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MPEG Aspect Ratios, Pixel Aspect Ratio MPEG-1

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MPEG 99 MPEG Aspect Ratios MPEG pixels, especially those encoded for video device playback, are often not square. Because of this, the aspect ratio must be defined in order to display MPEG video. There are two different ways to define aspect ratio: Pixel aspect ratio and image aspect ratio. Pixel Aspect Ratio (MPEG-1) The pixel aspect ratio defines the proportions of the pixels in the image. Given this ratio and the number of pixels, the MPEG decoder figures out how large to display the final image onscreen. The MPEG-1 display aspect ratio is specified as the pixel aspect ratio, which is the ratio of a pixel's height to its width. The standard pixel aspect ratio for NTSC MPEG-1 is 1.0950, which means that the pixels are slightly taller than they are wide. The standard pixel aspect ratio for PAL MPEG-1 is .9157, which means that the pixels are slightly wider than they are tall. A pixel aspect ratio of 1.0000 (1:1) is a square pixel aspect ratio and results in square pixels throughout the entire image. For example, if the dimensions of the MPEG source is 352x240 pixels and the pixel aspect ratio is 1.095:1, some MPEG players, including QuickTime, will generally display the image at about 320x240 on a normal square pixel computer monitor (352/1.095 = 321, evened off to 320; the 240 dimension is unaltered). QuickTime compensates for this non-square ratio properly during playback and displays MPEG-1 files undistorted. QuickTime plays standard 352x240 MPEG correctly as 320x240 square pixels. You have to take special care with Windows Media Player, however, because it displays MPEG pixels at 1:1 no matter what the pixel aspect ratio of the source. This makes standard NTSC MPEG-1 video appear wider than it should. Because QuickTime takes the pixel aspect ratio of MPEG-1 content into account, the safest solution for cross-platform desktop playback is to encode MPEG video with square pixels instead of the standard MPEG-1 pixel aspect ratio. QuickTime Player also correctly displays square-pixel MPEG-1 streams, so this works using both QuickTime Player and Windows Media Players. However, some MPEG devices, such as Video CD players, may not be able to handle square pixels properly.

Section	Page
Introduction	9
What’s New in Cleaner 6.5	9
Installation	10
System Requirements	10
Activating Cleaner 6.5	11
Registration	11
Streaming Basics	12
Progressive Streaming	12
Real-Time Streaming	13
Standard and Streaming Servers	13
Bandwidth Scalability	13
Buffering	14
Streaming Architectures	14
Typical Workflow	15
Capture	17
Capturing Video	17
Digital Video Capture	18
Analog Capture	18
Choosing a Camera	20
Shooting Video for Streaming	21
Shooting Techniques	21
Batches	25
The Batch Window	26
Project Modification Icons	28
Batch Files	28
Adding Files	29
Importing from Audio CDs	29
Connecting Files	29
Adding Numbered Stills	30
Replacing a File	30
Removing Files	30
Assigning Settings	31
File Naming	32
Processing Order	33
Skipping Files	33
Selecting Destinations	34
Default Destination	34
Custom Destinations	34
Customizing Output File Names	35
Processing a Batch	36
Pausing	36
Stopping	37
Changing and Restarting	37
Status	37
Clearing Project Status	38
Getting Project Status Details	38
The Batch Log	38
Projects	39
The Project Window	40
The Movie Controller	41
The Source File Tab	42
The Data Rate Graph	44
The Settings, Modifiers, and EventStream Tabs	45
Cropping	47
Manual Cropping	48
Numeric Cropping	49
Preventing Distortion	49
Trimming Files	50
Manually Setting In/Out Points	50
Numerically Setting In/Out Points	51
The Cleaner Time System	51
Go to Frame/Go to Time	51
Enhanced Movie Playback	53
Settings	55
Using Settings	56
Choosing a Setting	57
Organizing Settings	61
Creating a Setting	62
Modifying Settings	62
Assigning a Setting to a Project	63
Assigning a Setting to Multiple Projects	63
Assigning Multiple Settings to Multiple Projects	64
Settings Modifiers	64
Previewing Settings	66
Sharing Settings	66
Using Aliases	66
Protecting Settings	67
Automating Setting Creation	67
Pre-processing	69
The Image Tab	70
Crop	70
Image Size	71
De-interlace	72
Shift Fields	75
Telecine	75
Blur	75
Sharpen	75
Adaptive Noise Reduction	76
Static Mask	77
Watermark	78
The Adjust Tab	79
Gamma	79
Brightness	80
Contrast	80
Black Restore and White Restore	81
Hue	81
Saturation	82
QuickTime Effects	82
The Audio Tab	84
Using Audio Filters	85
Sample Rate	85
Data Rate (only for MP3, MPEG Layer 1, MPEG Layer 2)	85
Depth	85
Channels	86
Speed vs. Quality (only for MP3)	86
Options	86
Volume	86
Low Pass	86
High Pass	87
Noise Removal	87
Dynamic Range	88
Noise Gate	89
Notch	90
Reverb	91
Experimenting with Audio Filters	92
Begin/End Tab	93
Video Fades	93
Audio Fades	93
High Quality First/Last Frames	94
End Frame URL Link	94
In Point	94
Out Point	94
Formats	95
Video Formats	95
Audio Formats	95
Still Image Formats	96
Animation and 3-D Formats	96
AVI (Video for Windows )	97
Required Components for AVI	97
Creating AVI Files	97
DivX	98
DV	99
Working with DV Sources	99
Creating DV Streams	99
Flash Video Formats (FLV, SWF)	101
Kinoma	101
Video Encoding	101
Audio Encoding	102
MP3	103
Creating MP3 Files	103
Choosing Encoding Parameters	103
MP3 and QuickTime	105
Copyright Settings	105
MP3 Licensing	105
MPEG	106
MPEG Playback	106
MPEG Aspect Ratios	107
Group of Pictures	109
MPEG Licensing	109
QuickTime	110
Preparing QuickTime	110
QuickTime Scalability	111
Required Software	112
QuickTime Version Compatibility	112
QuickTime Codecs	114
Audio-only Movies	115
QuickTime Movie Suffix	116
QuickTime Streaming	116
Alternates	117
Creating Alternates	120
Organizing Alternates	124
Alternate Movie Fallbacks	130
Single Version Fallback	132
Putting QuickTime Online	132
QuickTime MIME Types	135
Special QuickTime Options	135
Real 10	141
Real 10 Scalability	141
Streaming Real 10 Files	141
Downloadable Real 10 Files	142
Audio-Only Real 10 Files	142
Viewing Real 10 Files	143
Putting Real 10 Files on a RealServer	143
Windows Media	144
Windows Media formats	144
Windows Media codecs	145
Creating Windows Media Files	145
Downloadable Windows Media Files	145
Uploading to a Windows Media Server	146
Adding Downloadable Files to a Web Page	147
Encoding	149
Output Tab	150
The Format Menu	150
QuickTime	151
MPEG-1	154
MPEG-2	155
AVI	155
Windows Media 7	156
DivX 6	156
JPEG	161
PNG	161
PICT	162
QuickTime Image (QTIF)	162
3G	162
AIFF	164
BMP	164
FLC	165
Kinoma Media	166
Hinted Movie	173
MPEG Audio Layer-3 (MP3)	174
RealMedia	174
QuickTime TeXML	176
AU	177
WAVE	178
Wildform Flash Video (FLV, SWF)	179
DV Stream	181
QuickTime Media Link	182
Image Sequence	183
MPEG-4	184
Tracks Tab	186
Flatten Only Option (QuickTime)	186
Track Options	186
Other Tracks	187
Encode Tab	188
Codec	188
Bit Depth	188
Spatial Quality and Temporal Quality Sliders	189
Frame Rate	189
Keyframes or Insert Keyframes	190
Compare Uncompressed Frames	192
Video Data Rate	192
Compression Buffer Window (Windows Media only)	197
Video Quality (Windows Media only)	197
Encoding Speed (MPEG-1, MPEG-2 only)	198
Frames or Fields (MPEG-2 only)	198
Video Buffer Verifier (MPEG-1, MPEG-2 only)	198
Group of Pictures (GOP) (MPEG-1, MPEG-2 only)	198
New GOP on Scene Change (MPEG-1, MPEG-2 only)	198
Open GOPs (MPEG-1, MPEG-2 only)	198
Chroma Format (MPEG-2 only)	199
Output Field Dominance (MPEG-2 only)	199
Frame Rate versus Frame Size	200
Frame Size	200
Display Size	200
Testing	201
Variations for Testing	202
Processing Still Images	202
Making Still Images from Movies	203
Enhancing Still Images	203
Making Movies Out of Still Images	204
Optimizing Stills for Encoding	204
Audio Tab	205
AVI Audio Codecs	205
MPEG-1 and MPEG-2 Audio Codecs	206
QuickTime Audio Codecs	206
Sample Rate	207
Data Rate (only for MP3, MPEG Layer 1, MPEG Layer 2)	207
Depth	208
Channels	208
Speed vs. Quality (MP3)	208
Options	208
Volume	208
Low/High Pass	208
Noise Removal	208
Dynamic Range	209
Noise Gate	209
Notch	209
Reverb	209
Begin/End Tab	210
Video/Audio Fades	210
High-Quality First/Last Frames	210
End Frame URL Link	211
In/Out Points	211
Metadata Tab	211
Summary Tab	213
Preview Windows	213
Dynamic Preview	213
The Output Window	217
EventStream	221
EventStream Authoring	222
Adding EventStreams	222
Adding Markers in Real Time	223
Saving	224
Exporting/Importing	224
Supported Events	225
Playback Events	225
Processing Events	231
Publishing	233
Setting Streaming Server Paths	234
QuickTime Streaming Server Preferences	234
RealServer Preferences	235
Windows Media Server Preferences	236
StreamPublisher	237
Specifying the Destination for Streaming Files	237
Workflow	239
Preproduction	240
Watch Folders	240
Context Menus	242
Improving Processing Speed	242
Upgrade Your Computer	242
Turning Off Video Display	243
Minimize Processing	243
Helpers	243
Using Helpers	243
Opening Source Movies with Helpers	244
Opening Output Movies with Helpers	244
Using AppleScripts with Helpers	244
Helpers and Function Keys	244
Preferences	245
Interface	245
Processing	246
QT Alternates	247
Server Paths	247
Troubleshooting	249
Common Problems and Solutions	249
Hardware Codecs	249
Image Quality Problems	249
Older Computers	250
Progressive-streaming Movies	250
Real-Time-streaming Movies	250
Servers	251
Technical Support	252
Before You Contact Us	252
Glossary	255

Match case Limit results 1 per page

MPEG

MPEG Aspect Ratios

MPEG pixels, especially those encoded for video device playback, are often not square. Because

of this, the aspect ratio must be defined in order to display MPEG video. There are two different

ways to define aspect ratio: Pixel aspect ratio and image aspect ratio.

Pixel Aspect Ratio (MPEG-1)

The pixel aspect ratio defines the proportions of the pixels in the image. Given this ratio and

the number of pixels, the MPEG decoder figures out how large to display the final image

onscreen. The MPEG-1 display aspect ratio is specified as the pixel aspect ratio, which is the

ratio of a pixel’s height to its width.

The standard pixel aspect ratio for NTSC MPEG-1 is 1.0950, which means that the pixels are

slightly taller than they are wide. The standard pixel aspect ratio for PAL MPEG-1 is .9157,

which means that the pixels are slightly wider than they are tall. A pixel aspect ratio of 1.0000

(1:1) is a square pixel aspect ratio and results in square pixels throughout the entire image.

For example, if the dimensions of the MPEG source is 352x240 pixels and the pixel aspect ratio

is 1.095:1, some MPEG players, including QuickTime, will generally display the image at about

320x240 on a normal square pixel computer monitor (352/1.095 = 321, evened off to 320; the 240

dimension is unaltered).

QuickTime compensates for this non-square ratio properly during playback and displays

MPEG-1 files undistorted. QuickTime plays standard 352x240 MPEG correctly as 320x240

square pixels. You have to take special care with Windows Media Player, however, because it

displays MPEG pixels at 1:1 no matter what the pixel aspect ratio of the source. This makes

standard NTSC MPEG-1 video appear wider than it should.

Because QuickTime takes the pixel aspect ratio of MPEG-1 content into account, the safest

solution for cross-platform desktop playback is to encode MPEG video with square pixels

instead of the standard MPEG-1 pixel aspect ratio. QuickTime Player also correctly displays

square-pixel MPEG-1 streams, so this works using both QuickTime Player and Windows Media

Players. However, some MPEG devices, such as Video CD players, may not be able to handle

square pixels properly.