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| author | Dan Everton <dan@iocaine.org> | 2007-02-10 11:44:26 +0000 |
|---|---|---|
| committer | Dan Everton <dan@iocaine.org> | 2007-02-10 11:44:26 +0000 |
| commit | 7bf62e8da66ca8ff0acc2702f92ea4fe06eb94b1 (patch) | |
| tree | c9db4558a73ae3094839c4655fa0b8ebc2231c56 /apps/codecs/libspeex/resample.c | |
| parent | 51587512635a8b19e6a5f19a20074d0d4d1f17da (diff) | |
| download | rockbox-7bf62e8da66ca8ff0acc2702f92ea4fe06eb94b1.zip rockbox-7bf62e8da66ca8ff0acc2702f92ea4fe06eb94b1.tar.gz rockbox-7bf62e8da66ca8ff0acc2702f92ea4fe06eb94b1.tar.bz2 rockbox-7bf62e8da66ca8ff0acc2702f92ea4fe06eb94b1.tar.xz | |
* Sync Speex codec with Speex SVN revision 12449 (roughly Speex 1.2beta1).
* Redo the changes required to make Speex compile in Rockbox. Should be a bit easier to keep in sync with Speex SVN now.
* Fix name of Speex library in codecs Makefile.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12254 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/codecs/libspeex/resample.c')
| -rw-r--r-- | apps/codecs/libspeex/resample.c | 625 |
1 files changed, 625 insertions, 0 deletions
diff --git a/apps/codecs/libspeex/resample.c b/apps/codecs/libspeex/resample.c new file mode 100644 index 0000000..d6bfa3e --- /dev/null +++ b/apps/codecs/libspeex/resample.c @@ -0,0 +1,625 @@ +/* Copyright (C) 2007 Jean-Marc Valin + + File: resample.c + Arbitrary resampling code + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + 1. Redistributions of source code must retain the above copyright notice, + this list of conditions and the following disclaimer. + + 2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + + 3. The name of the author may not be used to endorse or promote products + derived from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, + INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + POSSIBILITY OF SUCH DAMAGE. +*/ + +/* + The design goals of this code are: + - Very fast algorithm + - SIMD-friendly algorithm + - Low memory requirement + - Good *perceptual* quality (and not best SNR) + + The code is working, but it's in a very early stage, so it may have + artifacts, noise or subliminal messages from satan. Also, the API + isn't stable and I can actually promise that I *will* change the API + some time in the future. + +TODO list: + - Variable calculation resolution depending on quality setting + - Single vs double in float mode + - 16-bit vs 32-bit (sinc only) in fixed-point mode + - Make sure the filter update works even when changing params + after only a few samples procesed +*/ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#ifdef OUTSIDE_SPEEX +#include <stdlib.h> +void *speex_alloc (int size) {return calloc(size,1);} +void *speex_realloc (void *ptr, int size) {return realloc(ptr, size);} +void speex_free (void *ptr) {free(ptr);} +#else +#include "misc.h" +#endif + +#include <math.h> +#include "speex/speex_resampler.h" + +#ifndef M_PI +#define M_PI 3.14159263 +#endif + +#ifdef FIXED_POINT +#define WORD2INT(x) ((x) < -32767 ? -32768 : ((x) > 32766 ? 32767 : (x))) +#else +#define WORD2INT(x) ((x) < -32767.5f ? -32768 : ((x) > 32766.5f ? 32767 : floor(.5+(x)))) +#endif + +/*#define float double*/ +#define FILTER_SIZE 64 +#define OVERSAMPLE 8 + +#define IMAX(a,b) ((a) > (b) ? (a) : (b)) + +struct QualityMapping { + int base_length; + int oversample; + float downsample_bandwidth; + float upsample_bandwidth; +}; + +/* This table maps conversion quality to internal parameters. There are two + reasons that explain why the up-sampling bandwidth is larger than the + down-sampling bandwidth: + 1) When up-sampling, we can assume that the spectrum is already attenuated + close to the Nyquist rate (from an A/D or a previous resampling filter) + 2) Any aliasing that occurs very close to the Nyquist rate will be masked + by the sinusoids/noise just below the Nyquist rate (guaranteed only for + up-sampling). +*/ +const struct QualityMapping quality_map[11] = { + { 8, 4, 0.70f, 0.80f}, /* 0 */ + { 16, 4, 0.74f, 0.83f}, /* 1 */ + { 32, 4, 0.77f, 0.87f}, /* 2 */ + { 48, 8, 0.84f, 0.90f}, /* 3 */ + { 64, 8, 0.88f, 0.92f}, /* 4 */ + { 80, 8, 0.90f, 0.94f}, /* 5 */ + { 96, 8, 0.91f, 0.94f}, /* 6 */ + {128, 16, 0.93f, 0.95f}, /* 7 */ + {160, 16, 0.94f, 0.96f}, /* 8 */ + {192, 16, 0.95f, 0.96f}, /* 9 */ + {256, 16, 0.96f, 0.97f}, /* 10 */ +}; + +typedef enum {SPEEX_RESAMPLER_DIRECT_SINGLE=0, SPEEX_RESAMPLER_INTERPOLATE_SINGLE=1} SpeexSincType; + +typedef int (*resampler_basic_func)(SpeexResamplerState *, int , const spx_word16_t *, int *, spx_word16_t *, int *); + +struct SpeexResamplerState_ { + int in_rate; + int out_rate; + int num_rate; + int den_rate; + + int quality; + int nb_channels; + int filt_len; + int mem_alloc_size; + int int_advance; + int frac_advance; + float cutoff; + int oversample; + int initialised; + int started; + + /* These are per-channel */ + int *last_sample; + int *samp_frac_num; + int *magic_samples; + + spx_word16_t *mem; + spx_word16_t *sinc_table; + int sinc_table_length; + resampler_basic_func resampler_ptr; + + int in_stride; + int out_stride; + SpeexSincType type; +} ; + +#ifdef FIXED_POINT +/* The slow way of computing a sinc for the table. Should improve that some day */ +static spx_word16_t sinc(float cutoff, float x, int N) +{ + /*fprintf (stderr, "%f ", x);*/ + x *= cutoff; + if (fabs(x)<1e-6f) + return WORD2INT(32768.*cutoff); + else if (fabs(x) > .5f*N) + return 0; + /*FIXME: Can it really be any slower than this? */ + return WORD2INT(32768.*cutoff*sin(M_PI*x)/(M_PI*x) * (.42+.5*cos(2*x*M_PI/N)+.08*cos(4*x*M_PI/N))); +} +#else +/* The slow way of computing a sinc for the table. Should improve that some day */ +static spx_word16_t sinc(float cutoff, float x, int N) +{ + /*fprintf (stderr, "%f ", x);*/ + x *= cutoff; + if (fabs(x)<1e-6) + return cutoff; + else if (fabs(x) > .5*N) + return 0; + /*FIXME: Can it really be any slower than this? */ + return cutoff*sin(M_PI*x)/(M_PI*x) * (.42+.5*cos(2*x*M_PI/N)+.08*cos(4*x*M_PI/N)); +} +#endif + +static int resampler_basic_direct_single(SpeexResamplerState *st, int channel_index, const spx_word16_t *in, int *in_len, spx_word16_t *out, int *out_len) +{ + int N = st->filt_len; + int out_sample = 0; + spx_word16_t *mem; + int last_sample = st->last_sample[channel_index]; + int samp_frac_num = st->samp_frac_num[channel_index]; + mem = st->mem + channel_index * st->mem_alloc_size; + while (!(last_sample >= *in_len || out_sample >= *out_len)) + { + int j; + spx_word32_t sum=0; + + /* We already have all the filter coefficients pre-computed in the table */ + const spx_word16_t *ptr; + /* Do the memory part */ + for (j=0;last_sample-N+1+j < 0;j++) + { + sum += MULT16_16(mem[last_sample+j],st->sinc_table[samp_frac_num*st->filt_len+j]); + } + + /* Do the new part */ + ptr = in+st->in_stride*(last_sample-N+1+j); + for (;j<N;j++) + { + sum += MULT16_16(*ptr,st->sinc_table[samp_frac_num*st->filt_len+j]); + ptr += st->in_stride; + } + + *out = PSHR32(sum,15); + out += st->out_stride; + out_sample++; + last_sample += st->int_advance; + samp_frac_num += st->frac_advance; + if (samp_frac_num >= st->den_rate) + { + samp_frac_num -= st->den_rate; + last_sample++; + } + } + st->last_sample[channel_index] = last_sample; + st->samp_frac_num[channel_index] = samp_frac_num; + return out_sample; +} + +static int resampler_basic_interpolate_single(SpeexResamplerState *st, int channel_index, const spx_word16_t *in, int *in_len, spx_word16_t *out, int *out_len) +{ + int N = st->filt_len; + int out_sample = 0; + spx_word16_t *mem; + int last_sample = st->last_sample[channel_index]; + int samp_frac_num = st->samp_frac_num[channel_index]; + mem = st->mem + channel_index * st->mem_alloc_size; + while (!(last_sample >= *in_len || out_sample >= *out_len)) + { + int j; + spx_word32_t sum=0; + + /* We need to interpolate the sinc filter */ + spx_word32_t accum[4] = {0.f,0.f, 0.f, 0.f}; + float interp[4]; + const spx_word16_t *ptr; + float alpha = ((float)samp_frac_num)/st->den_rate; + int offset = samp_frac_num*st->oversample/st->den_rate; + float frac = alpha*st->oversample - offset; + /* This code is written like this to make it easy to optimise with SIMD. + For most DSPs, it would be best to split the loops in two because most DSPs + have only two accumulators */ + for (j=0;last_sample-N+1+j < 0;j++) + { + spx_word16_t curr_mem = mem[last_sample+j]; + accum[0] += MULT16_16(curr_mem,st->sinc_table[4+(j+1)*st->oversample-offset-2]); + accum[1] += MULT16_16(curr_mem,st->sinc_table[4+(j+1)*st->oversample-offset-1]); + accum[2] += MULT16_16(curr_mem,st->sinc_table[4+(j+1)*st->oversample-offset]); + accum[3] += MULT16_16(curr_mem,st->sinc_table[4+(j+1)*st->oversample-offset+1]); + } + ptr = in+st->in_stride*(last_sample-N+1+j); + /* Do the new part */ + for (;j<N;j++) + { + spx_word16_t curr_in = *ptr; + ptr += st->in_stride; + accum[0] += MULT16_16(curr_in,st->sinc_table[4+(j+1)*st->oversample-offset-2]); + accum[1] += MULT16_16(curr_in,st->sinc_table[4+(j+1)*st->oversample-offset-1]); + accum[2] += MULT16_16(curr_in,st->sinc_table[4+(j+1)*st->oversample-offset]); + accum[3] += MULT16_16(curr_in,st->sinc_table[4+(j+1)*st->oversample-offset+1]); + } + /* Compute interpolation coefficients. I'm not sure whether this corresponds to cubic interpolation + but I know it's MMSE-optimal on a sinc */ + interp[0] = -0.16667f*frac + 0.16667f*frac*frac*frac; + interp[1] = frac + 0.5f*frac*frac - 0.5f*frac*frac*frac; + /*interp[2] = 1.f - 0.5f*frac - frac*frac + 0.5f*frac*frac*frac;*/ + interp[3] = -0.33333f*frac + 0.5f*frac*frac - 0.16667f*frac*frac*frac; + /* Just to make sure we don't have rounding problems */ + interp[2] = 1.f-interp[0]-interp[1]-interp[3]; + /*sum = frac*accum[1] + (1-frac)*accum[2];*/ + sum = interp[0]*accum[0] + interp[1]*accum[1] + interp[2]*accum[2] + interp[3]*accum[3]; + + *out = PSHR32(sum,15); + out += st->out_stride; + out_sample++; + last_sample += st->int_advance; + samp_frac_num += st->frac_advance; + if (samp_frac_num >= st->den_rate) + { + samp_frac_num -= st->den_rate; + last_sample++; + } + } + st->last_sample[channel_index] = last_sample; + st->samp_frac_num[channel_index] = samp_frac_num; + return out_sample; +} + + +static void update_filter(SpeexResamplerState *st) +{ + int i; + int old_length; + + old_length = st->filt_len; + st->oversample = quality_map[st->quality].oversample; + st->filt_len = quality_map[st->quality].base_length; + + if (st->num_rate > st->den_rate) + { + /* down-sampling */ + st->cutoff = quality_map[st->quality].downsample_bandwidth * st->den_rate / st->num_rate; + /* FIXME: divide the numerator and denominator by a certain amount if they're too large */ + st->filt_len = st->filt_len*st->num_rate / st->den_rate; + /* Round down to make sure we have a multiple of 4 */ + st->filt_len &= (~0x3); + } else { + /* up-sampling */ + st->cutoff = quality_map[st->quality].upsample_bandwidth; + } + + /* Choose the resampling type that requires the least amount of memory */ + if (st->den_rate <= st->oversample) + { + if (!st->sinc_table) + st->sinc_table = (spx_word16_t *)speex_alloc(st->filt_len*st->den_rate*sizeof(spx_word16_t)); + else if (st->sinc_table_length < st->filt_len*st->den_rate) + { + st->sinc_table = (spx_word16_t *)speex_realloc(st->sinc_table,st->filt_len*st->den_rate*sizeof(spx_word16_t)); + st->sinc_table_length = st->filt_len*st->den_rate; + } + for (i=0;i<st->den_rate;i++) + { + int j; + for (j=0;j<st->filt_len;j++) + { + st->sinc_table[i*st->filt_len+j] = sinc(st->cutoff,((j-st->filt_len/2+1)-((float)i)/st->den_rate), st->filt_len); + } + } + st->type = SPEEX_RESAMPLER_DIRECT_SINGLE; + st->resampler_ptr = resampler_basic_direct_single; + /*fprintf (stderr, "resampler uses direct sinc table and normalised cutoff %f\n", cutoff);*/ + } else { + if (!st->sinc_table) + st->sinc_table = (spx_word16_t *)speex_alloc((st->filt_len*st->oversample+8)*sizeof(spx_word16_t)); + else if (st->sinc_table_length < st->filt_len*st->oversample+8) + { + st->sinc_table = (spx_word16_t *)speex_realloc(st->sinc_table,(st->filt_len*st->oversample+8)*sizeof(spx_word16_t)); + st->sinc_table_length = st->filt_len*st->oversample+8; + } + for (i=-4;i<st->oversample*st->filt_len+4;i++) + st->sinc_table[i+4] = sinc(st->cutoff,(i/(float)st->oversample - st->filt_len/2), st->filt_len); + st->type = SPEEX_RESAMPLER_INTERPOLATE_SINGLE; + st->resampler_ptr = resampler_basic_interpolate_single; + /*fprintf (stderr, "resampler uses interpolated sinc table and normalised cutoff %f\n", cutoff);*/ + } + st->int_advance = st->num_rate/st->den_rate; + st->frac_advance = st->num_rate%st->den_rate; + + if (!st->mem) + { + st->mem = (spx_word16_t*)speex_alloc(st->nb_channels*(st->filt_len-1) * sizeof(spx_word16_t)); + for (i=0;i<st->nb_channels*(st->filt_len-1);i++) + st->mem[i] = 0; + st->mem_alloc_size = st->filt_len-1; + /*speex_warning("init filter");*/ + } else if (!st->started) + { + st->mem = (spx_word16_t*)speex_realloc(st->mem, st->nb_channels*(st->filt_len-1) * sizeof(spx_word16_t)); + for (i=0;i<st->nb_channels*(st->filt_len-1);i++) + st->mem[i] = 0; + st->mem_alloc_size = st->filt_len-1; + /*speex_warning("reinit filter");*/ + } else if (st->filt_len > old_length) + { + /* Increase the filter length */ + /*speex_warning("increase filter size");*/ + int old_alloc_size = st->mem_alloc_size; + if (st->filt_len-1 > st->mem_alloc_size) + { + st->mem = (spx_word16_t*)speex_realloc(st->mem, st->nb_channels*(st->filt_len-1) * sizeof(spx_word16_t)); + st->mem_alloc_size = st->filt_len-1; + } + for (i=0;i<st->nb_channels;i++) + { + int j; + /* Copy data going backward */ + for (j=0;j<old_length-1;j++) + st->mem[i*st->mem_alloc_size+(st->filt_len-2-j)] = st->mem[i*old_alloc_size+(old_length-2-j)]; + /* Then put zeros for lack of anything better */ + for (;j<st->filt_len-1;j++) + st->mem[i*st->mem_alloc_size+(st->filt_len-2-j)] = 0; + /* Adjust last_sample */ + st->last_sample[i] += (st->filt_len - old_length)/2; + } + } else if (st->filt_len < old_length) + { + /* Reduce filter length, this a bit tricky */ + /*speex_warning("decrease filter size (unimplemented)");*/ + /* Adjust last_sample (which will likely end up negative) */ + /*st->last_sample += (st->filt_len - old_length)/2;*/ + for (i=0;i<st->nb_channels;i++) + { + int j; + st->magic_samples[i] = (old_length - st->filt_len)/2; + /* Copy data going backward */ + for (j=0;j<st->filt_len-1+st->magic_samples[i];j++) + st->mem[i*st->mem_alloc_size+j] = st->mem[i*st->mem_alloc_size+j+st->magic_samples[i]]; + } + } + +} + + +SpeexResamplerState *speex_resampler_init(int nb_channels, int ratio_num, int ratio_den, int in_rate, int out_rate, int quality) +{ + int i; + SpeexResamplerState *st = (SpeexResamplerState *)speex_alloc(sizeof(SpeexResamplerState)); + st->initialised = 0; + st->started = 0; + st->in_rate = 0; + st->out_rate = 0; + st->num_rate = 0; + st->den_rate = 0; + st->quality = -1; + st->sinc_table_length = 0; + st->mem_alloc_size = 0; + st->filt_len = 0; + st->mem = 0; + st->resampler_ptr = 0; + + st->cutoff = 1.f; + st->nb_channels = nb_channels; + st->in_stride = 1; + st->out_stride = 1; + + /* Per channel data */ + st->last_sample = (int*)speex_alloc(nb_channels*sizeof(int)); + st->magic_samples = (int*)speex_alloc(nb_channels*sizeof(int)); + st->samp_frac_num = (int*)speex_alloc(nb_channels*sizeof(int)); + for (i=0;i<nb_channels;i++) + { + st->last_sample[i] = 0; + st->magic_samples[i] = 0; + st->samp_frac_num[i] = 0; + } + + speex_resampler_set_quality(st, quality); + speex_resampler_set_rate(st, ratio_num, ratio_den, in_rate, out_rate); + + + update_filter(st); + + st->initialised = 1; + return st; +} + +void speex_resampler_destroy(SpeexResamplerState *st) +{ + speex_free(st->mem); + speex_free(st->sinc_table); + speex_free(st->last_sample); + speex_free(st->magic_samples); + speex_free(st->samp_frac_num); + speex_free(st); +} + + + +static void speex_resampler_process_native(SpeexResamplerState *st, int channel_index, const spx_word16_t *in, int *in_len, spx_word16_t *out, int *out_len) +{ + int j=0; + int N = st->filt_len; + int out_sample = 0; + spx_word16_t *mem; + int tmp_out_len = 0; + mem = st->mem + channel_index * st->mem_alloc_size; + st->started = 1; + + /* Handle the case where we have samples left from a reduction in filter length */ + if (st->magic_samples) + { + int tmp_in_len; + tmp_in_len = st->magic_samples[channel_index]; + tmp_out_len = *out_len; + /* FIXME: Need to handle the case where the out array is too small */ + /* magic_samples needs to be set to zero to avoid infinite recursion */ + st->magic_samples = 0; + speex_resampler_process_native(st, channel_index, mem+N-1, &tmp_in_len, out, &tmp_out_len); + /*speex_warning_int("extra samples:", tmp_out_len);*/ + out += tmp_out_len; + } + + /* Call the right resampler through the function ptr */ + out_sample = st->resampler_ptr(st, channel_index, in, in_len, out, out_len); + + if (st->last_sample[channel_index] < *in_len) + *in_len = st->last_sample[channel_index]; + *out_len = out_sample+tmp_out_len; + st->last_sample[channel_index] -= *in_len; + + for (j=0;j<N-1-*in_len;j++) + mem[j] = mem[j+*in_len]; + for (;j<N-1;j++) + mem[j] = in[st->in_stride*(j+*in_len-N+1)]; + +} + +#ifdef FIXED_POINT +void speex_resampler_process_float(SpeexResamplerState *st, int channel_index, const float *in, int *in_len, float *out, int *out_len) +{ + int i; + int istride_save, ostride_save; + spx_word16_t x[*in_len]; + spx_word16_t y[*out_len]; + istride_save = st->in_stride; + ostride_save = st->out_stride; + for (i=0;i<*in_len;i++) + x[i] = WORD2INT(in[i*st->in_stride]); + st->in_stride = st->out_stride = 1; + speex_resampler_process_native(st, channel_index, x, in_len, y, out_len); + st->in_stride = istride_save; + st->out_stride = ostride_save; + for (i=0;i<*out_len;i++) + out[i*st->out_stride] = y[i]; +} +void speex_resampler_process_int(SpeexResamplerState *st, int channel_index, const spx_int16_t *in, int *in_len, spx_int16_t *out, int *out_len) +{ + speex_resampler_process_native(st, channel_index, in, in_len, out, out_len); +} +#else +void speex_resampler_process_float(SpeexResamplerState *st, int channel_index, const float *in, int *in_len, float *out, int *out_len) +{ + speex_resampler_process_native(st, channel_index, in, in_len, out, out_len); +} +void speex_resampler_process_int(SpeexResamplerState *st, int channel_index, const spx_int16_t *in, int *in_len, spx_int16_t *out, int *out_len) +{ + int i; + int istride_save, ostride_save; + spx_word16_t x[*in_len]; + spx_word16_t y[*out_len]; + istride_save = st->in_stride; + ostride_save = st->out_stride; + for (i=0;i<*in_len;i++) + x[i] = in[i+st->in_stride]; + st->in_stride = st->out_stride = 1; + speex_resampler_process_native(st, channel_index, x, in_len, y, out_len); + st->in_stride = istride_save; + st->out_stride = ostride_save; + for (i=0;i<*out_len;i++) + out[i+st->out_stride] = WORD2INT(y[i]); +} +#endif + +void speex_resampler_process_interleaved_float(SpeexResamplerState *st, const float *in, int *in_len, float *out, int *out_len) +{ + int i; + int istride_save, ostride_save; + istride_save = st->in_stride; + ostride_save = st->out_stride; + st->in_stride = st->out_stride = st->nb_channels; + for (i=0;i<st->nb_channels;i++) + { + speex_resampler_process_float(st, i, in+i, in_len, out+i, out_len); + } + st->in_stride = istride_save; + st->out_stride = ostride_save; +} + + +void speex_resampler_set_rate(SpeexResamplerState *st, int ratio_num, int ratio_den, int in_rate, int out_rate) +{ + int fact; + if (st->in_rate == in_rate && st->out_rate == out_rate && st->num_rate == ratio_num && st->den_rate == ratio_den) + return; + + st->in_rate = in_rate; + st->out_rate = out_rate; + st->num_rate = ratio_num; + st->den_rate = ratio_den; + /* FIXME: This is terribly inefficient, but who cares (at least for now)? */ + for (fact=2;fact<=sqrt(IMAX(in_rate, out_rate));fact++) + { + while ((st->num_rate % fact == 0) && (st->den_rate % fact == 0)) + { + st->num_rate /= fact; + st->den_rate /= fact; + } + } + + if (st->initialised) + update_filter(st); +} + +void speex_resampler_set_quality(SpeexResamplerState *st, int quality) +{ + if (quality < 0) + quality = 0; + if (quality > 10) + quality = 10; + if (st->quality == quality) + return; + st->quality = quality; + if (st->initialised) + update_filter(st); +} + +void speex_resampler_set_input_stride(SpeexResamplerState *st, int stride) +{ + st->in_stride = stride; +} + +void speex_resampler_set_output_stride(SpeexResamplerState *st, int stride) +{ + st->out_stride = stride; +} + +void speex_resampler_skip_zeros(SpeexResamplerState *st) +{ + int i; + for (i=0;i<st->nb_channels;i++) + st->last_sample[i] = st->filt_len/2; +} + +void speex_resampler_reset_mem(SpeexResamplerState *st) +{ + int i; + for (i=0;i<st->nb_channels*(st->filt_len-1);i++) + st->mem[i] = 0; +} + |