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How to maintain high sound quality, low file size?

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Hi,

 

I'm using Switch to convert Real Audio (.ra) files to mp3s. I would like to maintain the highest possible audio quality, whilst creating the smallest possible file sizes.

 

The .ra files have the following characteristics: bitrate=32 kbps and sample rate=44,100, channels=2 (info obtained from MPlayer).

 

Switch doesn't allow any control over the sample rate, so I selected an mp3 bitrate of 64kbps (thinking that twice the original bitrate should be fine) BUT the resulting mp3s have a sample rate of 22,050.

 

Obviously I don't know what's going on, as I've doubled the bitrate but only obtained half the original sample rate...

 

Can anyone shed any light on what's going on. Can I use switch to set the bitrate and sample rate = the original values in the .ra file?

 

Or, any other ideas about how to maintain high quality and small file sizes?

 

Thanks!

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The Lame Mp3 encoder automatically uses the sample rate of 22500 for files between 32-64 kbps (or somewhere around those bitrate levels). I'm pretty sure that if you want to it is possible to force the command line encoder to use the 44100 sample rate it's possible but NCH more than likely allowed sample rates in Switch to be defined automatically for user friendliness.

You'll more than likely notice high pitched sounds relayed or some light static on playback if you attmpt to force 44100Hz on low bitrate files in Mp3 anyway.

 

The simple fact of the matter is that for bitrates that low, a high sample rate just isn't necessary. 44100 (as you'll know) is the standard sample rate used for CD audio but for Mp3's at 64 kbps the quality loss is practically detrimental by comparison so the sample rates can be incrementally decreased for better efficiency with decoding and playback.

 

If you encode a file at around 16 kbps you'll notice the sample rate defaults to 11000Hz. Basically when it comes to lossy encoding you need to find a level that both you (and your clients) will find acceptably useful, it's basically experimentation with touch and go to see which settings will best suit your needs.

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Thanks for your reply, I appreciate your time.

 

The Lame Mp3 encoder automatically uses the sample rate of 22500 for files between 32-64 kbps (or somewhere around those bitrate levels). I'm pretty sure that if you want to it is possible to force the command line encoder to use the 44100 sample rate it's possible but NCH more than likely allowed sample rates in Switch to be defined automatically for user friendliness.

You'll more than likely notice high pitched sounds relayed or some light static on playback if you attmpt to force 44100Hz on low bitrate files in Mp3 anyway.

 

The simple fact of the matter is that for bitrates that low, a high sample rate just isn't necessary. 44100 (as you'll know) is the standard sample rate used for CD audio but for Mp3's at 64 kbps the quality loss is practically detrimental by comparison so the sample rates can be incrementally decreased for better efficiency with decoding and playback.

 

If you encode a file at around 16 kbps you'll notice the sample rate defaults to 11000Hz. Basically when it comes to lossy encoding you need to find a level that both you (and your clients) will find acceptably useful, it's basically experimentation with touch and go to see which settings will best suit your needs.

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