aresample: increase n_out buffer size a bit to reduce delay in some corner cases

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

libavfilter/af_aresample.c

@@ -174,7 +174,7 @@ static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *insamplesref)
 {
     AResampleContext *aresample = inlink->dst->priv;
     const int n_in  = insamplesref->audio->nb_samples;
-    int n_out       = FFMAX(n_in * aresample->ratio * 2, 1);
+    int n_out       = n_in * aresample->ratio * 2 + 256;
     AVFilterLink *const outlink = inlink->dst->outputs[0];
     AVFilterBufferRef *outsamplesref = ff_get_audio_buffer(outlink, AV_PERM_WRITE, n_out);
     int ret;