diff options
Diffstat (limited to 'libswresample/resample.c')
| -rw-r--r-- | libswresample/resample.c | 44 |
1 files changed, 40 insertions, 4 deletions
diff --git a/libswresample/resample.c b/libswresample/resample.c index 036eff391f..c881ed8f41 100644 --- a/libswresample/resample.c +++ b/libswresample/resample.c @@ -74,7 +74,7 @@ static int build_filter(ResampleContext *c, void *filter, double factor, int tap int filter_type, int kaiser_beta){ int ph, i; double x, y, w; - double *tab = av_malloc_array(tap_count, sizeof(*tab)); + double *tab = av_malloc_array(tap_count+1, sizeof(*tab)); const int center= (tap_count-1)/2; if (!tab) @@ -84,9 +84,10 @@ static int build_filter(ResampleContext *c, void *filter, double factor, int tap if (factor > 1.0) factor = 1.0; - for(ph=0;ph<phase_count;ph++) { + av_assert0(phase_count == 1 || phase_count % 2 == 0); + for(ph = 0; ph <= phase_count / 2; ph++) { double norm = 0; - for(i=0;i<tap_count;i++) { + for(i=0;i<=tap_count;i++) { x = M_PI * ((double)(i - center) - (double)ph / phase_count) * factor; if (x == 0) y = 1.0; else y = sin(x) / x; @@ -110,7 +111,8 @@ static int build_filter(ResampleContext *c, void *filter, double factor, int tap } tab[i] = y; - norm += y; + if (i < tap_count) + norm += y; } /* normalize so that an uniform color remains the same */ @@ -118,18 +120,52 @@ static int build_filter(ResampleContext *c, void *filter, double factor, int tap case AV_SAMPLE_FMT_S16P: for(i=0;i<tap_count;i++) ((int16_t*)filter)[ph * alloc + i] = av_clip(lrintf(tab[i] * scale / norm), INT16_MIN, INT16_MAX); + if (tap_count % 2 == 0) { + for (i = 0; i < tap_count; i++) + ((int16_t*)filter)[(phase_count-ph) * alloc + tap_count-1-i] = ((int16_t*)filter)[ph * alloc + i]; + } + else { + for (i = 1; i <= tap_count; i++) + ((int16_t*)filter)[(phase_count-ph) * alloc + tap_count-i] = + av_clip(lrintf(tab[i] * scale / (norm - tab[0] + tab[tap_count])), INT16_MIN, INT16_MAX); + } break; case AV_SAMPLE_FMT_S32P: for(i=0;i<tap_count;i++) ((int32_t*)filter)[ph * alloc + i] = av_clipl_int32(llrint(tab[i] * scale / norm)); + if (tap_count % 2 == 0) { + for (i = 0; i < tap_count; i++) + ((int32_t*)filter)[(phase_count-ph) * alloc + tap_count-1-i] = ((int32_t*)filter)[ph * alloc + i]; + } + else { + for (i = 1; i <= tap_count; i++) + ((int32_t*)filter)[(phase_count-ph) * alloc + tap_count-i] = + av_clipl_int32(llrint(tab[i] * scale / (norm - tab[0] + tab[tap_count]))); + } break; case AV_SAMPLE_FMT_FLTP: for(i=0;i<tap_count;i++) ((float*)filter)[ph * alloc + i] = tab[i] * scale / norm; + if (tap_count % 2 == 0) { + for (i = 0; i < tap_count; i++) + ((float*)filter)[(phase_count-ph) * alloc + tap_count-1-i] = ((float*)filter)[ph * alloc + i]; + } + else { + for (i = 1; i <= tap_count; i++) + ((float*)filter)[(phase_count-ph) * alloc + tap_count-i] = tab[i] * scale / (norm - tab[0] + tab[tap_count]); + } break; case AV_SAMPLE_FMT_DBLP: for(i=0;i<tap_count;i++) ((double*)filter)[ph * alloc + i] = tab[i] * scale / norm; + if (tap_count % 2 == 0) { + for (i = 0; i < tap_count; i++) + ((double*)filter)[(phase_count-ph) * alloc + tap_count-1-i] = ((double*)filter)[ph * alloc + i]; + } + else { + for (i = 1; i <= tap_count; i++) + ((double*)filter)[(phase_count-ph) * alloc + tap_count-i] = tab[i] * scale / (norm - tab[0] + tab[tap_count]); + } break; } } |