Program Selector For Digital High Definition Television (HDTV)
Visual and technical quality control for high definition television
-
Upload
vrt-medialab -
Category
Technology
-
view
7.535 -
download
0
description
Transcript of Visual and technical quality control for high definition television
![Page 1: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/1.jpg)
16/10/08
Tom Beckers
Wim Ermens
Visual and Visual and technicaltechnical qualityquality controlcontrolforfor high high definitiondefinition televisiontelevision
![Page 2: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/2.jpg)
VRT-medialab: onderzoek en innovatie2
Overview
Video quality control in a filebased world
Impact of HDTV emergence on quality control
Video quality evaluation
Production chain simulation
Broadcast chain simulation
![Page 3: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/3.jpg)
VRT-medialab: onderzoek en innovatie3
Video quality control in a filebased world
AudioVisual Quality Control
! Audio
! Video
! Interaction between audio and video : e.g. lipsync
File based AV Quality Control
! Part of an automated or manual workflow
– Diagnose
– Repair / Redo
![Page 4: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/4.jpg)
VRT-medialab: onderzoek en innovatie4
![Page 5: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/5.jpg)
VRT-medialab: onderzoek en innovatie5
Video quality control in a filebased world
Technical quality control
! Container
! Metadata
! Interaction between container, audio and video : e.g. duration of tracks
File based technical quality control
! Part of an automated or manual workflow
! Application specifications
![Page 6: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/6.jpg)
VRT-medialab: onderzoek en innovatie6
![Page 7: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/7.jpg)
VRT-medialab: onderzoek en innovatie7
Video quality control in a filebased world
Automated QC
![Page 8: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/8.jpg)
VRT-medialab: onderzoek en innovatie8
Video quality control in a filebased world
MXF analysis & application
specification validation
MXF
fileMXF
analysis
IRT MXF
Analyzer
Ardendo
CheckMXF
Application
Specification
Validator
MXF
analysis
report
Archive
Play-out
Production
Contribution
D-10 (APP)DV-25 (News)Application Specs HD
![Page 9: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/9.jpg)
VRT-medialab: onderzoek en innovatie9
Video quality control in a filebased world
Application specification
validation report
![Page 10: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/10.jpg)
VRT-medialab: onderzoek en innovatie10
720p !
1080i
1080i !
720p
720p !
1080i
1080i !
720p
1080p !
1080i
1080i !
1080p
720p !
1080p
1080p !
720p
Safeguarding audiovisual quality
! Maintaining quality throughout the production chain
– Choose material as close to source as possible
– prevent unneeded multi-generation
– Try to produce with the shortest/’most apt’ chain
– Prevent unneeded multi-generation
– Prevent transcoding
– Check quality
! Carefully design the production chain
– Choose the right codecs
– Choose the right equipment
Black Box
(in production/broadcast
chain)
720p
1080i
720p
1080i
Video quality control in a filebased world
![Page 11: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/11.jpg)
VRT-medialab: onderzoek en innovatie11
Impact of HDTV emergence on quality control
Proliferation of raster formats
HD TVSD TV
720p50 1080i50
1080p25
1080p50
PAL
576i50
![Page 12: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/12.jpg)
VRT-medialab: onderzoek en innovatie12
Impact of HDTV emergence on quality control
Proliferation of codecs
YUV
RGB4:2:0 / 4:1:1
4:2:24:4:4
HDCAM
HDCAM-SRDVCProHD
XDCAM HD
XDCAM HD422
HDV
AVCHDAVC-Intra
JPEG2K
DNxHD
ProRes Dirac
SVC
50 Mbps
100Mbps180Mbps
440Mbps
8 bit sampling
10 bit sampling
![Page 13: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/13.jpg)
VRT-medialab: onderzoek en innovatie13
Impact of HDTV emergence on quality control
Viewer quality expectation
! Consumer expects ROI from flat panel investment
! Depends on content type (drama, news, sports, soap)
What codec to choose?
! Picture quality
! Bit rate
! Performance
! Support
! Scalability
! quality evaluation needed
![Page 14: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/14.jpg)
VRT-medialab: onderzoek en innovatie14
Video quality evaluation
![Page 15: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/15.jpg)
VRT-medialab: onderzoek en innovatie15
Video quality evaluation
Video sequence used for testing
(source EBU) :
! High quality source material
! 10-bit YCBCR samples
! Chroma subsampling 4:2:2
! HD-SDI compatible
! 720p50
![Page 16: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/16.jpg)
VRT-medialab: onderzoek en innovatie16
Note on viewing conditions
Expert evaluation :
! Class 1 reference monitor @ 1H, 3H
! High quality consumer device (FullHD, Plasma) @ 1H, 3H
Present demo setup
! Overhead projector (internal processing?)
! Not sufficiently dark room
! Sub ideal circumstances
Interested parties : ask for demo in better circumstances...
![Page 17: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/17.jpg)
VRT-medialab: onderzoek en innovatie17
Video quality in production chain
Simulation chain
without
pixelshift with
pixelshift (+2H, +6V)
Camera
encoding
Post production encoding
(4 generations)
![Page 18: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/18.jpg)
VRT-medialab: onderzoek en innovatie18
Video quality in production chain
Codecs tested :
! Camera : AVC-I, DVCProHD, XDCAM HD422
! PostProduction : DNxHD, AVC-I, DVCProHD, XDCAM HD422
Codec properties
LongGOP
(n=12 @ 720p)
I frames only
I frames only
I frames only
GOP
None84:2:2115DNxHD
None84:2:250XDCAM
HD422
3:4 horizontal :
960 luma samples/line
84:2:2100DVCProHD
None104:2:2100AVC-I
Spatial subsamplingSample
size
(bits)
Chroma
subsampling
Bitrate
(Mbps)
Codec
![Page 19: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/19.jpg)
VRT-medialab: onderzoek en innovatie19
Video quality in production chain
Test setup
Sony PDW-HD1500*
XDCAM HD422
Panasonic AJ-HPM110**
DVCProHD
AVC-I
Avid Airspeed + DNXchange
DNxHD
* test model provided by Sony Belgium** test model provided by Panasonic Belgium
![Page 20: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/20.jpg)
VRT-medialab: onderzoek en innovatie20
Video quality in production chain
Test setup
Uncompr.
source
Gen 0
(Cam)
Gen 4
(PP4)
Gen 1
(PP1)
Gen 2
(PP2)
Gen 3
(PP3)
Gen 3
shifted
Encode Decode
HD-SDI HD-SDI
Uncompressed YCbCr storage
HD-SDI ingest & playout
![Page 21: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/21.jpg)
VRT-medialab: onderzoek en innovatie21
Video quality evaluation
Evaluation methods :
! Objective tests
! Subjective tests
! Automated subjective tests
! Expert viewing
![Page 22: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/22.jpg)
VRT-medialab: onderzoek en innovatie22
Video quality evaluation
Objective tests : PSNR, SSIM, ...
!!"
=
"
=
"=1
0
1
0
2),(),(
1 m
i
n
j
frame jiIjiRmn
MSE )(log20 10
frame
Rframe
MSE
MAXPSNR !=
Reference Impaired Squared difference
![Page 23: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/23.jpg)
VRT-medialab: onderzoek en innovatie23
Video quality evaluation
Objective tests : PSNR, SSIM, ...
3 resultsets per sequence (Y, Cb,
Cr)
unsensitive to grouping of pixel
differences
objective
reproducible
automated test
DisadvantagesAdvantages
![Page 24: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/24.jpg)
VRT-medialab: onderzoek en innovatie24
Video quality evaluation
Subjective tests : DSCQS, TSCES, ...
![Page 25: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/25.jpg)
VRT-medialab: onderzoek en innovatie25
Video quality evaluation
(D)MOS scores
Upper anchor
Source material
Material to be
evaluated
Lower anchor
Worst case
![Page 26: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/26.jpg)
VRT-medialab: onderzoek en innovatie26
Video quality evaluation
Subjective tests :
DSCQS, TSCES, ...
difficult to test many sequences
timeconsuming to setup
difficult to get sufficient statistics
worst case reference definition
closest to real life experience
DisadvantagesAdvantages
![Page 27: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/27.jpg)
VRT-medialab: onderzoek en innovatie27
Video quality evaluation
Automated subjective tests : Tektronix PQA-500, Opticom PEVQ Analyzer, ...
! Aims to provide (D)MOS score
! Simulate :
– Monitor setup and characteristics
– Viewing setup and conditions
– Viewer setup and characterisics
– Human visual system (= tricky)
good correlation to subjective test
results to be proven
typically slower than objective tests
automated test
closer correlation to subjective test
results than PSNR
no worst case reference mandatory
DisadvantagesAdvantages
![Page 28: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/28.jpg)
VRT-medialab: onderzoek en innovatie28
Video quality evaluation
Expert viewing
! Aim :
– Visually evaluate video quality
– Determine typical artefacts
– Compare source with test material
– Compare test material with other test material
! Method :
– Create splitscreen images
– Evaluate on (reference) monitor
– Create ranking from intercomparison
![Page 29: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/29.jpg)
VRT-medialab: onderzoek en innovatie29
Video quality in production chain
Expert viewing (“The proof of the pudding is in the eating”)
![Page 30: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/30.jpg)
VRT-medialab: onderzoek en innovatie30
Video quality in production chain
Uncompressed vs Compressed video material
![Page 31: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/31.jpg)
VRT-medialab: onderzoek en innovatie31
Video quality in production chain
Compressed vs Compressed video material
![Page 32: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/32.jpg)
VRT-medialab: onderzoek en innovatie32
Video quality due to de-interlacing
De-interlacing: difficult to perform
Good quality converters exist (price!)720p - DNxHD (Gen0) 1080i - DNxHD (Gen0) – de-interlace – 720p
source de-interlaced
![Page 33: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/33.jpg)
VRT-medialab: onderzoek en innovatie33
Video quality in distribution chain
![Page 34: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/34.jpg)
VRT-medialab: onderzoek en innovatie34
Distribution encoder
Distribution encoder = device that compresses the broadcaster’s signal into
a format suitable for transmission/distribution
Codecs: MPEG-2 or MPEG-4 H.264 (tested)
Interfaces: HD-SDI " ASI
Typical bitrate in/out:
! From 50-200 Mbit/s " 10 Mbit/s (or less)
Parameters:
! Encoding delay
! Encoder bit-rate
! Profile/Noise reduction/GOP size/…
![Page 35: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/35.jpg)
VRT-medialab: onderzoek en innovatie35
Distribution encoder: bit-rate
Which bit-rate to choose?
! Distribution channel ‘defines’ available bit-rate
! MPEG-4 does a fine job
! Motion in video is important
Uncom
pre
ssed
AV
C/D
NxH
D –
16M
bit/s
H.2
64
AV
C/D
NxH
D –
10M
bit/s
H.2
64
AV
C/D
NxH
D –
8M
bit/s
H.2
64
![Page 36: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/36.jpg)
VRT-medialab: onderzoek en innovatie36
Distribution encoder and production codec
Uncompressed HD ~ 1 500 Mbit/s
Production bitrate ~ 100 Mbit/s
Distribution encoder ~ 10 Mbit/s
Do we actually see the influence of the production codec?
AVC/AVC + 8 Mbit/s H.264 DVC/DVC + 8 Mbit/s H.264
![Page 37: Visual and technical quality control for high definition television](https://reader034.fdocuments.net/reader034/viewer/2022050804/547ec347b37959a22b8b54c4/html5/thumbnails/37.jpg)
VRT-medialab: onderzoek en innovatie37
Distribution: the end of the chain
Receiver (set-top-box)
! Interlacing – de-interlacing
! Scaling
Television
! A lot of choice
! De-interlace
! Scale
! Process (sharpen – noise reduction)
Make sure there’s no unnecessary signal conversion