My Digilite test and aligment with Tutioune

[F6DZP]

Since 3 years, I very often work in multicast mode inside my schack for DATV transmission.
That allow me to use sometimes one PC for DV or HDV capture or HDMI capture and coding in Mpeg2 or H264 muxed in a TS and multicast the stream
another PC for webcam, webcam 3D acquisition/coding and mux in TS
on another PC I can capture the part of the PC-screen when I want to explain in real time how to use a software, coding and muxing in a TS ready to be sent on the air
... another PC for DVB reception with Tutioune and multicast the stream...
Finally, on the PC used for transmission I can receive all streams multicasted and eventually remux them before sending to my DVB modulator...
On each PC I can start a VLC and look/verify each stream running on my local network.
on a same PC multicast is often used to send any stream from one application to another
( for example TSreader or many more powerful TS analyzer receive and analyze my streams using a multicast address/port)
Multicast is a natural need when we use streams.
When we broadcast a stream we don't need to know to which PC or station we do it, just send to the local network.
some time I use multicast with only using a single PC, never mind to know where to send, the stream will be disposable anywhere on my network for any UDP receiver, I don't always know which it will be in my next use...
UDP implies quickly Multicast (or Unicast If I use Internet = external IP like when we are sending a stream between F50E0 house and mine house)

I can't imagine than you add UDP mode to Digilite Transmit if it is not for multicast use.

Jean Pierre F6DZP

[F6DZP]

For those that can read some French like you, you can find a presentation I have made about use of Multicast for DATV in a ATV meeting Montpellier 2010 here:
http://www.vivadatv.org/viewtopic.php?f=56&t=18

Jean Pierre F6DZP

[G4EWJ]

Thanks, that was useful.

I have modified DL Transmit to treat the UDP Sender IP as a multicast address if it falls in the range 224xxx-239xxx. I am running GraphEdit + PVRUSB + UDP sender on 2 PCs using multicast addresses 230.0.0.1 and 230.0.0.2 and I can make DL Transmit choose either stream by putting the multicast address in DL Config.

You mentioned NICs. To select the required network card, do you prefer to use the MAC of the network card or the IP address it has been assigned? I assume the MAC, as the IP address may change

Brian

[F6DZP]

Wonderful news!

You are making a great job and it will open enormous possibilities for future applications.

To select the network card, all softwares I know use always IP address, never MAC

Jean Pierre

[F6DZP]

Take care to make tests on your stream in realtime to look at jitters that UDP transmission can introduce. I don't know what tools you have to analyze these characteristics.

Jean Pierre

[G4EWJ]

>>To select the network card, all softwares I know use always IP address, never MAC

That makes it easier.

One strange thing: I cannot open the (PS) multicast stream with VLC. Nothing happens. 127.0.0.1 is OK.

Brian

[F6DZP]

I have just tested my DV camera connected to IEEE 1394 input with VLC broadcasting UDP with the 2 methods:

PS encapsulated ==>
:sout=#transcode{vcodec=mp2v,vb=3000,fps=25,scale=1,acodec=mpga,ab=128,channels=2,samplerate=44100}:udp{mux=ps,dst=230.0.0.1:1234} :no-sout-rtp-sap :no-sout-standard-sap :ttl=1 :sout-keep


TS encapsulated ==>
:sout=#transcode{vcodec=mp2v,vb=3000,fps=25,scale=1,acodec=mpga,ab=128,channels=2,samplerate=44100}:udp{mux=ts,dst=230.0.0.1:1234} :no-sout-rtp-sap :no-sout-standard-sap :ttl=1 :sout-keep

Both work well, I can look at video with a second VLC set on this UDP address.

Only second method can be received and analyzed by TSreader - normal, TSreader accepts only TS encapsulation

I have never tried before to multicast PS or see a tool multicasting PS. always found TS multicast.

But I have just tested to tell you how it works at home. No problem for VLC to receive PS via UDP address, but all others software I use for analyzing refuse PS, only work with TS.

If you look at VLC menu, when we choose to Broadcast via UDP, the menu selection says "VLC transcodage = Video – MPEG2 + MPGA (TS)" with TS at the end, even if we change setup to PS encapsulation.
I think broadcasting PS over IP is not a "normal ' use.
I have found this document for example:
http://www.vbrick.com/docs/VB_WhitePape ... am_rd2.pdf

Jean Pierre F6DZP

[G4EWJ]

I am using PS for the UDP testing, as I cannot easily generate TS at the exact rate, but the transmission method is the same.

I found that I have to put @ in front of the address for a multicast stream and then VLC will play it.

udp://@230.0.0.1:1234

Does VLC work with any port other than 1234?

Brian

[F6DZP]

yes you need the @ . VLC is not very explicit on that.

UDP IP address use class D address = 1110bbbb = 1110 0000 to 1110 1111 (224.0.0.0 to 239.255.255.255)
port can be any value, but we can find some values that are known for some application
53 : DNS request
69 : TFTP
137 : NetBios serviceName
138 : NetBios Datagram Service
161 : SNMP

I use 1234 because it's free and easy to hit on keyboard....

Jean Pierre

[F6DZP]

"I cannot easily generate TS at the exact rate"
If you look at my description:

http://www.vivadatv.org/viewtopic.php?f=27&t=16

You will see how you can create the exact rate Value for your TS

It's like that I do to send TS directly to my DTA107 modulator, with the exact rate value.
(capture is made with my DV camera connected to my PC firewire input.

Jean Pierre