Howdy forum folks,

A little background, I have a lot of audio engineering experience, and a little audio streaming experience.  I was involved in a streaming project that operated with CentovaCast software (Icecast 2) for about 7 months with no issues, for whatever that’s worth.

I’ve recently tried to launch a new streaming project, so I purchased precisely the same streaming product I’d had before, with the same host, same gear, only this time, intermittent issues have plagued me from the start.

I’m on Mac OS and have been using Nicecast (later trying Ladiocast).  We have a Comcast cable modem with d/l speeds of over 100 mbps and upload of around 12 mbps.  The modem feeds a wireless router (and I’ve tried 2, a Linksys EA7500 v2 and an Apple AirPort Extreme).

I first experienced a series of server shut-downs - the host told me I was ‘over streaming’, 256 kbps to a 128 kbps account. I couldn’t find the source of this alleged data doubling.. I tried reducing the Bitrate to 64 kbps.. I tried mono vs stereo, never could get a stable stream going, tech support could only tell me the problem was ‘on my end’, and I eventually decided to switch hosts. 

With the second host, I haven’t had any server shutdowns, but instead will stream successfully for 10 to 30 minutes, then start getting intermittent ‘blinks’ of AutoDJ content.  Usually after that, I’ll hear some streamed audio that skips forward, sort of like scanning a digital file, interruptions in the audio, etc.  I never lose connection to the server, it doesn't shut down, but the stream is full of glitches and errors.

The host suggested these fixes (none of which worked):

• Changing bitrate to 64 kbps
• Switching from Icecast to Shoutcast (which we did.. they set up a different account for me)

I tried these things which had no effect:

• Streaming from 2 different computers, one ethernet cabled to the wireless router, one on wi-fi
• Swapping wireless routers (from Linksys to the Airport mentioned above)
• Using a different streaming client, Nicecast, then Ladiocast
• Adjustments to the internal computer audio (44.1 kHz and 48 kHz)
• Different bitrates, sample rates and channel formats in the streaming clients.

The results remain the same.  I have no idea what else I can or should change.  I’ll reiterate that I did in fact stream successfully from this location using this gear in this configuration for the better part of a year.  Anyone have any idea what the issue might be?

Thanks much in advance for the assistance!

I'll also add that I can stream via the Nicecast internal server, listen to the stream over the internet and it works fine. 

Hello Ray,

The bit-rate exceeded issues is probably because you are using VBR instead of CBR in your encoding settings, either that, or you are really just setting the wrong value for the bit-rate.

As for the intermittent connection between your source program and streaming server. This kind of issues are usually the result of packet-loss, which in turn is the result of either network congestion, or your ISP throttling traffic between you, and the machine where your station is being hosted.

You can use a program like mtr (or winmtr for windows), to measure packet loss and see the point at which is occurring.


Regards.

Thanks very much for the info Roger.  I have been streaming at a constant bit rate, so that's not it... I'll check the app you mention and see what I can determine, thanks again!

Haven't used MTR before, but I'm getting the gist.  I'm streaming to an IP address.. which I ran a WHOIS query on, located the host and location.  I ran MTR, there are 15 hops, on 6 of those I'm seeing packet losses of.3 to .4%.  I don't know what the relative impact of this is on a 128 kbps stream.

The server is located in France, and I'm in the Southeast USA. 

Does this indicate the kind of interference that could consistently tank a stream?

For what it's worth, here's another test's results

Host                                                                   Loss%   Snt   Last   Avg  Best  Wrst StDev
 1. 10.0.2.1                                                             0.0%   211    0.4   0.3   0.2   0.5   0.0
 2. 96.120.4.49                                                          0.0%   211    8.2   9.3   7.5  22.3   2.2
 3. xe-9-3-0-sur01.y3canton.ga.atlanta.comcast.net                       0.0%   211   10.1  13.7   5.8  53.8   7.2
 4. ae-70-ar01.b0atlanta.ga.atlanta.comcast.net                          0.0%   211   10.4  12.7   7.5  44.0   5.4
 5. be-7725-cr02.56marietta.ga.ibone.comcast.net                         0.5%   211   12.8  12.9   7.3  23.8   1.6
 6. be-10614-cr01.chicago.il.ibone.comcast.net                           0.0%   211   29.9  31.1  26.0  40.2   1.7
 7. be-10506-cr02.350ecermak.il.ibone.comcast.net                        0.9%   211   31.9  31.0  25.6  40.6   1.8
 8. be-10563-pe01.350ecermak.il.ibone.comcast.net                        0.0%   211   32.4  30.0  27.9  38.8   2.0
 9. be100-153.chi-5-a9.il.us                                             0.0%   211   29.3  30.3  27.5  49.6   2.6
10. ?
11. ?
12. vl1305.rbx-d2-a75.fr.eu                                              0.0%   211  116.7 117.7 114.0 126.9   1.6
13. ?
14. ?
15. quasar.shoutca.st                                                    1.0%   210  114.8 115.5 113.2 257.8  10.1

You sent 211 packets and your Stream Host received 210 packets, which is good.  But there is a 1% loss at the final hop, not real bad.

However, the average time is 114.8 ms and the worst is 257.8 ms at the Stream Host end.

So, it takes about 1/4 of a second to receive your signal, worst case and about 1/8 of a second best case.  Going from the US to Europe is (don't quote me) usually about 170 ms from West Coast US and about 90 ms from the East Coast US.  The lower the latency (ping time) the better the signal and less buffering.  At higher speeds like 128 kbps and above, you should keep it under 100 ms to avoid buffering.

So, bottom line, is you should find a Stream Host that is closer to your PC.  If you are in the US, find a host in the US.  If you are in Europe, find a EU host.   The lower the latency, the better the signal and less buffering you will have.  Also a high latency (over 100 ms) will cause the signal to 'drop and re-buffer'.  I'm sure that this is what is causing you to get dumped at speeds of 128 - 256 kbps. 

PS - Not real sure why Centova pulled my original post.  I'm not selling or promoting anything, just trying to help you out.

Thanks for the analysis Dennis - I appreciate it very much.  I think this host actually has servers in TX, so maybe I can get my account set up on one of those. 

Cheers,
Ray

I switched hosts to a company with servers in St. Louis.. everything works exactly as it should, so in the first case where I was informed I was 'double streaming', I have serious doubts as to whether that could have been the issue.  In the second case, latency appears to have been the problem. 

Thanks for the help here.. very informative!

You're welcome, glad I could help.