Realtime Streaming # Urgent #

[roli8200]

Hello

Currently I notice that streaming from dv or v4l generates delays from about 1-2 seconds. I tried all options about caching. Currently my caching settings are:

Stream server side
v4l-caching=95
dv-caching=10
file-caching=1280 (dvgrab - |vlc - ...)

Client side
http-caching=10

If I set the caches lower than these settings the caching server continuous looses frams or cannot prefill the buffer. But the current project is for full resolution video conferencing and 2 seconds delay it definitly to much. Are there some experts who can advise me to reduce the delay to around 1/2 second. Recompiling etc. is not the problem but I should have a solution.

I currently use a brand new Pentium D 3 Ghz. Are there hardware types which are faster for this job? Is it possible to use hardware encoder (cards) to boost ffmpeg etc?

Many thanks for all Your help

Roland Kaeser

[wlarsong]

What protcol are you streaming out with Http: or UDP or mms. UDP can eliminate buffer fillers because it is a burst protocol. Http has to wait to fill then send so it sounds like you are using http to stream out. If you need help on UDP let me know.

[roli8200]

Hello

Yes any help on udp streaming whould be welcome. Currently I always stream in http because I couldn't get udp running. Every time when I try to stream udp it gives me errors about rejected packages from the other machine. Can You tell me what I have to make diffrent to transmit udp streams because the only streaming currently I get to run is http streaming.

Many thanks

Roland

[wlarsong]

Alright for a simple UDP do this...

I am not sure what OS you are on so i am just going to give a generic explanation.

Alright lets assume you are within a LAN:

Server IP for example:10.0.0.2
Client: 10.0.0.3

On the Server
Find the File/Output Source, on stream out select UDP protocol, enter the client machines IP address (10.0.0.3) Select your trans code options and hit ok

On the Client
Open Network Stream, Select UDP port 1234 ( 1234 is default for VLC). and Volia you have a low overhead protocol stream.

You can now go into the preferences and adjust the cacheing times.

UDP has NO packet guarentee built in the protocol so it will send thing in bursts and doesn't care about order so I you jack the Stream up too high you will get pixilated/distorted pictures.

But UDP is a great protocol to move a lot of data quickly.

Also I prefer the DIV3 codec for streaming out, as of Verison 0.8.4 mpv4 would freeze my machine client side after a few minutes DIV3 no such problems.

Let me know if you need more help

[roli8200]

Hello

Tried it with:

/opt/vlc/bin/vlc -v v4l:/dev/video:norm=pal:channel=1:size=720x576:adev=/dev/audio:audio=0 --sout '#transcode{vcodec=mp4v,acodec=mp3,vb=1524,ab=128}:standard{access=udp,mux=ts,dst=192.168.1.111:1234}'

on the serverside and

vlc udp:192.168.1.82@192.168.1.111:1234

The cache settings are

server: sout-udp-caching=10, v4l-caching=80
client: udp-caching=0

So I get a picture on the client computer But the delay remains.

But was I noticed is that I get a log of these error messages:

[00000309] main private warning: late buffer for mux input (2940)
[00000309] main private warning: late buffer for mux input (19173)
[00000309] main private warning: late buffer for mux input (10348)
[00000309] main private warning: late buffer for mux input (13910)
[00000309] main private warning: late buffer for mux input (15480)
[00000309] main private warning: late buffer for mux input (1255)

So it seems very strongly to me that it is a matter of the vl4-transcoding and the performance on the machine.

Is it possible to stream the raw vl4 content or raw1394 content directly over udp without recoding it?