diff --git a/libavcodec/gsmdec.c b/libavcodec/gsmdec.c
index f51a083085..3e1b86a981 100644
--- a/libavcodec/gsmdec.c
+++ b/libavcodec/gsmdec.c
@@ -37,7 +37,8 @@ static av_cold int gsm_init(AVCodecContext *avctx)
 
     avctx->channels       = 1;
     avctx->channel_layout = AV_CH_LAYOUT_MONO;
-    avctx->sample_rate    = 8000;
+    if (!avctx->sample_rate)
+        avctx->sample_rate = 8000;
     avctx->sample_fmt     = AV_SAMPLE_FMT_S16;
 
     switch (avctx->codec_id) {