Hello and welcome to the eleventh video in this Beginner's Guide to Adobe After Effects.
In this tutorial I'm going to demonstrate how you can easily slow down
or speed up your video and keyframe sequences in After Effects. So over the
last few episodes we have learnt about animation principles and how to create
simple animations. Now one of the main factors when creating video sequences is
time, we use the timeline to set our keyframes to animate and to edit our
video to create a video presentation to a specific time. As you start to build in
After Effects there are going to be various occasions where you'll want to
customize the time it takes for an effect to happen, the speed of an
animation, or even the speed of a video. Now you may want to slow something down
or speed something up, in this video I'm going to demonstrate how you can easily
slow down or speed up your keyframe sequences and use a feature called time
stretching to slow down or speed up your video. So in this video we are going to
be covering the following topics: Adjusting a keyframe sequence over time
and video time stretching. So let's get into it!
So here I am in After Effects and I have the project open that we worked on in
the previous video. Now to follow along in this video I suggest you have the
project you worked on in the previous video open, if you can open it great
though if you don't have it to hand or you're new to this course and wish to
follow along you can open this document I have prepared especially for you in
the project folder that goes with this course. You can download this project
folder for a small fee the download link with instructions is in the description.
The download folder comes with lots of exercise documents we will be using on
this course that have been carefully developed to
aid your learning experience. The folder also comes with document resources such
as videos, graphics and images you can use to build your first video
presentation from scratch later on in this course. To get the full learning
experience I recommend you get the project folder. Download link with
instructions is in the description. So with the project folder open, click
into the S2 essential practice folder, into the 11th folder, time stretch and
let's start with the time stretch After Effects file. So open this up and you will
have the same document I have opened here. So if we look down in the timeline
panel and look at the numbers on the time ruler, we can see that the
composition time space is approximately 10 seconds, so I'll make sure my time
indicator is at the start of the timeline and I'll press spacebar to
activate preview and here we can see that the animation sequence spans the
entire 10 seconds of the comp. OK so what if I want to speed up the animation
sequence. Now we could click and drag the keyframes individually to change the
sequence but that would be tedious and time-consuming, here is a quick tip. So
I'll press spacebar to stop the preview and I'll carefully come down into the
timeline panel and click before the first position keyframe and drag over
the first keyframes for position, scale and opacity then I will hold shift and
click and drag to select all the other keyframes. When we select the keyframes
they will turn blue, so make sure you have all the keyframes selected and with
them all selected I'm going to come to the end frame then press and hold alt on
the keyboard then click and drag my keyframes in like so, by holding alt and
dragging we can alter the time of the entire sequence of keyframes. So instead
of my sequence spanning 10 seconds let's hold down alt and drag the sequence to 5
seconds so it's half the composition. So I'll make sure my time indicator is at
the start of the timeline and I'll press spacebar to activate preview. So now we
can see that the animation sequence happens a lot faster, now notice when the
preview line gets to the end of the keyframes the circle stops, well this is
because the sequence has ended. Now if you want to preview just the sequence
between 0 and 5 seconds here is another quick tip. So I'll press spacebar to stop
the preview and now if I click and drag my time indicator over to the last
keyframe while holding shift, the time indicator will snap to the keyframe
below, so on the keyboard I will press N, upon click
you will see the work area just below the time ruler snap to the time
indicator. So now the work area is set to five seconds. So I'll make sure the time
indicator is at the start of my time line and I'll press spacebar to activate
preview. So now I can watch the animation in a loop and it's much faster and I'll
press spacebar to stop the preview. OK so with the keyframes still selected I'm
going to come to the end keyframes and press and hold alt on the keyboard then
click and drag my keyframes out again like so, this time I'll drag out to
around seven seconds. So now instead of my sequence spanning five seconds it now
spans seven seconds. Now if I click and drag my time indicator over to the last
keyframe while holding shift the time indicator will snap to the keyframe below,
on the keyboard I will press N, upon click we will see the work area just
below the time ruler snap to the time indicator. So now the work area is set to
seven seconds, so I'll make sure the time indicator is at the start of the
timeline and I'll press spacebar to activate preview and now we can see the
animation sequence happens a little slower but faster than at ten seconds. So
that's a really easy way to alter the timing of an entire set of keyframes
applied to an effect. So next I'm going to show you how you can alter time for
video, so with the project folder open click back into the S2 Essential
practise folder, into the 11th folder time stretch and open the video time
stretch After Effects file and you will have the same document I have opened
here. So if I make sure the time indicator is set to the start of the
timeline, I'll press spacebar to activate preview, so here I have a video of a
little Bee I took in Hyde Park in London collecting some pollen and right now
this is playing at its original speed and right now we can see that this clip
is spanning 25 seconds on the timeline. Now what if I want to speed this video
footage up or slow it down. Well here is how you can do this. So I'll press
spacebar to stop the preview and I'll first click on the layer to select it
then I'll right-click and come up to time, then scroll over and select time
stretch, upon click we will active this little option window. So here we can
see the original duration and under this there is a stretch factor which is
currently set to 100%. OK so let's try and speed this up first. So in the
stretch factor I'm going to type in 50, so by doing that I'm going to speed up
the video clip by half, so it's going to play at twice the speed. With 50 entered
I'll click OK, now upon click notice the bar for the video clip has now
changed, it no longer spans the entire length of the composition, this is
because we just changed the time of this clip. OK so I'm going to drag the time
indicator towards the end of the bar holding shift, when the time indicator
snaps to the end of the bar I'll press N on the keyboard to snap the work area to
the end of the clip like so. So I'll make sure the time indicator is at the start
of the timeline and I'll press spacebar to activate preview and now we can see
the video is playing faster. OK let's try even more, so I'll press spacebar to
stop the preview, again I'll click on the layer to select it right-click come up
to time, then scroll over and select time stretch, again we will activate this
little option and this time in the time stretch factor I'll type in 25 and click
OK. Notice the bar from the video clip has changed again and is now smaller
than before. So again I'm going to drag the time indicator towards the end of
the bar while holding shift, when the time indicator snaps to the end of the
bar I will press N on the keyboard to snap the work area to the end of the
clip, I'll make sure the time indicator is set to the start of the timeline and
I'll press spacebar to activate preview and now we can see the video plays
really fas,t that is a busy bee! OK so this time let's try slowing it down, so
I'll press spacebar to stop the preview, again I'll click on the layer to select
it right-click and come up to time, then scroll over to select time stretch, we
will activate the little option here this time in the time stretch factor
I'll type in 200, this will now double the original time and I'll click OK.
Notice the bar for the video clip has now stretched over the entire composition
and now exceeds the timeline span. What I can do this time is come up to
composition down to composition settings and in
duration I can change this from 25 seconds to 50 and click OK.
So now I want to span the work area to the entire composition, a neat trick here
is to come up and simply double-click on the workspace area, by double-clicking on
this it will quickly snap to the entire duration of the comp. So I'll make sure
the time indicator is at the start of the timeline and I'll press spacebar to
activate preview and now we can see the video has slowed down. So by using time
stretch you can speed up or slow down your video easily in After Effects. Now
what if we want to apply this effect to a series of clips at once, instead of
just one clip well in a previous video we learned how to edit multiple video
clips in After Effects in a single composition. Now at this point it would
be helpful for you to learn about pre composing in After Effects. Pre composing
basically allows you to take multiple layers in compositions and place them
into a single composition to allow you to control that one composition
separately. Pre composing in After Effects can make your workflow much
easier and improve your organization and it allows you to work much more
effectively. In the next video we are going to look at pre composing in After Effects.
So see you in the next video!