[Live-devel] RTP packets duplication after a PAUSE/PLAY

[Ross Finlayson]

> On Jan 20, 2022, at 8:51 PM, BENMOUSSA Yahia - Contractor via live-devel <live-devel at us.live555.com> wrote:
> 
> 
> From: BENMOUSSA Yahia - Contractor <yahia.benmoussa at external.thalesgroup.com>
> Subject: RTP packets duplication after a PAUSE/PLAY
> Date: January 20, 2022 at 8:51:26 PM GMT+13
> To: "'live-devel at lists.live555.com'" <live-devel at us.live555.com>
> 
> 
> Hi Ross,
>  
> We have observed a strange behavior in media server starting from version 2021.05.22. 
>  
> After sending a PAUSE/PLAY command, the RTP packets are duplicated. Actually, the wireshark trace shows that each RTP packet is sent twice with the same payload and sequence number.
>  
> If we send another PAUSE/PLAY commands within the same session, the RTP packets are then duplicated 3 times and so on ...
>  
> It seems that it is a true packet duplication since the bandwidth usage increases after each PAUSE/PLAY commands.
>  
> This issue  can be reproduced using ffplay and the last version of live555MediaServer.

I wasn’t able to reproduce this using “live555MediaServer” and VLC as the client.  I suspect that the problem is “ffplay”; it’s not a very good RTSP client implementation.  I suspect that it’s not really sending a RTSP “PAUSE” command, but is sending a new RTSP “PLAY” command each time it resumes, which will produce the duplicated stream.


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/