Figure 10.16

An HDMI splitter can send your HD video signal to two monitors.

Figure 10.17

Not all HD cables are created equal: SDI (left) has a mechanism for locking into position and HDMI (right) does not.

Double-System Audio Recording

Although your HD camera can potentially do a great job of recording audio, there will be times when you’ll want to record audio onto a separate recording device like the digital audio recorder shown in Figure 10.18.

Here are a few common reasons to record audio to a separate device:

nIf you have a very small video camera and are planning on doing a lot of handheld camera movements, it might not be practical to have an external microphone or mixer plugged into the camera.

nMost cameras only record two channels of audio, but the ideal sound recording scenario is that each actor wears a wireless lav. In addition, the sound recordist holds a boom mic to make an additional recording. So even if you only have two actors in a scene, that’s three channels of audio. You’ll need a 4-channel recorder to record all three tracks.

228 The Digital Filmmaking Handbook, 4E

Figure 10.18

The Olympus LS-11 handheld

PCM audio recorder.

nAny scene in which actors are inside a car having a conversation, but you’re shooting the exterior of the car from a chase vehicle. In this case, you’ll need to have an audio recorder inside the car with the actors.

nAny scene in which the logistics of your set or camera movements make it impractical to keep your camera cabled to your microphones.

nA scene in which the action is a long way from the camera—for example, action scenes, wide landscape shots, or any time you want to shoot something from far away.

nMulti-camera shoots— where all cameras will share the same audio later in post.

Recording audio separately from your video makes the shoot more involved and postproduction more complicated. But that doesn’t mean you should avoid it. Recent developments in postproduction software, such as Plural Eyes and Dual Eyes, have made synchronizing easier, and the result is well worth the trouble. Plus, by recording with both boom and lavs, you’ll have an instant backup of your audio. If one mic goes bad, there is a good chance the dialogue will be covered in the boom audio track. And you’ll also have the audio from the camera mic as a backup or guide track.

Be Sure to Record Camera Mic Audio, Too

Automated synchronizing apps like Plural Eyes use the audio recorded with your onboard camera mic and compare it to the audio recorded on a separate audio recording device in order to synchronize sound and video later in post. So be sure to record audio with your camera even though it won’t be of high quality. Some producers actually add a decent camera-top shot gun mic to insure that the camera records audible audio.

How to Record Double-System Audio

Shooting double-system sound is, obviously, more involved than shooting standard, synched audio, and it requires the careful cooperation of a number of people. First, you’ll want to have an operator for your audio recording device. This person, the production recording mixer, will monitor the recording levels and take care of starting and stopping the recording device. You’ll also want a camera assistant to handle the slate.

We’ve all seen the classic shot of the black-and-white chalkboard with the clapper bar that is held before a camera. “Scene 1, take 1” says a voice, and then the top of the board is clapped down to make a loud cracking sound. Slating is used both to label the shot and to provide an audio/visual cue that can be used to synchronize the video and audio. Once in the editing room, the editor looks for the frame where the clapper bar is down and lines this up with the sharp crack of the audio. If all has gone well, the rest of the scene will be in sync. You can use this same method when shooting HD.

Today, most productions that shoot with double-system sound use a timecode slate (Figure 10.19). These are electronic devices that, in addition to displaying scene, shot, and take numbers, also display an electronic timecode readout. The electronic slate is connected to a timecode-capable audio deck or camera through a special cable. When editing, rather than having to sync your audio manually, by looking at the clap of the slate, you can simply line up the timecode on your audio and video.

Timecode audio recorders are more expensive to buy or rent, and a timecode slate adds even more money. It’s easy enough to sync audio the old-fashioned way or use a postproduction tool like Singulary Software’s Dual Eyes, so don’t avoid double-system sound just because the timecode devices are too expensive.

Figure 10.19

PureBlend MovieSlate is an iPhone and iPad digital slating app useful for shooting double-system sound or multi-cam footage. It can generate timecode, accept timecode from a camera with the right cabling and synchronize timecode across iOS devices via Bluetooth and WiFi.