[vlc-devel] [RTP] timestamp decrease

[vlc at sosend.de]

Hi!

I am running vlc 0.9.6 here as video on demand server that serves
"`Big Buck Bunny"' [0] via RTSP.
The streaming performs well and I can watch the streamed movie.

But the RTP data packets of the videostream have wrong timestamps.
Here is the tcpdump output:

<tcpdump>
[ snip RTSP session setup with
     c96: H264/90000
     c97: mpeg4-generic/48000
]

264921 IP 192.168.108.23.59054 > 192.168.108.24.53902: udp/rtp 25 c97  
* 26034 3089794010
020999 IP 192.168.108.23.59054 > 192.168.108.24.53902: udp/rtp 279 c97  
* 26035 3089795034
018961 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 21 c96   
19066 1014206540
000012 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 8 c96   
19067 1014206540
000009 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 10 c96   
19068 1014206540
000010 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 10 c96   
19069 1014206540
000008 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 10 c96   
19070 1014206540
000009 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 10 c96   
19071 1014206540
000009 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 11 c96   
19072 1014206540
000010 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 11 c96   
19073 1014206540
000009 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 11 c96  
* 19074 1014206540
[ snipped two audio (c97) packets ]
019001 IP 192.168.108.23.54347 > 192.168.108.24.64270: udp/rtp 21 c96   
19075 1014202791
                                                                        
        ^^^^^^^^^^
</tcpdump>
The sequence number is incremented (to 19075) but the timestamp has decreased
(to 1014202791) for payload type 96!
This only happens for the video stream.  The audio RTP packets are OK.

Is this bug located within VLC oder within the live555 RTP layer?

Thanks in advance,
Martin


[0] http://www.bigbuckbunny.org/index.php/download/