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AMR to WAV converter

4 replies [Last post]
oakleaf
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Joined: 2008-09-18

Dear all,

I have been looking for a Java AMR decoder for a long time. It is not so easy to find something to this subject.

Does anybody know about a java library
- that can be run in the J2ME context, i.e. on mobiles,
- and that converts an AMR stream into a wave curve form signal?

AMR is Adaptive Multi-Rate speech codec, based on CELP (Code Excited Linear Prediction).

Thanks a lot for any help :-)

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sfitzjava
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Joined: 2003-06-15

Hi Oakleaf,

I am confused as to why you would want to convert AMR to WAV on a mobile device.
Usually the media player (MMAPI) can support AMR decoding, at leasts as a H.263/264 RTSP Stream. We would transcode input into a H.263/AMR format using an Apple MacOS software, but I think FFMPEG or VideoLAN should be able to do that on a server or desktop.
1) http://stephenjungels.com/jungels.net/articles/ffmpeg-howto.html
2) http://www.macosxhints.com/article.php?story=20030826232829387

Running a transcoder on an ME device, I would imagine, would be very slow, and require a great deal of resources to store the information.

Maybe some explaination as to what you are trying to accomplish would help determine the best solution for your issue.

-Shawn

honky
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Joined: 2009-02-23

Hey Shawn

the reason for me is: I would like to record an amr file, convert it to a e.g. wav file and then send it with my mobile phone via email to a friend and he'll be able to listen to it right away!

You see men could use such an application :)

Any help is appreciated!
// Chris

sfitzjava
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Joined: 2003-06-15

Well your friend should have a codec already installed on his desktop that can play it.
The QTime player from Apple supports 3GPP which is what a phone captures.
WinMedia player has this codec available from 3rd parties too, and can be installed to play these files.

If you want or have the codec knowledge to write the converter then go for it.
However a few roadblock will be memory on the device. Remember that a wav file is an uncompressed mp3. While a 3min song is roughly 3M at 128k encoding, but is 35M as a WAV file. Something a bit too large for JavaME enabled cellphones. Oh and that's just audio, for Video too.. well better get a notebook for that. ;)

If I remember correctly I worked on a project where we took videos from cellphones and transcoded them to several formats, it would take a Mac server about a minute to encode a 30sec video..... your cellphone battery may run out before you can complete the encoding.

-Shawn

lion3
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Joined: 2010-07-05

I use MelodyCan. It is the best, easiest and fastest device i found. You can try it)