swresample/resample: optimize exact_rational=on:linear_interp=on case

separate dsp.resample to dsp.resample_common and dsp.resample_linear
and choose to call faster resample_common even when linear_interp=on
when c->frac and c->dst_incr_mod are both zero

speed up resampling when exact_rational and linear_interp are both
enabled because exact_rational force c->frac and c->dst_incr_mod to
be zero when soft compensation does not happen

benchmark on exact_rational=on:linear_interp=on
        old     new
real    8.432s  5.097s
user    7.679s  4.989s
sys     0.125s  0.107s

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Muhammad Faiz <mfcc64@gmail.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/libswresample/resample_dsp.c b/libswresample/resample_dsp.c
index 41369f3f8a..6ffbb87766 100644
--- a/libswresample/resample_dsp.c
+++ b/libswresample/resample_dsp.c
@@ -48,19 +48,23 @@ void swri_resample_dsp_init(ResampleContext *c)
     switch(c->format){
     case AV_SAMPLE_FMT_S16P:
         c->dsp.resample_one = resample_one_int16;
-        c->dsp.resample     = c->linear ? resample_linear_int16 : resample_common_int16;
+        c->dsp.resample_common = resample_common_int16;
+        c->dsp.resample_linear = resample_linear_int16;
         break;
     case AV_SAMPLE_FMT_S32P:
         c->dsp.resample_one = resample_one_int32;
-        c->dsp.resample     = c->linear ? resample_linear_int32 : resample_common_int32;
+        c->dsp.resample_common = resample_common_int32;
+        c->dsp.resample_linear = resample_linear_int32;
         break;
     case AV_SAMPLE_FMT_FLTP:
         c->dsp.resample_one = resample_one_float;
-        c->dsp.resample     = c->linear ? resample_linear_float : resample_common_float;
+        c->dsp.resample_common = resample_common_float;
+        c->dsp.resample_linear = resample_linear_float;
         break;
     case AV_SAMPLE_FMT_DBLP:
         c->dsp.resample_one = resample_one_double;
-        c->dsp.resample     = c->linear ? resample_linear_double : resample_common_double;
+        c->dsp.resample_common = resample_common_double;
+        c->dsp.resample_linear = resample_linear_double;
         break;
     }