Re: [LAU] loop speeding in sample level accuracy

From: Jari Suominen <jari.suominen@email-addr-hidden>
Date: Thu Sep 18 2008 - 21:58:56 EEST

Thanks Dan!

I will give it a try. I actually really need the length of the resulting
audio file to be exactly what desired but as I'm not doing that hazard
shifts this might work. And perhaps running same file through the script
more than once would give the result I'm aiming at.

More theoretical question is, are speed shifting algoritms actually
using the ratio given to them or converting them to some other value
before doing the conversion. And is the sample accurate 'speeding' even
possible in reality, or is it always +/- couple samples. I tried to look
at the SoX source but it was a bit too C:ish for me to give me an answer
straight away.

......j

Dan Richert kirjoitti:
> SoX can do the job with some help. Here's a little Perl script to
> figure out the speed scaling ratio based on the desired new length in
> samples:
>
> #!/usr/bin/perl
>
> if(@ARGV != 3){ die "Usage: resize-audio.pl <in_file> <new_size>
> <out_file>\n"; }
> ($in_file,$new_size,$out_file) = @ARGV;
> $size = `sox $in_file -n stat 2>&1 |grep ^Samples |awk '{print \$3}'`;
> $ratio = $size / $new_size;
> print "$ratio\n";
> `sox $in_file $out_file speed $ratio`;
>
>
>
> In the couple tests I ran, it doesn't get to the *exact* new size
> specified in samples, but pretty close -- I converted a file 12486
> samples long to 3000 samples and ended up with a file with 3002 samples.
>
>
>
> Jari Suominen wrote:
>> Tiago Tavares kirjoitti:
>>
>>> Can SoX do the job?
>>>
>> Nope. Speed shift takes in prosent or cents.
>>
>> ....j
>>
>>
>>> On Thu, Sep 18, 2008 at 1:51 PM, Jari Suominen <jari.suominen@email-addr-hiddenwrote:
>>>
>>>
>>>> Hello,
>>>>
>>>> I'm trying to search a program (with no success) that could used for
>>>> speeding up an audio file to a certain length. I mean, I would have a
>>>> audio file that has 40000 samples, and I would need it to be 40010. And
>>>> the pitch of the file can/should change. All speed change stuff that I
>>>> have found will take semitones/cents/procents as a input parameter. I
>>>> would wan't to only input the exact length (in samples) that I need.
>>>>
>>>> My purpose is basically make bunch of files that are loopable and have
>>>> equal length with each other.
>>>>
>>>> Does this thing exist or do I have to make it myself?
>>>>
>>>> Thanks!
>>>>
>>>> ..j
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>>>>
>>>>
>>>
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Received on Fri Sep 19 00:15:05 2008

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