Presentation on theme: "St. Paul Public Television Quality Workshop - July 8-9, 2010"— Presentation transcript:
1St. Paul Public Television Quality Workshop - July 8-9, 2010 Aspect Ratio and Active Format Description How do we make it all fit? Gerry Field American Public TelevisionSt. Paul Public Television Quality Workshop - July 8-9, 2010
2Aspect Ratio Television Aspect Ratio Defined: Picture frame: Ratio of image width to image height.Not directly tied to resolution.HD Screens are typically 16:9.SD Screens are both 4:3 and 16:9.Programming is varied.16:9, 4:3, 15:9, 14:9, 1.85:1, 2.39:1 etc.Mixed aspect ratio programs
3How do we make it all fit?We must deal with two display sizes 16:9 and 4:3.16:9 sets have over 50% household penetration.Number of TV sets in the average U.S. household: 2.86.U.S. homes with three or more TV sets: 54%
4How do we make it all fit?There are two programming sizes 16:9 and 4:3.Treat all widescreen as 16:9 unless we wish to crop other formatsUpconversion, Downconversion
21What is the proper way to treat this? It depends.Commercial Networks Up Convert 4:3 with side panels. Down Convert 16:9 by Center Cut.PBS Stations Up Convert primarily 4:3 with side panels and Down Convert by Center Cutting or Letterboxing.
22Anamorphic Commonly defines 16:9 “squashed” into 4:3 (Can also apply to 4:3 “stretched” to 16:9)Used as a distribution techniqueMost common is SD widescreen on D-BetaMust be properly handled prior to emissionIf not, viewer sees “squashed” picture
25Anamorphic Anamorphic or 16:9 SD programming may be upconverted to 16:9 HD and distributed (at a bandwidth cost).Alternatively, 16:9 SD can be distributed with MPEG2 encoder flag set to 16:9.16:9 SD included in ATSC A/53 standard.SD 16:9 can co-exist with SD 4:3Member station IRD will output correct format as desired.
26If the MPEG2 flag is set to 16:9 at the MPEG2 Encoder, the Sencore IRD will properly recognizeThe format and provide properly formatted video16:9 HD or 16:9 SDSencore IRDMRD31874:3 SD Center CutSource SD 16:94:3, 16:9 Letterbox SD
27Down Converting Some stations and channels are still SD only. 50 % of our viewers are still SD.Most HD households still have 2nd and 3rd SD sets.
28Active Format Description - AFD A four bit code to define the active and protected image area.Intended to guide professional video equipment, consumer receivers and set-top boxes to optimize the displayed image.Very few ATSC receivers and consumer decoders act on AFD.
29Active Format Description - AFD May also be used for format conversion signaling in the post and pre-broadcast chain.References:- SMPTE ST :2009- PBS TOS-1, 4.4- PBS TOS-21, 4.3.7- PBS Connect > Engineering/Compute >Technical Reference Library
30AFD Codes SMPTE ST 2016-1:2009 defines 17 AFD Codes. Four are in common use:1000 – Full Frame1001 – Full 4:3 / Pillarbox1010 – Protected 16:91111 – Center Cuts(14:9, 15:9, 2.35 etc. treated as 16:9)
31AFD = ‘1000’ (Full Frame) In a 4:3 coded frame In a 16:9 coded frame 31
32AFD = ‘1001’ (Full 4:3 / Pillarbox) In a 4:3 coded frameIn a 16:9 coded frameIn a 4:3 coded frame, AFD code ‘1001’ represents the same image display asAFD code ‘1000’.AFD code ‘1000’ is the preferred coding for afull frame 4:3 image32
33AFD = ‘1010’ (Protected 16:9) In a 4:3 coded frame 33
34AFD = ‘1111’ (Center Cuts) In a 4:3 coded frame In a 16:9 coded frame 34
36Consumer IssuesBroadcasters cannot rely on consumers to maintain aspect.AFD is not widely implemented on consumer devices.
37So What do we do? Educate. Implement AFD. Discuss with Cable and Satellite providers to Implement AFD on their SD Down convert.Produce when appropriate 16X9 Center cut safe material.If necessary up convert Letterbox to 16X9 Full frame.