wma files size not as the original

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wma files size not as the original

Permanent link to this post Posted by JhonDave2012 » Wed Sep 12, 2012 7:25 pm

Hi, I have windows 7 64 bit.
I have some wma files that I recorded with a pocket audio recorder.
When I opened it with audicity (I already installed FFmpeg_v0.6.2 and Lame_v3.99.3 plugin) and saved it as wma, the saved file was much larger than the original file. I don't understand why aren't they identical in size. How can I solve it, so the saved wma file would be the exact format as the origin wma file (I need to do this because I need to cut some parts of the file and save it so there will be no loss of data from the original wma file) ?
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Re: wma files size not as the original

Permanent link to this post Posted by Gale Andrews » Wed Sep 12, 2012 8:21 pm

JhonDave2012 wrote:Hi, I have windows 7 64 bit.
I have some wma files that I recorded with a pocket audio recorder.
When I opened it with audacity (I already installed FFmpeg_v0.6.2 and Lame_v3.99.3 plugin) and saved it as wma, the saved file was much larger than the original file.

When you export, you have to choose the same bit rate as the original file, or the exported file will be a different size. To choose the export bit rate, click the "Options..." button when you export.

To see the bit rate of the original file, right-click over the file in Explorer, choose "Properties" , then click on the "Details" tab.

JhonDave2012 wrote:I need to do this because I need to cut some parts of the file and save it so there will be no loss of data from the original wma file) ?

WMA is a lossy format (apart from WMA lossless, which FFmpeg and Audacity don't support yet).

So every time you re-encode the WMA, you will lose quality. The lower the bit rate you export at, the more quality you will lose.


Gale
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Re: wma files size not as the original

Permanent link to this post Posted by kozikowski » Wed Sep 12, 2012 8:24 pm

Audacity works by always creating a whole new sound file when you're finished. This means you get to choose the compression value, file size and all the other characteristics of your sound file fresh each time. Audacity is a production sound editor not a WAV editor.

We tell people to do simple cutting and editing outside of Audacity. Find an editor that doesn't try to decompress the sound file while it's editing. This is unlikely with WMA because it's based on H.264 in which all the parts of a sound file depend on all the others. Terrific idea until you need to edit one.

In any event, you're unlikely to be happy with the finished sound file because compressed audio gets more and more damaged each time you make a new one. WMA, MP3, etc are delivery formats, not editing formats.

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Re: wma files size not as the original

Permanent link to this post Posted by JhonDave2012 » Thu Sep 13, 2012 10:22 am

It would be very useful and appreciated if someone of the Audicity developers would consider to add the ability to read the original audio file parameters (bit rate, compression method, ...) and when cutting and saving, the saving default would be the same format and parameters as the origin.

As for "compressed audio gets more and more damaged each time you make a new one", I think that is true, but negligibly, because the most affected parts are few millisecond at the start and at the end of an audio piece. Sometimes it is inevitable, but need (cut few parts of an audio piece).

Thanks for the information :)
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Re: wma files size not as the original

Permanent link to this post Posted by steve » Thu Sep 13, 2012 2:32 pm

JhonDave2012 wrote:As for "compressed audio gets more and more damaged each time you make a new one", I think that is true, but negligibly, because the most affected parts are few millisecond at the start and at the end of an audio piece. Sometimes it is inevitable, but need (cut few parts of an audio piece).

I would disagree about the the loss of sound quality being negligible, but perhaps I am more fussy about sound quality.
Encoding into a lossy format loses some of the audio information and degrades the sound quality. This sound quality loss is irreversible and it occurs each time the audio is encoded. Using a high bit rate will minimise the loss, but there will always be some loss of sound quality and the damage is cumulative - it gets worse every time the audio is re-encoded.
Last edited by Gale Andrews on Thu Sep 13, 2012 9:24 pm, edited 1 time in total.
Reason: Typo fixed
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)
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Re: wma files size not as the original

Permanent link to this post Posted by kozikowski » Thu Sep 13, 2012 4:30 pm

The damage happens all through the show. If you need to edit a production that's just on the edge of bubbling from high compression, creating a new sound file at the same compression will destroy the show.

If you start with work at an impossibly high compression like 320, you can create a new show at 64 or 128 and nobody has to know. But most people want to take ratty internet downloads and create "Chicago, the Musical" at home.

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Re: wma files size not as the original

Permanent link to this post Posted by Gale Andrews » Thu Sep 13, 2012 9:26 pm

JhonDave2012 wrote:It would be very useful and appreciated if someone of the Audicity developers would consider to add the ability to read the original audio file parameters (bit rate, compression method, ...) and when cutting and saving, the saving default would be the same format and parameters as the origin.

OK those are quite popular feature requests so your vote will be added.


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Re: wma files size not as the original

Permanent link to this post Posted by kozikowski » Fri Sep 14, 2012 9:15 pm

saving default would be the same format and parameters as the origin.

And you accept the quality loss.
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Re: wma files size not as the original

Permanent link to this post Posted by Gale Andrews » Fri Sep 14, 2012 10:32 pm

kozikowski wrote:
saving default would be the same format and parameters as the origin.

And you accept the quality loss.

Yes, the objective is the same size (or proportional size if you change the length).


Gale
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