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--- pcap_to_ts [2016/12/14 21:44] – walkeradmin
+++ pcap_to_ts [2023/03/09 22:35] (current) – external edit 127.0.0.1
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 ====== PCAP to TS ======
+<color orange>Capture and Convert MFEL streams</color>
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-<color red>This page is incomplete</color>
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 Sometimes it is useful to capture the video streams we are generating (or someone else is generating) that are present on the network. Using a Dektec is useful here, however we don't always have the opportunity to use an analyser.
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-==== Using tcpdump ====
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+----
+==== Using tcpdump to create .pcap files ====
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 tcpdump is a tool to capture IP Packets at a command line level, its similar to the PCAP used by Wireshark (Wireshark is just a GUI to control PCAP). I say just a GUI, its rather good and saying it is 'just' a GUI is a little harsh.
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     The format for tcpdump is - tcpdump -i <interface> -s 65535 -w <some-file>
     tcpdump -i eth2 -B 64000 dst host 239.0.12.1 and port 1234 and multicast -w /home/ts_capture_test.pcap
+    Example:
+    tcpdump -i eth2 -B 64000 dst host 239.0.100.1 and port 1234 and multicast -w /home/hd_tennis_10Mbs.pcap
     if the syntax is correct, the tcpdump will start:
     tcpdump: listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
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+----
+==== Convert .pcap to .ts ====
+<color red>This is done on your computer, not on the MFEL</color>
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+Having created a .pcap file means we have all of the information we need to replay and analyse any captured stream. However before we access the stream we need to extract the Transport Stream from the .pcap file and save it as a .ts.
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+There is a tool available called <color red>Extractor.exe</color> that we can use to extract the TS from the .pcap file.
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+Download the extractor file here {{ :extractor.zip |}}
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+Before we extract the TS data, we need to know what the <color red>original multicast</color> details are (multicast:port) as we will need these for the extractor to work. If you know these details then fine, if not you may need to open the .pcap file in Wireshark to work out the exact multicast and port.
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+To use the extractor, use the following syntax:
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+    extractor source_file.pcap output.ts multicast port
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+If I have a source file called <color red>mfel.pcap</color> and I want to extract this to <color red>mfel.ts</color>, assuming the original multicast details are 239.0.12.1:1234 then my command line will be:
+\\
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+    extractor mfel.pcap mfel.ts 239.0.12.1 1234
+    If successful then you will see an output
+    SkyStream Networks sniffer-to-MPEG Extractor Utility
+    Built May  5 2005 11:29:37
+    File had 119658 packets, 119658 extracted
+\\
+The number of packets will change of course, but you should now have an extracted TS file.
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+<color red> When using tcpdump, after capture you will get a packet count, when using extractor the packet count should be around the same, if not then the extract did not do the entire file.</color>
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+----
+==== And Finally... ====
+See the FFMPEG section where you can convert .ts files to .mpg files (great for converting captures for replay on TVs via USB).[[ffmpeg|FFMPEG]]