const char *ptr = avpkt->data;
const char *end;
- if (!ptr || avpkt->size <= 2)
- return avpkt->size ? AVERROR_INVALIDDATA : 0;
+ if (!ptr || avpkt->size < 2)
+ return AVERROR_INVALIDDATA;
+
+ /*
+ * A packet of size two with value zero is an empty subtitle
+ * used to mark the end of the previous non-empty subtitle.
+ * We can just drop them here as we have duration information
+ * already. If the value is non-zero, then it's technically a
+ * bad packet.
+ */
+ if (avpkt->size == 2)
+ return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;
/*
* The first two bytes of the packet are the length of the text string