Sample rate for Icecast introduction file

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RickZed

New Member
We are experimenting with Icecast for community talk radio ...
Bit rate: 32 kbits/s
Sample rate: 22.05 kHz

It's working exactly as we hoped, with butt as source software.

However, we have noticed a strange and unwelcome effect if we use our short introduction MP3 file - which was recorded with butt, and the same bit rate and sample rate as the server ...

After the intro file has finished, and the server switches to the source, the relayed stream slows down so that there are long gaps between almost every word. If we remove the intro file and restart the server, everything is OK again.

It's almost as if the intro file resets the bitrate or sample rate of its own accord.

What can we do about this?

Cheers :)
 
Support

Support

Level 1 Support
Staff member
We think this is possibly caused by using a bitrate of 22.05 khz.

Have you tried using a bitrate of 32 kbps with a samplerate of 44.1 khz?
 
R

RickZed

New Member
Support said:
We think this is possibly caused by using a bitrate of 22.05 khz.
Click to expand...
You mean sample rate 22.05 khz?
I know 44.1 is standard. We thought going down to 22.05 would help make data upload more compact and quicker.

Support said:
Have you tried using a bitrate of 32 kbps with a samplerate of 44.1 khz?
Click to expand...
We will try it. It's an experimental PAYG account - experimental so that we can get on top of the technology before we begin - so we are open to all suggestions.

What about 24kbps bit rate & 44.1 khz sample rate? That should work for talk radio, I think. The quality of the sound is not the most important thing.
 
R

RickZed

New Member
Support said:
Ok. It still sounds as though there is some kind of mismatch with the intro file? Is it in 'Stereo' or 'Joint Stereo'?
Click to expand...

The source and the intro file are both mono.

Ok - what I'm going to do is make a set of 32 kbit/s intro files, 22.05 and 44.1 sample rates, mono and stereo. I use butt as the source encoder and to record the intro files - but I will double-check them in Audacity before uploading. I will try them all, one at a time.
 
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Support

Support

Level 1 Support
Staff member
You will need to use 'Stereo' for this. We suggest using 'Stereo' files with a sample rate of 44.1 khz. The bitrate will also need to be the same bitrate that you have subscribed too on the account as well. If it is not, this will cause problems. We would also recommend recording and encoding these intro files in Audacity (or a program similar) rather than using BUTT, which is a broadcast tool and not an audio editor.

Please do let us know how you get on with this. Thanks. :)
 
R

RickZed

New Member
Support said:
Please do let us know how you get on with this. Thanks. :)
Click to expand...
Ok - I think we have solved this. It was actually two problems confounding each other!
  1. All files and streams must use the same bitrate, sample rate and channel. It's not difficult to implement this for the fixed files and tracks uploaded to the AutoDJ FTP host. We used Audacity to check, and then checked again with winLAME ( winLAME home page ). Our audio encoder for the live stream (butt) seems to be wholly reliable.
  2. See FFMp3 :: Changelog - The Flash MP3/OGG Live Stream Player! - haXed for the other problem. We noticed that all players except FFMP3 were behaving correctly. Upgrading to FFMP3 v0.4.4 (released 24 March 2012) fixed that.

Everything is OK now - at least for the IceCast server, which is the one we want to use. Our tests of live streaming and AutoDJ are working perfectly :)
 
Support

Support

Level 1 Support
Staff member
RickZed said:
Ok - I think we have solved this. It was actually two problems confounding each other!
  1. All files and streams must use the same bitrate, sample rate and channel. It's not difficult to implement this for the fixed files and tracks uploaded to the AutoDJ FTP host. We used Audacity to check, and then checked again with winLAME ( winLAME home page ). Our audio encoder for the live stream (butt) seems to be wholly reliable.
  2. See FFMp3 :: Changelog - The Flash MP3/OGG Live Stream Player! - haXed for the other problem. We noticed that all players except FFMP3 were behaving correctly. Upgrading to FFMP3 v0.4.4 (released 24 March 2012) fixed that.

Everything is OK now - at least for the IceCast server, which is the one we want to use. Our tests of live streaming and AutoDJ are working perfectly :)
Click to expand...

Great, we are pleased that you resolved this issue. 8)
 
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