diff --git a/libavcodec/flicvideo.c b/libavcodec/flicvideo.c
index 157f0c31a7..5c66d225bc 100644
--- a/libavcodec/flicvideo.c
+++ b/libavcodec/flicvideo.c
@@ -178,7 +178,7 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
     int lines;
     int compressed_lines;
     int starting_line;
-    signed short line_packets;
+    int line_packets;
     int y_ptr;
     int byte_run;
     int pixel_skip;
@@ -277,7 +277,7 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
                     break;
                 if (y_ptr > pixel_limit)
                     return AVERROR_INVALIDDATA;
-                line_packets = bytestream2_get_le16(&g2);
+                line_packets = sign_extend(bytestream2_get_le16(&g2), 16);
                 if ((line_packets & 0xC000) == 0xC000) {
                     // line skip opcode
                     line_packets = -line_packets;
@@ -507,7 +507,7 @@ static int flic_decode_frame_15_16BPP(AVCodecContext *avctx,
 
     int lines;
     int compressed_lines;
-    signed short line_packets;
+    int line_packets;
     int y_ptr;
     int byte_run;
     int pixel_skip;
@@ -571,7 +571,7 @@ static int flic_decode_frame_15_16BPP(AVCodecContext *avctx,
                     break;
                 if (y_ptr > pixel_limit)
                     return AVERROR_INVALIDDATA;
-                line_packets = bytestream2_get_le16(&g2);
+                line_packets = sign_extend(bytestream2_get_le16(&g2), 16);
                 if (line_packets < 0) {
                     line_packets = -line_packets;
                     if (line_packets > s->avctx->height)