Hello,
I sniffed some RTP-Dynamic Packets from a Webcam
Session between me and a friend.
I Selected "Decode As" --> RTP on the RTP
Packets. In "Statistics" -> "RTP" -> "Show all streams" I see 4 Streams.
2 Streams are Payload Type 121 the other 2 Streams are Payload Type
118.
I uses "save payload as" to save the Payload of
the 4 streams. I always saved only the forward direction.
Someone Told me that the new MSN Messenger uses
now the VC1 Codec and not longer the ml20.
I renamed the Payload Files to *.vc1. Now ffplay
can play the stream Files with payload Type 121. But it can´t play the stream
with Payload Type 118.
The Stream Files with PT 121 are playing very
very fast. The Framerate is to high. And only the upper half of the video will
be correcty displayed. The lower half is only a color and pixel
mixture.
I Used a Hex Editor and removed the following
Character Chains from the File. "CC000000" "DC000000" and "DF000000". These 3
Character Chains are very often in this file. I Used the "replace with"
feature from my Hex Editor.Now i can see the
lower half of the Video File too, but it runs still to fast.
Theres the Character Chain "CF000000" in the
File, too.But if i delete this, ffplay is unable to play the Video
File.
It seems, that there are only a Type of Key
Frames in the PT 121 Video Stream. Perhaps theres the rest of the Video in the
PT 118 stream.
Does anyone know, how to combine this 2 Streams
to one Videofile ?
Is MSN 2009 Really using VC-1 for Webcam sessions
?
Greetings
Chris
