Welcome to DMW TV, the online learning resource for students using the Digital Media Workshop at Middlesex University , Hendon Campus. Here you'll find software tutorials, guides to using our equipment and tips on getting the most out of the facility while you are at the Uni.
One of the commonest problems on any film shoot is poorly recorded sound. Often sound levels are too low meaning a lot of 'gain' has to be added to make the sound louder. Alternatively, faulty equipment or a bad recording environment can ruin the sound. Either way you can end up with very noisy audio which can be very distracting.
Luckily there have been major improvements in sound processing tech which mean (some of) these problems can be fixed. For example, Adobe Audition has powerful noise reduction filters which can rescue badly recorded sound. Here's how you do it:
First, import your noisy sound clip into Audition:
You'll see a standard 'waveform' sound display. Its sometimes easier to see the noise damage by turning on the Spectral Frequency Display by pressing SHIFT D
The example sound file is a ticking clock. The 'Ticks' are the tall spikes in the frequency display. The noise shows up as grainy dots all over the background. Before Audition can remove the noise, you have to tell it what the noise sounds like by selecting a section of the clip where there is only noise and no 'foreground' sounds. Press T to turn on the Time Selection Tool then drag out a box on the sound between two sound peaks.
With just the noise selected, go to Effects > Noise Reduction / Restoration > Capture Noise Print or press SHIFT P and Audition will analyse the noise to identify specific frequencies.
Once you have a noise print, select a bigger portion of the clip, one including the recorded sound and go to Effects > Noise Reduction / Restoration > Noise Reduction (process) and a new window will open up.
Press the Play button in the bottom left of the new window to listen to the processed sound. The filter will only affect the section you have highlighted. By pressing Play a few times, you can listen to the whole sound to get a 'before' and 'after' of the noise reduction. If the sound is really noisy, you can adjust the sliders to remove more or less noise but remember that overdoing it will start to make the sound 'tinny' and synthetic. Once you are happy with the result press the Select Entire File button, then click Apply and the sound is fixed; just save it back out to your Final Cut Pro project folder and import it back into Final Cut and you're done!
P.S. Audition is only installed on the iMacs in DMW 4 (room G123b)
There are a few rules you have to follow when editing audio.
One of the most important is that you should always cut sound clips on a 'Zero Crossing'. What's a zero crossing? -- well, digital sound is just a series of numbers, CD sound for example is stored as numbers ranging from -127 to +127. The number Zero is the same as silence. The further away from zero the number values get, the louder the sound.
In most programmes, audio waveforms are drawn with Zero along the middle of the track, with +127 at the top and -127 at the bottom (assuming you're using CD quality sound). If you zoom right into the waveform, you'll see that the sound wave goes up and down passing through Zero over and over again. In the screenshot from Final Cut Pro 7 below, Zero happens to be along the dark purple line and a single frame of video is highlighted in black:
Each point where the waveform passes through Zero is a 'Zero Crossing' and this is where you should ideally cut the audio.
But there are a couple of problems. Firstly, FCP 7 only lets you make cuts exactly on video frames. Chances are there won't be a zero crossing exactly at the beginning or end of the frame. The next problem is that wherever you have two sound clips together that don't both start and end at Zero, you'll get a nasty 'click' on the sound track where they join. So how to fix this?
The easiest and most effective way is simply to add a subtle 'Fade-In' and 'Fade-Out' effect to everysingle Sound FX clip. That way you can guarantee that every clip will start and end on Zero and there will be no chance of getting a glitch on the sound track.
You could use audio transitions from the Effects menu to add the Fade-In and Fade-Out but there is another way which is worth knowing about. Make sure you have clip overlays turned on and put a Fade-In and Fade-Out on one clip like this.
Next select the clip and go to Edit > Copy
Now select all of the other sound effects clips by pressing A for the arrow tool and drawing a box around them in the timeline. When they are all selected, go to Edit > Paste Attributes
The Paste Attributes window will open up. We only want to copy and paste the 'Levels' keyframes we put on the first clip. We also want to make sure that the keyframes are squashed or stretched to the length of the other clips otherwise they might drop off the end of the clip. Make sure "Scale Attribute Times" is ticked and then tick "Levels" as the only attribute we want to paste:
Click OK and you should end up with Fade-In and Fade-Out on every Sound FX clip with no more worries about bad clicking on the audio track.
In this quick tip I'll be reviewing the workshop session from last week about 'Audio Sweetening'.
A very common problem in post-production is editing together sound tracks with different volumes or 'levels'. Sound recorded on different shoots or with different equipment may be louder or quieter than they should be. You could adjust the levels on each clip until they match -- but there is a better way.
The Normalisation Gain tool will analyse the sound volume and automatically adjust the levels so that the volume is constant through-out your edit. Here is how to use it:
In the timeline select all the clips you want to fix
You can see from the waveforms that the volume of the sound in each clip don't match. Next go to Modify > Audio > Apply Normalization Gain
A small window will open which allows you to set the target volume in decibels (dB). Your dialog track should usually be set to around -12dB. Move the slider to -12bB and click OK.
If you play back the edit the sound levels should now match with no really loud or really quite dialog. The waveforms in the timeline haven't changed though. That's because the Normalize Gain tool doesn't alter the sound directly, instead it adds a Gain Filter to the sound. This means the changes aren't permanent and each clip can be easily adjusted if you want. Double click a clip to open it in the Viewer and click the Filters tab to see the Gain Filter settings:
Remember, negative dB values make the sound quieter, and every 3dB doubles the effect.
Here as promised is an After Effects tutorial to recreate the 'floating title' effect from last week's workshop. Before we begin, have another look at the final result as a reminder:
Stage 1: Tracking the Camera Move
Open After Effects and make a new Composition matching your video settings
Import your video file and drag it onto the composition.
You'll need to add a Camera Tracker to the video by clicking on the 'Tracker' tab of the bottom right panel. If there is no 'Tracker' tab, go up to the Window menu and make sure 'Tracker' has a tick next to it.
There are two basic options: 'Track Motion' and 'Stabilize Motion'. Stabilize lets you take shaky, hand-held video and stabilize it to look like it was shot on a tripod. It works quite well but is not going to give you as good results as a proper tripod shot -- there are no short cuts in cinematography!
We're going to use the first option. Click the 'Track Motion' button and the rest of the panel will switch on. Because there is only one video track the 'Motion Source' option should automatically select your video. The only option we need to change is 'Track Type'. Set this to 'Perspective Corner Pin'
You should now have a tracker called 'Tracker 1' on your video and some extra buttons will have appeared under the picture.
The tracker is made up of four labeled 'Track Points' at the corners of a white square. The track points are used to mark an object in the video so that After Effects knows what colours and shapes to track from frame to frame. Its important you pick a feature in the picture which is easy to track. The best features are high-contrast corners or dots. For example the white painted window frames against the red bricks make really strong tracking targets, especially if you put the track point right on the corner of the window frame.
You can move each track point by clicking in the smaller square inside it. Move the mouse inside the square until you get a black arrow head and direction arrows. If you see a white arrow head, move the mouse a bit more until it is over the edge of the little square. You can then click and move the tracker. You should see a magnified section of the video to let you easily pick a good tracking target. Move it until the corner of the window paintwork is in the middle of the square like this:
Do the same for the other Tracking Points until you've got a large rectangle lined up with the background. Remember each tracker needs to be on a clearly visible corner in the picture.
When all the tracking points are positioned properly, its time to start tracking. Down in the Tracking panel at the bottom right there are some 'Analyse' buttons. Pressing the 'Analyse Forward' button will start After Effects looking through all the frames of video. The tracking points should stay stuck to their track targets in the video and follow them like they were pinned to the picture. At the end of the analysis, the path followed by the Track Points will be shown as a grey 'squigly' line:
If everything has worked, After Effects has tracked the video and created keyframes recording the movement of the track points through-out the video. If you click on the arrows on the video track to open up the properties, you'll see the Tracker and Track Points along with their keyframes in the timeline:
Section 2: The Titles
Now that we have a track of the video its time to create the titles. We'll be using a Text layer with Layer Styles to very quickly create solid looking text with shadows and highlights. By adjusting the lighting on the layer styles to match the real lighting in the video, a much more realistic and convincing effect can be achieved.
First off, make a new Text layer: Layer > New > Text
You can adjust the basic font settings in the Character panel which should be on the middle right of the screen. Because we'll be shrinking the text layer into the background of the video, we want to start off with the text as big as possible so that it fills the tracked rectangle. You can change any of the yellow coloured values just by clicking on them and moving the mouse left to decrease the value or right to increase it. To help the text to 'sit' in the picture better you should make sure you colour it to match the colours in your video. The buildings already have a dramatic colour scheme. The red bricks contrast nicely with the battleship grey of the metal cladding. You can use the 'eye dropper' tool to pick the grey colour for the text which will make it stand out against the brickwork in the background. Make sure you select the text before you make changes to the font.
After adjusting the size and colour of the text, you should have something like this:
At the moment its a bit dull and flat, but its easy to make the text look more 'solid' with some layer styles. Go to the menus and find Layer > Layer Styles > Bevel and Emboss, this will put shadows and highlights around the text edges to make look less flat. Next put a drop shadow behind the text with Layer > Layer Styles > Drop Shadow. Both of these effects take light direction into account. To make the text look like its really in the video, we need to adjust the light direction to match the real world. Its obvious from the video that the sun is coming in from the right and the shadows are pointing to the left. The properties for the effects are accessible in the bottom panel next to the time line. Click on the arrows to open the properties for each effect and change the Angle value to match the lighting.
Play around with the other properties, especially Distance and Opacity until you get something like:
Stage 3 Corner Pin
To create the illusion that the text is floating in the video, we have to "map" the text layer onto the rectangle made by the Tracker. The Corner Pin effect does just what it says -- it pins the corners of a layer on to four points on the screen. If the points move, the layer will follow. The Tracker has already created keyframes for its four corner points under the Feature Centre property. All we have to do is add a corner pin effect to the text layer, then literally copy and paste the keyframes from the tracker points to the corner pin effect. First, click on the text layer to select it then go to Effect > Distort > Corner Pin
Open up the properties of the text layer and expand the Effects section, then Corner Pin.
The four corners of the text layer are set to the corners of the composition size ( 0, 0 for the top left and 1280, 720 at the bottom right). Scroll down to the video layer and expand its properties until you find the first Tracker Point's Feature Center keyframes. To select all the keyframes, just click on the name of the property. The selected keyframes will be coloured yellow.
Then just go to Edit > Copy or press CMD C go back to the Corner Pin effect and click on "Upper Left" and paste the keyframes ( Edit > Paste or CMD V ). The Tracker points and corner pin points are in the same order so copy and paste keyframes from each one in turn.
And that's it! If you play back the composition, the text should move along with the video as if it was always part of the picture. The last thing to do is render out a video to edit into your film.
You probably know that you can fade audio tracks in or out by adding a "Fade" effect to your clips in the timeline. But you can do the same thing much quicker by using Clip Overlays and Keyframes.
You can turn on Clip Overlays by pressing the Toggle Clip Overlays button underneath the timeline. The keyboard shortcut for this is ALT and W. When you turn this option on, Final Cut puts a pink line over the audio tracks. The pink line is a volume control for the sound clip measured in Decibels (dB). Pulling the line down with the mouse will make the whole clip quieter and pushing it up will make it louder. Even better, you can also adjust the volume of parts of the clip by adding keyframes to split the line into sections.
To add keyframes to the volume, turn on Clip Overlays then select the Pen tool from the tool box by clicking on the icon at the bottom -- it looks just like the Pen tool icon in Photoshop. The quickest way to activate the Pen tool is to press the P key. Switch back to the normal mouse pointer by pressing A for Arrow. If you hold down the Pen icon you'll see that there are actually three versions of the tool. For now you'll only need the standard Pen but once you've mastered that, play around with the others to see what they do.
Once you have the Pen activated, just click on the pink Clip Overlay line to add keyframes. If you want a fade in or fade out, you'll need at least two keyframes -- one to set the clip's normal playback volume and one to turn the volume down to silence. When you're measuring volume in Decibels, silence isn't Zero like you might expect. Instead silence is defined as minus Infinity Decibels. Put two keyframes near the end or begining of the sound clip then press A to turn the Arrow tool back on so you can pull the line up or down. Moving the line sections nearest to the ends of the clip down to -inf dB (minus Infinity) will create a Fade-In or Fade-Out Effect. You should see that the line makes a smooth curve from the playback volume down to silence. This gives the best sounding fade effect, but you can set this to go in a straight line if you want.
Fade-In and Fade-Out added to a clip by using Keyframes in the Timeline
Here's a very quick tip for customizing the timeline in Final Cut.
You can show your video and audio clips visually in the timeline by using the Timeline Layout Menu. Click on the small, right pointing arrow below the timeline to open the Layout Menu. The top two options are off by default. "Show Audio Waveforms" will draw the sound waves in the green audio tracks. This gives a really quick visual guide to spot things like audio peaks. "Show Video Filmstrip" will add still frames along the whole video track giving a quick way to spot where the action is. It can sometimes make the edits hard to see though so you'll probably want to switch it off occasionally.
Turning on both options makes the timeline look like this:
Here's another quick tip for Final Cut that will make all your editing work easier.
While you're editing your movies, you'll spend most of your time working with Final Cut's Sequence Timeline. By default, the timeline shows you the minimum you need to edit your clips and sound track, but there is a lot more information that can be shown.
The basic timeline looks like this:
Along the bottom of the timeline window are some really small buttons which control the display
Timeline Track Height
This little panel controls the size of the video and audio tracks in the timeline. Selecting the different sized boxes makes the tracks taller or smaller. You can also press the SHIFT and T keys to cycle through the different track height settings.
Clicking the tallest box makes the timeline look like this:
You can zoom into the timeline to focus on a few shots or zoom out to get an overview of the whole sequence. There are few ways to zoom. First, you can use the Zoom Slider control at the bottom of the timeline. Moving the small grey pointer to the right zooms out, showing you more of the edit and moving to the left zooms in to focus on a shorter time period.
Zoom Slider
There are also keyboard shortcuts for the same thing. Pressing the CMD key and = together zooms in while CMD and - will zoom out. If you have a Mac laptop, you can zoom in and out by doing a two finger 'pinch' gesture on the trackpad just like on an iPad or iPhone.
Zooming in completely lets you see individual frames of video which is really useful if you have an 'orphan' frame left between clips caused by a messy edit. Final Cut draws a dark grey highlight over the time code strip of the timeline representing one frame right next to the play head like this:
The final way you can zoom in and out of the timeline is to use the tags at each end of the window sliding bar at the bottom of the timeline. Pulling the tags apart stretches the sliding bar showing more you more of your edit (zoom out). Pushing them together does the opposite.
Window Slider: Use Left and Right Tab to Zoom In and Out
If anyone needs any inspiration for their film titles, check out ArtoftheTitle.com one of the best film related sites you'll see. They have full breakdowns of the title sequences of some of the most famous and less well known films including work by Saul Bass and Kyle Cooper.
Hi Guys,
Some of you have been having problems exporting your soundtrack from Final Cut. If you've had issues with the sound freezing and stuttering in your Quicktime files, check to see if you've got any .mp3 files in your edit. Final Cut really doesn't like editing mp3 sounds 'natively' ( i.e. without converting it to some other format first).
You should always use uncompressed sound in your Sequence. Compressed formats such as mp3 cause lots of problems; for example, Final Cut has to render the file before it will play back slowing down the overall editing process, mp3's are often so compressed that the sound quality starts to suffer, and finally, lots of mp3's use variable bit rate encoding which can lead to timing and sync issues.
No professional editor would use mp3's on their soundtrack so you shouldn't either! The same goes for other compressed formats such as OGG, AAC, or WMA.
Always use something like Soundtrack Pro or iTunes to convert your compressed files into AIFF files before you start editing in Final Cut.
Check the blog post about converting files to AIFF using Soundtrack Pro. Your audio file settings should always match the settings of your Final Cut project. For the DMW this will be set to: 16 bit integer, 48000 samples / second.
BlackMagic DaVinci Resolve Lite has been installed in all the Digital Media Workshops. If you are TVP or TVP Tech Arts student learning about colour correction, you can use any open access workstation to correct your footage or just spend time learning the software. The Resolve manual and sample files are available in the folder /Users/Shared/Resolve
Loads of you have been asking about shooting on green screen so here's a quick tutorial covering the basics of chroma keying with After Effects. I'll be showing you how to 'pull a matte' from your green screen shot with Keylight, then replace the background with another still image or video.
First things first: setting up the project.
Open up After Effects and click on "New Composition" on the Welcome screen
On the Composition Settings window, set up the resolution and frame rate to match your video. If you're using the JVC HM100 with our standard settings, you'll want to set this to HDV 1280 by 720 at 25 frames per second
After that click OK then import your video from the Film menu.
Next you will need to drag your video onto the viewer of your Composition. You'll see an outline of the frame to help you line up the footage.
The box will snap to the edge of the Composition to make sure its centered properly.
Now the Comp is set up, you're ready to add a keying effect to the video. Click open the Keying section of the Effects & Presets panel and find KeyLight (1.2)
Drag it onto your video strip in the timeline and let go. You should get the Keylight controls appear on the left of the screen.
Find the setting called "Screen Color" and click on the eyedropper next to the Black colour swatch. Use the dropper to select the green colour of the background. You need to pick a part of the screen with an average green tone, not over-lit or under-lit and not too close to the foreground subject otherwise you'll risk picking an off green colour which doesn't match the actual colour of the backing.
It looks like nothing has happened, but if you go to the View setting and pick "Screen Matte" from the menu, you'll see the alpha matte you've just made from the green screen plate.
This grey-scale image is what will make your video semi-transparent. Solid Black is completely transparent and lets the background show through, Solid White is fully opaque and shows the foreground image.
There are a couple of problems with the matte right now. Firstly there is some grey noise in the background especially in the corners. This is going to make the green screen show through a bit and discolour the background. Second, there are patches of grey on the actress particularly on her dress. Remember, anything but solid white is going to be slightly transparent so in the final shot you'll see the background showing through her body. To fix this, you'll need to increase the contrast of the matte image until the background is solid black and the actress' body is solid white.
Her shawl is trickier because its naturally transparent and needs to stay a shade of grey.
Keylight provides settings to control the matte's contrast. Click on "Screen Matte" to open the controls, then click open "Clip Black" and "Clip White"
Increasing the Clip Black will start to 'eat away' at the noise in the background. Turning down Clip White will start to fill in the grey regions of the dress. Its REALLY important that you adjust the sliders by the absolute minimal amount that gives a good result. If you over do it, you'll damage the matte image and end up with an ugly final composite.
Finally you should test the matte to check its giving good results. The best way to do this is by putting a coloured solid behind your subject. To add a solid, click on the matte image, then go to Layer -> New -> Solid
Make sure the size matches your original video resolution then pick a bright red with the colour swatch.
Click OK and the new Solid will appear on the timeline. You may have to re-order it in the layer stack to get it behind the video by using the Layer -> Arrange menu. Finally you'll need to set the View property of Keylight back to "Final Result".
Hopefully you should have a nice clean foreground subject on a solid red background. If not, go back to Keylight and adjust the settings until you get a good, clean key. Once you've done that, you can swap the Red Solid for a still image or video and you're done!
That's it for now. If you're trying a green screen shot and get stuck any of the DMW technicians will be able to help you out.
