[Solved] What multimedia player for RTP protocol with manual SDP insertion?

[Yansi]

Hello,

do you know of any multimedia player application (for Windows, preferably), that could play an RTP stream, but manually inserting the SDP data (stream parameters)?

I thought of a well known VLC media player, the famous traffic cone, but it seams, that it is lost without RTSP.  I do not want RTSP. For testing purposes, it'd be handy to have a player capable of receiving RTP data, while being able manually set the stream parameter (enter SDP descriptor) - i.e. entering the number of channels, sample rate, etc.

The "payload type" field on its own in the RTP packet is not explicit enough for the RTP stream to be interpreted and played.

Thank you for any hints & tips, how to debug a RTP streaming device.
Y.

[Marco]

Are you quite sure VLC can't simply open SDP extension files to load RTP streams?

[Yansi]

Not sure at all. How would you open an "extension SDP file"?

Imagine, I have a device producing (only) an RTP stream, with no other protocol containing the required SDP. So I need to constraint the stream manually, to be able to play it correctly (at all).


//EDIT: Well, wait a moment: Will VLC eat a *.sdp text file from a local disk directly? That would probably help a lot too!

[Yansi]

Ok! I have verified, VLC can eat and play a stream constrained using SDP file.

I have put just this into a text file with SDP extension:

Code: [Select]

v=0
c=IN IP4 239.0.0.1
m=audio 5004 RTP/AVP 10

This works great, however what doesn't is the VLC streaming function itself.  When testing an RTP audio stream (payload type 10, the "L16 Stereo 44100Hz" using the VLC's "Audio-CD" streaming profile), VLC produces a stream with a LOT OF missing packets.

The resulting audio (when received) was sounding very choppy with occasional longer pauses (hundreds of ms of data missing). Investigation with Wireshark shows a lot of packets missing. When following the RTP stream "sequence number", on about every tenth number there is a missing packet.  And it is not a network problem, it does it even when streaming unicast between two computers on a straight piece of cable, or even when streaming from localhost to localhost. I get missing packets.

Now I am quite confused, as if there is a problem with my computer, or if the current version of VLC is so uselessly buggy (I found other issues within minutes). 

Any ideas? Shall I report this as a bug? What other can be tested? (apart from trying a different computer to stream from)

[Yansi]

Well, not a bug in VLC,  a feature of Windows instead. 

I have summarized the solution here:

https://superuser.com/questions/1472275/rtp-streaming-using-vlc-getting-huge-transmit-udp-packet-loss-on-my-pc-why/1472521