wmavoice: move overflow handling to common code.

[ffmpeg] / libavcodec / pngdec.c

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 36275ae43f58aff3b0ef2d0cdb1b00568838228a..2f8d266c2779ef3734af2b4f35e44c9a763fe878 100644 (file)
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -922,7 +922,8 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
         return AVERROR_INVALIDDATA;
     }
 
-    if (sequence_number == 0 && dispose_op == APNG_DISPOSE_OP_PREVIOUS) {
+    if ((sequence_number == 0 || !s->previous_picture.f->data[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
         dispose_op = APNG_DISPOSE_OP_BACKGROUND;