"
@ -341,6 +367,8 @@ main( int argc, char*argv[] )
unsigned int sample_rate = 48000;
unsigned int nchannels = 1; // FIXME: only works with one channel
unsigned int tx_sin_table_len = 4096;
/* validate the default system audio mechanism */
#if !(USE_PULSEAUDIO || USE_ALSA)
# define _MINIMODEM_NO_SYSTEM_AUDIO
@ -360,6 +388,7 @@ main( int argc, char*argv[] )
enum {
MINIMODEM_OPT_UNUSED=256, // placeholder
MINIMODEM_OPT_LUT,
MINIMODEM_OPT_FLOAT_SAMPLES,
MINIMODEM_OPT_BENCHMARKS,
};
@ -385,6 +414,7 @@ main( int argc, char*argv[] )
{ "quiet", 0, 0, 'q' },
{ "alsa", 0, 0, 'A' },
{ "samplerate", 1, 0, 'R' },
{ "lut", 1, 0, MINIMODEM_OPT_LUT },
{ "float-samples", 0, 0, MINIMODEM_OPT_FLOAT_SAMPLES },
{ "benchmarks", 0, 0, MINIMODEM_OPT_BENCHMARKS },
{ 0 }
@ -453,6 +483,9 @@ main( int argc, char*argv[] )
exit(1);
#endif
break;
case MINIMODEM_OPT_LUT:
tx_sin_table_len = atoi(optarg);
break;
case MINIMODEM_OPT_FLOAT_SAMPLES:
sample_format = SA_SAMPLE_FORMAT_FLOAT;
break;
@ -587,6 +620,8 @@ main( int argc, char*argv[] )
*/
if ( TX_mode ) {
simpleaudio_tone_init(tx_sin_table_len);
int tx_interactive = 0;
if ( ! stream_name ) {
tx_interactive = 1;