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<div class="moz-cite-prefix">Thank you, Doug!<br>
<br>
This didn't exactly work, but your overall approach gave the the
solution I've been looking for.<br>
<br>
First, to clarify, all our recordings are digital; even digital
devices often run at slightly different speeds, according to the
Internet.<br>
<br>
I also had to reverse the ratio (video/audio) and changed the
audio speed rather than the video speed, because I want the
resulting audio track to be in sync with the actual video in ELAN.<br>
<br>
One minor complication is that my audio and video files aren't
exactly the same length; of course I can trim the beginning or end
off of either file, but for the total duration ratio to work I
will need to trim very precisely.<br>
<br>
The reason it didn't work to use Praat is that I couldn't find any
Convert menu. I'm using Praat version 5.3.85. I found Convert
here and there a few places, but nowhere with a "Lenthen..."
option.<br>
<br>
However, the basic idea of figuring out the ratio of length
between the two files did work. Here's what I ended up doing (in
case anyone else also struggles with this):<br>
<br>
1) Open both files in Audacity (the original audio file and the
audio file extracted from video).<br>
2) Find a salient sound event as close to the beginning of both
recordings as possible, and a salient sound event as near the end
of both. I'm trying to get into the habit of clapping my hands at
the beginning and at the end of a session.<br>
3) Carefully measure the distance between the salient sounds on
both recordings.<br>
4) Determine the ratio of audio / video. Convert to a percent by
shifting the decimal 2 places to the left.<br>
5) Under the Effects menu in Audacity, change tempo for the audio
track by the indicated percent. If the original audio file is
longer, it needs to be a negative percent.<br>
6) Voila! Both files should be at the same speed now. Now just
align them, and I'm good to go!<br>
<br>
Thanks, and I hope this helps someone else.<br>
<br>
Lindsay<br>
<br>
On 9/17/14, 10:20 AM, Doug Whalen wrote:<br>
</div>
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cite="mid:2C91F821-B94B-4543-AAAE-9097147DC338@haskins.yale.edu"
type="cite">
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Dear Lindsay,
<div> It seems likely that your video recorder was not digital;
hopefully the audio recorder was. If so, do the following:
Open the two audio files in Praat. Get the (exact) ratio of
the from-audio wav file to the from-video wav file
(dur_from_audio/dur_from_video). Select the from-video sound
object. From the Convert menu, choose "Lengthen (overlap-add)".
This will use the PSOLA algorithm to change the duration but
maintain the original F0. Put your ratio in the "Factor" field
and click OK. This should create a new sound object with the
same duration as the from-audio file. Check to make sure it all
seems right. </div>
<div> Don't forget to save the new sound object! It's not a file
until you save it.</div>
<div> Hope this works, Doug DhW</div>
<div><br>
</div>
<div><br>
<div>
<div>On Sep 15, 2014, at 4:16 PM, Lindsay Marean <<a
moz-do-not-send="true" href="mailto:lmarean@bensay.org">lmarean@bensay.org</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">I'm hoping that someone here on ILAT
has run into this problem and can suggest a way to deal with
it:<br>
<br>
We're recording fluent speakers talking, with both audio
recorders and video recorders. Recently I recorded a
session in which an audio recorder picked up one speaker
really well, and a video recorder picked up another speaker
really well. I can use Audacity to combine the audio (one
on each stereo channel) into a single WAV file that I can
then use with ELAN for transcription.<br>
<br>
The problem is that the two recorders don't record at
exactly the same speed. In a long session, this difference
becomes very noticeable - the two tracks may be perfectly
synchronized at the beginning, but they will be out of sync
by the end.<br>
<br>
Here are a few things I've found on the Internet that I
think discuss the same issue: <a moz-do-not-send="true"
href="http://www.acoustica.com/mixcraft/v4/help/hs1550.htm">http://www.acoustica.com/mixcraft/v4/help/hs1550.htm</a>
and <a moz-do-not-send="true"
href="http://forum.audacityteam.org/viewtopic.php?f=46&t=75868">http://forum.audacityteam.org/viewtopic.php?f=46&t=75868</a>.<br>
<br>
I've been trying to use the change tempo function of
Audacity to adjust one track, but it's been trial-and-error
- change by a small value, see if it works, and then when it
doesn't, undo the change, and change by a different small
value. So far my approach is really time-consuming but
still not really successful for making a transcribable
track.<br>
<br>
Has anyone else dealt with this problem? How? Does anyone
know of a better way to get both tracks moving at the same
speed, beginning to end?<br>
<br>
Thank you!<br>
Lindsay Marean<br>
</blockquote>
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<br>
<br>
<div apple-content-edited="true">
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<div><span class="Apple-style-span"
style="font-family: Tahoma, Verdana, Arial,
sans-serif; ">Douglas H. Whalen, President <br>
Endangered Language Fund <br>
300 George St., Suite 900 <br>
New Haven, CT 06511 <br>
USA <br>
+1-203-865-6163, ext. 265 (or 234 for Whalen) <br>
<a moz-do-not-send="true"
href="mailto:elf@endangeredlanguagefund.org">elf@endangeredlanguagefund.org</a> <br>
<a moz-do-not-send="true"
href="http://www.endangeredlanguagefund.org">www.endangeredlanguagefund.org</a></span></div>
</span></span></span></div>
</span></span>
</div>
<br>
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