PETELIN.RU → Книги → Adobe Audition: Soundtracks for Digital Video

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Petelin, Roman, and Yury Petelin.

Adobe Audition: Soundtracks for Digital Video

Wayne: A-LIST, 2004.- 288 p.
ISBN 1931769354

Click here to buy at Amazon.com

A project-based book that deals with Adobe Audition (formerly Cool Edit Pro), included in the Adobe Video Collection, this guide explores creating soundtracks for digital video and demonstrates how to use the software to start recording, editing, and producing immediately. Examined are how to edit, mix, and add built-in effects to AVI soundtracks while watching movie playback, how to clean up poor quality audio with powerful noise reduction tools, and how to use sound effects such as sweetening and mixing. Recording engineers will learn how to customize Audition, record multitrack sessions, transform the multitrack mix into a stereo or surround-sound experience, edit audio files using sample-accurate tools, and mix up to 128 tracks of audio. Working with powerful DSP and analysis tools including DirectX effects is covered, as is importing audio (WAV) files from Adobe Audition into projects created with Adobe Premiere Pro or Adobe After Effects.

Table of Contents

Introduction

To our beloved daughter
and granddaughter Anna

This book is about Adobe Audition, one of the most powerful sound editors available today. In it, we look at how the application can be used to record and process a high-quality sound track for digital video.

The predecessors of Adobe Audition are Cool Edit and Cool Edit Pro. The best features of these applications have been retained in Adobe Audition, and new tools for sound processing have also appeared.

Some time ago, we wrote book [3], which contains a comprehensive description of Cool Edit Pro 2 interface and techniques for using the application. The print run sold out, and we began to prepare the second edition. We were planning to add a descrip-tion of new features in the latest version, Cool Edit Pro 2.1, but it turned out that the application had changed its name and owner. It is now called Adobe Audition, and the rights to it belong to Adobe Systems Incorporated (http://www.adobe.com).

Thus, the rights to a powerful sound editor were purchased by a company well known for its applications for working with images. In our opinion, this indicates that professional and amateur movie directors are concerned with improving the quality of the sound that accompanies digital video.

This is a book about the latest version (at the time of writing) of an application that, under its new name, is likely to become even more popular.

In this book, we describe the application's features while working on a particular project. For the project, we chose to create a video clip with a sound track. We re-corded sound in two ways: with a video camera (speech synchronous with video) and directly to an Adobe Audition file (a narrator's voice accompanying an independent video image). Each chapter, in turn, describes and demonstrates with examples how this original material can be improved by using processing and effects available in the application. All the important intermediate results of the conversions are saved in files on the disc that accompanies this book.

The book isn't a comprehensive description of Adobe Audition. Readers who wish to know all the features of the application should refer to [3].

Features to Keep in Mind

To get the most out of Adobe Audition in your creative work, you should keep in mind some of its important features. Let's look at them more closely.
Adobe Audition is intended for work with digital audio. This means that analog sound waves must be first converted to a series of binary digital samples (this process is called sampling). Conversion is done using an analog-to-digital converter (ADC). As a result, a digital image of the sound is obtained that is called a waveform.

Waveforms are stored on the hard disk as files of various formats. Most often, these are WAV files. Thus, when you are "assembling" an audio composition in Adobe Audition, you are using the WAV files as building blocks.

Adobe Audition has two principally different working modes: editing individual waveforms and multitrack editing a set of waveforms. Each mode has a main menu and main window: Edit Waveform View and Multitrack View. In fact, there are two sound editors that have different purposes and are combined in one functional whole. You should be aware that editing operations done in Edit Waveform View (such as cut, paste, and processing with effects) are destructive by nature. When you save a file, the changes are introduced directly into the waveform. Editing done in Multitrack View (such as moving and joining waveforms, changing the volume and panorama, adjusting the parameters of real-time effects, etc.) is non-destructive.

The Undo function gives you freedom when working with waveforms. You need not worry that an interesting result in your creative work might be lost. However, freedom has its cost. The ability to repeatedly undo operations requires memory space. Although all automatically created copies will be automatically deleted from the hard disk after you close the file or exit the application, you need a lot of free space on your hard disk when working with Adobe Audition. However, you can decrease the number of Undo levels or disable this function completely if you are short of memory.

Many musical editors with audio data processing tools offer two ways to use ef-fects: applying an effect in real time and recomputing audio data. The first is more convenient, because you can adjust the parameters of the effect and hear the result immediately. However, you need a powerful computer to do this. Using an effect in the recomputing mode allows you to process audio data with a relatively "weak" com-puter, but the process can take a long time. This might discourage you from experi-mentation or introducing improvements.

The best strategy of using effects could be the following. First, turn on the loop play-back of a waveform and find the effect parameters that fit best to your intentions. Then, recompute the waveform once by applying the effect with the found parameters to it.

In Adobe Audition, you can use both its native, built-in effects and those con-nected using DirectX.

An important feature of Adobe Audition is support for real-time effects in the Multitrack View mode.

The main use of effects in the Edit Waveform View mode is recomputation of audio data. A full-featured real-time mode is not provided in Edit Waveform View. However, there is a substitute for the real-time mode. The Preview button is available in the effect dialog box, so you can try the parameters of the effect. Any changes to the parameters that you make in the effect dialog box using its controls are heard immediately. How-ever, to use this feature effectively, you should have a powerful computer. Unlike the "true" real-time mode, the preview mode only lets you use one effect at a time.

We already mentioned that Adobe Audition is a multitrack environment that allows a user to put any number of waveforms (blocks) on different tracks to play them simultaneously or combine all the tracks into one later. Mixing involves combin-ing all waveforms on the tracks into two (or more) output channels. You can edit, add, or remove blocks, and Adobe Audition will continually monitor the changes (such as moving or deleting a block, changing the volume, etc.) made during this multichannel session. As soon as you change something, Adobe Audition computes the changes and corrects the mix sent to the application's output. These corrections are done by the ap-plication in the background mode, i.e., background mixing directed to a pair of output devices (a single stereo sound card) or to several output devices (a few stereo sound cards, or one multichannel sound card). Adobe Audition generates mixes for any set of the output devices used. If you use one stereo sound card, Adobe Audition generates only one stereo mix. If your computer is connected to a multichannel system, a separate mix must be created for each output device.

The multichannel output requires a lot of processing, meaning that mixing becomes slower. The sound card and the computer should match each other, and it is pointless to install an expensive sound-digitizing device in a cheap computer.

In addition to audio files of various formats, such as WAV, Adobe Audition al-lows you to use 'session files' (with the extension SES). Earlier, we called WAV files the building blocks, using which any audio composition, such as a song, can be as-sembled. Now we can say that a session file is a song proper, although an SES file does not actually contain any audio data. It is very small in size, and it contains only instructions for Adobe Audition in the following form:

• Paths to the WAV files used
• Track names
• Playback start/stop times of particular WAV files
• Volume level and panorama set before playing each file, and how these parameters should change during the playback
• Connected real-time effects, and how their parameters should change

You could compare an SES file to a conductor, and WAV files to the members of an orchestra. The conductor instructs each performer when he or she must start play-ing and how the part should be played. The conductor needs the orchestra. Similarly, an SES file is meaningful only when it and the session WAV files are located in cer-tain folders. You cannot just copy an SES file onto a diskette and insert the diskette into another computer, and you cannot rename a session WAV file or move it to an-other folder. If you do, and then try to open the SES file to play the composition, it will not work. The conductor won't find the musicians at the appropriate places, and the concert won't take place. This doesn't mean it is impossible to move SES files and the related WAV files from one folder to another. For this purpose, Adobe Audition includes special file-saving operations.

In Adobe Audition, it is possible to extract audio data from AVI files and tracks of audio CDs. In the multitrack mode, MIDI and AVI files can be used in addition to au-dio files. The ability to work with video is most important.

The multitrack mode implements modern editing technologies using automation envelopes. Real-time effects can be applied not only to individual tracks, but also to track groups that make up buses. Using a mixer, you can route signals between effects connected to a bus. Also available are operations related to creating and using loops and grooves.

The application recognizes DX effects installed in the system, and decides whether they are compatible with it.

In addition to the tools for analyzing the processed sound properties that were al-ready available in earlier versions of Cool Edit Pro (such as the current and instanta-neous spectrum analyzers and the histogram of audio signal level distribution), Adobe Audition has a virtual stereo goniometer that allows the user to judge the quality of the stereo field (in particular, the mono compatibility of a composition) from the appear-ance of Lissajous figures.

Adobe Audition also has a built-in proprietary WAV-to-MP3 converter.

The Structure of the Book

This book consists of twelve chapters, an introduction, two appendices, and an index. It is accompanied by a CD Extra-format disc.

Chapter 1 covers an extremely important issue: How to prepare Adobe Audition for work. The convenience of working and the quality of the results depend on making the necessary preliminary settings correctly.

The chapter describes the options of dialog boxes you'll be using when preparing the application for work. The following issues are considered:

• General and system settings
• Selecting audio data processing parameters and multitrack editing parameters
• Editing lists of recording/playback devices

We recommend that you return periodically to the first chapter as you master new techniques. This will allow you to better understand the goals of the preparation op-erations and their influence on the result.

Chapter 2 covers working with files and waveforms. It looks at how to open, save, and close files, control the waveform view, and play audio. In addition, we'll examine how to collect a waveform sequence on one track, allow other applications to use the opened file, clear the disk space from unwanted files, and extract audio data from a digital audio CD to Adobe Audition.

In Chapter 3, we'll look at how to record sound with a microphone. This involves choosing and connecting a microphone, creating a new project, setting a record level, starting recording, and monitoring its course.

This chapter also contains a plan for creating a video clip using recorded sound. The following chapters will demonstrate the main techniques of analysis and process-ing audio data that are recorded from a microphone and intended to be a component of the asynchronous audio accompaniment of the video clip.

The source material consists of a few takes with a narrator's voice (the file EX03_02.WAV located in the EXAMPLES folder on the CD accompanying the book). This is a "raw" recording that was intentionally made under conditions unfa-vorable for work with a microphone.

Chapter 4 demonstrates the tools that should be used for analyzing a recording, and how this should be done. The essence of analysis is clarified, and the following techniques are described:

• Monitoring the recording
• Qualitative (visual) and quantitative (with meters) analysis of the waveform and the level of the recorded audio signal
• Spectral analysis of instantaneous (Spectral View) and classical (Frequency Analysis) spectrum

This chapter also includes a clarification of the file statistics contained in a level distribution histogram and examples of using the histogram for choosing the parame-ters of dynamic range processing.

The use of the analytical tools is illustrated with examples (the files EX04_01.WAV and EX04_02.WAV, located in the EXAMPLES folder on the CD accompanying the book).

Finally, the chapter presents a signal processing strategy (including montage, noise reduction, filtration, dynamic processing, and processing with effects) that is imple-mented in the subsequent chapters.

In Chapter 5, we look at how to get rid of flaws, noise, and distortions that are present in the recording. This involves deleting unwanted fragments, montage of the recording, waveform normalization, and many other operations.

In this chapter, we also discuss the techniques of using tools that help to struggle against distortions: Clip Restoration and Noise Reduction (the latter is based on analy-sis of a noise sample).

All intermediate operations are illustrated with the files from EX05_01.WAV to EX05_03.WAV, and the final result is saved in the EX05_04.WAV file (all the files are located in the EXAMPLES folder on the CD accompanying the book).

In Chapter 6, we discuss frequency filtration and examine filters built into the ap-plication:

• Dynamic EQ - an equalizer with the dynamic control of the adjustment fre-quency, gain, and bandwidth
• FFT Filter - a filter based on the Fast Fourier Transform
• Graphic Equalizer - a universal graphic equalizer
• Notch Filter - a multiband notch filter
• Parametric Equalizer - a seven-band parametric equalizer
• Quick Filter - an eight-band graphic equalizer
• Scientific Filters - Bessel, Butterworth, and Chebyshev filters

Continuing our work on the project, we demonstrate how to remove the alternate-current background noise with the Notch Filter and, most importantly, obtain a signal (the file EX06_01.WAV), in which unwanted spectral components are attenuated with the FFT Filter.

In Chapter 7, we discuss dynamic processing and examine Dynamics Range Processing, one of the dynamic processing devices available in Adobe Audition.

Based on the statistical analysis described in Chapter 4, we select the parameters of the dynamic range processing and apply it to the signal. The result is saved in the NSINC1.WAV file.

We apply the complete set of processings to the other audio files and save the re-sults in the file NSINC2.WAV (the second asynchronous fragment of the sound track) and in the files SINC1.WAV, SINC2.WAV, and SINC3.WAV (the synchronous fragments of the sound track). The order of these files in the project should be as fol-lows: SINC1.WAV, NSINC1.WAV, SINC2.WAV, NSINC2.WAV, and SINC3.WAV.

In Chapter 8, we introduce built-in effects based on the signal delay: Delay, Dy-namic Delay, Multitap Delay, Echo, Echo Chamber, QuickVerb, Reverb, and Full Re-verb.

For demonstration purposes, we process the signal saved in the NSINC1.WAV file with some of the effects and save the results in the files from EX08_01.WAV to EX08_03.WAV.

In Chapter 9, we describe techniques for using plug-ins connected to Adobe Audi-tion via DirectX. We introduce one of the DirectX plug-ins from the package Waves Platinum Native Bundle 4: Waves RVox, which is a gate, compressor, and limiter at the same time.

We use Waves RVox to reduce noise and amplify the level of the signal saved in the EX07_01.WAV file. The result is saved in the EX09_01.WAV file.

In Chapter 10, we comprehensively describe the work in the multitrack environ-ment. Along with general principles of work in the Multitrack View mode, we de-scribe in detail:

• Methods of recording audio data during a multitrack session and techniques of im-porting waveforms into the session
• Techniques of choosing track attributes and connecting effects to the tracks
• Working with buses and a mixer and locking tracks to free up processor resources
• Peculiarities of using the parametric equalizers connected to each track

The chapter also describes operations with blocks (such as moving, copying, split-ting, deleting, grouping, and selecting fragments and groups of blocks), loops, and grooves. All available methods of tempo control and tonality transposition are de-scribed.

Much attention is paid to automation. We describe methods for creating and edit-ing automation envelopes.

Chapter 11 covers work with the sound track of a digital video. It describes the techniques of exporting the sound track of a movie from Adobe Premiere Pro and im-porting it to Adobe Audition. A few tricks of working in a multitrack project are illus-trated with an example of mixing a stereo sound track in Adobe Audition.

Chapter 12 considers issues of creating surround-sound projects. We present brief information about multichannel audio, discuss the peculiarities of building a 5.1 studio, and describe the Multichannel Encoder dialog box that allows the user to position imagi-nary sound sources over the surround panorama and control their movement.

The chapter also discusses passing a 5.1 sound track mixed in Adobe Audition to an Adobe Premiere Pro project.

Appendix 1 describes the contents of the CD that accompanies this book. A special feature of this disc is that it is in CD Extra format, i.e., is suitable for both playing with a CD player and reading with a computer.

Its CD-ROM partition contains example projects and files with intermediate and final results of processing, as well as some useful information and a few musical compositions. The material is arranged as an offline version of our site www.musicalpc.com.

The CD Digital Audio partition contains our musical compositions mixed down using Adobe Audition.

Appendix 2 contains a list of files with examples located in the EXAMPLES folder on the CD accompanying the book. It also contains a brief description of each file and the relations between the available files.