diff --git a/libavcodec/ra144enc.c b/libavcodec/ra144enc.c
index e0fb827..bc1d82c 100644
--- a/libavcodec/ra144enc.c
+++ b/libavcodec/ra144enc.c
@@ -57,6 +57,10 @@ static av_cold int ra144_encode_init(AVCodecContext * avctx)
                avctx->channels);
         return -1;
     }
+    if (avctx->sample_rate != 8000) {
+        av_log(avctx, AV_LOG_ERROR, "only 8kHz sample rate is supported\n");
+        return -1;
+    }
     avctx->frame_size = NBLOCKS * BLOCKSIZE;
     avctx->delay      = avctx->frame_size;
     avctx->bit_rate = 8000;