Change 4xm demuxer and video decoder to pass the video format version in

extradata instead of codec_tag.

Originally committed as revision 10253 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 6 insertions, 1 deletions

diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index 7af22c7963..83e1b92ec4 100644
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -789,7 +789,12 @@ static void common_init(AVCodecContext *avctx){
 static int decode_init(AVCodecContext *avctx){
     FourXContext * const f = avctx->priv_data;
 
-    f->version= avctx->codec_tag == 0x40000;
+    if(avctx->extradata_size != 4 || !avctx->extradata) {
+        av_log(avctx, AV_LOG_ERROR, "extradata wrong or missing\n");
+        return 1;
+    }
+
+    f->version= AV_RL32(avctx->extradata) == 0x40000;
     common_init(avctx);
     init_vlcs(f);