[Live-devel] H.223 for video streaming

[paolo passeggieri]

Hello,

I'm just working on the Video Call using this new
mobiles are supporting the H.263.

I fetch the video streaming exchanged between 2
different mobiles and I got a different situation!

According the standard explaining h.223, the protocol
to set up the channels (video, data and speech), there
is an HEADER in front of every MUX-PDU, and according
the spec is H'E1 H'4D. (Spec H.223 Chapter A.2.1.1)

One of those streams was according the spec, and I
managed to decode.

I got the problem with another stream using for HEADER
H'87 H'B2 and making a comparison with the previsious
I realized that every octect is 7 bit cyclic shifted, 

I mean H'87 -> 1000 0111 ---shifted is 1110 0001
->H'E1

It sounds like the mobiles considered the bit
transmitted using different MSB and LSB.

If could you help me to find a solution to convert the
file in the first format I'd very gratefull.

Paolo


	

	
		
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