aacenc: make sure to encode enough frames to cover all input samples.

Currently, any samples in the final frame are not decoded because they are
only represented by one frame instead of two. So we encode two final frames to
cover both the analysis delay and the MDCT delay.

libavcodec/aacenc.c

@@ -510,14 +510,12 @@ static int aac_encode_frame(AVCodecContext *avctx,
     int chan_el_counter[4];
     FFPsyWindowInfo windows[AAC_MAX_CHANNELS];
 
-    if (s->last_frame)
+    if (s->last_frame == 2)
         return 0;
 
-    if (data) {
-        deinterleave_input_samples(s, data, avctx->frame_size);
-        if (s->psypp)
-            ff_psy_preprocess(s->psypp, s->planar_samples, s->channels);
-    }
+    deinterleave_input_samples(s, data, data ? avctx->frame_size : 0);
+    if (s->psypp)
+        ff_psy_preprocess(s->psypp, s->planar_samples, s->channels);
 
     if (!avctx->frame_number)
         return 0;
@@ -648,7 +646,7 @@ static int aac_encode_frame(AVCodecContext *avctx,
     }
 
     if (!data)
-        s->last_frame = 1;
+        s->last_frame++;
 
     return put_bits_count(&s->pb)>>3;
 }