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Apple MA261Z/A User Manual - Page 584

Signal-to-Noise Ratio, Headroom and Distortion

UPC - 885909087914

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Signal-to-Noise Ratio Every electrical system produces a certain amount of low-level electrical activity called noise. The noise floor is the level of noise inherent in a system. It is nearly impossible to eliminate all the noise in an electrical system, but you don't have to worry about the noise if you record your signals significantly higher than the noise floor. If you record audio too low, you raise the volume to hear it, which also raises the volume of the noise floor, causing a noticeable hiss. The more a signal is amplified, the louder the noise becomes. Therefore, it is important to record most audio around the nominal (ideal) level of the device, which is labeled 0 dB on an analog audio meter. The signal-to-noise ratio is the difference between the nominal recording level and the noise floor of the device, and is typically measured in dB. For example, the signal-tonoise ratio of an analog tape deck may be 60 dB, which means the inherent noise in the system is 60 dB lower than the ideal recording level. Headroom and Distortion If an audio signal is too strong, it will "overdrive" the audio circuit, causing the shape of the signal to distort. In analog equipment, distortion increases gradually the more the audio signal overdrives the circuit. For some audio recordings, this kind of distortion can add a unique "warmth" to the recording that is difficult to achieve with digital equipment. However, for audio post-production, the goal is to keep the signal clean and undistorted. 0 dB on an analog meter refers to the ideal recording level, but there is some allowance for stronger signals before distortion occurs. This safety margin is known as headroom, meaning that the signal can occasionally go higher than the ideal recording level without distorting. Having headroom is critical when recording, especially when the audio level is very dynamic and unpredictable. Even though you can adjust the recording level while you record, you can't always anticipate quick, loud sounds. The extra headroom above 0 dB on the meter is there in case the audio abruptly becomes loud. 584 Part VIII Audio Mixing

Section	Page
Final Cut Express HD User Manual	1
Contents	3
Final Cut Express HD Documentation and Resources	25
Getting Started	25
Onscreen Help	25
Onscreen User Manual	26
Information About New Features	26
Apple Websites	26
Final Cut Express HD Websites	26
Apple Service and Support Website	26
Part I: An Introduction to Final Cut Express HD	27
About the Post-Production Workflow	29
The Industry Workflow	29
The Post-Production Workflow	30
Video Formats and Timecode	35
About Nonlinear and Nondestructive Editing	35
Video Formats Compatible With Final Cut Express HD	36
Using Multiple Video Formats	36
Audio Formats Compatible With Final Cut Express HD	36
Video Format Basics	36
Video Standards	37
Image Dimensions and Aspect Ratio	37
Frame Rate	38
Scanning Method	38
Understanding Projects, Clips, and Sequences	39
The Building Blocks of Projects	39
What Are Media Files?	39
What Are Clips?	40
What Are Sequences?	41
What Are Projects?	42
What Are Bins?	43
Working With Projects	43
Organizing Your Projects	44
Using More Than One Sequence in a Project	44
Creating and Saving Projects	44
Opening and Closing Projects	46
About the Connection Between Clips and Media Files	47
Relationship Between Source Tapes, Media Files, and Clips	48
Reconnecting Clips to Media Files	48
Filenaming Considerations	49
Avoiding Special Characters	50
Restricting Length of Filenames	51
Using Filename Extensions	51
Adding Times and Dates to Final Cut Express HD Project Names	51
Using Multiple Hard Disks	51
Part II: Learning About the Final Cut Express HD Interface	53
Overview of the Final Cut Express HD Interface	55
Basics of Working in the Final Cut Express HD Interface	55
Using Keyboard Shortcuts, Buttons, and Shortcut Menus	57
Using Keyboard Shortcuts	57
Using Button Bars	57
Using Shortcut Menus	58
Learning Commands by Using Tooltips	59
Customizing the Interface	59
Moving and Resizing Windows	59
Working With Tabs and Tabbed Windows	60
Moving Windows	62
Using Different Screen Layouts	62
Showing and Positioning the Dock	62
Undoing and Redoing Changes	63
Entering Timecode for Navigation Purposes	64
Browser Basics	65
How You Use the Browser	65
Learning About the Browser	66
Working in the Browser	67
Creating Sequences	67
Selecting Items in the Browser	67
Navigating Within the Browser Using the Keyboard	67
Copying and Deleting Items in the Browser	68
Renaming Clips, Sequences, and Bins	68
Using Columns in the Browser	69
Customizing the Browser Display	70
Choosing Views in the Browser	70
Working With the Browser in List View	71
Working With the Browser in Icon View	74
Setting the Poster Frame	77
Viewer Basics	79
How You Can Use the Viewer	79
Opening a Clip in the Viewer	80
Learning About the Viewer	82
Tabs in the Viewer	83
Video Tab	83
Audio Tabs	83
Filters Tab	84
Motion Tab	84
Controls Tab	84
Transport (or Playback) Controls	84
Playhead Controls	85
Playhead and Scrubber Bar	85
Jog Control	86
Shuttle Control	86
Marking Controls	87
Zoom and View Pop-Up Menus	88
Zoom Pop-Up Menu	88
View Pop-Up Menu	89
Recent Clips and Generator Pop-Up Menus	90
Recent Clips Pop-Up Menu	90
Generator Pop-Up Menu	90
Canvas Basics	91
How You Use the Canvas	91
Opening, Selecting, and Closing Sequences in the Canvas	92
Learning About the Canvas	93
Editing Controls in the Canvas	94
Edit Overlay	95
Transport (or Playback) Controls	95
Playhead Controls	96
Playhead and Scrubber Bar	96
Jog Control	98
Shuttle Control	98
Marking Controls	98
Zoom and View Pop-Up Menus	99
Navigating and Using Timecode in the Viewer and Canvas	101
How the Viewer and Canvas Are Different	101
Navigating in the Viewer and Canvas	101
Playing Clips and Sequences	102
Scrubbing, or Moving, Through a Clip or Sequence	104
Shuttling Through a Clip or Sequence	105
Jogging Through a Clip or Sequence	106
Looping Playback	107
Working With Timecode in the Viewer and Canvas	108
Navigating With Timecode in the Viewer and Canvas	108
Dragging Timecode Values	110
Timeline Basics	111
How You Use the Timeline	111
Opening and Closing Sequences in the Timeline	113
Learning About the Timeline	114
Sequence Tabs in the Timeline	114
Editing Controls	115
Vertical Multitrack Controls	116
Horizontal Time Controls	117
Timeline Display Controls	119
Audio Controls	120
Other Miscellaneous Controls	120
Real-Time Effects and the Render Status Bar	122
Sequence Clips in the Timeline	123
Changing Timeline Display Options	123
About Timeline Display Options in the Sequence Settings Window	124
About Timeline Display Controls in the Timeline	126
Timeline Display Options Available From the Track Layout PopUp Menu	126
Navigating in the Timeline	127
Positioning the Playhead Using the Ruler	127
Using Timecode to Navigate in the Timeline	128
Zooming and Scrolling in the Timeline	128
Zooming In and Out of the Timeline	128
Scrolling Horizontally Through a Zoomed-In Timeline	132
Scrolling Vertically Through Multiple Tracks	133
Customizing the Interface	135
Changing Browser and Timeline Text Size	135
Moving and Resizing Final Cut Express HD Windows	135
Using Screen Layouts	137
Choosing a Screen Layout	138
Customizing Screen Layouts	138
Working With Shortcut Buttons and Button Bars	139
Adding Shortcut Buttons to a Button Bar	140
Rearranging, Moving, and Copying Shortcut Buttons	141
Changing Shortcut Button Colors	141
Removing Shortcut Buttons	141
Saving and Using Custom Shortcut Button Bars	142
Part III: Setting Up Your Editing System	143
Connecting Your Equipment	145
Connecting Your Camcorder	145
Connecting an External Video Monitor and Audio Speakers	146
Opening Final Cut Express HD and Choosing Your Initial Settings	146
What Is an Easy Setup?	146
Choosing an Easy Setup	147
Specifying Scratch Disks for Capturing Video and Storing Render Files	148
When Scratch Disks Become Unavailable	150
Assigning Search Folders for Reconnecting Media Files	150
What Is FireWire?	150
The Differences Between Apple FireWire and FireWire Basic	151
What Is Device Control?	151
Choosing a Device Control Preset	151
Understanding Device Control Status Messages	152
Determining Your Hard Disk Storage Options	153
Working With Scratch Disks and Hard Disk Drives	153
Data Rates and Storage Devices	153
Determining How Much Space You Need	154
Know Your Shooting Ratio	154
Planning for Additional Media Files	154
Calculating Hard Disk Space Requirements	155
Example Calculation for Disk Space Requirements	155
Choosing a Hard Disk	156
Types of Hard Disk Drives	157
ATA Disk Drives	157
FireWire Disk Drives	158
SCSI Disk Drives	159
Using a RAID or Disk Array	160
External Video Monitoring	161
Using an External Video Monitor While You Edit	161
Consumer Video Monitors Versus Broadcast Monitors	162
Connecting DV/FireWire Devices to an External Monitor	162
Using Digital Cinema Desktop Preview	163
About Digital Cinema Desktop Preview Options	164
Using Digital Cinema Desktop Preview to Monitor Your Video	165
Troubleshooting Digital Cinema Desktop Preview	166
About the Display Quality of External Video	167
Troubleshooting External Video Monitoring Problems	167
Part IV: Capturing and Importing	169
Capturing Your Footage to Disk	171
Overview of the Capturing Process	171
Overview of the Capture Window	172
Transport Controls	174
Jog and Shuttle Controls	174
Marking Controls	175
Capture Tab	175
Capture Bin Controls	175
Logging Fields	176
Using Slate Buttons	177
Marker Controls	177
Capture Buttons	178
Preparing to Capture	178
Organizing and Labeling Your Tapes	178
Choosing Reel Names for Tapes	178
Additional Tape Label Information	179
Logging Your Tapes	179
Choosing a Filenaming Scheme	180
Determining How Much Disk Space You Need	180
Capturing Individual Clips in the Capture Window	181
Automatic Filenaming During Capture	184
Using Capture Now	185
Adding Markers to Clips in the Capture Window	187
Marker Controls in the Capture Window	188
Setting Markers	188
Recapturing Clips	189
Using Capture Project	189
About the Additional Items Found Dialog	191
Finding Your Media Files After Capture	192
Where Are Captured Media Files Stored?	192
Consolidating Media Files to One Folder	193
Modifying a Media File’s Reel Name Property	194
Avoiding Duplicate Timecode Numbers on a Single Tape	195
Logging Tapes with Duplicate Timecode Numbers	196
Avoiding Multiple Occurrences of the Same Timecode Number on a Single Tape	196
Importing Media Files Into Your Project	199
What File Formats Can Be Imported?	199
How Is Importing Different From Capturing?	200
Importing Media Files	200
Tips When Importing	203
About Importing Video Files	203
About Importing Audio Files	204
What Kinds of Audio File Formats Can Be Imported?	204
Choosing Audio File Sample Rate and Bit Depth	204
Mixing Sample Rates and Using Real-Time Sample Rate Conversion	205
Converting Audio Clips to Match Sequence Settings	205
Using Audio CD Tracks in Your Project	206
Working With HDV	207
About HDV	207
HDV Formats Supported by Final Cut Express HD	208
Standard Definition Recording With an HDV Camcorder	208
About MPEG-2 Compression	208
Spatial (Intraframe) Compression	208
Temporal (Interframe) Compression	209
More About Long-GOP Video	209
Editing HDV Using Apple Intermediate Codec	209
HDV Apple Intermediate Codec Editing Workflow	210
Connecting an HDV Device to Your Computer	210
Choosing an Easy Setup	211
Capturing HDV Video to the Apple Intermediate Codec	211
Capturing Footage With Scene Breaks	212
Editing Video Using the Apple Intermediate Codec	212
Outputting HDV to Tape or Exporting to a QuickTime Movie	213
HDV Format Specifications	214
Part V: Organizing Footage and Preparing to Edit	217
Organizing Footage in the Browser	219
Using Bins to Organize Your Clips	219
Creating New Bins	220
Opening Bins in the Browser	221
Opening Bins in a Separate Window or Tab	222
Moving Items Between Bins	225
Sorting Items in the Browser Using Column Headings	227
Searching for Clips in the Browser	228
About Search Options	228
Options for Defining the Scope of a Search	229
Options for Defining the Criteria of a Search	230
Search Commands	230
Searching for Items in the Browser	231
Searching for Multiple Items in the Browser	232
Searching for Unused Clips in Your Project	232
Manipulating Items in the Find Results Window	233
Using Markers	235
Learning About Markers	235
What Can You Do With Markers?	235
Differences Between Sequence and Clip Markers	236
Types of Markers	237
Working With Markers	238
Viewing Markers in the Viewer or Canvas	238
Viewing Markers in the Browser	238
Adding Markers in Clips and Sequences	238
Deleting Markers in Clips and Sequences	242
Navigating With Markers	243
Renaming Markers, Adding Comments, and Changing the Kind of Marker	244
Moving a Marker	245
Aligning Items in the Timeline by Their Markers	246
Extending a Marker’s Duration	248
Editing Markers Into Sequences	249
Exporting Markers With Your QuickTime Movies	249
Creating Subclips	251
Learning About Subclips	251
Removing Subclip Limits	253
Master-Affiliate Clip Relationships	253
Manually Breaking Large Clips Into Subclips	254
Turning Markers Into Subclips	254
Creating Subclips Manually	256
Editing With Subclips	256
Automatically Creating Subclips Using DV Start/Stop Detection	257
Part VI: Rough Editing	259
Working With Projects, Clips, and Sequences	261
Specifying Preferences Before You Start Editing	261
Working With Projects	262
Working With Multiple Projects in the Browser	262
Choosing Whether the Last Previously Opened Project Opens on Launch	262
Viewing and Changing the Properties of a Project	262
Backing Up and Restoring Projects	263
What Is Contained in a Project File	263
Returning to Saved Projects	264
Using the Revert Project Command	264
Automatically Saving Projects With Autosave	264
Learning About the Different Types of Clips	265
Types of Clips	265
About Offline Clips	266
Sequences as Clips	266
Viewing and Changing the Properties of a Clip	266
Changing Clip Properties in the Browser	267
Viewing and Changing Clip Properties in the Item Properties Window	268
Viewing and Modifying Clip Properties	268
Finding a Clip’s Media File	268
Changing the Properties of Affiliate Clips	269
Creating and Working With Sequences	270
Creating and Deleting Sequences	270
Opening and Closing Sequences	271
Duplicating a Sequence	272
Copying a Sequence Into Another Project	272
Nesting a Sequence	273
Basic Sequence and Timeline Settings	273
When Rendering Is Required	274
Viewing an Existing Sequence’s Settings	274
The Fundamentals of Adding Clips to a Sequence	275
Creating a Rough Edit	275
Basic Steps Involved in a Rough Edit	275
How Clips Appear in the Timeline	276
Undoing and Redoing Actions	278
Overview of Ways to Add Clips to a Sequence	278
Methods for Adding Clips to Sequences	278
Determining What Parts of Clips You Want in Your Sequence	280
Preparing a Sequence Order in the Browser	280
Sorting to Create a Sequence Order	281
Visually Storyboarding in the Browser	281
Setting Edit Points for Clips and Sequences	283
About In and Out Points	283
Learning About the Out Point Inclusive Rule	284
Things to Keep in Mind When Setting an Out Point	285
Setting Clip In and Out Points in the Viewer	286
Specifying an Edit Point Using Timecode	288
Setting In and Out Points to Include a Whole Clip	289
Reviewing Your Edit Points	289
Setting Sequence In and Out Points in the Canvas or Timeline	290
Options for Setting Sequence In and Out Points	291
When No Sequence In or Out Points Are Set	292
When You Set One Sequence In or Out Point	293
When You Set Both Sequence In and Out Points	295
Setting Sequence In and Out Points	296
Setting In and Out Points to Match a Clip or Gap	297
Setting In and Out Points Based on a Selection in the Timeline	298
Navigating to In and Out Points	300
Moving In and Out Points	301
Clearing In and Out Points	303
Working With Tracks in the Timeline	305
Adding and Deleting Tracks	305
Adding Tracks	306
Deleting Tracks	308
Specifying Destination Tracks in the Timeline	309
Understanding Source and Destination Controls	309
Setting Destination Tracks	310
Changing Source and Destination Control Connections	311
Disconnecting Source and Destination Controls	311
Resetting Destination Tracks to the Default State	313
Exceptions to Normal Use of Source and Destination Controls	313
Locking Tracks to Prevent Edits or Changes	314
Disabling Tracks to Hide Content During Playback	315
Customizing Track Display in the Timeline	316
Resizing Timeline Tracks	316
Resizing Tracks by Dragging	316
Resizing All Tracks Using the Track Height Control	317
Resizing All Tracks Using the Track Layout Pop-Up Menu	317
Creating a Static Region in the Timeline	318
Drag-to-Timeline Editing	321
Overview of the Drag-to-Timeline Editing Process	321
Dragging Clips to the Timeline	322
Doing Simple Insert and Overwrite Edits in the Timeline	323
Automatically Adding Tracks to Your Sequence While Dragging	326
Three-Point Editing	329
Understanding Three-Point Editing	329
Overview of the Three-Point Editing Process	329
Different Ways to Do Three-Point Editing	330
Dragging to the Edit Overlay in the Canvas	331
Using Keyboard Shortcuts	331
About Edit Types in the Edit Overlay	332
Performing the Different Types of Edits	333
Performing an Insert Edit	333
Performing an Insert With Transition Edit	335
Performing an Overwrite Edit	336
Performing an Overwrite With Transition Edit	338
Performing a Replace Edit	339
Superimposing Clips	346
Three-Point Editing Examples	348
Example: Editing a Specific Clip Into Your Sequence	348
Example: Editing a Clip Into a Gap in Your Sequence	350
Example: Backtiming a Clip Into Your Sequence	352
Example: Editing a Clip With No Specified In or Out Points Into Your Sequence	353
Finding and Selecting Content in the Timeline	355
Understanding What’s Currently Selected	355
Identifying Selections in the Timeline	356
How Selections Are Prioritized in the Timeline	357
Direct Methods for Selecting Content in a Sequence	357
An Introduction to the Selection Tools	358
Selecting Clips	360
Selecting an Individual Clip	360
Selecting a Group of Clips by Dragging	361
Selecting Multiple Clips	362
Deselecting an Item in a Multiple Selection	362
Selecting a Range of Timeline Content	363
Selecting All Clip Items on a Track	364
Selecting All Items on All Tracks Forward or Backward	365
Selecting or Deselecting All Clips in a Sequence	367
Finding and Selecting Based on Search Criteria	367
Selecting a Vertical Range Between In and Out Points	369
Using Auto Select to Specify Tracks for Selections	370
Arranging Clips in the Timeline	373
Snapping to Points in the Timeline	373
Moving Items Within the Timeline	375
Moving by Dragging	375
Moving Clips Numerically	376
Using the Command Key to Drag More Slowly	378
Performing Shuffle Edits	378
Copying and Pasting Clips in the Timeline	380
Copying Clips by Option-Dragging	380
Modifying Selections and Commands Using the Option Key	381
Copying, Cutting, and Pasting Clips in the Timeline	382
Example: Copying and Pasting Audio and Video Clip Items to Different Tracks in the Timeline	384
Deleting Clips From a Sequence	385
Deleting With a Lift Edit (Leaving a Gap)	385
Deleting With a Ripple Edit (Leaving No Gap)	386
Finding and Closing Gaps	387
Cutting Clips and Adjusting Durations	391
Performing Basic Cut Edits	391
Cutting Clips in the Timeline	391
Using the Add Edit Command to Cut Clips	393
Joining Through Edits (Splicing Cut Clips Back Together)	394
Changing the Duration of Clips in the Timeline	395
Opening Sequence Clips in the Viewer to Change Durations	396
Linking and Editing Video and Audio in Sync	397
Linked Sync Relationships Between Video and Audio Clips	397
When Linked Clips Are Moved Out of Sync	398
Understanding Sync Relationships Between Multiple Linked Audio Items	401
Linking and Unlinking Video and Audio Clip Items in the Timeline	402
Linking Video and Audio Clip Items	402
Unlinking Video and Audio Clip Items	404
Selecting Individual Clip Items While They Are Linked	405
Getting Clip Items Back in Sync	406
Moving a Clip Into Sync	406
Slipping a Clip Item Into Sync	408
Moving or Slipping All Clip Items Into Sync at Once	409
Establishing a Different Sync Relationship Between Linked Clip Items	411
Marking a Clip as In Sync	411
Learning About Linking Behavior in Audio Channel Pairs	413
Split Edits	415
Learning About Split Edits	415
How Split Edits Look in the Viewer and Canvas	416
Setting Up Split Edit Points in the Viewer	417
Setting Up a Split Edit While Playing a Clip	418
Modifying and Clearing Split Edits	419
Split Edit Examples	421
Example: Split Edit in the Viewer and a Simple Edit Point in the Canvas	421
Example: Split Edit in the Viewer and a Single Split Edit Point in the Canvas	422
Example: Simple Edit in the Viewer and a Split Edit in the Canvas	423
Audio Editing Basics	425
The Goals of Audio Editing	425
Using Waveform Displays to Help You Edit Audio	427
Learning About the Audio Controls in the Viewer	428
Editing Audio in the Viewer	431
Opening Audio Clips in the Viewer	431
Viewing Audio Tracks in the Viewer	432
Zooming In or Out of the Waveform Display Area	432
Scrolling Through a Zoomed-In Audio Clip	434
Using the J, K, and L Keys to Hear Subtle Details	435
Turning Off the Audio Scrubbing Sounds	435
About Setting Edit Points for Audio	435
Dragging an Audio Clip to the Canvas, Browser, or Timeline	436
Trimming Audio Clips in the Viewer	436
Editing Audio in the Timeline	438
Timeline Audio Display Options	438
Displaying Waveforms in the Timeline	438
Displaying Overlays and Adjusting the Track Height	439
Zooming In and Out of Waveforms in the Timeline	440
Moving Audio Items From One Track to Another at the Same Frame	441
Using Audio Transitions to Smooth Audible Changes	442
Creating or Separating Stereo Pairs	442
Working With Audio at the Subframe Level	444
Viewing an Audio Clip at Single-Frame Resolution	444
Subframe Synchronization of Audio and Video	444

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584

Part VIII

Audio Mixing

Signal-to-Noise Ratio

Every electrical system produces a certain amount of low-level electrical activity called

noise

. The

noise floor

is the level of noise inherent in a system. It is nearly impossible to

eliminate all the noise in an electrical system, but you don’t have to worry about the

noise if you record your signals significantly higher than the noise floor. If you record

audio too low, you raise the volume to hear it, which also raises the volume of the

noise floor, causing a noticeable hiss.

The more a signal is amplified, the louder the noise becomes. Therefore, it is important

to record most audio around the

nominal

(ideal)

level of the device, which is labeled

0 dB on an analog audio meter.

The

signal-to-noise ratio

is the difference between the nominal recording level and the

noise floor of the device, and is typically measured in dB. For example, the signal-to-

noise ratio of an analog tape deck may be 60 dB, which means the inherent noise in

the system is 60 dB lower than the ideal recording level.

Headroom and Distortion

If an audio signal is too strong, it will “

overdrive”

the audio circuit, causing the shape of

the signal to

distort

. In analog equipment, distortion increases gradually the more the

audio signal overdrives the circuit. For some audio recordings, this kind of distortion

can add a unique “warmth” to the recording that is difficult to achieve with digital

equipment. However, for audio post-production, the goal is to keep the signal clean

and undistorted.

0 dB on an analog meter refers to the ideal recording level, but there is some allowance

for stronger signals before distortion occurs. This safety margin is known as

headroom

meaning that the signal can occasionally go higher than the ideal recording level without

distorting. Having headroom is critical when recording, especially when the audio level is

very dynamic and unpredictable. Even though you can adjust the recording level while

you record, you can’t always anticipate quick, loud sounds. The extra headroom above

0 dB on the meter is there in case the audio abruptly becomes loud.