avcodec/gif: fix disposal method for first frame and transparent gifs

Fixes #7902

diff --git a/libavcodec/gif.c b/libavcodec/gif.c
index e92dfa65d7c4bcf0610d222fc6b7fe51211a5df1..65a76cfde434f02f70d4deb26d33111bbfd4b477 100644 (file)
--- a/libavcodec/gif.c
+++ b/libavcodec/gif.c
@@ -267,7 +267,7 @@ static int gif_image_write_image(AVCodecContext *avctx,
     int bcid = -1, honor_transparency = (s->flags & GF_TRANSDIFF) && s->last_frame && !palette;
     const uint8_t *ptr;
 
-    if (!s->image && avctx->frame_number && is_image_translucent(avctx, buf, linesize)) {
+    if (!s->image && is_image_translucent(avctx, buf, linesize)) {
         gif_crop_translucent(avctx, buf, linesize, &width, &height, &x_start, &y_start);
         honor_transparency = 0;
         disposal = GCE_DISPOSAL_BACKGROUND;