I think you'd always end up with +/- a couple samples unless $size and
$new_size divide evenly. But I don't know much about the guts of the
sample speeding/slowing algorithm either.
Jari Suominen wrote:
> Thanks Dan!
>
> I will give it a try. I actually really need the length of the resulting
> audio file to be exactly what desired but as I'm not doing that hazard
> shifts this might work. And perhaps running same file through the script
> more than once would give the result I'm aiming at.
>
> More theoretical question is, are speed shifting algoritms actually
> using the ratio given to them or converting them to some other value
> before doing the conversion. And is the sample accurate 'speeding' even
> possible in reality, or is it always +/- couple samples. I tried to look
> at the SoX source but it was a bit too C:ish for me to give me an answer
> straight away.
>
> ......j
>
>
>
> Dan Richert kirjoitti:
>
>> SoX can do the job with some help. Here's a little Perl script to
>> figure out the speed scaling ratio based on the desired new length in
>> samples:
>>
>> #!/usr/bin/perl
>>
>> if(@ARGV != 3){ die "Usage: resize-audio.pl <in_file> <new_size>
>> <out_file>\n"; }
>> ($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@xxxxxxxxxxx>wrote:
>>>>
>>>>
>>>>
>>>>> 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
>>>>> _______________________________________________
>>>>> Linux-audio-user mailing list
>>>>> Linux-audio-user@xxxxxxxxxxxxxxxxxxxx
>>>>> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>> _______________________________________________
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>>> Linux-audio-user@xxxxxxxxxxxxxxxxxxxx
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>>>
>>>
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>>
>
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