Wireshark-users: Re: [Wireshark-users] how to measure MDI (media delivery index) and bandwidth wi
On Tue, May 12, 2009 at 3:54 AM, Haitham Al-Saif
<haithamfares81@xxxxxxxxx> wrote:
Hi I want to know whether I can measure (media delivery index) and
bandwidth with tshark. I'm runing tshark on embedded linux to analyze
MPEG transport stream. I know how to find jitter, delay and packet loss
using tshark. but now I want to detect the bandwidth and MDI too. to
analyze the MPEG transport stream I use the following command for tshark
tshark -i eth0 -a duration:15 -d udp.port==1234,rtp -z rtp,streams. can anyone tell me please how I can detect MDI and bandwidth with tshark?
You're not analyzing the MPEG transport stream with that command. More accurately, you're analyzing an RTP flow. That is, you're not delving into the MPEG frames, only the RTP header.
In order to determine MDI you must break down the individual MPEG frames within the RTP payload and study both the PID and the Continuity Counter in the MPEG_TS header (not all PIDs count toward MDI). MDI is defined, albeit poorly, in RFC 4445.
The Wireshark MPEG_TS dissector works well in versions greater than 1.04 and can produce both those values (mp2t.pid, mp2t.cc), you likely need to parse and interpret the output of tshark, however, since there is some logic and arithmetic involved.
--
-jp
Most of the time it was probably real bad being stuck down in a dungeon. But
some days, when there was a bad storm outside, you'd look out your little
window and think, ``Boy, I'm glad I'm not out in THAT.''
deepthoughtsbyjackhandey.com
