Stereo output selected but I'm only getting mono ?

[Thunder Bird]

Have tried converting several MP3 files of 320 kbps to 112kbps.

 

These original MP3 files are all stereo.

 

MP3 Encoder Settings

 

Channels - Stereo

 

Variable Bitrate - selected

 

Minimum Bitrate (kbps) - 16

 

Maximum Bitrate (kbps) - 112

 

Quality - 2

 

Converted files are all resulting in a Mono format

 

e.g. original MP3 file size 3.892 MB at 320 kbps

 

results in a Mono switched file of 1.132 MB at 96 kbps ??

 

Have tried several files with similar results.

 

Reinstalled Switch but results still the same.

 

Have tried same conversion at Maximum Bitrate of 128 kbps

 

but to no avail results were still mono MP3 files.

 

Have previously done this conversion with little or no problems.

 

At a loss to understand what has changed

 

Any help would be greatly appreciated.

[musikone]

Have tried converting several MP3 files of 320 kbps to 112kbps.

 

These original MP3 files are all stereo.

 

MP3 Encoder Settings

 

Channels - Stereo

 

Variable Bitrate - selected

 

Minimum Bitrate (kbps) - 16

 

Maximum Bitrate (kbps) - 112

 

Quality - 2

 

Converted files are all resulting in a Mono format

 

e.g. original MP3 file size 3.892 MB at 320 kbps

 

results in a Mono switched file of 1.132 MB at 96 kbps ??

 

Have tried several files with similar results.

 

Reinstalled Switch but results still the same.

 

Have tried same conversion at Maximum Bitrate of 128 kbps

 

but to no avail results were still mono MP3 files.

 

Have previously done this conversion with little or no problems.

 

At a loss to understand what has changed

 

Any help would be greatly appreciated.

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Are you saying that, using Switch, you previously converted an mp3 stereo file (compressed at a constant bit rate of 320kbps) to another mp3 file (compressed using a variable bit rate between the limits of 16kbps and 112kbps), and that the resulting file was a _stereo_ file?

 

[note: Although you did not mention it, and probably do not understand the significance of sampling rate, I also assume that the original file's sampling rate was the "standard" 44.1 khz, and that _this same sampling rate was preserved_ through the bit rate conversion process]

 

Check these numbers out (including the preservation of the sampling rate!) carefully before you answer, so that I will not be wasting my time with a pseudo-problem.

 

After you verify that you did indeed perform this test and obtained the indicated result, come back here and report, after which we can proceed to "solve" this mystery of here-today, gone-tomorrow. Please try to answer before next year. If you melt away into the woodwork at this point, I will accept this as your answer :-).

 

 

Musikone

(the metronome is ticking!)

[Thunder Bird]

Musikone

 

I've revisited the problem and have found I can convert as I did before by altering 2 values

 

Minimum Bitrate was increased from 16 to 32 kbps

 

Quality was reduced from 2 to 3 and everything is now working as before

 

As I had not written these values down I was doing it from memory

 

Did not think reducing Minimum Bitrate from 32 to 16 kbps would be so critical

 

Or increasing quality from 3 to 2 either

 

Original file was at a variable bitrate - Maximum Bitrate (320 kbps) - No idea on Minimum Bitrate

 

Changing the 2 values mentioned above my 320 variable bitrate MP3 file conversions to 112 variable bitrate

 

are now producing stereo MP3 files

 

The original file's sampling rate was the "standard" 44.1 khz

 

This same sampling rate has been preserved through the bit rate conversion process

 

(Had to reduce Quality from 2 to 3 to preserve this value)

 

Raises the question what is the lowest maximum bitrate coupled with the lowest minimum bitrate you can use

 

and still produce stereo MP3 files (not forgetting the Quality setting)

 

Thank you for your help

[musikone]

Musikone

 

I've revisited the problem and have found I can convert as I did before by altering 2 values

 

Minimum Bitrate was increased from 16 to 32 kbps

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This is indeed _critical_! These parameters cannot be chosen arbitrarily; they are inter-dependent. Yes, you have to go up to a minimum bit rate of 32 kbps before you can both get a stereo conversion and retain the sampling rate of 44.1 khz. Have you tried this with a bit rate of 24kbps instead of 32kbps?

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Quality was reduced from 2 to 3 and everything is now working as before

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I have not checked out the inter-dependence of "quality" with these other parameters.

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As I had not written these values down I was doing it from memory

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Here is the hitch. The moral to this story is not to make off-the-cuff statements without _written_ results, so that when challenged by curmudgeons such as myself, you will not come away with a red face!

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Did not think reducing Minimum Bitrate from 32 to 16 kbps would be so critical

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Repeating: what is critical is to take notes and avoid making casual statements of "fact," unless of course you acknowledge with that there is a question as to certainty. Unfortunately, you ran into a highly experienced and very-well-educated ELECTRONIC ENGINEER (as well as a musical scholar and performer on the side), and an experienced TEACHER, to boot.

 

Oh well; things are seldom what they appear to be in the Wonderful land of Oz :-)

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Or increasing quality from 3 to 2 either

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As I said, I have not researched this aspect of the conversion process. For some time I used a quality level of 2 in my VBR conversions, but switched to 0 not too long ago, since I am willing to trade a slightly larger file size for superior audio quality.

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Original file was at a variable bitrate - Maximum Bitrate (320 kbps) - No idea on Minimum Bitrate

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You didn't say this in your post. I assumed that the number which you gave was a _constant_ bit rate. It is assumed, by default, that a bit rate stated without any mention of a minimum bit rate is a constant bit rate. Here again, it is very important to be precise--when you are dealing with an engineer-teacher type!

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Changing the 2 values mentioned above my 320 variable bitrate MP3 file conversions to 112 variable bitrate

are now producing stereo MP3 files

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Yes, I know :-)

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The original file's sampling rate was the "standard" 44.1 khz

8 --------------------------------------------------------------------------------------

Just as I presumed.

8 --------------------------------------------------------------------------------------

This same sampling rate has been preserved through the bit rate conversion process

 

(Had to reduce Quality from 2 to 3 to preserve this value)

 

Raises the question what is the lowest maximum bitrate coupled with the lowest minimum bitrate you can use

and still produce stereo MP3 files (not forgetting the Quality setting)

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I don't know. I would suggest that you determine the answer--by experimentation.

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Thank you for your help

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You're welcome.

 

Hopefully you have learned a lesson about the need for_precision_ in technical matters. But don't feel too bad about this; you are hardly alone in this forum. In fact, you are in the overwhelming majority here. Where you differ, and this is to be commended, is in your very quick response to my challenge. Most folks around these parts simply melt away when under fire.

 

 

Musikone

[Gotcha with this moniker, didn't I? :-)]

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