lavf: allow BSFs to drop packets.

If pkt->size == 0 && pkt->side_data_elems == 0 after bsf->filter()
returns, the packet is considered dropped.

1 files changed, 2 insertions, 0 deletions

diff --git a/ffmpeg.c b/ffmpeg.c
index d1485888e8..25c9140a52 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -694,6 +694,8 @@ static void write_frame(AVFormatContext *s, AVPacket *pkt, OutputStream *ost)
         if (exit_on_error)
             exit_program(1);
     }
+    if (pkt->size == 0 && pkt->side_data_elems == 0)
+        return;
 
     if (!(s->oformat->flags & AVFMT_NOTIMESTAMPS)) {
         if (pkt->dts != AV_NOPTS_VALUE &&