[Libav-user] ffmpeg version 3.4 (Cantor) behaviour

[Francesco, Cuzzocrea]

Hi
inserting latest library version (ffmpg 3.4 "Cantor") in my code, I 
noticed a significant change in encoding behavior mainly in using MPEG2 
codec
at 50 Mbit. The same code that works fine with previous versions, in 
these latest didn't work as before.
Fist change:
In previous version assigning a buffer to the packet the encoded frame 
was put in it avoiding to allocate packet buffer. In latest versions
the packet is allocated regardless of pkt->data field.  Reading the code 
I didn't find any flag that restore previous behavior.
There is a way to restore it ?

Another great change is that allocated packet is of constant size 
excluding first 2  times the got_packet flag is set ( I'm using
gop_size=12 and max_b_frame = 2) and the buffer is mainly zero. Like if 
the pkt->size now indicate buffer size and not
output size.   Again: there is away to restore previous behavior ? How 
can I detect effective compressed frame size ?

regards
Francesco