avpacket: reset dst side_data fields in av_packet_copy_props

This effectively copies the side data elements from src instead of
potentially merging them with those already existing in dst.
This by extension also removes the only dependency on existing values
in the dst packet.

Reviewed-by: wm4 <nfxjfg@googlemail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
index 90b821592835e4285d18d006562194dc86742103..fe8113ab764553cdfded8dcb9cf814ff9e3652c4 100644 (file)
--- a/libavcodec/avpacket.c
+++ b/libavcodec/avpacket.c
@@ -571,6 +571,8 @@ FF_ENABLE_DEPRECATION_WARNINGS
     dst->flags                = src->flags;
     dst->stream_index         = src->stream_index;
 
+    dst->side_data            = NULL;
+    dst->side_data_elems      = 0;
     for (i = 0; i < src->side_data_elems; i++) {
          enum AVPacketSideDataType type = src->side_data[i].type;
          int size          = src->side_data[i].size;