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#1 Jul 1st 2005 23:07

Gerrit
Administrator

MP3 playing too fast or too slow

This is a well known bug within the Macromedia Flash Player Plugin. We can’t do anything about it, except for using only standard frequency values when creating MP3 files.

USE ONLY THE FOLLOWING FREQUENCY RATES:

* 11,025 kHz
* 22,050 kHz
* 44,100 kHz

Anything between this will sound like Alvin and the Chipmunks, you know? Don't use frequency values like 32 kHz or 8 kHz!!

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#2 Dec 31st 2005 11:54

Geeklog
Member

Re: MP3 playing too fast or too slow

Is there any alternative meanwhile? It is silly when you have files in 16kHz.

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#3 Feb 21st 2006 08:32

bradsears
Member

Re: MP3 playing too fast or too slow

Use a programs like mp3 doctor, dbpowerAmp, or even the free music match jukebox to convert the files.

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#4 Mar 12th 2006 16:52

johndmann
Member

Re: MP3 playing too fast or too slow

I have a recorded mp3 in 44.1khz, and it plays fine on my home system, and it plays fine in Loudblog administration after uploading, but on the main page it chipmunks.  Why would it play fine in Loudblog admin but not on the front page?

My encoder defaults to 128 bitrate for the mp3 - will that affect anything?

Edit:  I figured out the problem (I think - it works now anyway!): My recording program was recording in "32-bit float", changing this to 16-bit fixed it!

Last edited by johndmann (Mar 12th 2006 17:11)

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#5 Apr 16th 2006 12:23

peekj
Member

Re: MP3 playing too fast or too slow

I have the same problem, the mp3 is 128-bit (CBR), 44.1khz and it plays fine in the admin section and too fast on the main page.
I'm at my wit's end.

PS: It has actually changed! About a week ago the same mp3 played just fine, now it's playing too fast... wth?

Last edited by peekj (Apr 16th 2006 12:26)

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#6 Jan 11th 2007 13:44

pbarney
Member

Re: MP3 playing too fast or too slow

The reason it plays correctly in the admin page, but not on the front page is because your browser is caching the mp3 file. Empty your cache and reload the page and it should work again. This is the only reason you would be getting two different results.

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#7 Jan 15th 2007 14:18

pbarney
Member

Re: MP3 playing too fast or too slow

For those of you using Audacity with the Lame plug-in:

The simplest way to have the frequency set properly for normal playback when encoding at a lower bit rate is to use 48kpbs in the preferences dialog box of Audacity. Using 56 or 64 will encode at strange frequencies, inducing the fast-playing bug in flash.

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#8 Jan 17th 2007 01:12

raymer
Member

Re: MP3 playing too fast or too slow

pbarney,
You said >>>
For those of you using Audacity with the Lame plug-in:
The simplest way to have the frequency set properly for normal playback when encoding at a lower bit rate is to use 48kpbs in the preferences
<<<

I believe this has to do with a bug (or feature) in Audacity -- if it detects stereo content of any kind it will ignore your preferences and write out a file at the frequency IT wants rather than what YOU said you want...

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#9 Feb 16th 2007 09:20

pbarney
Member

Re: MP3 playing too fast or too slow

Thanks for the update, Raymer. But I've found that Audacity will pay attention to the bitrate you specify, but it will choose the frequency on its own. The only low-quality (for a small file size) bitrate I've found that will produce one of the flash-acceptable frequencies is 48kpbs.

I'm sure that specifying higher bitrates will produce files with one of the proper frequencies that Gerrit mentioned in the first post, but since most people will be using this for voice-quality podcasting and not high-quality streaming music, 48kpbs seems to be the best solution. What do you think?

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#10 Mar 15th 2007 20:42

raymer
Member

Re: MP3 playing too fast or too slow

pbarney,
Yeah, I think that is what is happening. Audacity is overriding the user's frequency selection based on the bitrate. I have also ended up using 48k for most speech content. You seem to have found the best compromise.

I've been thinking that a new version of Audacity is about due but so far, nothing....

pbarney wrote:

Thanks for the update, Raymer. But I've found that Audacity will pay attention to the bitrate you specify, but it will choose the frequency on its own. The only low-quality (for a small file size) bitrate I've found that will produce one of the flash-acceptable frequencies is 48kpbs.

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#11 Mar 18th 2007 19:52

raymer
Member

Re: MP3 playing too fast or too slow

By the way, I forgot to mention that it is easier in most cases to use LAME directly from the command line. I just work with WAV audio or some other losseless format in the editor and then when I'm ready to post the MP3 I run the following command line

lame -b 48 --resample 22.05 mysong.wav mysong.mp3

this works great for me and produces a good quality, small filesize for speech.

Hope this helps someone,
Ray Mercer
www.yokosukachurch.com

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#12 Mar 21st 2007 14:07

petercarter
Administrator

Re: MP3 playing too fast or too slow

I have compiled a table (Excel spreadsheet) for both WavePad and Audacity, showing the frequency at which each makes an mp3 file in different circumstances. You can find it here. Both of them will reduce the frequency at lower bit rates, but they do so in different ways. WavePad has possibilities for recording at a flash-compliant frequency at 64kbps, which is useful for good quality speech files. I hope you find the comparisons useful.
Actually, there are other advantages to WavePad over Audacity as well. It generates ID3 tags which Loudblog can read and edit - Audacity doesn't. It has a facility which you can use to upload the audio file on which you are working direct to the upload folder of your Loudblog site. Audacity argues with my anti-virus software (ZoneAlarm) which makes it very slow to create an mp3 file. I generally turn the anti-virus off when using Audacity to avoid this. There is no similar problem with WavePad. WavePad is to my mind rather easier to use, and is certainly a bit quicker. The downside is that you have to pay for it, although a free trial version is available with most features switched on and (apparently) no built in time limit.

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