[vlc-devel] Fix for mms RESET packets

Gregory Hartman bap0se at adelphia.net
Thu Dec 15 15:29:31 CET 2005

I have been trying to use vlc to listen to Naxos Radio under Debian 
Sarge. I am using the shipped version of Firefox, VLC, and the Mozilla 
plugin. When I go to the site:

http://www.naxosradio.com and select a channel I hear music until the 
end of a song.

I noticed that I was getting an error:

invalid chunk FATAL (0x4324), so I did more investigation.

It turns out that this web site inserts an 8 byte packet at the end of 
each some with type 0x4324. This seems to correspond to CHUNK_TYPE_RESET 
in the MMS protocol.

VLC needs two modifications to continue to decode the stream:

1. It should recognize 0x4324 as a valid packet
2. It needs to avoid reading 12 bytes for the packet headers, since the 
reset packet is only 8 bytes

The sequence numbers appear to go back to 0 after this packet, but the 
code already handles this condition.

The attached patch against 0.8.4a fixes the problem. I also checked this 
against the most recent snapshot and it looks like the patch should 
still apply.

I don't know the MMS protool well. There may have been a reason for 
ignoring the length field and always reading 12 bytes of header data. If 
so the header reading modification should probably be made sensitive to 
the packet type.

Let me know if there is anything else that I need to do.

Greg Hartman
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