diff --git a/libavcodec/wmalosslessdec.c b/libavcodec/wmalosslessdec.c
index 8fb08fb36d..e7c8266cf2 100644
--- a/libavcodec/wmalosslessdec.c
+++ b/libavcodec/wmalosslessdec.c
@@ -190,6 +190,16 @@ static av_cold int decode_init(AVCodecContext *avctx)
         return AVERROR(EINVAL);
     }
 
+    if (avctx->channels < 0) {
+        av_log(avctx, AV_LOG_ERROR, "invalid number of channels %d\n",
+               avctx->channels);
+        return AVERROR_INVALIDDATA;
+    } else if (avctx->channels > WMALL_MAX_CHANNELS) {
+        avpriv_request_sample(avctx,
+                              "More than %d channels", WMALL_MAX_CHANNELS);
+        return AVERROR_PATCHWELCOME;
+    }
+
     s->avctx = avctx;
     ff_llauddsp_init(&s->dsp);
     init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);
@@ -263,16 +273,6 @@ static av_cold int decode_init(AVCodecContext *avctx)
                 ++s->lfe_channel;
     }
 
-    if (s->num_channels < 0) {
-        av_log(avctx, AV_LOG_ERROR, "invalid number of channels %"PRId8"\n",
-               s->num_channels);
-        return AVERROR_INVALIDDATA;
-    } else if (s->num_channels > WMALL_MAX_CHANNELS) {
-        avpriv_request_sample(avctx,
-                              "More than %d channels", WMALL_MAX_CHANNELS);
-        return AVERROR_PATCHWELCOME;
-    }
-
     s->frame = av_frame_alloc();
     if (!s->frame)
         return AVERROR(ENOMEM);