shithub: libsamplerate

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Modify sndfile-resample to restart conversion if clipping has occurred.

--- a/ChangeLog

+++ b/ChangeLog

@@ -1,3 +1,8 @@

+2004-06-15  Erik de Castro Lopo  <erikd AT mega-nerd DOT com>

+

+    * examples/sndfile-resample.c

+    Modified to restart conversion if clipping has occurred.

+

 2004-06-09  Erik de Castro Lopo  <erikd AT mega-nerd DOT com>

     * tests/benchmark.c

--- a/examples/sndfile-resample.c

+++ b/examples/sndfile-resample.c

@@ -32,7 +32,8 @@

 #define	BUFFER_LEN		4096	/*-(1<<16)-*/

 static void usage_exit (const char *progname) ;

-static sf_count_t sample_rate_convert (SNDFILE *infile, SNDFILE *outfile, int converter, double src_ratio, int channels) ;

+static sf_count_t sample_rate_convert (SNDFILE *infile, SNDFILE *outfile, int converter, double src_ratio, int channels, double * gain) ;

+static double apply_gain (float * data, long frames, int channels, double max, double gain) ;

 int

 main (int argc, char *argv [])

@@ -40,7 +41,7 @@

 	SF_INFO sfinfo ;

 	sf_count_t	count ;

-	double		src_ratio = -1.0 ;

+	double		src_ratio = -1.0, gain = 1.0 ;

 	int			new_sample_rate = -1, k, converter, max_speed = SF_FALSE ;

 	if (argc == 2 && strcmp (argv [1], "--version") == 0)

@@ -150,7 +151,9 @@

 	printf ("Output file   : %s\n", argv [argc - 1]) ;

 	printf ("Sample Rate   : %d\n", sfinfo.samplerate) ;

-	count = sample_rate_convert (infile, outfile, converter, src_ratio, sfinfo.channels) ;

+	do

+		count = sample_rate_convert (infile, outfile, converter, src_ratio, sfinfo.channels, &gain) ;

+	while (count < 0) ;

 	printf ("Output Frames : %ld\n\n", (long) count) ;

@@ -164,7 +167,7 @@

 */

 static sf_count_t

-sample_rate_convert (SNDFILE *infile, SNDFILE *outfile, int converter, double src_ratio, int channels)

+sample_rate_convert (SNDFILE *infile, SNDFILE *outfile, int converter, double src_ratio, int channels, double * gain)

 {	static float input [BUFFER_LEN] ;

 	static float output [BUFFER_LEN] ;

@@ -171,6 +174,7 @@

 	SRC_STATE	*src_state ;

 	SRC_DATA	src_data ;

 	int			error ;

+	double		max = 0.0 ;

 	sf_count_t	output_count = 0 ;

 	sf_seek (infile, 0, SEEK_SET) ;

@@ -214,6 +218,8 @@

 		if (src_data.end_of_input && src_data.output_frames_gen == 0)

 			break ;

+		max = apply_gain (src_data.data_out, src_data.output_frames_gen, channels, max, *gain) ;

+

 		/* Write output. */

 		sf_writef_float (outfile, output, src_data.output_frames_gen) ;

 		output_count += src_data.output_frames_gen ;

@@ -224,9 +230,29 @@

 	src_state = src_delete (src_state) ;

+	if (max > 1.0)

+	{	*gain = 1.0 / max ;

+		printf ("\nOutput has clipped. Restarting conversion to prevent clipping.\n\n") ;

+		return -1 ;

+		} ;

+

 	return output_count ;

 } /* sample_rate_convert */

+static double

+apply_gain (float * data, long frames, int channels, double max, double gain)

+{

+	long k ;

+

+	for (k = 0 ; k < frames * channels ; k++)

+	{	data [k] *= gain ;

+

+		if (fabs (data [k]) > max)

+			max = fabs (data [k]) ;

+		} ;

+

+	return max ;

+} /* apply_gain */

 static void

 usage_exit (const char *progname)