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I'm sharing records from phone conferences on my website, and would like to save space. It would be nice if I could use speex as I get about 5:1 compression compared to mp3. However most people would need help getting speex to play on their computer, and can't play it on their portable devices.

What can I use to get good compression for speech that average people will be able to play?

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3 Answers

up vote 6 down vote accepted

The only ubiquitous one is mp3. AAC is great on Apple products, but only mp3 works on everything.

When storing voice audio you can go for a very low quality, and potentially use mono if you don't require stereo. This will give you very high compression - approaching that of speex.

From the Wikipedia comparison page

Bit Rate:

  • mp3 8 to 320 kbit/s
  • speex 2.15 to 44.2 kbit/s
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Agreed. Think about what you're trading off: Storage space (which is dirt cheap) vs Your Time (which is not cheap). Your Time will be taken as soon as you have to start writing instructions, pointing people towards codecs, etc. –  Michael Nov 21 '11 at 14:20
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It depends on what is your target platform. Is it computers or mobile phones or something else? What OS is this?

As such, I believe speex is definitely a better choice. It is a speech codec, whereas mp3 is an audio codec. Speex is supported by most platforms.

To ease the download try using Gstreamer or ffmpeg where this comes built-in. So user's don't have to put so much extra work into it.

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GSM encoded WAV files are a good option.

I did some testing and got very good file size reduction results with perfectly acceptable audio quality.

The original file directly from my phone system was 272 KB. The file I converted into GSM was 28KB.

Here are the links for the sample files. Orignal File http://dl.dropbox.com/u/3594910/random_audio/vmail_16783201700_221_20110217160445.wav

GSM File http://dl.dropbox.com/u/3594910/random_audio/vmail_16783201700_221_20110217160445_GSM.wav

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wav files are too much in date rate! Not at all compressed. –  Dipan Mehta Nov 24 '11 at 2:56
    
.wav is simply a container format generally (but not always) used with raw PCM data –  Corey Nov 27 '11 at 14:23
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