parser: add av_assert1 to make sure the codec matches

Otherwise this can have some surprising effects (crashes), so let's
better not allow it.

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>

libavcodec/parser.c

@@ -141,6 +141,13 @@ int av_parser_parse2(AVCodecParserContext *s, AVCodecContext *avctx,
     int index, i;
     uint8_t dummy_buf[AV_INPUT_BUFFER_PADDING_SIZE];
 
+    /* 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] ||
+               avctx->codec_id == s->parser->codec_ids[2] ||
+               avctx->codec_id == s->parser->codec_ids[3] ||
+               avctx->codec_id == s->parser->codec_ids[4]);
+
     if (!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
         s->next_frame_offset =
         s->cur_offset        = pos;