virtualenv/FFmpeg
1
0
Fork 0
mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-23 12:43:46 +02:00
Code Issues Releases Activity

make filter size, int32/int16 and a few other things selectable at compiletime

Browse Source 
Originally committed as revision 3615 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-10-20 18:02:34 +00:00
parent 2ac615da82
commit 51a880208a
1 changed files with 29 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
libavcodec/resample2.c
View File

@ -31,10 +31,28 @@
#define PHASE_SHIFT 10
#define PHASE_COUNT (1<<PHASE_SHIFT)
#define PHASE_MASK (PHASE_COUNT-1)
#define FILTER_SIZE 16
//#define LINEAR 1
#if 1
#define FILTER_SHIFT 15
#define FELEM int16_t
#define FELEM2 int32_t
#define FELEM_MAX INT16_MAX
#define FELEM_MIN INT16_MIN
#else
#define FILTER_SHIFT 24
#define FELEM int32_t
#define FELEM2 int64_t
#define FELEM_MAX INT32_MAX
#define FELEM_MIN INT32_MIN
#endif
typedef struct AVResampleContext{
short *filter_bank;
FELEM *filter_bank;
int filter_length;
int ideal_dst_incr;
int dst_incr;
@ -65,7 +83,7 @@ double bessel(double x){
* @param scale wanted sum of coefficients for each filter
* @param type 0->cubic, 1->blackman nuttall windowed sinc, 2->kaiser windowed sinc beta=16
*/
void av_build_filter(int16_t *filter, double factor, int tap_count, int phase_count, int scale, int type){
void av_build_filter(FELEM *filter, double factor, int tap_count, int phase_count, int scale, int type){
int ph, i, v;
double x, y, w, tab[tap_count];
const int center= (tap_count-1)/2;
@ -104,7 +122,7 @@ void av_build_filter(int16_t *filter, double factor, int tap_count, int phase_co
/* normalize so that an uniform color remains the same */
for(i=0;i<tap_count;i++) {
v = clip(lrintf(tab[i] * scale / norm + e), -32768, 32767);
v = clip(lrintf(tab[i] * scale / norm + e), FELEM_MIN, FELEM_MAX);
filter[ph * tap_count + i] = v;
e += tab[i] * scale / norm - v;
}
@ -121,10 +139,10 @@ AVResampleContext *av_resample_init(int out_rate, int in_rate){
memset(c, 0, sizeof(AVResampleContext));
c->filter_length= ceil(16.0/factor);
c->filter_bank= av_mallocz(c->filter_length*(PHASE_COUNT+1)*sizeof(short));
c->filter_length= ceil(FILTER_SIZE/factor);
c->filter_bank= av_mallocz(c->filter_length*(PHASE_COUNT+1)*sizeof(FELEM));
av_build_filter(c->filter_bank, factor, c->filter_length, PHASE_COUNT, 1<<FILTER_SHIFT, 1);
memcpy(&c->filter_bank[c->filter_length*PHASE_COUNT+1], c->filter_bank, (c->filter_length-1)*sizeof(short));
memcpy(&c->filter_bank[c->filter_length*PHASE_COUNT+1], c->filter_bank, (c->filter_length-1)*sizeof(FELEM));
c->filter_bank[c->filter_length*PHASE_COUNT]= c->filter_bank[c->filter_length - 1];
c->src_incr= out_rate;
@ -163,9 +181,9 @@ int av_resample(AVResampleContext *c, short *dst, short *src, int *consumed, int
int compensation_distance= c->compensation_distance;
for(dst_index=0; dst_index < dst_size; dst_index++){
short *filter= c->filter_bank + c->filter_length*(index & PHASE_MASK);
FELEM *filter= c->filter_bank + c->filter_length*(index & PHASE_MASK);
int sample_index= index >> PHASE_SHIFT;
int val=0;
FELEM2 val=0;
if(sample_index < 0){
for(i=0; i<c->filter_length; i++)
@ -173,17 +191,17 @@ int av_resample(AVResampleContext *c, short *dst, short *src, int *consumed, int
}else if(sample_index + c->filter_length > src_size){
break;
}else{
#if 0
#ifdef LINEAR
int64_t v=0;
int sub_phase= (frac<<12) / c->src_incr;
for(i=0; i<c->filter_length; i++){
int64_t coeff= filter[i]*(4096 - sub_phase) + filter[i + c->filter_length]*sub_phase;
int64_t coeff= filter[i]*(FELEM2)(4096 - sub_phase) + filter[i + c->filter_length]*(FELEM2)sub_phase;
v += src[sample_index + i] * coeff;
}
val= v>>12;
#else
for(i=0; i<c->filter_length; i++){
val += src[sample_index + i] * filter[i];
val += src[sample_index + i] * (FELEM2)filter[i];
}
#endif
}