X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fpngdec.c;h=b8011fea59108961aa98f58d4ecbadc4e5b3504f;hb=033144c0d13c6e83e128f1cd5e1d460be94bace0;hp=60c49758f101589dfed879626136bb846610f82c;hpb=f14fc55969d8662a7572ea5a3bc2fb151ea0d2ed;p=ffmpeg

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 60c49758f10..b8011fea591 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -851,13 +851,13 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
         cur_w > s->width - x_offset|| cur_h > s->height - y_offset)
             return AVERROR_INVALIDDATA;
 
-    if (sequence_number == 0 && s->dispose_op == APNG_DISPOSE_OP_PREVIOUS) {
+    if (sequence_number == 0 && dispose_op == APNG_DISPOSE_OP_PREVIOUS) {
         // No previous frame to revert to for the first frame
         // Spec says to just treat it as a APNG_DISPOSE_OP_BACKGROUND
-        s->dispose_op = APNG_DISPOSE_OP_BACKGROUND;
+        dispose_op = APNG_DISPOSE_OP_BACKGROUND;
     }
 
-    if (s->dispose_op == APNG_BLEND_OP_OVER && !s->has_trns && (
+    if (blend_op == APNG_BLEND_OP_OVER && !s->has_trns && (
             avctx->pix_fmt == AV_PIX_FMT_RGB24 ||
             avctx->pix_fmt == AV_PIX_FMT_RGB48BE ||
             avctx->pix_fmt == AV_PIX_FMT_PAL8 ||
@@ -865,8 +865,8 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
             avctx->pix_fmt == AV_PIX_FMT_GRAY16BE ||
             avctx->pix_fmt == AV_PIX_FMT_MONOBLACK
         )) {
-        // APNG_DISPOSE_OP_OVER is the same as APNG_DISPOSE_OP_SOURCE when there is no alpha channel
-        s->dispose_op = APNG_BLEND_OP_SOURCE;
+        // APNG_BLEND_OP_OVER is the same as APNG_BLEND_OP_SOURCE when there is no alpha channel
+        blend_op = APNG_BLEND_OP_SOURCE;
     }
 
     s->cur_w      = cur_w;
@@ -1283,6 +1283,7 @@ static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
         pdst->cur_h = psrc->cur_h;
         pdst->x_offset = psrc->x_offset;
         pdst->y_offset = psrc->y_offset;
+        pdst->has_trns = psrc->has_trns;
 
         pdst->dispose_op = psrc->dispose_op;