How many times have you heard this: If a video is technically poor, the audience might forgive it, but if the audio suffers, the audience will walk.
Audio is an extremely vital part of the final video product. Editing audio starts with verifying our sound file specifics and transcoding, if necessary, then cleaning up our SOT (Sound-On-Tape) and any V/O (Voice Over) work; after which we need to spot music and sound effects; followed by the final mixing of the whole composition. While some of these sound-editing processes overlap, each is unique. Having the software packages that suit your specific needs is very important to give you the tools and workflow that help you deliver quality products to your clients on time. And although all video-editing applications have the capability of performing audio editing internally, they are limited and can be bulky to work with in many situations.
This article is unable to cover every software package available, nor every unique audio mixing situation, so we'll cover a general overview of the process, and give the reader a good idea of what is on the market. The goal being to give readers who might be purchasing audio editing software a basis to make an intelligent decision and enjoy the rewards of having software that fits with their overall workflow. Please note that prices stated are approximations based on the market as of this writing (Summer 2011).
Video Editing Suites
Most all video editing applications have some built-in set of audio tools. Apple's Final Cut Pro X ($300), Avid's Media Composer ($2495), Adobe's Premiere Pro (Production Bundle $1699) and Sony Vegas Pro ($600) all have the ability to do basic audio edits, apply the common filters such as noise reduction, equalization, limiting and compression. They can also handle performing a final audio mix. You can keyframe level, pan and most filter parameters. For the most basic video and broadcast work, the built-in abilities will be enough. None of them provide the ease of use and power of dedicated audio editing software. The Suites, such as those in the CS5 family, include applications for working strictly with sound, like Adobe's Audition. Not only do you have much more power and flexibility in the tools offered for audio editing, but they provide the ability to access built-in and expandable libraries of sound effects, audio loops and completed music beds.
The first advantage is the ability to switch between multitrack projects and single audio file projects, access to powerful and easier-to-control filters, and greater ease in doing basic edits, as well as keyframing various parameters. Some of these, such as Soundtrack Pro, have voice over "multi-take" tools that make recording and compositing several takes into one very quick and easy. If you do need to record a lot of voice work you may want to look at multi-take recording/editing tools in the various packages. If you already own a video editing suite package, look into what you already have, take the necessary time to properly learn the basics and see if it will fulfill your needs, then decide what functions you'll need to purchase additional applications for. Let's look at where you would go from here to expand your studio's audio editing toolbox.
Transcoding and Repair
There are several smaller, very inexpensive audio applications available that do very basic work, such as Audacity (freeware), Amadeus Pro ($40), QuickTime Pro ($30) and others. These applications are great for doing the very basics of audio work. They can record individual voice and instrument tracks, clean up damaged audio and edit a file to be longer or shorter than it already is. They can also transcode between audio codecs such as AIFF, WAV, and MP3. For very quick, simple preparing of audio files, these types of applications can do the work quickly without the bulk and expense of larger, more heavy duty applications. Amadeus Pro also has a Batch function that can transcode many audio files at one time, and impressive audio repair tools. There is a hard limit to what these audio utility applications will do, but they can be handy for some workflows. These packages are so basic, you'll probably spend only a few minutes learning what you need to use them, so there is basically no time lost in that aspect.
Basic Stand Alone Packages
There are some basic stand-alone software packages for recording, sweetening and mixing sound. The higher end of this category would include Steinberg's Cubase (full package $500) with a full feature set. Apple also offers Logic Express ($199) in this category as a more full featured audio editing solution, comparable to Cubase. At the other end are the more simple Apple's GarageBand (iLife bundle $49) which has grown into a pretty powerful recorder and mixer, with direct access to the same audio library as Soundtrack Pro and Logic Studio/Express.
These packages will give you easy and powerful interfaces to navigate your project with, access to quality audio filters, the ability to keyframe level, pan and many filter parameters, and have a variety of output options for moving your final work to your video editing suite. They are plenty enough for many smaller to mid sized post-production needs. The price can vary quite a bit, as will feature sets, so shop this category of product carefully. Be sure to choose a package that will interface easily with your other applications and established workflow. The learning curve for these packages will be minimal for basic work, and much more than a few minutes for more complex tasks. You'll spend a couple of hours here and there achieving an appropriate level of competence.
Full Sized DAWs
DAW stands for Digital Audio Workstation. These are full-blown recording studio applications meant for professional music, voice, and effects recording, as well as top end professional level sweetening, compositing, and mixing of music, video, broadcast and film work. In this high-end category the more popular examples are Steinberg's Nuendo ($1,800), Avid's Pro Tools ($600) and Apple's Logic Pro ($499). These provide many more tools and much more complex workflows to handle the immensity of very large professional projects. Most post-production studios won't need anything this powerful unless they really are doing features, network series or are integrated with an actual audio recording studio. The expense is higher for both the software and to meet the hardware requirements needed. They also have a steeper learning curve to master, time spent away from paying work that should be considered in your purchase. You will spend a lot of time learning the ins and outs of these full sized DAW packages, as they were designed for complex professional work, and require the time to learn their professional, heavy duty tools and workflows.
Sidebar: Audio Encoding
Broadcast and digital video have an audio standard of AIFF 48kHz 16-bit. What this means is that it's encoded with no loss of fidelity, recorded at 48000 samples per second, with 16 bits (1s and 0s) per each word of data processed. Let's follow a layman's explanation for each of these three elements.
AIFF is a lossless professional audio file encoding format.
BWF is Broadcast Wave Format based on the Microsoft WAV file format that is also used in many parts of the broadcast world.
These two codecs (encode/decode algorithm) do not lose any of the sound's original fidelity or quality.
Sample Rate is equivalent to frames-per-second in video. Audio is not recorded in frames, but in samples, very similar. We express this as kilohertz per seco-nd, or thousands of hertz (Hz) per second. Kilo (k) saves us writing all those extra zeros. So 48000Hz is 48kHz. At this sample rate we are recording the full spectrum of frequencies that humans can hear with enough headroom to avoid degradation at the extremes. An important issue with video work is using audio recorded at non-standard sample rates (such as 44.1kHz).
When laid into a video-editing track that is set for 48kHz, the software re-counts the samples, and spreads them out incorrectly. The result is audio that starts out in sync with the video, then drifts out of sync more and more over time. If the software simply dropped samples, as it does with video to conform to different frame rates, the sound would become very choppy and incomprehensible. Thus sound can't be chopped up and manipulated in this manner as video can, all the samples must be kept intact.
Bit Rate is how long each word of data is that is processed. 16 bits means that one word is made up of 16 1s and 0s, and this is what computers read at one time. A computer reads data as individual words, like you're reading this article. Each word is a fixed length. Longer words such as 24-bits can convey more detailed data per word. Shorter words such as 12-bits conveys very little detail in each data word. This is similar to the bit depth of video, where each pixel is made up of a set number of bits. 8-bit video is not as sharp and clear as 10-bit video. So for each of our audio samples to be rich and full with enough data to achieve that level of fidelity, we use 16-bit data words. This is enough to carry the data that covers the dynamic range of human hearing, plus extra headroom for degradation at the extremes. Audio at different bit rates will not cause any sync issues, but the lower bit rates will make audio sound more flat, not as full bodied and robust.
Be aware that MP3 is not in any manner a professional quality audio format and should be avoided for professional work. It does not contain enough data to reproduce true professional quality audio with the full frequency spectrum (Sample Rate) and dynamic range (Bit Rate) necessary to maintain professional audio fidelity.
Click here to download a PDF of Videomaker's Audio Software Buyer's Guide
Ben Balser is a freelance Apple Certified Master Trainer, producer, and consultant.