dont check buffer size if the decode function wont be called at all

Originally committed as revision 8090 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/utils.c

@@ -894,6 +894,7 @@ int avcodec_decode_audio2(AVCodecContext *avctx, int16_t *samples,
 {
     int ret;
 
+    if((avctx->codec->capabilities & CODEC_CAP_DELAY) || buf_size){
         //FIXME remove the check below _after_ ensuring that all audio check that the available space is enough
         if(*frame_size_ptr < AVCODEC_MAX_AUDIO_FRAME_SIZE){
             av_log(avctx, AV_LOG_ERROR, "buffer smaller than AVCODEC_MAX_AUDIO_FRAME_SIZE\n");
@@ -905,7 +906,7 @@ int avcodec_decode_audio2(AVCodecContext *avctx, int16_t *samples,
             av_log(avctx, AV_LOG_ERROR, "buffer %d too small\n", *frame_size_ptr);
             return -1;
         }
-    if((avctx->codec->capabilities & CODEC_CAP_DELAY) || buf_size){
+
         ret = avctx->codec->decode(avctx, samples, frame_size_ptr,
                                 buf, buf_size);
         avctx->frame_number++;