diff --git a/libavcodec/parser.c b/libavcodec/parser.c
index d25d261acd..2c8fc69047 100644
--- a/libavcodec/parser.c
+++ b/libavcodec/parser.c
@@ -141,6 +141,8 @@ int av_parser_parse2(AVCodecParserContext *s, AVCodecContext *avctx,
     int index, i;
     uint8_t dummy_buf[AV_INPUT_BUFFER_PADDING_SIZE];
 
+    av_assert1(avctx->codec_id != AV_CODEC_ID_NONE);
+
     /* Parsers only work for the specified codec ids. */
     av_assert1(avctx->codec_id == s->parser->codec_ids[0] ||
                avctx->codec_id == s->parser->codec_ids[1] ||