After av_read_frame(), I wanted to queue up the packet.data directly into a
queue without copying. But it appears that this is not possible, since
ffmpeg re-uses the packet buffer when I call av_read_frame() again. I could
use av_dup_packet to make copies for those packets which need to be copied,
but not for others. But still, most packets need to be copied. Is there a
better way to configure ffmpeg to help in reducing copies?