avcodec/atrac3plusdec: consume only as many bytes as available

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

libavcodec/atrac3plusdec.c

@@ -384,7 +384,7 @@ static int atrac3p_decode_frame(AVCodecContext *avctx, void *data,
 
     *got_frame_ptr = 1;
 
-    return avctx->block_align;
+    return FFMIN(avctx->block_align, avpkt->size);
 }
 
 AVCodec ff_atrac3p_decoder = {