Aspect Ratio and Active Format


VideoA Video Frame is a grid of pixels with a defined geometry and resolution, consisting of lines of pixels. The resolution has a vertical and a horizontal component, where the vertical resolution defines the number of lines, and the horizontal resolution defines the number of pixels per line. Each pixel has a defined geometric shape, which can be of any aspect ratio, but is often square. The combination of resolution and pixel aspect ratio defines the frame aspect ratio, indicating the overall geometric shape of the full video frame. This diagram shows the geometric shape of a frame defined by frame and pixel aspect ratios, regardless of resolution.
Signal
ShapeThe image shows the geometry of the active video content, and bars that have been added around the active content to achieve the aspect ratio of the video signal.
Bars are shown in black, and the active content is shown in gray. The protected area of the active content is filled along the major axis with circles, with one circle with a minor axis diameter in the center.
Circles appearing as ovals indicate anamorphism of the video signal, i.e., non-square pixels. The image shows the pixel grid of the video signal, with non-square pixels stretched to become square pixels.


To get the above shape as a Scalable Vector Graphics image file, paste the copied text into a plain text file and save with a .svg file extension. Use in Word documents, post to Websites, etc.
Video Frame:Provide the geometry of the overall Video Frame, including any Letterbox or Pillarbox Adjustment Bars
 Show a
FrameSet the Aspect Ratio of the Video Frame
with a
PixelSet the Aspect Ratio of an individual Pixel. 64:63 is near-square, for 64:27 video formats with 720 lines. 128:129 is near-square, for 64:27 video formats with 1440 and 2880 lines.
Aspect Ratio
Active ContentProvide the geometry of the area containing Active Content (other than Letterbox or Pillarbox Adjustment Bars) within the Video Frame
: 		Show
ContentSet the Aspect Ratio of the Active Content within the Video Frame
with a
ProtectedSet the Aspect Ratio of the Protected Content within the Active Content
Area
AFD and BarsActive Format Descriptor and Bar Data
:
Describes the Active and Protected Content Aspect Ratios, and whether Active is at the Top, through an enumerated list entry
:
SubtitlesShow where Subtitles or Captions would be rendered
:
Whether to display Subtitles
:

Scaling for Display

Shown on 4:3 Display


ActiveThe Active Content Aspect Ratio of the remaining Image
= :,
ProtectedThe Protected Content Aspect Ratio of the remaining Image
= :

Shown on 16:9 Display


ActiveThe Active Content Aspect Ratio of the remaining Image
= :,
ProtectedThe Protected Content Aspect Ratio of the remaining Image
= :

Shown on "21:9" (64:27) Display


ActiveThe Active Content Aspect Ratio of the remaining Image
= :,
ProtectedThe Protected Content Aspect Ratio of the remaining Image
= :
SourceShows the scaling window into the source frame. WxH(x,y,w,h): WxH = source frame size, x,y = source window position, w,h = source window size
:
DestinationShows the scaling window onto the display frame. WxH(x,y,w,h): WxH = display frame size, x,y = destination window position, w,h = destination window size
:
SourceShows the scaling window into the source frame. WxH(x,y,w,h): WxH = source frame size, x,y = source window position, w,h = source window size
:
DestinationShows the scaling window onto the display frame. WxH(x,y,w,h): WxH = display frame size, x,y = destination window position, w,h = destination window size
:
SourceShows the scaling window into the source frame. WxH(x,y,w,h): WxH = source frame size, x,y = source window position, w,h = source window size
:
DestinationShows the scaling window onto the display frame. WxH(x,y,w,h): WxH = display frame size, x,y = destination window position, w,h = destination window size
:

Shown on other Display
Content
renderedScaling of the Video Frame, utilizing padding and/or cropping, based on the given Active and Protected Content Aspect Ratios, to fill the display as much as possible, while also showing as much as possible of the original content.
onto a
Display DeviceSet the Aspect Ratio of the Display Device where the indicated video signal is being shown

ActiveThe Active Content Aspect Ratio of the remaining Image
= :,
ProtectedThe Protected Content Aspect Ratio of the remaining Image
= :
SourceShows the scaling window into the source frame. WxH(x,y,w,h): WxH = source frame size, x,y = source window position, w,h = source window size
:
DestinationShows the scaling window onto the display frame. WxH(x,y,w,h): WxH = display frame size, x,y = destination window position, w,h = destination window size
:

AFD Chart: Frame with alternative Active Format Descriptors
Full Frame
0b1000
16:9 (top)
0b0010
4:3
0b1001
14:9 (top)
0b0011
16:9
0b1010
4:3 with 14:9 shoot&protect
0b1101
14:9
0b1011
16:9 with 14:9 shoot&protect
0b1110
64:27 (> 16:9)
0b0100
16:9 with 4:3 shoot&protect
0b1111
CTA-861 AVI InfoFrame:
Data Byte 1 Y2 Y1 Y0 A0= B1= B0= S1 S0
Data Byte 2 C1 C0 M = R =
Data Byte 3 ITC EC2 EC1 EC0 Q1 Q0 SC1 SC0
Data Byte 4 VIC1 =
Data Byte 5 YQ1 YQ0 CN1 CN0 PR3 PR2 PR1 PR0
Data Byte 6 ETB07-ETB00 =
Data Byte 7 ETB15-ETB08 =
Data Byte 8 SBB07-SBB00 =
Data Byte 9 SBB15-SBB08 =
Data Byte 10 ELB07-ELB00 =
Data Byte 11 ELB15-ELB08 =
Data Byte 12 SRB07-SRB00 =
Data Byte 13 SRB15-SRB08 =
Data Byte 14 ACE3 ACE2 ACE1 ACE0 FR3 FR2 FR1 FR0
Data Byte 15 F157=0 FR4 RID2 =
Notes:
1 VICs map to 23,24,25,48,50,60,100,120 Hz, with RID=0.
2 RID used for 144 Hz and up, or if VIC list is 0. Set VIC=0 if RID≠0.

Version 0.11, 2025-02-20

Support: sub-afdasp @ scara . com

Latest Version: https://scarabaeus.org/afd/

Copyright © 2025 Scarabaeus / Christian Wolff. All rights reserved.

Revision History:
  • 0.1: 2022-04-08, initial version
  • 0.2: 2024-10-20, added support for subtitles, AFD tag
  • 0.3: 2024-10-22, added support for vertical ARs, provide SVG source as XML in clipboard, style cleanup
  • 0.4: 2024-10-23, added support for resolutions
  • 0.5: 2024-10-30, added cropping / padding for 4:3, 16:9 and 64:27 displays
  • 0.6: 2024-10-31, added determination of scaling windows
  • 0.7: 2024-11-06, added CTA-861 AVI InfoFrame values, fixed scaling windows
  • 0.8: 2024-11-11, vertically oriented and more compact redesign of UI (mobile friendly), add DCI and 32:9 display, fix scaling calc for anamorphic pixels
  • 0.9: 2024-11-12, added tool tips, one adjustable display instead of five separate fixed ones
  • 0.10: 2024-11-20, restore three default displays, style updates
  • 0.11: 2025-02-20, improve SVG Copy button, now with feedback