A Guide To Visual Effects

If you want to know anything about how visual effects in film and video are achieved, there’s one word you should keep in mind…layers. All visual effects and optical illusions are constructed on the bases of images layered on top of each other. Before the advent of computers, visual effects were achieved by placing paintings in front of the camera, appearing on top of the action in order to create bigger and more fantasized locations. Another method was to reprint two layers of action into one single image to create an optical illusion.

matte

As technology advanced, filmmakers perfected methods to composite images together to create optical illusions. These advances came with the advent of motion controlled cameras and chroma keying (also known as blue or green screening). The ability to remove a single colour (blue or green) from one image, and replacing the colour with another image.

before-after-green-screen

We’re now in the digital age, we use computers for nearly everything, and so do filmmakers. Computers are now used for compositing images for optical illusion. They’re also used to create computer generated images. The most recent advancement is motion capture technology, giving a performer the ability to give life to a computer generated character. Whatever the method, the images created are always layered and composited from a range of sources to create a visual effect.

Lord Of The Rings Two Towers: the character Gollum who's role is crucial to the journey of Frodo and Sam--Gollum's movements are performed via computer program by actor Andy Serkis.  Photo: New Line Cinema
Lord Of The Rings Two Towers: the character Gollum who’s role is crucial to the journey of Frodo and Sam–Gollum’s movements are performed via computer program by actor Andy Serkis. Photo: New Line Cinema

Are you thinking of creating a visual effect for your film or video and unsure where to start? Then here’s my advice. Start by drawing the shot you’re trying to create. Now break it down into sections, this could include location and background, performers, and anything else that is moving in your shot. Think about what sections of the image you are definitely able to capture in camera on a one to one scale. Now think about the sections of the image that are more of a challenge to capture in camera. Could you use miniatures, puppeteers, animation and/or computer generation? It’s in this section where blue or green screening becomes an effective method of separating your elements and compositing them together into one image.
Things to keep in mind when creating your images are the lines between where one section of your image meets another and the one to one scale elements you can not miniaturize which are light, water and fire.



A Guide To Sound Design & Mixing

Happy New Year!

How was your Christmas and New Year Celebrations? Hope it was festive. Now on with this weeks topic, sound design and mixing.

As I said in my previous article on capturing sound, sound is as, if not more important than the visuals. Sound has to go through the same amount of cleaning and editing as the video.

Before I carry on with this article, it is worth pointing out, I only know information about the sound tools that I am using, and how they effect my audio files. I do not know the physical science behind sound, I am not a scientist. Now that I’ve got that out of the way, let’s begin.

Introduction To Sound Effects
In your sound editing software you should have a library of effects you can use to correct and create your sound. There are so many it would take me a lifetime to go through all of them and what they achieve. In this article I will start with the basics. Leveling, Noise Reduction, Parametric Equalization, Multi-band Compressor, Hard Limiter, Dynamics Processing and Reverb.

Leveling
The first stage in creating your master sound mix is to level everything contained within the sound file. For example if you have two voices in one clip and one voice is louder than the other, it’s important that both voices peak at the same level. If you read my previous article on sound recording, I mentioned the sound meter starting at -48dbs increasing to 0dbs. Your sound editing software should have the same meter and a waveform reader. Your sound should be kept between -24dbs and -6dbs. Pick a level between these numbers and keep your voices peaking at this level.

sound_levelling

sound_noisereduceNoise Reduction
No matter what microphone you use, it’s inevitable to pick up other noises. The first to look at removing is background hiss. In every sound recording there is a certain amount of background hiss. This process is simple, first highlight the only segment of your clip containing the hiss and tell your software to analyse it. Then highlight the whole clip and tell your software to reduce the background hiss. However there are some limitations. If the background hiss is quite loud, your audio will sound like it’s coming out of baked bean tin when reduced. There are settings you can adjust to get the perfect hiss reduction, but this is why it’s so important to get the capturing of sound spot on.

Now that the hiss has been reduced from your sound clip, you will notice certain clicks, pops and unwanted sound. For this it’s best to use a histogram reader whilst listening to your sound clip to become aware of them. Using the tools in your sound editing software you can reduce the unwanted noises in your histogram.

sound_EQParametric Equaliser
Simply put, the parametric equaliser tool in your sound editor is there so you can balance the frequencies in your sound file. When highlighted the graph presented to you should read on the Y axis the frequencies from 0hz to 48,000hz, and on the X axis how loud the frequency is in decibels. The line on the graph allows you to adjust the volume on each set of frequencies. As a baseline standard for vocals I like to use the preset “Vocal Enhancer”, and then click the LP on the right side of the toolbar to lower any high frequencies. This setup should be a good step in getting a nice crisp sounding vocal.

sound_multibandMulti-band Compressor
This is a different form of making sure your sound frequencies are perfectly levelled and do not peak above a certain decibel. In the Multi-band Compressor tool is the preset “Broadcast”. Once you select this you will notice a considerable jump in volume. Use the master decibel notch to take it down by three decibels. This setup will raise the desired frequencies to give you a nice crisp
sound without peaking too loud.

 

 

 

 

sound_dynamiccompressHard Limiter & Dynamics Processing
These two tools are a variation on the same job. These two tools again make sure that your sound file doesn’t peak too loud. The hard limiter is more of a harsh tool for making sure your sound doesn’t peak above a selected decibel. I prefer to set mine to 6db. With the Dynamics Processing tool, it uses a graph to create a more dynamic cut off point for loud peaking sounds. Your original sound decibels appear on the X axis of the graph, ranging from 100 to 0. On the Y axis is the final decibel output of your sound. By adjusting the line on the graph you have control over the output of your decibels. On my graph, I create my first point at X-20 and Y-20, and a second point at X-0 and Y-0. I take my second point and drop it to Y-10 on the graph.

 

Reverb
Reverb is the adjustment of yours sound’s reverberation. Noises sound different depending on the location and how the sound waves react to it’s surroundings. Reverb is an effect that allows you to adjust the way your sound reacts to it’s location, or create a location for your sound. For example you can use this tool to make something sound as though it’s coming from a grand hall, a small bathroom or a cave. Check out it’s presets and see what happens.

In summary you should now be able to create a sound mix for your vocal soundtrack and other sound recordings in your editor by:

  • Leveling your sound file using the decibel and waveform reader.
  • Reduce hiss, clicks, pops and other unwanted sound using Noise Reduction.
  • Equalize your sound frequencies using the Parametric Equalizer.
  • Level your sound frequencies using the Multi-band Compressor.
  • Create a harsh cut off point for your loud peaking sounds using Hard Limiter.
  • Create a dynamic cut off point for your loud peaking sounds using Dynamics Processing.
  • Create an environment for your sound using Reverb.


A Guide To Recording Sound For Video

This is where a lot of filmmakers fall short. It’s imperative that your video has good sound. Video and sound are as important as each other. If your visuals aren’t looking great, make sure your sound mix is perfect, and your audience will forgive you. If your visuals are much better than your sound mix, it will get ripped to shreds. A lot of this boils down to a great sound design in post-production, and in the film & video industry, more money is put into creating a top notch master sound mix. First you need good sound recordings to use for your master sound mix.

Listen To My Voice
All sound mixes in video productions are completely artificial. There are two things you want when recording sound during production. The first is good quality voice recording. All other sounds have the ability to be re-recorded and manipulated after production. The second is ambience. Because the sound gets mixed in post-production, the only thing the sound designer wants from the production recordings is crisp clear dialogue. The ambient sound is mixed under this.

microphoneH4n_screen_meterDirectional Microphones & Metering
There are different types of microphones used for a specific purpose. I use a directional microphone capturing 90° of the sound from where I point it, thus getting the specific sound I intend to capture. On my sound capturing device is a sound meter in decibels from -48 going up to 0. It’s best to avoid recording anything over -6bd as your sound will be distorted when played back. I recommend capturing sound between -24db and -6db.

Setting Up Your Sound Recording Device
Like a camera, you can set how many frames per second of sound you want to capture. I recommend keeping it as the same frame rate on your video. The last setting you can change is the frequency. Simply put this is the information of your captured sound. Most sound frequencies in the final video is outputted at 48000 kilobytes of information per second. I record 92000kps so I have as much dynamic range to manipulate in post-production, and then export at 48000kps.

boomopAs Far In As You Can
In video production you want to get the microphone as close as you can to the subject without the camera seeing it. You simply have to communicate with the camera operator to mark this position, and then camera can roll. A good tip I picked up from sound recordist Eduardo João Gama is to point the microphone at the person’s chest to get good quality voice recordings. (Don’t know why, possibly something to do with acoustics, all I know is it works.) I have a 3 metre boom pole, which is great for getting the microphone into medium sized shots. However, in a single take you might want to film a close-up of someone talking and zoom out to a wide shot. This is where a radio lavalier microphone comes in handy. Connecting a receiver to your sound recording device, and a transmitter with an attached microphone hidden under the shirt of the person you are filming, you will be able to hear everything they’re saying without getting a boom pole in the frame.

@EduardoJoaoGama

Recording Sound Effects
With recording sound effects and other sounds that is not dialogue on screen, the process is the same as when you record dialogue on set. Make sure that the sound is recorded clearly for the sound editor and mixer. Using a playback monitor to show the video you want to overlay with sound can help you judge the length, volume and intensity of the noise you are producing for your sound effect.

Know Your Sound Recording Device’s Limitations
With limitations to the amount of time sound devices can record, they’re pretty good. I use a Zoom H4N and the most amount of time I left it recording was three hours to record a stage show. However it was pretty hot when I picked it up. The next time I recorded for that amount of time, it packed in, so know the limits of your sound recording device. For recording a whole day of sound I recommend using a 16GB SDHC memory card with your sound recording device. Now you know how to capture good sound. Later I will be covering how to clean, manipulate and mix sound in post-production.

So when recording dialogue and sounds, remember:

  • The voice is key. Everything else can be rerecorded after.
  • Use a directional microphone.
  • Pay attention to your sound meter whilst listening.
  • Use the appropriate settings on your sound recording device.
  • Get the microphone as close you can without it being seen, using a boom pole or radio
    microphone.
  • Sound effects are recorded during post-production.
  • Know the limitations of your sound recording device.