swresample/resample: increase precision for compensation

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libswresample/resample.c

@@ -355,6 +355,10 @@ static ResampleContext *resample_init(ResampleContext *c, int out_rate, int in_r
     c->compensation_distance= 0;
     if(!av_reduce(&c->src_incr, &c->dst_incr, out_rate, in_rate * (int64_t)phase_count, INT32_MAX/2))
         goto error;
+    while (c->dst_incr < (1<<20) && c->src_incr < (1<<20)) {
+        c->dst_incr *= 2;
+        c->src_incr *= 2;
+    }
     c->ideal_dst_incr = c->dst_incr;
     c->dst_incr_div   = c->dst_incr / c->src_incr;
     c->dst_incr_mod   = c->dst_incr % c->src_incr;

tests/fate/libswresample.mak

@@ -366,16 +366,16 @@ fate-swr-resample_async-$(3)-$(1)-$(2): FUZZ = 0.1
 fate-swr-resample_async-$(3)-$(1)-$(2): REF = tests/data/asynth-$(1)-1.wav
 endef
 
-fate-swr-resample_async-fltp-44100-8000: CMP_TARGET = 4031.48
+fate-swr-resample_async-fltp-44100-8000: CMP_TARGET = 4020.62
 fate-swr-resample_async-fltp-44100-8000: SIZE_TOLERANCE = 529200 - 20310
 
-fate-swr-resample_async-fltp-8000-44100: CMP_TARGET = 11185.34
+fate-swr-resample_async-fltp-8000-44100: CMP_TARGET = 11186.69
 fate-swr-resample_async-fltp-8000-44100: SIZE_TOLERANCE = 96000 - 20344
 
-fate-swr-resample_async-s16p-44100-8000: CMP_TARGET = 4031.59
+fate-swr-resample_async-s16p-44100-8000: CMP_TARGET = 4020.73
 fate-swr-resample_async-s16p-44100-8000: SIZE_TOLERANCE = 529200 - 20310
 
-fate-swr-resample_async-s16p-8000-44100: CMP_TARGET = 11185.65
+fate-swr-resample_async-s16p-8000-44100: CMP_TARGET = 11187.01
 fate-swr-resample_async-s16p-8000-44100: SIZE_TOLERANCE = 96000 - 20344
 
 $(call CROSS_TEST,$(SAMPLERATES),ARESAMPLE,s16p,s16le,s16)