Hi,
I’m creating ads for a live audio stream, using TargetSpot through the Shoutcast ad revenue program,
Anyway, the adverts have to be exactly 2 minutes long and up until now any ad I created is exactly 00h:02m:00s
One stream is not showing ads the way it’s suppose to so I opened the mp3 again in audacity,
I can see it’s 00h:02m:00:033s so I cut it back down to 2 mins and save it again, but it still shows 00h:02m:00:033s when I open it in audacity.
Any advice what is going it?
It’s a limitation of the MP3 format. MP3s always have a bit of padding at the start because the format does not define the overall encoder/decoder delay.
Not sure exactly what you mean, but I did add some silent space at the start and at the end…
I lowered the volume by going to effects > amplify…
This never happened me before so I dunno,
I tried cutting the extra time off the end and the begnning of the file but no joy.
Is there a solution?
Ah I had to cut more time off the beginning, it works now… my brain is half fried, thanks for the tip 
Actually that didn’t even work.
It means, if you have a track that is, for example, 2 minutes long and you encode it as MP3, then the MP3 will be a little over 2 minutes long because encoding adds a bit of extra silence to the start of the file.
If you need the track to be no more than 2 minutes, there are two possible solutions: either you need to start with a track that is a little less than 2 minutes, or you need to export in a different format (such as WAV, FLAC, AIFF or OGG).
Note also that MP3 is a “lossy format”, which means that each time it is encoded, a bit of sound quality is lost. If you must use MP3, then when possible, always use a lossless format such as WAV, AIFF or FLAC during production, and only encode (once) at the end. Avoid re-editing MP3 files - go back to your original and re-edit that if necessary. Tip: Always keep a high quality backup of your work in a lossless format such as WAV, AIFF or FLAC.
I started with 3 x 30 sec mp3 audio ads, recorded into audacity, then added another 30 secs of vocals, that’s how I’ve done them all.
I have the other streams online with the targetspot ads working in those, so they must be exactly 2mins long or…
When I right the saved version of those 2 minute files, they’re not exactly 2 mins any more, so I’m not uploading those.
Something so minute as a few milliseconds,
I converted it to wav and it was 2 mins, then I saved an mp3, 33 milliseconds added on again… Jesus wept!!
This just started happening today.
Are you sure that it’s the length that is the problem and not something else?
What is the exact format they require?
Mono / Stereo?
VBR / CBR?
Bit rate?
Sample rate?
Stereo 44100Hz, 32 bit float, bit-rate mode: preset, joint stereo, the others are working fine, as long as I don’t update them like I did with this one.
I think I updated this advert about two weeks ago, that’s when I noticed there was no status on shoutcast rmo for the stream, not detecting the file.
I’m only going by what it says on the site, 2 minute advert. when the ad works, they are daily stats.
“32-bit float” is the Audacity track format and unrelated to the MP3 format.
The first thing that you should check is that the metadata for your files is correct.
“Advert:” must be in both the artist and title sections https://www.shoutcast.com/FAQ
If that doesn’t fix it…
Podcasts are usually “CBR” (constant bit rate). Audacity’s are “VBR” (variable bit rate).
The “Bit rate” for podcasts is usually between 64 kbps and 256 kbps. You may need to ask SHOUTcast support what bit-rate to use. Similarly you should ask them whether the advert should be stereo or mono.
I doubt that being a few milliseconds over 2 minutes is the problem as I would expect they would just trim off the end if its too long. Check the above first, and if that does not fix it, then contact Shoutcast support and ask them why they are not working.
That’s the thing…
I have the exact same mp3 advert / metadata on the other shoutcast streams,
The only difference is the last 30 secs of audio/vocals, they’re all working fine.
I don’t think the milliseconds matter, that was just verified.
Just have to mess around with it until I fix it again.
I’ll try recreate the authhash or something.
There is ALWAYS some silence at the beginning and end of an MP3. See the [u]LAME FAQ[/u].
So the question is, do you want a 2 minute file (with a slightly-shorter program) or a 2-minute program (with a slightly longer file)? Or, can you use a different format?
There are ways to get [u]gapless playback[/u] (where the silence isn’t played) but I don’t know if SHOUTcast supports it.
I think I figured it out, logged into shoutcast admin page, monetisation wasn’t working, had to delete and create the channel again on rmo.
Maybe I did something stupid like renaming the file on the server or something and it wasn’t recognized by the server that triggers the ads.
Thanks for your kind advise.
t’s a limitation of the MP3 format.
As used on its own. MP3’s full family name is MPEG1-Layer3. It’s the sound track part of a video format. When used as intended, it takes the timing of the video frames and edits perfectly.
We strongly recommend against editing or production directly in MP3 because of the slippery nature of the format. That over and above the quality issue. MP3 sound quality gets worse every time you edit.
As a fuzzy rule, 32 is the lowest acceptable quality for mono and 64 for stereo. If you edit a 64 show and save it as 64, the quality will actually be lower than that and may drop below where it’s acceptable to the client.
Always save production archive in WAV (or equivalent) and redo MP3s from that if they need to change, rather than opening and patching existing MP3s.
Do the “straight” MP3 editors affect the show length? That is, if I cut a show in half with MP3Direct, do I get half, or does it fudge the show length?
Koz
Missed one. MP3 quality damage is forever. Once you start down the MP3 road, you can’t convert the show to WAV format to delete the bubbly, honky distortion. The best you can do is work in WAV from now on to keep it from getting worse, or work in very high quality MP3 (320) to keep it from getting worse as fast.
Koz
Well luckily the milliseconds don’t matter with the TargetSpot ads, so I was told anyway.
I guess I was the only person on the planet havin a fit about a few milliseconds in my ads.
But it’s working now so all good!
Thanks for letting us know. I’ll close this topic now.