bitrates,encoders and music could this be the reason liquidsoap to crash and take down airtime? - Airtime Development Discussions on Sourcefabric Forum

Voisses Tech · Post edited by Voisses Tech at 2013-06-20 16:10:23

One of the most annoying thing is when airtime appear to crashes and no indication why.

I narrowed my crashes to bad MP3 or bad input stream.

The test environment I use

Equipments and Operating systems

Ubuntu 12.04 LTS Server 32bits with 1Gb Memory (Airtime install no additional service installed)

For this I set up a machine with vlc and then use butt to send to Master or Show source separating my webstreams from audio file and this works fine
Using M3W where I could vary the bit rate.

I found that if I use a mp3 encoded at 192kbps and a webstream that is >= 128kbps

I found that liquidsoap never crashes when I restream talk radio =<64kbps

The Results

if I set the Airtime stream out at 96kps for a shoutcast stream and 96kbps for Icecast (liquidsoap crashes frequently and need restart)

if I set the Airtime stream out at 96kps for a shoutcast stream and 128kbps for Icecast (liquidsoap will not crash).

if I set the Airtime stream out at 128kps for a shoutcast stream and 128kbps for Icecast (liquidsoap will not crash).

please note that with the two last airtime stream the mp3 can be 128kbps,160kbps or 192kbps without any crash.

Conclusion

Relevant reading is found here http://savonet.sourceforge.net/doc-svn/encoding_formats.html the last paragraph

but http://savonet.sourceforge.net/doc-svn/external_encoders.html suggest

" The restart mechanism strongly relies on the good behaviour of the encoding process. The restart operation will close the standard input of the encoding process. The encoding process is then expected to finish its own operations and close its standard output. If it does not close its standard output, the encoding task will not finish.

If your encoding process has this issue, you should turn the restart_on_crash option to true and kill the encoding process yourself. "

Suggestions

Should we have to implement this syntax

%external(channels=2,samplerate=44100,header=true,
          restart_on_crash=false,
          restart_on_new_track,
          restart_after_delay=<int>,
          process="")

to ensure airtime liquidsoap to restart on a crash? any suggestion from developers or testers

or is this a bug? lets test and file bug report if necessary.

hoerich

Voisses Tech said:

Ubuntu 12.04 LTS Server 32bits with 1Gb Memory (Airtime install no additional service installed)

For this I set up a machine with vlc and then use butt to send to Master or Show source separating my webstreams from audio file and this works fine
Using M3W where I could vary the bit rate.
I found that if I use a mp3 encoded at 192kbps and a webstream that is >= 128kbps

I found that liquidsoap never crashes when I restream talk radio =<64kbps

For m3w I can underline your comment.
When streaming with m3w, i cannot use bitrates higher than 192kbps or buffers lower than 3sec in a LAN.
This seems to be a problem with m3w itself, because for me BUTT streams any bitrate upto 320kbps with no errors for over 300hrs in our LAN.

But I have to notice, that I use m3w and BUTT for different things.
m3w streams 192kbps as a Showsource directly to Airtime. (Used as a fallback workaround)
BUTT streams 256kbps to a different Icecast-Server in our LAN and is scheduled as Webstream. (Used as BBC-Rebroadcaster)
BUTT streams 128kbps as Mastersource when doing Live-Event-Shows from abroad.

Everything working fine in this constellation

So maybe rebroadcasting a Webstream works fine and this problem occurs only with Master- / Showsource?
I try to reproduce this on my teststation. I'm especially interested in the differences of using BUTT as Master- / Showsource encoding with 320kbps.

bitdevil

What you think about Edcast?
http://code.google.com/p/edcast-reborn/

Voisses Tech

Yes when encoding,users has to take in consideration the specs of the machine you use.

https://wiki.sourcefabric.org/display/CC/FAQ+and+Support at paragraph "I'm getting choppy audio, help!" are very important.for me the "2011/03/25 16:13:17 [clock.wallclock_main:2] We must catchup 11.60 seconds!" was so infrequent that I never notice them in the logs and the seconds was like less than 1secs.

Processor / Chipset

    Type Intel Celeron 2.4 GHz
    CPU Qty 1.0
    Max CPU Qty 1.0
    CPU Socket Socket 478
    Chipset Type Intel 845GV
    Front Side Bus 533.0 MHz

Cache Memory

    Installed Size L2 cache - 512.0 KB
    Cache Per Processor 512 KB

RAM

    Installed Size 1.0 GB

The Best with airtime running 24/7 I can get from this specs is running

Two streams   one at 96kbps(stereo) and another at 32kbps(mono) this is my monitor stream (currently in Use)

One stream at 128kbps (stereo or Mono).

Edcast and M3w are for windows.I try not to use desktop windows in production enviroment.they have too much instabilty.

Things to Do

Only tested M3w, not in my production use,I might try edcast reborn but I BUTT is the so reliable on both windows and Linux

Run A local out LAN Streamer/Server with relay with Icecast and ShoutCast. (hoerich setup)

Conclusion

In hoerich set up would it be better to use an ogg or AAC+ codecs which give better stream at lower rates ?

I will test the failsafe mention above

hoerich

Voisses Tech said:

In hoerich set up would it be better to use an ogg or AAC+ codecs which give better stream at lower rates ?

I currently only use ogg for streaming and I want to stream with the highest Quality available.
Since streaming is for me just an alternative for missing Hardware-Live-Inputs!

I work on MS-Servers since 1998, with Linux only for 2 years.
Our Win2003Srv at the station runs for years without any restart. Like in 75% of any corporation.
Our Ubuntu-Airtime is restarted once a month or week since we implemented it in March this year.
just my 2 cents about reliability...

hoerich

on Windows I also used edcast-reborn with no problems for weeks.
But I prefer BUTT, since it's also stable with a better GUI and less buttons. Perfect for dummy-users.

Voisses Tech

James harrison a rivendell user has develope software using the rasberry pi for remote broadcasting.
worthy of noting since airtime now support opus
found here.
https://github.com/JamesHarrison/openob

There is some nice article from him at http://www.talkunafraid.co.uk/2012/02/introducing-openob/

I am interested also about the OGG streamer .

The openob might be a cheaper alternative to a barix instreamer and extreamer

hoerich

I would also prefer opus, but where are clients supporting it?

The OggStreamer-Developer is a friend of mine.
I think he currently has 12 pieces in stock.

I also own a raspberry pi, but currently got no usage for it.
would love to use it for anything.

Albert FR

I'm agree with you Opus seems really good !
But for the moment no players/encoders are available for dummies...

yes i know VLC can encode/decode opus, but ...

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