Audio Time Stretch

[davegee]

Some Audio editors, Soundbooth for example, have a feature called "Time Stretch". With it you can alter the length of time a piece of music plays, albeit with the inevitable change in Tempo of the piece.

Example: Using Time Stretch on a short clip of 23.3 seconds it is possible to vary the duration of the clip from 2 seconds to 3 minutes with great accuracy. However, with my 23.3 second clip I would not foresee stretching beyond the 20 - 30 second range.

It is extremely useful for making a piece of music fit a sequence of slides as opposed to the present "Fit Slides to Music" - within certain limitations. Care is needed to maintain the "musicality" of the clip but nevertheless it is a very useful tool.

Would it be possible to include "Time Stretch" in the Audio section of a future version of PTE?

DG

[cjdnzl]

Some Audio editors, Soundbooth for example, have a feature called "Time Stretch". With it you can alter the length of time a piece of music plays, albeit with the inevitable change in Tempo of the piece.

Example: Using Time Stretch on a short clip of 23.3 seconds it is possible to vary the duration of the clip from 2 seconds to 3 minutes with great accuracy. However, with my 23.3 second clip I would not foresee stretching beyond the 20 - 30 second range.

It is extremely useful for making a piece of music fit a sequence of slides as opposed to the present "Fit Slides to Music" - within certain limitations. Care is needed to maintain the "musicality" of the clip but nevertheless it is a very useful tool.

Would it be possible to include "Time Stretch" in the Audio section of a future version of PTE?

DG

Hello Dave et al,

I use Goldwave, a so-called professional sound editor - which does appear to be professional in its abilities - and it also will stretch or compress running time of music pieces, which it does without altering pitch.

Given programs that do this already, I am not sure that I would want such a feature included in PTE. I am from the school that thinks PTE should do what it does well, without needing or having to provide capability that other programs already have.

My work flow for AV productions includes DxOptics for RAW image processing, DxViewpoint for correcting perspective distortion, Photoshop for image handling, and Goldwave for editing and concatenating music pieces into a single audio file, all before the process of making the AV show starts.

Do we want PTE to be able to do some or all of these things within the one program? Some might think so, to avoid having to purchase a number of programs, but the flipside of that is separate programs can be used where the result is not for an AV show, like compiling a music track for a gathering, or making exhibition prints, or even just holiday snaps. If it's all built into PTE then other uses are inhibited.

I wonder what other forum members think about this?

Regards,

Colin

[Barry Beckham]

Dave

I did that 20 years ago with film using a Fostex 4 track player. The Fostex had a wheel located on the body to speed up or slow down the tape speed. I discovered, that within the limitations you have already mentioned that it was often far better to extend the music by slowing it a little, rather than try and fit the slides to the music.

It works and would be a nice addition to PTE.

[Guest Yachtsman1]

I usee Audacity to compile my sound tracks, been using it over 5 years & stll finding things in it I haven't tried. It will stretch or compress using a couple of methods I know of & maybe some I don't. The add or reduce functions I've tried can only a change by couple of seconds in a 3 minute track without it becomming noticeable, particularly if the track includes voice. So IMO it would just be a gimmick unless it could do what Colin claims Goldwave will do. Better to make the current audio system more user friendly.

Yachtsman1.

[davegee]

Dave

I did that 20 years ago with film using a Fostex 4 track player. The Fostex had a wheel located on the body to speed up or slow down the tape speed. I discovered, that within the limitations you have already mentioned that it was often far better to extend the music by slowing it a little, rather than try and fit the slides to the music.

It works and would be a nice addition to PTE.

Fostex 4 Track Tape - that takes me back!

I have stuck with the Fostex brand over the years and graduated from 4 track tape to 8 track digital to my present (ageing) 16 Track VF160 16 Track Digital.

It has =/- 6% speed variation but it is much easier to do it via Soundbooth (or similar).

I believe that it would be a valuable extra tool if Igor could implement it - to be able to "fit music to slides" at the press of a button as well as "fit slides to music".

DG

[PGA]

I usee Audacity to compile my sound tracks, been using it over 5 years & stll finding things in it I haven't tried. It will stretch or compress using a couple of methods I know of & maybe some I don't.

The one I use is Effect > Change Tempo. Select the piece to change (doesn't have to be the entire clip); open the Effect window; note the total length of the selection; key a new length and observe the percentage change that will occur. Changes under 5% will usually sound OK. Changes between 5 and 10% will still often sound OK but you will be more aware of the speed difference from the original. Of course, your audience will not have the original available to do an immediate compare.

regards,

Peter

[PGA]

I believe that it would be a valuable extra tool if Igor could implement it - to be able to "fit music to slides" at the press of a button as well as "fit slides to music".

Using such a technique will nearly always leave the user with one problem: the slide transition points will not always line up with the points of musical emphasis. There will still be a need to hand-craft the matching of the slides to the music.

regards,

Peter

[davegee]

The one I use is Effect > Change Tempo. Select the piece to change (doesn't have to be the entire clip); open the Effect window; note the total length of the selection; key a new length and observe the percentage change that will occur. Changes under 5% will usually sound OK. Changes between 5 and 10% will still often sound OK but you will be more aware of the speed difference from the original. Of course, your audience will not have the original available to do an immediate compare.

regards,

Peter

Hi Peter,

So would you use it if it were available in PTE's new Audio Editor?

DG

[aplman]

If it's a one-off change to tempo, it's obviously do-able outside of PTE. My question is ... would any PTE user want to have several PTE shows, all using the same audio clip, at different tempos? If the answer is yes, I can see a case for allowing tempo adjustment within PTE. If not, there's no need for PTE to provide for tempo adjustment.

On the other hand, if it's a relatively easy matter for Igor and team to implement, it's his call.

Ken T (aplman)

[PGA]

So would you use it if it were available in PTE's new Audio Editor?

Dave,

Probably not. If the music was driving the pace and mood of the sequence, I would adjust the duration or number of images to get a pleasing fit. If I wanted to have those exact images for that exact duration, I would try and find a piece of music that fitted near enough to allow the necessary adjustments to be made using the durations of the Title/Credits slides.

However, I find I am using less and less music with my sequences. Of the last three sequences made: the one about Killhope Lead Mine used only location recordings, the one about Tocketts Mill used two short extracts from the same piece of music over the titles and closing credits, with location recordings providing the bulk of the soundtrack, whilst the most recent sequence uses 100% location sound.

When I said: "The one I use is Effect > Change Tempo", I was referring to my use of this feature during demonstration sessions and in workshops. Perhaps I should have made that clearer, but that didn't seem necessary in the context of my reply to yachtsman1.

regards,

Peter

[davegee]

Dave,

Probably not. If the music was driving the pace and mood of the sequence, I would adjust the duration or number of images to get a pleasing fit. If I wanted to have those exact images for that exact duration, I would try and find a piece of music that fitted near enough to allow the necessary adjustments to be made using the durations of the Title/Credits slides.

Hi Peter,

But didn't my OP specifically refer to fitting music to slides and not the other way around?

"If the music was driving the pace and mood of the sequence" - That's a different scenario altogether.

Never mind,

DG

[PGA]

Dave,

You asked whether I would use your proposed feature. I explained why I wouldn't.

Peter

[jkb]

If I wish to increase or reduce the duration of a piece of music I will either copy or remove a 'phrase' to get the required length.

I will then adjust slide timings to suit.

My sequences are always driven by the pace & mood of the music (or sound effects), along with achieving the best transitions possible trying to create third images. Both music & transitions are equal & both are adjusted to suit each other. I never know how long a sequence will be until I finish it!

Although I too have used 'Adjust Tempo' in demonstrations I very rarely need to use it in a sequence.

But there are times when I have, such as when I needed a ticking clock to speed up & slow down for example.

So yes, the stretch facility could be useful if easy to implement, but is not a high priority feature for me.

Something that may be more useful is change Pitch, which is needed if two pieces are not in the same key.

But then we are getting into Audio editing rather than Audio mixing which is what PTE is.

Jill

[davegee]

Time stretch and Pitch Change are both available in the same module in Soundbooth.

DG