diff --git a/libavcodec/jvdec.c b/libavcodec/jvdec.c
index 8acd50a45c..a8c3336ccc 100644
--- a/libavcodec/jvdec.c
+++ b/libavcodec/jvdec.c
@@ -142,7 +142,7 @@ static int decode_frame(AVCodecContext *avctx,
     buf += 5;
 
     if (video_size) {
-        if (video_size < 0 || video_size > avpkt->size) {
+        if (video_size < 0 || video_size > avpkt->size - 5) {
             av_log(avctx, AV_LOG_ERROR, "video size %d invalid\n", video_size);
             return AVERROR_INVALIDDATA;
         }
@@ -153,7 +153,7 @@ static int decode_frame(AVCodecContext *avctx,
 
         if (video_type == 0 || video_type == 1) {
             GetBitContext gb;
-            init_get_bits(&gb, buf, 8 * FFMIN(video_size, buf_end - buf));
+            init_get_bits(&gb, buf, 8 * video_size);
 
             for (j = 0; j < avctx->height; j += 8)
                 for (i = 0; i < avctx->width; i += 8)