avfilter/af_asetnsamples: add missing error check

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavfilter/af_asetnsamples.c

@@ -140,11 +140,14 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *insamples)
             return -1;
         }
     }
-    av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples);
-    if (asns->next_out_pts == AV_NOPTS_VALUE)
+    ret = av_audio_fifo_write(asns->fifo, (void **)insamples->extended_data, nb_samples);
+    if (ret > 0 && asns->next_out_pts == AV_NOPTS_VALUE)
         asns->next_out_pts = insamples->pts;
     av_frame_free(&insamples);
 
+    if (ret < 0)
+        return ret;
+
     while (av_audio_fifo_size(asns->fifo) >= asns->nb_out_samples)
         push_samples(outlink);
     return 0;