ref: 1bb5e8adc3cd6686b492a369b83cb9eb440b42ef
parent: 2da4fd035cc44db3cd75543eeec100cdb5447081
author: Erik de Castro Lopo <erikd@mega-nerd.com>
date: Sat Dec 13 10:40:54 EST 2008
src/src_sinc.c : Rejig converter so filter coefficients are calculated once per frame and special case channel counts of 1, 2 and 4.
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,10 @@
* tests/multichan_throughput_test.c
Do throughput test on all three SINC based converters.
+ * src/src_sinc.c
+ Rejig converter so filter coefficients are calculated once per frame and
+ special case channel counts of 1, 2 and 4.
+
2008-12-12 Erik de Castro Lopo <erikd AT mega-nerd DOT com>
* src/samplerate.c examples/audio_out.c tests/*.c
--- a/src/src_sinc.c
+++ b/src/src_sinc.c
@@ -65,11 +65,15 @@
coeff_t const *coeffs ;
int b_current, b_end, b_real_end, b_len ;
- float buffer [1] ;
+
+ /* C99 struct flexible array. */
+ float buffer [] ;
} SINC_FILTER ;
static int sinc_multichan_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data) ;
-static int sinc_1chan_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data) ;
+static int sinc_quad_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data) ;
+static int sinc_stereo_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data) ;
+static int sinc_mono_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data) ;
static void prepare_data (SINC_FILTER *filter, SRC_DATA *data, int half_filter_chan_len) ;
@@ -164,10 +168,20 @@
temp_filter.channels = psrc->channels ;
if (psrc->channels == 1)
- { psrc->const_process = sinc_1chan_vari_process ;- psrc->vari_process = sinc_1chan_vari_process ;
+ { psrc->const_process = sinc_mono_vari_process ;+ psrc->vari_process = sinc_mono_vari_process ;
}
else
+ if (psrc->channels == 2)
+ { psrc->const_process = sinc_stereo_vari_process ;+ psrc->vari_process = sinc_stereo_vari_process ;
+ }
+ else
+ if (psrc->channels == 4)
+ { psrc->const_process = sinc_quad_vari_process ;+ psrc->vari_process = sinc_quad_vari_process ;
+ }
+ else
{ psrc->const_process = sinc_multichan_vari_process ;psrc->vari_process = sinc_multichan_vari_process ;
} ;
@@ -300,9 +314,102 @@
return (left + right) ;
} /* calc_output_single */
-static inline double
-calc_output_multi (SINC_FILTER *filter, increment_t increment, increment_t start_filter_index, int ch)
-{ double fraction, left, right, icoeff ;+static int
+sinc_mono_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data)
+{ SINC_FILTER *filter ;+ double input_index, src_ratio, count, float_increment, terminate, rem ;
+ increment_t increment, start_filter_index ;
+ int half_filter_chan_len, samples_in_hand ;
+
+ if (psrc->private_data == NULL)
+ return SRC_ERR_NO_PRIVATE ;
+
+ filter = (SINC_FILTER*) psrc->private_data ;
+
+ /* If there is not a problem, this will be optimised out. */
+ if (sizeof (filter->buffer [0]) != sizeof (data->data_in [0]))
+ return SRC_ERR_SIZE_INCOMPATIBILITY ;
+
+ filter->in_count = data->input_frames * filter->channels ;
+ filter->out_count = data->output_frames * filter->channels ;
+ filter->in_used = filter->out_gen = 0 ;
+
+ src_ratio = psrc->last_ratio ;
+
+ /* Check the sample rate ratio wrt the buffer len. */
+ count = (filter->coeff_half_len + 2.0) / filter->index_inc ;
+ if (MIN (psrc->last_ratio, data->src_ratio) < 1.0)
+ count /= MIN (psrc->last_ratio, data->src_ratio) ;
+
+ /* Maximum coefficientson either side of center point. */
+ half_filter_chan_len = filter->channels * (lrint (count) + 1) ;
+
+ input_index = psrc->last_position ;
+ float_increment = filter->index_inc ;
+
+ rem = fmod_one (input_index) ;
+ filter->b_current = (filter->b_current + filter->channels * lrint (input_index - rem)) % filter->b_len ;
+ input_index = rem ;
+
+ terminate = 1.0 / src_ratio + 1e-20 ;
+
+ /* Main processing loop. */
+ while (filter->out_gen < filter->out_count)
+ {+ /* Need to reload buffer? */
+ samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
+
+ if (samples_in_hand <= half_filter_chan_len)
+ { prepare_data (filter, data, half_filter_chan_len) ;+
+ samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
+ if (samples_in_hand <= half_filter_chan_len)
+ break ;
+ } ;
+
+ /* This is the termination condition. */
+ if (filter->b_real_end >= 0)
+ { if (filter->b_current + input_index + terminate >= filter->b_real_end)+ break ;
+ } ;
+
+ if (filter->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > 1e-10)
+ src_ratio = psrc->last_ratio + filter->out_gen * (data->src_ratio - psrc->last_ratio) / filter->out_count ;
+
+ float_increment = filter->index_inc * 1.0 ;
+ if (src_ratio < 1.0)
+ float_increment = filter->index_inc * src_ratio ;
+
+ increment = double_to_fp (float_increment) ;
+
+ start_filter_index = double_to_fp (input_index * float_increment) ;
+
+ data->data_out [filter->out_gen] = (float) ((float_increment / filter->index_inc) *
+ calc_output_single (filter, increment, start_filter_index)) ;
+ filter->out_gen ++ ;
+
+ /* Figure out the next index. */
+ input_index += 1.0 / src_ratio ;
+ rem = fmod_one (input_index) ;
+
+ filter->b_current = (filter->b_current + filter->channels * lrint (input_index - rem)) % filter->b_len ;
+ input_index = rem ;
+ } ;
+
+ psrc->last_position = input_index ;
+
+ /* Save current ratio rather then target ratio. */
+ psrc->last_ratio = src_ratio ;
+
+ data->input_frames_used = filter->in_used / filter->channels ;
+ data->output_frames_gen = filter->out_gen / filter->channels ;
+
+ return SRC_ERR_NO_ERROR ;
+} /* sinc_mono_vari_process */
+
+static inline void
+calc_output_stereo (SINC_FILTER *filter, increment_t increment, increment_t start_filter_index, double scale, float * output)
+{ double fraction, left [2], right [2], icoeff ;increment_t filter_index, max_filter_index ;
int data_index, coeff_count, indx ;
@@ -313,9 +420,9 @@
filter_index = start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
- data_index = filter->b_current - filter->channels * coeff_count + ch ;
+ data_index = filter->b_current - filter->channels * coeff_count ;
- left = 0.0 ;
+ left [0] = left [1] = 0.0 ;
do
{ fraction = fp_to_double (filter_index) ;indx = fp_to_int (filter_index) ;
@@ -322,10 +429,11 @@
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
- left += icoeff * filter->buffer [data_index] ;
+ left [0] += icoeff * filter->buffer [data_index] ;
+ left [1] += icoeff * filter->buffer [data_index + 1] ;
filter_index -= increment ;
- data_index = data_index + filter->channels ;
+ data_index = data_index + 2 ;
}
while (filter_index >= MAKE_INCREMENT_T (0)) ;
@@ -333,9 +441,9 @@
filter_index = increment - start_filter_index ;
coeff_count = (max_filter_index - filter_index) / increment ;
filter_index = filter_index + coeff_count * increment ;
- data_index = filter->b_current + filter->channels * (1 + coeff_count) + ch ;
+ data_index = filter->b_current + filter->channels * (1 + coeff_count) ;
- right = 0.0 ;
+ right [0] = right [1] = 0.0 ;
do
{ fraction = fp_to_double (filter_index) ;indx = fp_to_int (filter_index) ;
@@ -342,7 +450,8 @@
icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
- right += icoeff * filter->buffer [data_index] ;
+ right [0] += icoeff * filter->buffer [data_index] ;
+ right [1] += icoeff * filter->buffer [data_index + 1] ;
filter_index -= increment ;
data_index = data_index - filter->channels ;
@@ -349,11 +458,12 @@
}
while (filter_index > MAKE_INCREMENT_T (0)) ;
- return (left + right) ;
-} /* calc_output_multi */
+ output [0] = scale * (left [0] + right [0]) ;
+ output [1] = scale * (left [1] + right [1]) ;
+} /* calc_output_stereo */
static int
-sinc_1chan_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data)
+sinc_stereo_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data)
{ SINC_FILTER *filter ;double input_index, src_ratio, count, float_increment, terminate, rem ;
increment_t increment, start_filter_index ;
@@ -422,9 +532,8 @@
start_filter_index = double_to_fp (input_index * float_increment) ;
- data->data_out [filter->out_gen] = (float) ((float_increment / filter->index_inc) *
- calc_output_single (filter, increment, start_filter_index)) ;
- filter->out_gen ++ ;
+ calc_output_stereo (filter, increment, start_filter_index, float_increment / filter->index_inc, data->data_out + filter->out_gen) ;
+ filter->out_gen += 2 ;
/* Figure out the next index. */
input_index += 1.0 / src_ratio ;
@@ -443,14 +552,75 @@
data->output_frames_gen = filter->out_gen / filter->channels ;
return SRC_ERR_NO_ERROR ;
-} /* sinc_1chan_vari_process */
+} /* sinc_stereo_vari_process */
+static inline void
+calc_output_quad (SINC_FILTER *filter, increment_t increment, increment_t start_filter_index, double scale, float * output)
+{ double fraction, left [4], right [4], icoeff ;+ increment_t filter_index, max_filter_index ;
+ int data_index, coeff_count, indx ;
+
+ /* Convert input parameters into fixed point. */
+ max_filter_index = int_to_fp (filter->coeff_half_len) ;
+
+ /* First apply the left half of the filter. */
+ filter_index = start_filter_index ;
+ coeff_count = (max_filter_index - filter_index) / increment ;
+ filter_index = filter_index + coeff_count * increment ;
+ data_index = filter->b_current - filter->channels * coeff_count ;
+
+ left [0] = left [1] = left [2] = left [3] = 0.0 ;
+ do
+ { fraction = fp_to_double (filter_index) ;+ indx = fp_to_int (filter_index) ;
+
+ icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
+
+ left [0] += icoeff * filter->buffer [data_index] ;
+ left [1] += icoeff * filter->buffer [data_index + 1] ;
+ left [2] += icoeff * filter->buffer [data_index + 2] ;
+ left [3] += icoeff * filter->buffer [data_index + 3] ;
+
+ filter_index -= increment ;
+ data_index = data_index + 4 ;
+ }
+ while (filter_index >= MAKE_INCREMENT_T (0)) ;
+
+ /* Now apply the right half of the filter. */
+ filter_index = increment - start_filter_index ;
+ coeff_count = (max_filter_index - filter_index) / increment ;
+ filter_index = filter_index + coeff_count * increment ;
+ data_index = filter->b_current + filter->channels * (1 + coeff_count) ;
+
+ right [0] = right [1] = right [2] = right [3] = 0.0 ;
+ do
+ { fraction = fp_to_double (filter_index) ;+ indx = fp_to_int (filter_index) ;
+
+ icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
+
+ right [0] += icoeff * filter->buffer [data_index] ;
+ right [1] += icoeff * filter->buffer [data_index + 1] ;
+ right [2] += icoeff * filter->buffer [data_index + 2] ;
+ right [3] += icoeff * filter->buffer [data_index + 3] ;
+
+ filter_index -= increment ;
+ data_index = data_index - filter->channels ;
+ }
+ while (filter_index > MAKE_INCREMENT_T (0)) ;
+
+ output [0] = scale * (left [0] + right [0]) ;
+ output [1] = scale * (left [1] + right [1]) ;
+ output [2] = scale * (left [2] + right [2]) ;
+ output [3] = scale * (left [3] + right [3]) ;
+} /* calc_output_quad */
+
static int
-sinc_multichan_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data)
+sinc_quad_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data)
{ SINC_FILTER *filter ;double input_index, src_ratio, count, float_increment, terminate, rem ;
increment_t increment, start_filter_index ;
- int half_filter_chan_len, samples_in_hand, ch ;
+ int half_filter_chan_len, samples_in_hand ;
if (psrc->private_data == NULL)
return SRC_ERR_NO_PRIVATE ;
@@ -515,11 +685,161 @@
start_filter_index = double_to_fp (input_index * float_increment) ;
- for (ch = 0 ; ch < filter->channels ; ch++)
- { data->data_out [filter->out_gen] = (float) ((float_increment / filter->index_inc) *- calc_output_multi (filter, increment, start_filter_index, ch)) ;
- filter->out_gen ++ ;
+ calc_output_quad (filter, increment, start_filter_index, float_increment / filter->index_inc, data->data_out + filter->out_gen) ;
+ filter->out_gen += 4 ;
+
+ /* Figure out the next index. */
+ input_index += 1.0 / src_ratio ;
+ rem = fmod_one (input_index) ;
+
+ filter->b_current = (filter->b_current + filter->channels * lrint (input_index - rem)) % filter->b_len ;
+ input_index = rem ;
+ } ;
+
+ psrc->last_position = input_index ;
+
+ /* Save current ratio rather then target ratio. */
+ psrc->last_ratio = src_ratio ;
+
+ data->input_frames_used = filter->in_used / filter->channels ;
+ data->output_frames_gen = filter->out_gen / filter->channels ;
+
+ return SRC_ERR_NO_ERROR ;
+} /* sinc_quad_vari_process */
+
+static inline void
+calc_output_multi (SINC_FILTER *filter, increment_t increment, increment_t start_filter_index, int channels, double scale, float * output)
+{ double fraction, left [channels], right [channels], icoeff ;+ increment_t filter_index, max_filter_index ;
+ int data_index, coeff_count, indx, ch ;
+
+ /* Convert input parameters into fixed point. */
+ max_filter_index = int_to_fp (filter->coeff_half_len) ;
+
+ /* First apply the left half of the filter. */
+ filter_index = start_filter_index ;
+ coeff_count = (max_filter_index - filter_index) / increment ;
+ filter_index = filter_index + coeff_count * increment ;
+ data_index = filter->b_current - channels * coeff_count ;
+
+ memset (left, 0, sizeof (left)) ;
+
+ do
+ { fraction = fp_to_double (filter_index) ;+ indx = fp_to_int (filter_index) ;
+
+ icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
+
+ ch = channels ;
+ while (-- ch >= 0)
+ left [ch] += icoeff * filter->buffer [data_index + ch] ;
+
+ filter_index -= increment ;
+ data_index = data_index + channels ;
+ }
+ while (filter_index >= MAKE_INCREMENT_T (0)) ;
+
+ /* Now apply the right half of the filter. */
+ filter_index = increment - start_filter_index ;
+ coeff_count = (max_filter_index - filter_index) / increment ;
+ filter_index = filter_index + coeff_count * increment ;
+ data_index = filter->b_current + channels * (1 + coeff_count) ;
+
+ memset (right, 0, sizeof (right)) ;
+ do
+ { fraction = fp_to_double (filter_index) ;+ indx = fp_to_int (filter_index) ;
+
+ icoeff = filter->coeffs [indx] + fraction * (filter->coeffs [indx + 1] - filter->coeffs [indx]) ;
+
+ ch = channels ;
+ while (-- ch >= 0)
+ right [ch] += icoeff * filter->buffer [data_index + ch] ;
+
+ filter_index -= increment ;
+ data_index = data_index - channels ;
+ }
+ while (filter_index > MAKE_INCREMENT_T (0)) ;
+
+ ch = channels ;
+ while (-- ch >= 0)
+ output [ch] = scale * (left [ch] + right [ch]) ;
+
+ return ;
+} /* calc_output_multi */
+
+static int
+sinc_multichan_vari_process (SRC_PRIVATE *psrc, SRC_DATA *data)
+{ SINC_FILTER *filter ;+ double input_index, src_ratio, count, float_increment, terminate, rem ;
+ increment_t increment, start_filter_index ;
+ int half_filter_chan_len, samples_in_hand ;
+
+ if (psrc->private_data == NULL)
+ return SRC_ERR_NO_PRIVATE ;
+
+ filter = (SINC_FILTER*) psrc->private_data ;
+
+ /* If there is not a problem, this will be optimised out. */
+ if (sizeof (filter->buffer [0]) != sizeof (data->data_in [0]))
+ return SRC_ERR_SIZE_INCOMPATIBILITY ;
+
+ filter->in_count = data->input_frames * filter->channels ;
+ filter->out_count = data->output_frames * filter->channels ;
+ filter->in_used = filter->out_gen = 0 ;
+
+ src_ratio = psrc->last_ratio ;
+
+ /* Check the sample rate ratio wrt the buffer len. */
+ count = (filter->coeff_half_len + 2.0) / filter->index_inc ;
+ if (MIN (psrc->last_ratio, data->src_ratio) < 1.0)
+ count /= MIN (psrc->last_ratio, data->src_ratio) ;
+
+ /* Maximum coefficientson either side of center point. */
+ half_filter_chan_len = filter->channels * (lrint (count) + 1) ;
+
+ input_index = psrc->last_position ;
+ float_increment = filter->index_inc ;
+
+ rem = fmod_one (input_index) ;
+ filter->b_current = (filter->b_current + filter->channels * lrint (input_index - rem)) % filter->b_len ;
+ input_index = rem ;
+
+ terminate = 1.0 / src_ratio + 1e-20 ;
+
+ /* Main processing loop. */
+ while (filter->out_gen < filter->out_count)
+ {+ /* Need to reload buffer? */
+ samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
+
+ if (samples_in_hand <= half_filter_chan_len)
+ { prepare_data (filter, data, half_filter_chan_len) ;+
+ samples_in_hand = (filter->b_end - filter->b_current + filter->b_len) % filter->b_len ;
+ if (samples_in_hand <= half_filter_chan_len)
+ break ;
} ;
+
+ /* This is the termination condition. */
+ if (filter->b_real_end >= 0)
+ { if (filter->b_current + input_index + terminate >= filter->b_real_end)+ break ;
+ } ;
+
+ if (filter->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > 1e-10)
+ src_ratio = psrc->last_ratio + filter->out_gen * (data->src_ratio - psrc->last_ratio) / filter->out_count ;
+
+ float_increment = filter->index_inc * 1.0 ;
+ if (src_ratio < 1.0)
+ float_increment = filter->index_inc * src_ratio ;
+
+ increment = double_to_fp (float_increment) ;
+
+ start_filter_index = double_to_fp (input_index * float_increment) ;
+
+ calc_output_multi (filter, increment, start_filter_index, filter->channels, float_increment / filter->index_inc, data->data_out + filter->out_gen) ;
+ filter->out_gen += psrc->channels ;
/* Figure out the next index. */
input_index += 1.0 / src_ratio ;