swresample/resample: Fix fractional part of index in the filter_size = 1 filters = 1 case

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libswresample/resample_template.c

@@ -104,7 +104,7 @@ int RENAME(swri_resample)(ResampleContext *c, DELEM *dst, const DELEM *src, int
     av_assert1(c->felem_size == sizeof(FELEM));
 
     if(compensation_distance == 0 && c->filter_length == 1 && c->phase_shift==0){
-        int64_t index2= ((int64_t)index)<<32;
+        int64_t index2= (1LL<<32)*c->frac/c->src_incr + (1LL<<32)*index;
         int64_t incr= (1LL<<32) * c->dst_incr / c->src_incr;
         dst_size= FFMIN(dst_size, (src_size-1-index) * (int64_t)c->src_incr / c->dst_incr);
 

tests/fate/libswresample.mak

@@ -326,13 +326,13 @@ fate-swr-resample_nn-$(3)-$(1)-$(2): REF = tests/data/asynth-$(1)-1.wav
 fate-swr-resample_nn-fltp-44100-8000: CMP_TARGET = 590.98
 fate-swr-resample_nn-fltp-44100-8000: SIZE_TOLERANCE = 529200 - 20486
 
-fate-swr-resample_nn-fltp-8000-44100: CMP_TARGET = 6330.39
+fate-swr-resample_nn-fltp-8000-44100: CMP_TARGET = 3163.03
 fate-swr-resample_nn-fltp-8000-44100: SIZE_TOLERANCE = 96000 - 20480
 
 fate-swr-resample_nn-s16p-44100-8000: CMP_TARGET = 590.97
 fate-swr-resample_nn-s16p-44100-8000: SIZE_TOLERANCE = 529200 - 20486
 
-fate-swr-resample_nn-s16p-8000-44100: CMP_TARGET = 6330.47
+fate-swr-resample_nn-s16p-8000-44100: CMP_TARGET = 3163.10
 fate-swr-resample_nn-s16p-8000-44100: SIZE_TOLERANCE = 96000 - 20480
 endef