Hi all,
OS. Slackware Gnu Linux 14.2 (the present stable release of slackware)
Audacity Version: 2.1.2
I’m trying audacity to synchronize an “italian” audio track against the original one in “english”. I have the english version of this movie (audio/video) and I want to add the italian language track.
The problem seems that the “out of sync” is not just “constant” nor “linear”, but changes “randomly”: if you synchronize an “event” at the beginning and an other near the end of the track, you will not obtain a fully synchronized track. Hope I explained that clear enough (sorry for my english).
I solved by working from the beginning of the track, synchronizing a first part, a second, and so on until the end of the whole track.
I used the Audacity “change tempo” effect to “stretch” or “compress” the part I was synchronizing. I used also labels to mark the “referring events” which the sync is based on.
The following points explain what I did exactly:
1- load “master track in english” (to not altered because it perfectly fit the video stream)
2- load the italian track to edit
3- looking for the first ref event: let’s name R1eng that event on the english track and R1ita the same event on the english track.
This event has to be as near as possible to the begining of the movie, it could be a big clean noise suhc as a gun shot, a “slam” of a closing door or something similar. Also a word, for example in my case I chose one of the first words spoken at the beginning, it was “alive” in english and “vivo” on the italian track).
4- I selcted that “R1ita” on the italian track and added a label for it (tracks - add label to selection). Then selected R1eng on the english track and add its label.
5- Finally I shifted the italian track so that R1ita and R1eng were exactly at the same time. For this the label R1eng it is very useful thanks to the “lighting alert” when the mouse pointer.
Then I had to add a silence at the beginning of the ita track or to cut its first exceeding part…
Now we have the first event in sync: R1 is at the same time on both the tracks and occur exactly at the same time of the set label R1eng. We can rename it “R1” and delete R1ita label.
6- I now check the tracks, look for an other event out of sync “R2” and set labels “R2ita” and “R2eng”.
7- This time we can’t shift the italian track, otherwise the R1 would go out of sync. We have to keep R1 in place and “stretch” or “compress” the italian track so as R2ita = R2eng.
To achieve that I used the following operations:
- select the portion R1-R2eng
- effects, change tempo
- annotation of the time duration R1-R2eng
- this will must be the time duration of R1-R2ita so that R2ita=R2eng…
- exit from the change tempo dialog window by pressing “cancel”: we opened this effect just for reading present duration with the needed precision “seconds,cents”…
There must be a smarter way to obtain that value, but I didn’t know none… - select R1–R2ita, open change tempo effect and set the new duration “seconds,cents” annotated before and finally apply the effect.
8- Now R2ita should coincide exactly with R2eng. We can delete R2ita label and rename R2eng to R2.
And so on, looking for R3 out of sync, labels, keep in place R2, drag R3ita so that is in sync with R3eng, etc, etc…
Following the above operations I obtained a new ita track synchronized with the original english video. Anyway I think there should be an easier method, especially to drag the end of the track portion out of sync and make coincide it to the corresponding event on the “master” track.
Change tempo effect is too uncomfortable to set (time annotation, portions selections and so on slow down all the work). I think it could be much easier:
- set the two labels, for example R2ita on the ita track and R2eng on the english track
- select the portion of ita track from R1 to R2ita
- select a “change tempo tool”
- click on R1ita extremity of the selected portion and hold down
- drag the R1ita and place it at the same time of R2eng label
In this way there would no need to know any numerical duration of the portion R1-R2. Would be all just visually done and much speedy. I suspect should already be a similar way to work… But I don’t know audacity, I haven’t used it since a week ago. So I’m there to asking for suggestions or explanations.
Could anyone suggest a better method to do this tracks sync operation with audacity?
PS. 1
Other software suggestions would be welcome too, if you had any idea about a more suitable tool for this purpose.
PS. 2
I think this topic it isn’t related to a specific OS. Anyway I’m using Linux, so I posted in this section. It could not be the most appropriate (perhaps in windows section or mac-os was seen by more users).
In case moderators please move this to the right section.
PS.3
Sorry for the length of the post!