Merge commit '796dca02'

* commit '796dca02':
  alac: do not return success if nothing was decoded

See e11983bdMerged-by: Clément Bœsch <u@pkh.me>

libavcodec/alac.c

@@ -460,7 +460,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
                avpkt->size * 8 - get_bits_count(&alac->gb));
     }
 
-    if (alac->channels == ch)
+    if (alac->channels == ch && alac->nb_samples)
         *got_frame_ptr = 1;
     else
         av_log(avctx, AV_LOG_WARNING, "Failed to decode all channels\n");