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How to improve sound quality and decrease file size?
Posted: Tue Oct 07, 2014 5:14 pm
by ixodid
I have Audacity 2.0.6 newly installed but my question refers to 2.0.2. Windows 7 x64, .exe installer.
I use Audacity for stitching together segments from my telephone recording software - it records in 15-minute segments. The output is mp3.
One event I regularly record is a conference call. When the conference call host provides the recording (mp3), the sound quality is better and the file size is 30% smaller than my Audacity-processed version.
So I compared the raw telephone recording software mp3 files' sound quality to the conference call provided version and they are similar in sound quality.
Is there a way I can improve the sound quality while decreasing the file size from what I have been achieving with Audacity?
Re: How to improve sound quality and decrease file size?
Posted: Tue Oct 07, 2014 5:45 pm
by kozikowski
They may be using an MP3 editor. Audacity is not an MP3 editor. Audacity converts everything to an internal sound format and then converts to a whole new MP3 on Export adding compression distortion. If all you're doing is cutting and simple editing, an MP3 editor is perfect. They won't do special effects and any work that depends on changing the character of the sound such as equalization.
http://mp3splt.sourceforge.net/mp3splt_page/home.php
Koz
Re: How to improve sound quality and decrease file size?
Posted: Tue Oct 07, 2014 6:01 pm
by ixodid
That's great - thanks for the link and your help, Koz!
Re: How to improve sound quality and decrease file size?
Posted: Tue Oct 07, 2014 10:27 pm
by ixodid
I tried mp3splt-gtk and didn't see how to use it to splice two or more files together.
I played with it and read about it. It appears to be for splitting larger files into smaller files.
The documentation is written above my head.
Is there another choice available for free that you know of?
I tried MP3 Audio Editor from MAESystems but during installation it does everything it can to trick you into installing toolbars and crap a ridiculous number of times. Then I find it's free for 30 days. Then I had trouble uninstalling it.
Re: How to improve sound quality and decrease file size?
Posted: Wed Oct 08, 2014 1:01 am
by Trebor
...decrease file size...
Use mono rather than stereo if possible.
Reduce
sample-rate to 16kHz for telephone conversation (maybe even lower).
Reduce
mp3 bit-rate to the lowest you can tolerate, (this will degrade the audio quality).
[a similar question (&answer) here ...
http://forum.audacityteam.org/viewtopic.php?p=247565 ]
Re: How to improve sound quality and decrease file size?
Posted: Wed Oct 08, 2014 1:40 am
by Gunnar
Trebor wrote:...decrease file size...
Use mono rather than stereo if possible.
Reduce
sample-rate to 16kHz for telephone conversation (maybe even lower).
Reduce
mp3 bit-rate to the lowest you can tolerate, (this will degrade the audio quality).
In addition to that:
* Be sure you are using the
latest version of
LAME for MP3 encoding, which is the best MP3 encoder out there
* Be sure you are using ABR (average bitrate) or even better VBR (variable bitrate) mode, do
not use CBR (constant bitrate) unless you absolutely have to
* LAME also has an
algorithm quality option, which can be used to squish out more quality
at the same bitrate - at the cost of slower encoding speed (use
-q0 for max. quality)
If the audio format is
not necessarily MP3, you could use
AAC instead, which beats MP3 at very low bitrates. Or, even better, use a dedicated
Speech-Codec like
Opus.
Re: How to improve sound quality and decrease file size?
Posted: Wed Oct 08, 2014 7:36 am
by Gale Andrews
ixodid wrote:I tried mp3splt-gtk and didn't see how to use it to splice two or more files together.
I played with it and read about it. It appears to be for splitting larger files into smaller files.
The documentation is written above my head.
Is there another choice available for free that you know of?
Yes. This is the link Koz should have given you for multiple tools that let you split and/or join and/or adjust the volume of MP3's losslessly:
http://wiki.audacityteam.org/wiki/Lame_ ... tion#lossy .
Gale
Re: How to improve sound quality and decrease file size?
Posted: Wed Oct 08, 2014 7:49 am
by Gale Andrews
Gunnar wrote:* Be sure you are using the
latest version of
LAME for MP3 encoding, which is the best MP3 encoder out there
Just to be clear, the lame_enc.dll's on that page will not work with Audacity:
Code: Select all
08:41:31: Error: Couldn't find symbol 'get_lame_version' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_encode_buffer' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_quality' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_brate' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_VBR' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_VBR_q' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_VBR_min_bitrate_kbps' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_mode' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_preset' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_error_protection' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_disable_reservoir' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_padding_type' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_set_bWriteVbrTag' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Error: Couldn't find symbol 'lame_get_lametag_frame' in a dynamic library (error 127: the specified procedure could not be found.)
08:41:31: Failed to find a required symbol in the LAME library.
If you must have 3.99.5 for use in Audacity, you need libmp3lame.dll from "libmp3lame 3.99.5" on
http://www.rarewares.org/mp3-lame-libraries.php .
Gale