HDV Progressive Primer - sony-asia.com

HDV Progressive Primer

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Table of contentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

• What is HD? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

• What is HDV? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

• Progressive Shooting in HDV Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

• Interlace and Progressive Scanning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

• Progressive Programme Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Interlace and Progressive Imagers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Interlace and Progressive Recording . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

• Progressive Shooting Functions in Sony’s Professional HDV Camcorders . . . . . .10

CineframeTM (HVR-A1, HVR-Z1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Progressive Scan Mode (HVR-V1, HVR-Z5, HVR-Z7, HVR-S270) . . . . . . . . . . . . . . . . . . . . . .11

Native Progressive Recording Mode (HVR-Z5, HVR-Z7, HVR-S270) . . . . . . . . . . . . . . . . . . .12

• Edit and Distribute the Video Taken in Progressive Shooting Functions . . . . . . . .13

For Video Distribution in an Interlace Format with Progressive-look Motion . . . . . . . . . . . .13

For Video Distribution in a Progressive Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Appendix

• 50i/60i Switchable Option of HVR-Z5, HVR-Z7 and HVR-S270: . . . . . . . . . . . . . . . .15

• Why 29.97 and 23.98 fps, not 30 and 24 fps? . . . . . . . . . . . . . . . . . . . . . . . . . . . .15

• 24p to 60i Transfer – 2:3 pull-down – . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

• 24P Scan Modes in HVR-V1/Z5/Z7/S270 – “24” or “24A” ? – . . . . . . . . . . . . . . . . .17

• HDV Native Progressive Recording format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

An Optional Specification in HDV Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Compression Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Output Signal (in HVR-Z5/Z7/S270/M15A/M25A/M35) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19

Recorded and Output TimeCode (in HVR-Z5/Z7/S270/M15A/M25A/M35) . . . . . . . . . . . .19

• HDV Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

The Concept of Entropy and Redundancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Inter-frame Coding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Intra-frame Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Building an HDV Stream . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

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Welcome to this Sony HDV TM Progressive Primerdesigned to explain the art and craft of shooting progressive, the technology behind progressive video,and show you the controls, functions and benefits ofthe latest range of Sony HDV progressive products.

The Purpose of This PrimerHDV, and high definition video, push the boundaries of quality and artisticexpression. Camera operators can be more adventurous, and editors have agreater range of techniques to play with.Now, the latest Sony HDV camcorders bring the ability to shoot in the HDV nativeprogressive recording format. While this new capability opens the envelope ofopportunities to those using these camcorders, progressive also brings with itseveral new technologies. Technologies that have been used very little instandard definition programme making.Although Sony HDV progressive products will record a perfectly good image withlittle or no effort, anyone wanting to gain the most from these products shouldunderstand the new controls, functions and technologies behind progressive.This primer tells the story behind progressive video. It provides a technicalexplanation of the progressive shooting capabilities of the Sony range ofprofessional HDV camcorders, referring to both the operation of thecamcorderÅfs image sensors and the video signals they produce.By using this primer and Sony HDV progressive products, you will find the bestcombination of controls and functions, for a wider range of shooting conditions,and a greater variety of final video clips, allowing you to shoot a superb imageand build a well crafted edit. Progressive recording will become part of youroverall programme making process, and another expressive technique to add tothose you already have.

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◆◆◆ What is HD?Standard Definition (SD) video has been available in two versions with 525 linesand 625 lines per video frame. Europe, Australia, India and some other countrieshave adopted the 625 line version commonly referred to as PAL. The USA, Canadaand some other countries have adopted the 525 line version commonly referredto as NTSC.(A third standard, SECAM, was devised as an alternative to PAL, and is used byFrance, Russia and some other countries for transmitting television into the home.However, because of its relative complexity, but close similarity to PAL, all countriesthat use SECAM to transmit to the home use PAL for original recording and in thetelevision studio.)The term “High Definition” has been used throughout the history of television tomean the next and best television format. For example, in the 1930s monochromeanalogue television broadcasting began in Europe at only 405 lines per frame. At the time this was also called “High Definition” simply because it was better thanprevious television of the time!With modern television High Definition (HD) has come to mean anythingsignificantly better than 625 line television, and probably approaching 1000 linesper frame. HD is now available in two types with 720 and 1080 lines per videoframe. Both are significantly better than existing SD television formats offeringbetter movement capture and higher resolution.

1920

1080 (HD)1920x1080

720 (HD)1280x720

SD (DV)720x480, 720x576

CIF352x288

OCF176x144

1280720352176

144

288

720

1080

480 or576

Chart illustrating the relative pixel resolution of different video formats.

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Srandard Definition High Definition (1920x1080)

Comparing standard definition and high definitionThere are about 5 times as many 1080 HD pixels as SD television.Comparing standard definition and high definitionThere are about 5 times as many 1080 HD pixels as SD television.

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◆◆◆ What is HDV?DV and its professional brother DVCAMTM have enjoyed huge success as a costeffective compact SD format, and many users, both non-professional andprofessional, have adopted both DV and DVCAM as their entry level programmemaking formats. Now HDV maintains the heritage into the exciting new world of HD video.HDV is a tape recording format using DV tape to record HD video, thus providingall the quality and resolution benefits of HD but using equipment that is compactand easy to operate, with media that is both easy to obtain and cost effective.In a nutshell, HDV is the entry level HD format for broadcasters, videographers andprogramme makers alike.Both 720 and 1080 high definition types are supported by HDV. The 720 lines HDVtype uses progressive scanning and is generally called HDV720p. The 1080 line HDVtype traditionally uses interlaced scanning and is generally called HDV1080i.Initially Sony adopted HDV1080i for its HDV products. Recently, the HDVspecification was widened to include native 1080P recording capability.The HDV1080 features 1080 lines and 1440 pixels per line. HDV compresses the fullHD image, by using one of the MPEG-2 Long GOP profiles, Main Profile at High1440 Level (MP@H-14). This highly efficient and robust MPEG-2 Long GOP codec is also used in the Sony XDCAM HDand XDCAM EX series of professional products and enables users to recordstunning-quality HD video. For more details of HDV compression, please refer to the Appendix at the end ofthis Primer.

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◆◆◆ Progressive Shooting in HDV FormatTraditionally HD progressive shooting was reserved for the 720 line HD specification.More recently, 1080 progressive capabilities have also been adopted in the manytypes of HD camcorders. The Sony HDV camcorders are no exception.Sony professional HDV camcorders have several types of progressive shootingfunctions. The HVR-Z1 and HVR-A1 have “CineframeTM” progressive-look mode , theHVR-V1 has the “Progressive Scan” mode and the latest HVR-Z5/Z7/S270 have theadditional “Native Progressive Recording” mode. When a suitable mode is selected, programme makers can enjoy all the benefitsof shooting in progressive.

◆◆◆ Interlace and Progressive ScanningVideo portrays a moving scene as a series of images displayed at such a fast ratethat we perceive a moving picture. Each of these images is called a frame(a term borrowed from film).The chosen frame rate for SD video is 25 frames per second for 625 line areas, and30 frames per second for 525 line areas. These rates were originally chosen tomatch AC mains power supplies in countries around the world, and to reduce theobjectionable beating effects that would otherwise occur when televisions androom lighting interfere with one another.However, at 25 or 30 frames per second television image tends to flicker. Toreduce flicker without increasing the required bandwidth for the television signal,each video frame is divided into two scans called fields, with field 1 for the oddlines and field 2 for the even lines.The screen is therefore scanned at 50 and 60 fields a second respectively,reducing flicker, and each frame is made up from two fields. This technique iscalled interlaced raster scan or simply interlace.

Movement looks smoother with interlace thanks to its relatively high field-rate.However, interlace may give jagged edges on moving objects when viewing asingle frame on its own, commonly referred to as jaggies. This is because theposition of the object has moved from field 1 to 2.Jaggies are undesirable in some applications such as image composition, viewingon computer screen, film transfer, etc..

Sony has adopted HDV1080i for all its HDV products.

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Scan lines

1/25 or 1/30 sec.

1/50 or 1/60 sec.

Fly-back(blanking)Field 1 Field 2

An object moving from left to right quickly

Interlace scanning

1/50 sec.or

1/60 sec.

TimeDifference

Jaggies appear on the edge

Field 1 (Odd field)

Object

Frame

Field 2 (Odd field)

Frame

Scan lines

Fly-back(blanking)

1/25 or 1/30 sec.

In these cases the “filmic” look is often a better alternative over interlace, whereeach video frame is kept as a single scan. This is called progressive raster scan orsimply progressive.With progressive, jaggies do not occur. This makes it much better than interlace ifyou plan to capture still images from your video. It also gives the video acharacteristic filmic look.

Jaggies

Interlace scanning

Jaggies

Progressive scanning

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25P 24P

1

1 sec.

1 sec.

2

•••

•••

24

25

1

1

2

24

1

2

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◆◆◆ Progressive Programme DistributionThe following are examples of progressive programme distribution:

Film: For film-making with video camcorders, it is necessary to print film for finaldistribution. Progressive shooting is ideal for film-out because each frame iscaptured at once, just as a film camera would and at the same frame rate as film.

Web movie and computer graphics: A computer display uses progressive scanning. It is ideal to make a video inprogressive format for viewing on this type of display.

24P on Blu-ray DiscTM

DVD and Blu-ray Disc are capable of storing native 24P content. Most Hollywoodmovies are recorded on the disc as a 24P (23.976p) stream.24P-capable DVD and Blu-ray Disc players can deliver the 24P signal to acomputer monitor or a 24P-capable TV set at 24 fps with no 2:3 pull-down just as itwould appear in a movie theatre.

For 25P users, it is possible to convert the 25P to 24P and vice versa by copyingframes one on one.There is a difference of only one frame per second. It is equivalent to a 4% speeddifference.Some NLE software or digital motion graphics software have a frame rateconversion function.

Conversion between 25P and 24P

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Interlace and Progressive ImagersCamcorders can adopt image sensors that capture video frames using eitherinterlace or progressive scans. For true interlace recording the imager should scanin an interlace pattern, and for true progressive recording the imager should scanin a progressive pattern.

Interlace and Progressive RecordingCamcorders can record to media using either an interlace method or aprogressive method. When using progressive recording the video frame isrecorded to media as one block of data. When using interlace recording thevideo frame is recorded in two blocks, one for the odd lines and the other for theeven lines.

Recording

Interlace Progressive

Imager

Interlace

Progressive

[HVR-A1 & HVR-Z1]True interlace recording with the imager and recording system matched. Used in 1080i mode.

Not used in Sony HDV equipment. May be used in HDV equipment from other manufacturers. Could result in degraded image quality due to lack of scanning lines.

[HVR-V1, HVR-Z5, HVR-Z7, HVR-S270]

(1): Interlace scanning A Progressive imager can work as an interlace imager. In interlace recording mode, true interlace recording is realized.

(2):Progressive scanning Progressive segmented Frame (PsF) recording. True progressive capture. Frame split into two segments and recorded using the same technique as interlace recording. PsF is a progressive signal that can be displayed on an interlace-only monitor. Used in “Progressive Scan” mode.

[HVR-Z5, HVR-Z7, HVR-S270]True progressive recording with the imager and recording system matched.Used in HVR-Z7 and HVR-S270 as “Native Progressive Recording” mode.

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Field1 (odd field)

Field2 (even field)

1. Extact one field

2. Duplicate toanother field

3. Progressive-look motionby these two fields

◆◆◆ Progressive Shooting Functions in Sony’s Professional HDVCamcordersThe Sony range of professional camcorders has several types of progressiveshooting functions.

CineframeTM (HVR-A1, HVR-Z1)Cineframe gives a progressive-look motion to the video captured by the interlaceimager, which is then processed and recorded as a normal interlace signal.As described previously, each interlace frame is composed of two fields. InCineframe mode, one field is ignored and another field is duplicated to make acomplete video frame free from jaggies. Although each frame has half theresolution (540 lines), the recorded video can be conveniently viewed and editedby normal interlace facilities.The Cineframe method is a useful way of recording a filmic look on a camcorderthat uses interlace imagers. However this method falls short of the true qualityattainable by a camcorder fitted with progressive imagers that can record truenative progressive.

Cineframe is also available in DVCAM and DV recording modes.

For 60i model:60i models of the HVR-Z1 and HVR-A1 include the Cineframe24 mode, which uses2:3 pull-down to synchronize the frame/field frequency.For more detail about the 2:3 pull-down method, please refer to the Appendix inthis Primer.

Cineframe

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Progressive Scan Mode (HVR-V1, HVR-Z5, HVR-Z7, HVR-S270)The HVR-V1, HVR-Z5, HVR-Z7 and HVR-S270 camcorders all use 3 ClearVid CMOSSensorTM system which can capture 1080p full-HD quality video. These models haveProgressive Scan mode. In this mode, the captured 1080p image is just dividedinto two halves, then recorded or output as interlace signal. The halves are calledsegments, not fields, because there is no temporal difference between them. Thismethod is also called as PsF (Progressive segmented Frame) recording. The 1080p picture quality is completely kept unlike the Cineframe so that you canuse this mode instead of the Cineframe.

The Progressive Scan mode is suitable for the feature films, documentaries, musicvideos which have to be recorded as interlaced video for viewing on interlacedmonitors, but want to offer “progressive-look” to their motion.

Besides, the video taken in the Progressive Scan mode can be edited and outputas true progressive video if needed.For 25p or 30p scan, most NLE can output the edited timeline in progressive formatby merging the divided odd and even fields again.

For 60i model:For 24p scan of the 60i models , the image is recorded through the 2-3 pull-downprocess. You can use your current interlace-based editing system because therecording is done in interlace. For more detail about the 24p scan mode, pleasealso refer to the Appendix in this Primer.

1080p

1080i

Even Field

Odd Field

1080p

1080iProgressive-look Motion

1080p 1080i 1080p or 1080i 1080p or 1080iDeliverEditRecordCapture

Progressive Scan mode

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Native Progressive Recording Mode (HVR-Z5, HVR-Z7, HVR-S270)The HVR-Z5, HVR-Z7 and HVR-S270 can record the captured 1080p image as HDVnative 1080 progressive signal which is defined as an optional format of HDV1080ispecification. (Please refer to : http://www.hdv-info.org/).

In this mode, the captured 1080p image is recorded on the media without anyconversion. A compatible NLE can directly capture the HDV1080/24p/25p/30p i.LINK outputstream and edit it natively.

The picture quality of Native Progressive Recording mode is theoretically betterthan Progressive Scan mode. In practice it is difficult to determine the difference inmost video sequences.Please refer to the flow chart in this Primer to know the better mode for you.

Native Progressive Recording has been called 24F/25F/30F in some camcorders,while actually using interlace CCD imagers. However the Sony HVR-Z5, HVR-Z7 andS270 have true 1080p CMOS imagers, and true progressive processing.The compatible Sony’s HDV products have the following logo :

1080p 1080p1080p1080p

Capture Record Edit Deliver

Nativeprogressive

recording mode

Progressivescan modeCineframeImagerModel

Camcorder models and progressive shooting functions

HVR-S270

HVR-Z7

HVR-Z1

HVR-V1

HVR-A1

HVR-HD1000

NO

NO

NO

NO

YES

YES

YES

YES

YES

NO

NO

NO

YES

YES

YES YES

NO

NO

NO

NO

1/3-type 3 ClearVid CMOS Sensor system



1/2.9-type single ClearVid CMOS Sensor

HVR-Z5 NO1/3-type 3 ClearVid CMOS Sensor system

1/3-type HD 3CCD

1/3-type single CMOS

HDV Native Progressive Recording mode.

For more information about the HDV Native Progressive Recording format, pleaserefer to the Appendix of this Primer.

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◆◆◆ Edit and Distribute the Video Taken in Progressive Shooting Functions

For Video Distribution in an Interlace Format with Progressive-lookMotionIf you decide to deliver your programme in an interlace format only, you shouldrecord material in Cineframe or Progressive Scan mode.Material is recorded in an interlace fashion, but has a progressive look, and canbe edited as an interlace (60i or 50i) project on standard NLE software. The resultcan be authored to Blu-ray Disc, DVD, tape etc. as an interlaced video forviewing on a television with a progressive or “filmic” look.

For 60i model users:If you just need a progressive-look image for viewing on a television screen, pleaseconsider shooting 30P scan. 30P scanned images look more natural than 24P.

For Video Distribution in a Progressive FormatYou can distribute video shot in a progressive mode as, for example, progressiveBlu-ray Disc, film, web movie or any other progressive format media. There are several options for this case.

1. Video shot in Native Progressive Recording mode (HVR-Z5, HVR-Z7 and HVR-S270)If you have an NLE software compatible with this format, it is recommended toshoot footage in this mode. The NLE can capture the HDV native progressivesignal through the i.LINK cable and you can edit the material as a23.98p/25p/29.97p project.

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2. Video shot in Cineframe or Progressive Scan modeIf your NLE software does not support native progressive editing, but your goal isa 25p or 30p programme, you can use “Cineframe25/30” or “Progressive Scan25p/30p” mode. Capture the material in either of these modes, and edit as an50i/60i project. Output the finished timeline as a progressive format by selectingthe suitable output settings in the NLE. Most NLEs can merge the odd and evenfields to make one frame during output.

For 60i model users:If you would like to make 24p programme, you have to have NLE softwarecompatible with 24A Progressive Scan mode. The 24A compatible NLE candetect 2-3 cadences and remove them in order to edit in 23.98p.For the detail about the 24A Progressive Scan mode, please also refer to theAppendix of this Primer.

The following flow chart explains the recommended progressive shooting functions.

•Native 24P/25P/30P

Only Interlace

Only Progressive

Both or Not decided

No

No

No

No

YesYes

Yes

Yes

25p/30p

25p/30p

24p

24p

25p/30p or 24p ?

25p/30p or 24p ?

Do you have any NLE compatible with the native progressive format ?

What formatfor the finaldistribution ?

Do you have a 24Acompatible NLE ?

Do you have any NLE compatible with the native progressive format ?

Do you have a 24Acompatible NLE ?

*1: Some application software such as Adobe After Effects®, Apple® Cinema ToolsTM, Cineform Aspect HDTM can remove the 2-3 frames from “24” scan video materials by their inverse telecine function. For more details, please ask the reseller of these software.

*2: NLE needs to insert the 2-3 pull-down frames to the 24p data.

•Cineframe 24/25/30•Progressive Scan 24/25/30

•Progressive Scan 25/30•Cineframe 25/30Interace: Edited in 50i/60iProgressive: Converted to progressive by NLE

•Progressive Scan 25/30•Cineframe 25/30Converted to progressive by NLE

•Progressive Scan 24•Cineframe 24Use software withinverse telecine function*1

•Progressive Scan 24•Cineframe 24Interlace: Edited in 60iProgressive: Use softwarewith inverse telecine function*1

•Native 24PInterlace: NLE inserts 2-3 frames*2

Progressive: Edited in native Progressive

•Progressive Scan 24AInterlace: Edited in 60iProgressive: NLE removes 2-3 frames

Progressive Scan 24ANLE removes 2-3 frames

Find your best progressive function

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◆◆◆ 50i/60i Switchable Option of HVR-Z5, HVR-Z7 and HVR-S270:50i/60i switchable function is added on the HVR-Z5/Z7/S270 when modified at anauthorized Sony service centre. The following recording modes are added:

HDV1080i recording:• 60i, 24p and 30p modes on 50i model• 50i and 25p modes on 60i model

DVCAM/DV recording:• 60i mode on 50i model• 50i mode on 60i model

Please consult your local Sony service centre for the fee and details.

◆◆◆ Why 29.97 and 23.98 fps, not 30 and 24 fps?NTSC video equipment brochures and manuals often mention 29.97 or 59.94 fpsrather than 30 or 60 fps. Why?Original monochrome NTSC video, set in 1941, ran at 30 frames per second,interlaced at 60 fields per second. This standard worked well and many Americantelevision stations adopted the standard, and thousands of viewers at homebought televisions to receive monochrome NTSC.However when the NTSC colour standard was designed it was found that theadditional colour signal interfered with audio when the signal was transmitted outto the home.The standards authorities therefore decided to alter the video frame rate slightlyfrom 30 frames per second to 29.97 frames per second, removing the interference.This is sometimes called drop-frame because timecode needs to drop a fewframes every so often to ensure that its count is kept in line with real time. Thus drop frame NTSC runs at 29.97 frames per second, or 59.95 fields per second.Many American broadcasters shoot at film frame rate, 24 frames per second.Therefore a TV version of 24 frames per second was also devised at 23.98 (23.976)frames per second.These frame rates are used to this day, even in high definition video and all SonyHDV equipment actually operates at 29.97 frames per second when 30 frames persecond is selected, and at 23.98 frames per second when 24 frames per second isselected.In this primer, 30p, 60i and 24p actually mean 29.97p, 59.94i and 23.98prespectively unless otherwise specified.

Appendix

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Original 24 Frames

Odd Field(60i)

Even Field(60i)

ResultingVideo Frame

16


◆◆◆ 24p to 60i Transfer – 2:3 pull-down –Film is recorded at 24 complete frames per second. This frame rate was chosen forhistoric reasons because it is about the slowest frame rate possible before filmicjudder becomes unacceptable, using a little film stock as possible, as film wasexpensive, certainly in the early day of cinema. Cinemas, however, show film at 48frames per second by displaying each frame twice. While this does not alter filmicjudder because movement is still running at 24 images per second, it does makethe picture appear smoother by improving flicker In 60Hz regions, film transfersmust be converted from 24 frames per second to 60 fields per second interlace forTV broadcast by repeating some fields. The process is known as 2:3 pull-down (sometimes also called as 3:2 pull-down). This process is also used in camcorders which have 24p scanning capability.The first 24P frame is used to make the first two 60i fields (first complete 60i frame).The second 24P frame is used to make the next three 60i fields, that is the secondcomplete 60i frame and the first field of the third 60i frame. The third 24P frame isused to make the next 2 fields, that is the second field of the third 60i frame andthe first field of the forth 60i frame. The forth 24P frame is used to make the nextthree fields, that is the second field of the forth 60i frame and both fields of the fifth60i frame.Thus every four 24P frames make ten 60i video fields. 2:3 pull-down repeats thisprocess again and again to transfer from 24 frames per second to 60 interlacevideo fields per second.2:3 pull-down builds some strange looking video frames with fields taken from twofilm frames. Editors need to recognise the 2:3 pull-down sequence to avoid theseframe, especially in edits that will be transferred back to 24P in the future.

2:3 pull-down method

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◆◆◆ 24P Scan Modes in HVR-V1/Z5/Z7/S270 – “24” or “24A” ? –The HVR-V1/Z5/Z7/S270 have the Progressive Scan modes. In these modes, thecaptured 1080p image is just divided into two halves, then recorded or output asinterlace signal. For the 24P Scan modes, the 2:3 pull-down method is used. It ispossible to edit the 24P scanned images as 23.98p by using compatible NLEsoftware. The NLE software can remove the 2:3 pull-down frames. For 24P scan, please note that there are two options in the menu. One is “24”setting and another is “24A”.In non HDV camcorders, 24A means “advanced” pull-down with a 2:3:3:2 cadence.

24A has a different meaning in the HVR-V1/Z5/Z7 and S270 NTSC models. Thesecamcorder’s “24A” setting embeds markers in the HDV1080/60i recorded stream inorder for the NLE software to identify and remove 2:3 pull-down frames. Once theNLE software removes the pull-down fields, full progressive 23.98 editing is possibleon the timeline.

Note that interruption of video, audio and TC may occur in between clips in the“24A” setting playback.Non compatible NLE may lose one or two seconds at the head of each clip. In thiscase, it is recommended to allow for longer pre-roll or to use the HVR-MRC1Memory Recording Unit or HVR-DR60 Hard Disk Recording Unit for file importing.

While the compatible NLE software can effectively remove the 2:3 pull-downframes during capture by using this marker signal, some application software suchas Cineform Aspect HD analyzes the video and removes the unwanted frames,then converts the video to 23.98p without needing the marker signal. But it maytake longer than the workflow with the compatible NLE software.

*There is no “24A” setting for DV and DVCAM recording modes.

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◆◆◆ HDV Native Progressive Recording Format

An Optional Specification in HDV FormatThe HDV native progressive recording format is defined as an option of HDV1080ispecification.There are three types of frequency, 24(23.98), 25 and 30 (29.97) frames / sec. The compatible Sony’s HDV products have the following logo :

Compression Structure The MPEG-2 compression is done in the 15 GOP structure for 1080/25p and 30p aswell as 1080/50i and 60i. On the other hand, the compression is done in 12 GOPstructure for 1080/24p.

Products without this logo can not playback the tape recorded in this format orcan not accept the HDV native progressive i.LINK stream.

Name of Specifications HDV 720p Specification HDV 1080i SpecificationMedia Same as DV format (DV cassette tape)Video Video Signal 720/60p, 720/30p 1080/60i, 1080/50i

720/50p, 720/25pOptional 720/24p 1080/30p, 1080/25p, 1080/24p

Number of Pixels 1280 x 720 1440 x 1080(Horizontal x Vertical)Aspect Ratio 16:9Compression MPEG2 Video

Profile & Level: MP@H-14(in case of 720/60p and some

720/50p:MP@HL)Sampling Frequency for Luminance 74.25MHz 55.7MHzSampling Format 4:2:0Quantization 8 bit (both luminance and chrominance)Bit rate after Compression Approximately 19Mbps Approximately 25MbpsAudioCompression Mpeg1 Audio Layer IISampling Frequency 48kHzQuantization 16 bitsBit rate after Compression 384kbpsAudio Mode Stereo (2 channels)Optional Audio Recording PCM MPEG2 Audio Layer II

(2 channels or 4 channels, can be (4 channels)simultaneously recorded with

MPEG1 Audio Layer II 2 channelsSystemData Format MPEG2 SystemsStream Type Transport Stream Packetized Elementary StreamStream Interface IEEE1394 (MPEG2-TS)

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Recorded 24p image and time code

Converted 60i image and time code

0 1 2 3 5 6 7 8 10 11 12 13

1Sec

24pto60i

1GOP 1GOP

15 16 17 18 20 21 22 23 25 26 27 28A B C D E F G H I J K L M N O P Q R S T U V W X

Time codeimage

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

1Sec

1GOP 1GOP

15 16 17 18 19 20 21 22 23 24 25 26 27 28 29A A B B B C C D D D E E E F F G G H H H I I J J J K K L L L O O P P P R R R S S T T T U U V V V W W X X XQ QM M N N N

Time codeimage

Interpolated TC Interpolated TC Interpolated TC Interpolated TC Interpolated TC Interpolated TC

1GOP=15 frames

For 1080/50i/60i/25p/30p

1GOP=12 frames 1GOP=12 frames

1GOP=15 frames

•••

For 1080/24p

Output Signal (in HVR-Z5, Z7, S270, M15A, M25A, M35)The i.LINK connector can output the HDV native progressive signal.For other connectors such as HDMI and SDI, the progressive signals are convertedto interlace signals to be output. The 2-3 pull-down is used for 24P.

Recorded and Output TimeCode (in HVR-Z5, Z7, S270, M15A, M25A, M35)For 25p and 30p, the time code is recorded within the video in the cycle of 25frames/sec. or 30 frames/sec. as well as 50i and 60i respectively.For 24p, the time code is based on the 30 frames/sec. cycle because the HDVnative 24p format was developed using 1080/60i specification. So it is necessary todrop one frame for every five frames in terms of time code.The output signal from the i.LINK connector has the source timecode. The missingnumber of time codes are inserted in the output interlace signal from otherconnectors or down-converted DV signal.

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◆◆◆ HDV CompressionHDV compresses the video signal to fit it onto the DV tape. High definitioncomprises much more data than standard definition. Therefore the compressionsystem needs to be very advanced. The techniques used are similar to those usedby DV and MPEG2 compression.HDV compression can be divided into two basic sections, inter-frame coding andintra-frame compression. Although these two names are very similar, they are verydifferent in practice.

The Concept of Entropy and RedundancyAll video signals consist of a mixture of entropy and redundancy. Entropy is theinformation within the video signal that needs to be retained. If any entropy is lost,the quality of the image is reduced.

Redundancy is the information within the video signal than can be removed withoutreducing the quality of the image.

Complexity

Redundancy

Entropy

Da

ta ra

te

Simple0Mbps

270Mbps

Complex

2:1 compression

Idealised

Realistic

10:1 compression

Perfect 10:1compression

Imperfect 2:1compression

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The amount of redundancy and entropy varies throughout a video sequence,and some sequences contain more entropy than others.Any video compressor aims to reduce the amount of information by removingredundancy only, thus maintaining the quality of the sequence. Somecompression systems are better than others, and some remove a certain amountof entropy as well as redundancy in order to reduce the overall amount ofinformation sufficiently to record to tape.

DC a1 a2 a3 a4 a5 a6 a7 a8

b1 b2 b3 b4 b5 b6 b7 b8

c1 c2 c3 c4 c5 c6 c7 c8

d1 d2 d3 d4 d5 d6 d7 d8

e1 e2 e3 e4 e5 e6 e7 e8

f1 f2 f3 f4 f5 f6 f7 f8

g1 g2 g3 g4 g5 g6 g7 g8

h1 h2 h3 h4 h5 h6 h7 h8

DCTInverse

DCT

Examples

DCT DCT

DCT DCT

DCT DCT

Big number somewhere here






a1 a2 a3 a4 a5 a6 a7 a8

b1 b2 b3 b4 b5 b6 b7 b8

c1 c2 c3 c4 c5 c6 c7 c8

d1 d2 d3 d4 d5 d6 d7 d8

e1 e2 e3 e4 e5 e6 e7 e8

f1 f2 f3 f4 f5 f6 f7 f8

g1 g2 g3 g4 g5 g6 g7 g8

h1 h2 h3 h4 h5 h6 h7 h8

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Inter-frame CodingInter-frame coding compares one frame with another to remove redundantinformation. In most video sequences each video frame is very similar to itsneighbour.There are two types of comparison, a P frame and a B frame. A P frame is acomparison to the previous frame only, and a B frame is a comparison to theprevious frame and the next frame.Both P and B frames significantly reduce entropy and increase redundancy, but Bframes result in less entropy than P frames and are therefore more efficient.Inter-frame coding does not reduce the amount of data at all. Instead it increasesthe amount of redundancy and reduces the amount of entropy. The resultingframe is then passes through Intra ?frame compression (described below) whichdramatically reduces the total amount of data in each frame with no loss, muchmore effectively than simply using Intra-frame compression on its own.

Intra-frame CompressionIntra-frame compression compresses each frame within itself, without comparisonto any other frames. This is accomplished by using a sequence of processes whichrearrange the data or replace it with smaller codes.

Discrete Cosine Transform (DCT)The first process in intra-frame compression is DCT. This process cuts the videoframe into blocks of 8 by 8 pixels. Each block is processed separately. DCT doesnot reduce the amount of data at all. Instead it replaces each block with 64numbers called coefficients. These coefficients describe how the original pixelschange across the block.Any block with slow or gradual change will result in larger coefficients in the topleft corner of the DCT block. Fast horizontal change results in high coefficients inthe top right corner. Fast vertical change results in large coefficients in the bottomleft corner.Various rates of change and angles of change result in various coefficients spreadacross the block. DCT is entirely lossless. The 64 coefficients can be replaced withtheir original 64 pixels with not loss of quality.

Entropy CodingThis stage in the intra-frame compressor replaces coefficients with shorter codes.Entropy coding uses a look-up table of coefficients and codes, based onextensive research into many different types of video sequence. Entropy coding isthe heart of any intra-frame compressor. It is entirely lossless. The codes can bereplaced with the original coefficients with no loss of quality. If the entropy coder isable to reduce the amount of data sufficiently, the video signal can be recordedto tape with no overall loss of quality at all.

DiscreteCosine

TransformQuantisation Zig-zag

ScanningCompressed

outputBase band

InputEntropyCoding

DataBuffer

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Data BufferThe data buffer acts a little like a gate-keeper. It stores the data from the entropycoder and prepares it for recording to tape. It also checks that the entropy coderhas been able to reduce the overall amount of data sufficiently to fit on the tape.If it has, all is well and the data is recorded to tape. If not, then the data buffersends a signal back to the Quantiser requesting it to remove entropy to allow thedata to fit onto the tape.

QuantiserThe quantiser is the single process in the whole compressor that reduces quality. Itacts under control from the Data Buffer and divides coefficients to reduce theoverall amount of data. This effectively removes entropy and therefore reducesquality.The Quantiser therefore attacks those coefficients first that do not affect theoverall quality too much. High frequency coefficients are divided first. If this is notenough, lower frequency coefficients are divided.

Building an HDV StreamThe HDV compressor uses both Intra-frame and Inter-frame compression.Compression is performed in a sequence of video frames called a Group ofPictures (GOP). The first frame in each GOP is an I frame, one frame compressedwithin itself with no reference to any other frames.The next two frames are B frames. Compared to the I frame before and the next Pframe, and then Intra-frame compressed, these frames contains significantly lessdata than the I frame with little loss of quality.

Intra-FrameCompression






——


— — —SUM SUM SUM SUM SUM

The forth frame is a P frame, compared to the I frame before intra-framecompression this frame results in slightly more data than the two B frames but stillsignificantly less data than the I frame.The sequence is then repeated with two B frames and a P frame until 12 frames havebeen processed. A new GOP is then started by compressing a single I frame.

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Distributed by

MKPRG0805012

©2008 Sony Corporation. All rights reserved.Reproduction in whole or in part without permission is prohibited.Features and specifications are subject to change without notice.

All non-metric weights and measurements are approximate.Sony,DVCAM, ClearVid CMOS Sensor,Cineframe, XDCAM and

their respective logos are trademarks of Sony Corporation.3 ClearVid CMOS Sensor logo is a trademark of Sony Corporation.

HDV and the HDV logo are trademarks of Sony Corporation andVictor Company of Japan, Limited.

Adobe After Effects is a registered trade mark of Adobe Systems Inc.Cinema Tools is a trademark of Apple Inc.Aspect HD is a trademark of Cineform Inc.

All other trademarks are the property of their respective owners.

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HDV Progressive Primer - sony-asia.com