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Topic: LAME files created as MPEG V2 instead of V1 (Read 6022 times) previous topic - next topic
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LAME files created as MPEG V2 instead of V1

Hi I am trying to use LAME 3.96 to create some test mp3 files from a WAV file, but they are always created as MPEG Version2 Layer III, I was expecting them to be created as MPEG Version 1 LAYER III (like most of my existing mp3 files). Is LAME making a choice based on the data file ( they are short sound effects files) or does it always create files as Version 2.

Is there an option to force it to create as MPEG Version 1 (oe even MPEG Version 2.5), Ive had a look but i cant find one ?

LAME files created as MPEG V2 instead of V1

Reply #1 –
Some bitrates/sampling rates are not available in the mpeg-1 layer 3 specs, have a look at this table.

LAME files created as MPEG V2 instead of V1

Reply #2 –
Quote from: paultaylor on
Hi I am trying to use LAME 3.96 to create some test mp3 files from a WAV file, but they are always created as MPEG Version2 Layer III, I was expecting them to be created as MPEG Version 1 LAYER III (like most of my existing mp3 files). Is LAME making a choice based on the data file ( they are short sound effects files) or does it always create files as Version 2.

Is there an option to force it to create as MPEG Version 1 (oe even MPEG Version 2.5), Ive had a look but i cant find one ?


I think it might just depend on the sampling rate... MPEG 2/2.5 files are for lower bitrates.

LAME files created as MPEG V2 instead of V1

Reply #3 –
Quote from: Jebus on
I think it might just depend on the sampling rate... MPEG 2/2.5 files are for lower bitrates.


Ok so if I tried a more complex file (with talking/speaking) it would probably used Version 1.
But some bitrates such as 32 appear valid for both version 1and version 2, so how does it decide which to use ?

LAME files created as MPEG V2 instead of V1

Reply #4 –
Are you using low sampling rates? Version 1 only allows 48KHz, 44.1KHz, and 32KHz.

LAME files created as MPEG V2 instead of V1

Reply #5 –
Quote from: Firon on
Are you using low sampling rates? Version 1 only allows 48KHz, 44.1KHz, and 32KHz.

God knows, that is a property of the original WAV is it?

LAME files created as MPEG V2 instead of V1

Reply #7 –
It's actually quite simple; from the LAME-longhelp:

Code: [Select]
MPEG-1   layer III sample frequencies (kHz):  32  48  44.1
bitrates (kbps): 32 40 48 56 64 80 96 112 128 160 192 224 256 320

MPEG-2   layer III sample frequencies (kHz):  16  24  22.05
bitrates (kbps):  8 16 24 32 40 48 56 64 80 96 112 128 144 160

MPEG-2.5 layer III sample frequencies (kHz):   8  12  11.025
bitrates (kbps):  8 16 24 32 40 48 56 64 80 96 112 128 144 160


So, to force a specific version just resample. for example, you can use LAME's built-in "--resample <sfreq>"-option. For example, to encode speech.wav with Mpeg-2.5, you could use:

Code: [Select]
lame --resample 12 speech.wav


This reduces the samplerate to 12khz and encodes the file.

LAME files created as MPEG V2 instead of V1

Reply #8 –
22KHz is version 2. Why do you need version 1 anyway?
In any case, if you need version 1, stick to 32KHz, 44.1 KHz, or 48KHz. Resampling will work to force a version, like MedO said, but it may affect the quality when using low bitrates.
 

LAME files created as MPEG V2 instead of V1

Reply #9 –
Quote from: Firon on
22KHz is version 2. Why do you need version 1 anyway?


Hi I am actually trying to create some testdata for an ID3 tag API, so the quality of the resultant mp3 is immaterial but I want to check my api correctly calculates mp3 attributes such as the track length

thanks Paul