The document discusses several technical issues that arise with interlaced video formats compared to progressive formats. It explains that with interlacing, full vertical detail or motion can be achieved but not both, and that this causes problems for video compression algorithms. It also notes that while progressive formats avoid these interlacing artifacts, moving objects may appear flickering. Overall, the document analyzes various technical tradeoffs between interlaced and progressive video.
Automating Google Workspace (GWS) & more with Apps Script
Broadcaster Notes
1. To see why MPEG doesn’t like interlacing, it’s important to realize what
interlacing does. Figure 2 showed that, given a complete picture in which all of
the horizontal scan lines are present, interlacing takes every other line on the
first field and comes back later for the ones in between on the next field. When
there is no motion in the image, this works quite well. The problem becomes
apparent when anything in the image moves.
In a still picture, the vertical detail is shared between the fields, and both
fields are needed to display all of the vertical detail. But, when an object in
the image moves, its location changes from one field to the next. This makes it
impossible to combine the two fields to recover the vertical detail.
Consequently, with interlacing, you can have full vertical detail, or you can
have motion, but you can’t have full vertical detail in the presence of motion.
If the loss of vertical detail was just a softening effect, that wouldn’t be too
bad. However, Figure 2 shows that a single field is created by subsampling the
vertical axis of the original frame by a factor of two. Sampling theory says
that this will cause vertical aliasing. The vertical detail isn’t soft; instead,
it is simply incorrect. The good old Kell factor is the way of measuring the
damage interlacing does to vertical resolution.
Read more:
http://broadcastengineering.com/news/broadcasting_understanding_interlace_2/#ixz
z1qIsqbRto
MPEG DETESTS ÝNTERLACED SCAN!!!!!!!!!!
The problem an MPEG encoder has with interlacing is that, to compress
efficiently, it tries to measure the motion between successive pictures.
Interlacing prevents accurate motion measurement because adjacent fields don’t
contain pixels in the same place, so the encoder can’t compare like with like.
Differences between fields could be due to motion or to vertical detail, and the
motion estimator doesn’t know which it is. As a result, the motion vectors in
interlaced MPEG are less accurate, which means that the residual data will have
to be increased to compensate for the reduced power of the motion estimation. In
short, the bit rate has to go up.
Read more:
http://broadcastengineering.com/news/broadcasting_understanding_interlace_2/#ixz
z1qItArxh8
One of the greatest myths about the relative merits of interlacing and
progressive is that a progressive standard is just an interlaced standard but
with every line present in each picture. This is regularly put forward by the
pro-interlacing cave dwellers, but it’s simplistic. According to that premise,
one might conclude that the progressive picture has massively greater resolution
than the interlaced picture simply because it can represent detail in the
presence of motion. In fact, the absence of interlacing artifacts and loss of
dynamic resolution means that progressively scanned pictures have a better Kell
factor and don’t actually need as many lines as interlaced systems. Thus, 720p
can easily outperform 1080i, for example.
Camera manufacturers know all about interlacing artifacts, and one thing they
can do is to reduce the vertical resolution of the picture to reduce the amount
of aliasing. This results in a permanent softening of the image, but it is
probably more pleasing than intermittent motion-sensitive aliasing. In an
interlaced system, the maximum vertical resolution the system can manage to
produce from still images is never used because this full resolution never
leaves the camera.
Another problem with interlacing is that, although the field rate is 60Hz (or
50Hz in the old world), the light energy leaving the display is not restricted
to those frequencies alone. There is a fair amount of light output in the frame
rate (30- or 25Hz) visible to the viewer. You can see this for yourself if you
put a 26-inch interlaced display near a 26-inch progressive-scan display and
view them from a distance of over 100 feet. You won’t see any difference in
2. resolution or vertical aliasing (the human visual system simply isn’t that
good), but you will see flicker from the interlaced display.
BANDWIDTH
deinterlacing cannot always remove all the impurities or artifacts in the
image.
One problem that can arise with progressive scanning, however, is that objects
moving continuously through the camera scene, such as a car, can appear to
flicker. Since each line of the image is scanned every sixtieth of a second,
there is a brief gap of time between frames that does not account for objects
moving unremittingly.
a digital TV broadcast requires one-fourth the bandwidth of an analog TV
broadcast of the same resolution.
Good quality real-time encoded 480i MPEG-2 requires at least 4Mbps, and more
like 6Mbps. Current digital TV in the US can put 19.3Mbps in one 6MHz TV
channel, while analog puts one 480i channel in the same bandwidth.
So, 480i digital takes about 25-30% of the "bandwidth" of 480i analog. On a
cable system using 256QAM, they can put 40Mbps in a 6MHz channel, so 480i
digital would only take 12-15% as much as the analog there.
Actual real-time encoding samples show that the reduction in bitrate for the
same quality is far lower than this. A 720p stream that needs 15Mbps with MPEG-2
will need 10-12Mbps with MPEG-4. At 8Mbps, it becomes noticably lower quality.
So when screen action is high and processing time is low (say in real-time
football) the quality deteriorates slightly, because only the larger features on
the screen are coded for transmission before the next frame must be handled.
You'll often see the minimum requirement for MPEG2 given as 1.5 or 2Mb/s, but
this is for pre-recorded programs like movies, or for images of "VCR-quality'
which is considerably below true PAL-transmission standard.
To maintain quality, currently they need 6-8Mb/s of bandwidth for real-time
sports coverage. However if the encoder has more time to work on the compression
(eg. pre-recorded programs), this bandwidth requirement can be cut in half. With
pre-filmed Hollywood movies, it may be down to a third or a quarter.
DIGITAL TELEVISION
Sampling rate
# fs > 2fmax (Nyquist limit)
# fs > 3fmax (Preferred)
Bits/Sample
# 3x8=24 b/sample (colour video)
Data Rate
# Standard TV (PAL,SECAM): rn? 300Mb/s
fmax= 5MHz, fs= 13.5 Ms/s, rn = 13.5x24=324Mb/s
# HDTV: rn > 1Gb/s
fmax= 30MHz, fs> 60 Ms/s, rn > 1.4Gb/s
Such huge bandwidths are not available!
Transmission of such data is only possible after at least
50 times of Compression!
# MPEG-2 compresses STV data to 4..8Mb/s
Provides;
# 4 to 10 digital (SDTV) channels in 1-analog channel space
# Easier and more reliable scrambling
# Easier video-on-demand and Pay TV services
3. To the Service Provider
#Same picture quality with analog (sometimes worst)
#CD quality sound
#2 to 10 times more money to pay for the equipment!
To the Customer
Not a fair deal!
Source Coding by using DCT (Discrete Cosine
Transform)
#Based on
Converting the image to Spatial Frequency components
Assigning more bits to low-frequency components (large smooth
areas) and less bits to high-frequency components (since human
eye do not resolve the luminance levels on the fine details of the
picture)
#The picture is divided into 8x8 pixel Macroblocks
#The DCT is applied to each block
f(m,n): luminance of the pixel at coordinates m,n= 0,1,...7
F(u,v): DCT coefficient of 2-D frequency u,v= 0,1,...7
c(0)= 0.707; c(k)= 1 k=1,2,...7
f(m,n): luminance of the pixel at coordinates m,n= 0,1,...7
F(u,v): DCT coefficient of 2-D frequency u,v= 0,1,...7
c(0)= 0.707; c(k)= 1 k=1,2,...
You'll often see the minimum requirement for MPEG2 given as 1.5 or 2Mb/s, but
this is for pre-recorded programs like movies, or for images of "VCR-quality'
which is considerably below true PAL-transmission standard.
To maintain quality, currently they need 6-8Mb/s of bandwidth for real-time
sports coverage. However if the encoder has more time to work on the compression
(eg. pre-recorded programs), this bandwidth requirement can be cut in half. With
pre-filmed Hollywood movies, it may be down to a third or a quarter.
As faster multi-thread processing becomes available in the encoders, the image
quality of sports coverage will rise and the bandwidth requirements will fall.
The main problem with pumping out digital signals from conventional television
towers is that of multipath. In analogue television we see this phenomena as
'ghosts', and these are caused by secondary signals arrive slightly later than
normal, after having bounced off buildings, hills, bridges, etc., along the way.
In analogue television, these create a series of blurred positive and negative
images to the right side of the dominant image, but with digital signals, a
slightly delayed negative 'bit' can cancel out a positive 'bit' and change the
image substantially.
KAMERA KONTROL
Diyafram, tek baþýna deðiþtirilince pozlama deðerinde sapma olur. Bu durumu
deðiþtirmek için, ortam ýþýðý, örtücü deðeri (shutter speed) gibi pozlamayý
etkileyen etmenlerin deðitirilmesi gerekir ki, çok kameralý stüdyolarda bu
pratik bir uygulama deðilidir.
Kaydýrma hareketi ile optik kaydýrma hareketleri birbirlerinden fiziksel olarak
farklý olduklarý için farklý sonuçlar verirler. Kaydýrma hareketinde, kamera
konuya yaklaþmakdadýr. Dolaysýyla içerdiði nesneler bir süre sonra farklý
açýlardan görünmeye baþlar; hatta hareketin baþýnda görünmeyen bir nesne daha
sonra görünür olur. Ancak optik kaydýrma sýrasýnda kameranýn yeri deðiþmez.
Deðiþen, kameranýn gördüðü açýdýr. Her iki kaydýrma sýrasýnda nesnelerin görünen
boyutlarý deðiþmekteyse de , optik kaydýrmada(göreceli olarak) arka planda yer
alan nesneler daha büyük gönünür.
4. Konuya fiziksel olarak (kaydýrma hareketi ile) yaklaþýldýðý zaman(geniþ açý)
yanyana olan cisimler birbirinden uzaklaþýrlar. Ýleri optik kaydýrma ile konuya
yaklaþýldýðý zaman (dar açý), perspektif farký oluþmuþtur. Bunda tam tersi
cisimler birbirinden uzaklaþýyorlarmýþ gibi görünür. Geniþ açýda da , yanyana
olan cisimler birbirinden uzaklaþýyormuþ gibi gözükür.
24.09.12
kamerayý saða sola kaydýrma: truck or crab right-left(bu kavram bazen tracking
shot olarak adlandýrýlýr.)
kamerayý yukarý-aþaðý kaydýrma: pedestal(or ped) up-down.
kamerayý ileri-geri kaydýrma: dolly in-out.
kamerayý sað-sol(çapraz hareket ettirme): arc right-left.
vinç yukarý aþaðý: crane up-down.
vincin yanlamasýna kaymasý: tonguing. tongue right-left.
Main article: Retina
The retina consists of a large number of photoreceptor cells which contain
particular protein molecules called opsins. In humans, two types of opsins are
involved in conscious vision: rod opsins and cone opsins. (A third type,
melanopsin in some of the retinal ganglion cells (RGC), part of the body clock
mechanism, is probably not involved in conscious vision, as these RGC do not
project to the lateral geniculate nucleus (LGN) but to the pretectal olivary
nucleus (PON).[5]) An opsin absorbs a photon (a particle of light) and transmits
a signal to the cell through a signal transduction pathway, resulting in
hyperpolarization of the photoreceptor. (For more information, see Photoreceptor
cell).
Rods and cones differ in function. Rods are found primarily in the periphery of
the retina and are used to see at low levels of light. Cones are found primarily
in the center (or fovea) of the retina.[citation needed] There are three types
of cones that differ in the wavelengths of light they absorb; they are usually
called short or blue, middle or green, and long or red. Cones are used primarily
to distinguish color and other features of the visual world at normal levels of
light.[citation needed]
ILLUMINATION
Home Illumination Study, details results of a comprehensive study of ambient
light levels in typical television viewing locations. This information is useful
for determining how bright a television picture needs to be to provide a
satisfactory viewing experience. Brightness has a direct impact on the energy
consumption of the television.
IMAGE SIZE
The image size depends on image size, so lenses intended for 2/3 inch and 1/2
inch cameras have different focal lengths.
Angle of view can be derived from the following equation. w = 2tan-1 y/2f y =
image size, w = angle of view, f = focal length.
WHITE BALANCE
White balance (refer to ’White Balance’ ) electrically adjusts the amplitudes of
the red (R) and blue (B) signals to be equally balanced to the green (G) by use
of video amplifiers.We must keep in mind that using electrical amplification
will result in degradation of signal-to-noise ratio.
DEPTH OF FIELD FACTORS
1)The larger the iris F-number (refer to ’F-number’ ) (stopping down the amount
of incident light), the deeper the depth of field.
2)The shorter the focal length of the lens, the deeper the depth of field.
3)The further the distance between the camera and the subject, the deeper the
depth of field.
5. FLANGE-BACK/BACK FOCAL LENGTH
Flange-back is one of the most important matters to consider when choosing a
lens. Flange-back describes the distance from the camera's lens-mount reference
plane (ring surface
or flange) to the image plane (such as CCDs) as shown in the figure below.
In today's camera systems, flange-back is determined by the lens-mount system
that the camera uses. 3-CCD cameras use the bayonet mount system, while single
CCD cameras
use either the C-mount or CS-mount system. The flangeback of the C-mount and CS-mount
systems are standardized as 17.526 mm and 12.5 mm respectively. There are
three flange-back standards for the bayonet mount system, 35.74 mm, 38.00 mm,
and 48.00 mm.
FLARE
Flare is a phenomenon that is likely to occur when strong light passes through
the camera lens. Flare is caused by numerous diffused reflections of the
incoming light inside the
lens. This results in the black level of each red, green and blue channel being
raised, and/or inaccurate color balance between the three channels. On a video
monitor, flare
causes the picture to appear as a misty image, sometimes with a color shade. In
order to minimize the effects of flare, professional video cameras are provided
with a flare adjustment function, which optimizes the pedestal level and
corrects the balance between the three channels electronically.
VIDEO PROCESSING
Keeping this consistency in plant digital video means that video processing
(including timing) can increasingly be of the one-time-setup variety. Technology
advances have eliminated the need for an engineer to adjust every process
continually, enabling hands-free operation ’ and creating a clear paradigm shift
(as shown in Figure 1) in plant design.
AFD codes
Software-based video processing running in real time on multiple CPUs in the
video server make this conversion possible. In some cases, branding and
multiviewer functions are also incorporated into servers.
F NUMBER
F = f/D
This reciprocal relationship means that the smaller the Fnumber, the "faster"
the lens, and the higher the sensitivity it will provide on a camera.
LIGHT AND COLOR
vovo
Te reason we see each object with a different color is because each object has
different light-reflection/absorption characteristics. For example, a piece of
white paper reflects almost all light colors and thus looks white. Similarly, a
pure blue object only reflects the blue light (spectrum) and absorbs all other
light colors.
ZOOM
Technically, 'zoom' refers to changing a lens's focal length (refer to ’Focal
Length’ ). A lens that has the ability to continually alter its focal length is
well known as a zoom lens.
6. It also must be noted that the amount of light directed to the imager also
changes when changing the zoom position. In the telephoto position, less light
is reflected from the subject and directed through the lens, and thus the iris
must be adjusted accordingly.
Net fotoðraf çekebilmek için genel olarak odak uzaklýðý arttýkça poz süresinin
bununla orantýlý olarak azalmasý gerekir. Mesela kiþi 50mm lens ile 1/50 saniye
pozlama süresinde net fotoðraf çekebiliyorsa 200mm lens ile ancak 1/200 pozlama
süresinde net fotoðraf çekebilir. Poz süresini düþürmek için fotoðrafçýlar
diyaframý açmak ve/veya film süratini arttýrmak yollarýna boþvururlar.
WHITE BALANCE
In order to obtain the same color under each different light source, this
variation must be compensated for electrically by adjusting the video amps of
the camera. For example, imagine shooting a white object. The ratio between the
red, green, and blue channels of the camera video output must be 1:1:1 to
reproduce white.
As a result, the output of the three red, green, and blue CCDs will vary
depending on the light source under which the white object is shot. For example,
when the white
object is shot under 3200 K, the signal output from the blue CCD will be very
small while that of the red CCD will be very large.
white balance for 3200 K seems to require more adjustment of video amps than
5600 K. However, the video amps of most cameras are preset to operate on color
temperatures around 3200 K, and less gain adjustment is required.
When the dominant light source in a scene changes in any way, you must again
white balance your camera.
On the Kelvin scale, the lower the color temperature the redder the light and,
as you might assume, the higher the color temperature, the bluer the color.
Images created on Macs tend to look too dark on PCs; images created on PCs tend
to look too bright and washed out on Macs.
EVS/SUPER EVS
EVS (Enhanced Vertical Definition System) and Super EVS are features that were
developed to improve the vertical resolution of a camera. Since Super EVS is an
enhanced form of
EVS, let's first look into the basic technology used in EVS. EVS has been
developed to provide a solution when improved vertical resolution is required.
Technically, its
mechanism is based on Frame Integration (refer to “Field Integration and Frame
Integration Mode“ ), but reduces the picture blur inherent to this mode by
effectively using the
electronic shutter. As explained in Frame Integration, PICTURE BLUR IS SEEN DUE
TO THE LONGER 1/30-SECOND ACCUMULATION PERIOD. EVS eliminates this by discarding
the charges accumulated in the first 1/60 seconds (1/30 = 1/60 + 1/60), thus
keeping only those charges accumulated in the second 1/60 seconds. Just like
Frame Integration, EVS uses the CCD's even lines to create even fields and its
odd lines to create odd fields - thus providing the same high vertical
resolution. However, since the first 1/60 seconds of accumulated charges are
discarded, EVS sacrifices its sensitivity to one-half. Super EVS has been
created to provide a solution to this drop in sensitivity. The charge readout
method used in Super EVS sits between the Field Integration and EVS. Instead of
7. discarding all charges accumulated in the first 1/60 seconds, Super EVS allows
this discarded period to be linearly controlled. When the period is set to 0,
the results will be the same as when using Field Integration. Conversely, when
set to 1/60, the results will be identical to Frame Integration. And when set
between 0 to 1/60, Super EVS will provide a combination of the improved vertical
resolution of EVS but with less visible picture blur. Most importantly, the
amount of resolution improvement and picture blur will depend on the selected
discarding period.
AYDINLATMANIN KAMERA ÜZERÝNDEKÝ DOÐRUDAN
SONUÇLARI
Beyaz gömlekte fazla pozlama yapýlýrsa gömlekteki ayrýntýlar kaybolmaya baþlar.
THE TECHNICAL DIRECTOR
The Technical Director is the person responsible for setting up and maintaining
the technical parameters oeo images. In many cases this is the same person as
the CCU operator, but in any case the two jobs are closely linked.
Grey card for white balance not white card. Color wheel!!!!!!!!!!
MXF(MATERIAL EXCHANGE FORMAT)
Wraps audio, video, subtitles, and metadata into a single file
“ Uses standardized class hierarchies and “operational patterns“
“ Designed to work with a variety of digital file formats
“ Can be used for
“ File Exchange
“ Distribution
“ Playout
“ Archive
“ Format is used by Digital Cinema and other applications
“ Integrates with AAF, Advanced Authoring Format
“ Cameras can export MXF metadata today.
BXF
“ Broadcast Exchange Format
“ XML format used for broadcast operations
“ Program Management
“ Traffic
“ Automation
“ Content Distribution
“ Young standard, but integrated into commercial software
“ Not a KLV format today
“ First version recently published
“ Revision and expansion planned
4G - LTE
As opposed to earlier generations, a 4G system does not support traditional
circuit-switched telephony service, but all-Internet Protocol (IP) based
communication such as IP telephony. As seen below, the spread spectrum radio
technology used in 3G systems, is abandoned in all 4G candidate systems and
replaced by OFDMA multi-carrier transmission and other frequency-domain
equalization (FDE) schemes, making it possible to transfer very high bit rates
despite extensive multi-path radio propagation (echoes). The peak bit rate is
8. further improved by smart antenna arrays for multiple-input multiple-output
(MIMO) communications.
3GPP Long Term Evolution (LTE)[edit]
See also: LTE Advanced above
Telia-branded Samsung LTE modem
The pre-4G 3GPP Long Term Evolution (LTE) technology is often branded "4G-LTE",
but the first LTE release does not fully comply with the IMT-Advanced
requirements. LTE has a theoretical net bit rate capacity of up to 100 Mbit/s in
the downlink and 50 Mbit/s in the uplink if a 20 MHz channel is used “ and more
if multiple-input multiple-output (MIMO), i.e. antenna arrays, are used.
LTE, an initialism of long-term evolution, marketed as 4G LTE, is a standard for
wireless communication of high-speed data for mobile phones and data terminals.
It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the
capacity and speed using a different radio interface together with core network
improvements.[1][2] The standard is developed by the 3GPP (3rd Generation
Partnership Project) and is specified in its Release 8 document series, with
minor enhancements described in Release 9.
The world's first publicly available LTE service was launched by TeliaSonera in
Oslo and Stockholm on December 14, 2009.[3] LTE is the natural upgrade path for
carriers with both GSM/UMTS networks and CDMA networks such as Verizon Wireless,
who launched the first large-scale LTE network in North America in 2010,[4][5]
and au by KDDI in Japan have announced they will migrate to LTE. LTE is,
therefore, anticipated to become the first truly global mobile phone standard,
although the different LTE frequencies and bands used in different countries
will mean that only multi-band phones will be able to use LTE in all countries
where it is supported.
LTE is a standard for wireless data communications technology and an evolution
of the GSM/UMTS standards. The goal of LTE was to increase the capacity and
speed of wireless data networks using new DSP (digital signal processing)
techniques and modulations that were developed around the turn of the
millennium.
The LTE specification provides downlink peak rates of 300 Mbit/s, uplink peak
rates of 75 Mbit/s and QoS provisions permitting a transfer latency of less than
5 ms in the radio access network. LTE has the ability to manage fast-moving
mobiles and supports multi-cast and broadcast streams.
OFDMA for the downlink, SC-FDMA for the uplink to conserve power
Enhanced voice quality[edit]
To ensure compatibility, 3GPP demands at least AMR-NB codec (narrow band), but
the recommended speech codec for VoLTE is Adaptive Multi-Rate Wideband, also
known as HD Voice. This codec is mandated in 3GPP networks that support 16 kHz
sampling.[30]
Fraunhofer IIS has proposed and demonstrated Full-HD Voice, an implementation of
the AAC-ELD (Advanced Audio Coding “ Enhanced Low Delay) codec for LTE handsets.
[31] Where previous cell phone voice codecs only supported frequencies up to 3.5
kHz and upcoming wideband audio services branded as HD Voice up to 7 kHz, Full-
HD Voice supports the entire bandwidth range from 20 Hz to 20 kHz. For end-to-end
Full-HD Voice calls to succeed however, both the caller and recipient's
handsets as well as networks have to support the feature.
05.11.13
HDC 1400R
Set VF DETAIL to ON to activate the VF detail function to add the detail signal
to sharp edges in the image. You can adjust the signal level (strength) in the
range of 0 to 100% (default 25%). You can adjust the characteristics of the
9. detail signal with the menu items below.
19.11.13
SDI VS. IP
Migration from fixed-circuit based telecommunication services to IP based
connections reduces operational expenses as well as providing flexibility in
audio networking.
4K/UHD is currently limited to 30fps in existing consumer devices. This allows
4K movies to be displayed on consumer TV sets but 4K deployment will only happen
with the support of 50fps as the minimum temporal resolution for smooth motion
capture on sports events.
IMAGE SENSOR
In summary, as sensor size reduces, the accompanying lens designs will change,
often quite radically, to take advantage of manufacturing techniques made
available due to the reduced size. The functionality of such lenses can also
take advantage of these, with extreme zoom ranges becoming possible. These
lenses are often very large in relation to sensor size, but with a small sensor
can be fitted into a compact package. The lens for a smaller sensor requires a
greater resolving power.
29.01.14
SDI
Seri dijital görüntü verilerinde, ardýþýk 0 ya da 1 dizilimini engellemek ve
eþit yoðunlukta 0 ve 1 dizilimini saðlamak için özel olarak þifrelenirler.
Þifrelemede amaç, seri görüntü bilgisinin DC seviyesini azaltmak, geçiþleri
çoðaltmaktýr. En basit tekniklerden birisi PRBS "Pseudo Random Binary Sequence"
olarak bilinen ve 9 kademeli shift registerdan oluþan kendinden senkronlu
þifreleyici devresidir x9 + x4 + 1 olarak ta bilinir.
Seri görüntü sinyalinde, görüntüye baðlý olarak, 0 ve 1'ler, arka arkaya
0.0.0. ya da 1.1.1.1 olarak dizildiðinde, deðiþim olmayan bu noktalarda, iletim
hattýnýn sonunda baðlý bulunan, alýcý ünitede, referans saat darbelerinin tekrar
üretiminde kullanýlan, VCO-PLL osilatörü devresinin, tetiklenmesine referans
olacak, iniþ ya da çýkýþlar yeterince sýk olmayacaðýndan, VCO'nun referans
kilitlemesi hassas olmayacak ve seri görüntü kodlamasýnýn çözülmesinde sorunlar
çýkacaktýr.
Bir satýr için örneklem sayýsý 720 Y, 360 U, 360 V için örneklem alýnýr. Bir
satýr için toplam 1440 örneklem alýnmýþ olur. Kullanýlmayan bölge ve satýrlar
için yapýlan toplam örneklem miktarý; 48*1440 = 69120'dir yani noktacýktýr.
SDI giriþli her cihazýn, giriþ devresi dahili terminasyonlu(75 ohm) dizayn
edilir. Yani SDI video sinyali, bir cihazdan baþka bir cihaza ancak tek
baðlantýlý yapýlabilir. Giriþten "loop" bypass almak ya da "BNC, T" konntektör
kullanarak, ikinci cihaza aktarmak, kesinlikle mümkün deðildir. SDI iletim
hattý, hedefte sonlandýrýlmaz ise çok yüksek frekanslý olmasý nedeniyle,
harmonikler geri yansýyarak gelen sinyalin üzerine ters fazda binerek, sinyali
kullanýlamayacak hale getirecektir. SDI kkodlu sinyallerin, bir cihaz çýkýþýndan
birden fazla noktaya iletilmesi gerektiðinde, "aktif dijital daðýtým
yükselteçleri" kullanýlýr.
Dijital video sinyalleri ancak serileþtirilerek uzun mesafelere taþýnabilirler.
10 bit - 1024 deðer 1 Volt'ta 1 mV'luk deðiþimleri elektriksel olarak çevirme
olanaðý saðlar.
Ayrýmlý video için, seri veri iletimi formatý(SDI) 270 MBps olarak
standartlaþmýþtýr.
30.01.14
10. SDI
1 Voltluk video sinyalinin 8bit derinliðinde beyaz deðeri 235 siyah deðer 16
dýr. Parlaklýk seviyesi 10 bit derinliðinde dijitale çevrildiði zaman beyaz 940,
siyah 64 deðerini alýyor. Renk bileþenlerinde U ve V'de, siyah seviyesi 8 bit
için 128; 10 bit için 512 olur. Renk bileþenlerinin üst ve alt deðerleri 8 bit
sinyalde 16 ile 240 arasýnda deðiþirken, 10 bit sinyalde 64 ile 960 arasýnda
alýnýr.
OFDM modülasyonu tekniðinde ayný frekanstaki taþýyýcýlarýn modülasyondan sonra
üst üste bindirilebilmesi sayesinde daha dar bantta daha yüksek hýzlarda bilgi
iletilebilir.
Dijital kameralarda sadece ayar ve kontrol bilgileri iþlemci denetimindedir,
görüntü bilgileri ve görüntü düzeltme sinyalleri baðýmsýz çiplerde iþlenirler.
04.02.14
PTZ
A pan“tilt“zoom camera (PTZ camera) is a camera that is capable of remote
directional and zoom control.
In television production PTZ controls are used with professional video cameras
in television studios and referred to as camera robotics. These systems can be
remotely controlled by automation systems. The PTZ controls are generally sold
separately without the cameras.
PTZ is an abbreviation for pan, tilt, and zoom and reflects the movement options
of the camera. Other types of cameras are ePTZ where a megapixel camera zooms
into portions of the image and a fixed camera that remains in one position and
does not move. Surveillance cameras of this type are often connected to a DVR to
control the movement and record the video.
Auto tracking[edit]
An innovation to the PTZ camera is a built-in firmware program that monitors the
change of pixels generated by the video clip in the camera. When the pixels
change due to movement within the cameras field of view, the camera can actually
focus on the pixel variation and move the camera in an attempt to center the
pixel fluctuation on the video chip. This process results in the camera
following movement. The program allows the camera to estimate the size of the
object which is moving and distance of the movement from the camera. With this
estimate the camera can adjust the cameras optical lens in and out in an attempt
to stabilize the size of pixel fluctuation as a percentage of total viewing
area. Once the movement exits the cameras field of view the camera automatically
returns to a pre-programmed or "parked" position until it senses pixel variation
and the process starts over again.
07.02.14
Chromatic Aberration
chromatic aberration; CA; chromatic distortion; CD n. A lens defect
that bends light rays of different colors at different angles due to their
different indexes of refraction. As a result, a single lens will actually
create multiple images, each of a different wavelength (color) of light
and each offset slightly from the others, creating a blurred or colorfringed
effect.
10.02.14
Kompozit'ten SDI'ya Çevirici
11. Marka Kramer. 2 SDI çýkýþ var. 1 kompozit video, BNC baðlantý ile 1Vpp/75ohm; 1
s-video, 1Vpp, 4-pin baðlantý ile 0.3Vpp/75ohm elde edilir. Çýkýþta 2 adet SDI
SMPTE-259M arabirimi olup, BNC baðlantý ile ITU-R BT.601 koþullarýna uyum
saplanýr. 10 bit dijital çöznürlüðe sahip ürün, 5 MHz bant geniþliði sunuyor.
SNR 57 dB, K faktörü %0.2'nin altýnda. Renk-ton gecikmesi 15 nanosaniyeden kýsa
olup, RS-232 üzerinden parlaklýk, kontrast, renk, doygunluk ayarlarý
yapýlabiliyor.
S-VIDEO
Separate Video,[1] commonly known as S-Video, Super-video and Y/C, is a
signalling standard for standard definition video, typically 480i or 576i. By
separating the black-and-white and colouring signals, it achieves better image
quality than composite video, but has lower colour resolution than component
video.
12.02.14
ARRI ULTRA WIDE ZOOM TESTÝ
UWZ 33.7mm görüntü dairesine sahip ve geniþ sensörlü dijital kameralar.
Bozulmayý en aza indiren telesentrik optik tasarým. Bir lensin ortasýnda
normalde parlak bir nokta olup kenarlara doðru koyulaþýrken UWZ'de bu görülmez.
Çok geniþ bir binanýn bir ucundan diðer ucuna pan yapýldý ve düz çizgilerde bir
bozulma olmadý.
14.02.14
PILLARBOXING
Pillarboxing (reversed letterboxing) is the display of an image within a wider
image frame by adding lateral mattes (vertical bars at the sides); for example,
a 1.33:1 image has lateral mattes when displayed on a 16:9 aspect ratio
television screen.
QoS
Quality of service is the ability to provide different priority to different
applications, users, or data flows, or to guarantee a certain level of
performance to a data flow. For example, a required bit rate, delay, jitter,
packet dropping probability and/or bit error rate may be guaranteed.
LIVE STREAMING
Live streaming, which refers to content delivered live over the Internet,
requires a camera for the media, an encoder to digitize the content, a media
publisher, and a content delivery network to distribute and deliver the content.
AKTÝF AYGIT
Kendi güç beslemeleri olan aygýtlardýr(LAN Switch).
19.03.14
OTT(Over the top)
Over-the-top content (OTT) refers to delivery of video, audio and other media
over the Internet without a multiple system operator being involved in the
control or distribution of the content. The provider may be aware of the
contents of the Internet Protocol packets but is not responsible for, nor able
to control, the viewing abilities, copyrights, and/or other redistribution of
12. the content. This is in contrast to purchase or rental of video or audio content
from an Internet service provider (ISP), such as pay television video on demand
or an IPTV video service, like AT&T U-Verse. OTT in particular refers to content
that arrives from a third party, such as NowTV, Netflix, WhereverTV, Hulu, WWE
Network, RPI TV or myTV, and is delivered to an end user device, leaving the ISP
responsible only for transporting IP packets.
02.04.14
BROADBAND
broadband n. 1. A device or signal that includes a wide range of frequencies or
has a data capacity of at least 1.5 Mbps. 2. Digital: a technology that can
simultaneously carry voice, high-speed data (Internet), video, and interactive
services. Broadband is often used to describe high-speed Internet service,
without regard to the other services that can be offered by the same facility.
04.04.14
Koaksiyel Kablo
En yüksek performans sunan koaksiyel kablo en aðýr olandýr ve daha fazla yer
kaplar.
kÜÇÜK bnc(KONNEKTÖR) DEMEK 50 ohm demek ve daha ince kablo kullanmak
demektir(sinyal zayýflamasý ve empedans uyuþmazlýðý sorunu).
Günümüz BNC-koaksiyel kablo ve diðer ara baðlantýlarýn çoðu birçoðu 3 Gb/s
sinyaller için kullanýlamadýð açýk. 1,5 Gb/s için üretildiler ve 1,5Gb/s deki
yüksek frekanslý harmonikler için yeterli fazlalýða(3Gb/s) sahip olmuþ oldular.
Ýletken yollarýnýn uzunluðu mümkün olduðunca eþit olmalýdýr. Yoksa performansý
düþürüyor.
ÖZEL YÖNLENDÝRÝCÝ ANAHTARLAMA TEKNOLOJÝLERÝ
FARKLI VERÝ HIZLARINDAKÝ SÝNYALLERÝ ALABÝLMEK ÝÇÝN SAAT AYRINDA UYARLAMALI FAZ
KÝLÝTLÝ DÖNGÜ (ADAPTIVE PHASED-LOCKED LOOP) TEKNOLOJÝSÝ OLMASI GEREKÝR.
HDTV BITRATE
Bt = lv × lh × fr × qb × cs
Bt = total bit rate
lv = number of active vertical lines
lh = number of active horizontal lines
fr = frame rate of input video signal
qb = quantization depth (bits)
cs = color subsampling (1 for 3:0.5:0.5, 1.5 for 4:2:0; 2 for 4:2:2; 3 for RGB
full bandwidth)
Br = 1080 × 1920 × 29.97 × 8 × 1.5 = 745.750 Mbitps
07.04.14
CABLING
When building a facility that has critical timing requirements, keep cables as
short as possible to minimize signal attenuation and crosstalk. It is best to
locate all of the distribution equipment in the same or adjacent racks. Because
13. most video cabling among distribution elements must be timed or of matching
lengths, short cables make the job manageable, and, at the same time, cable
costs are kept low.
CABLE LOSS AND EQUALIZATION
The high frequency response of a cable decreases with increasing frequency. The
loss can be compensated for by using an equalizing amplifier with a response
curve that complements the cable loss. For video applications, a typical
distribution amplifier (DA) has six outputs isolated from one another by fan-out
resistors. Because the equalization is adjusted to produce a flat response at
the end of a length of a specific type of cable, all of the cables being driven
by the amplifier must be the same type and length.
DTV Plant Latency and Timing Issues
D = dd + dr + dc + ds + dt + dm
Where:
D = total delay
dd = distribution delay
dr = routing delay
dc = conversion delay
ds = switching delay
dt = transmission and multiplexer delay
dm = makeup delay to equalize the NTSC and DTV paths
a local station connected to the network by a short fiber connection might be
delayed by 7 s or less while a cable system sending QAM over the cable fed by a
local station connected, in turn, to the network by satellite might take 20 s.
Other Timing Considerations
Timing signals should be delayed before delaying the video. A slave sync
generator is desirable whenever timing advance is required, or whenever
approximately three or more pieces of equipment need equally delayed pulses.
Non-reentry designs are the most cost effective.
08.04.14
The velocity in the conductors is typically about one-half the speed of light.
If the transmission line were cut at some point and terminated in an impedance
Z, energy would continue to flow on the line as if it had infinite length. When
the wavefront reaches the termination, energy is dissipated per unit time rather
than being stored per unit time.
Conceptually, the serial digital interface is much like a carrier system for
studio applications. Baseband audio and video signals are digitized and combined
on the serial digital “carrier.“ (SDI is not strictly a carrier system in that
it is a baseband digital signal, not a signal modulated on a carrier wave.) The
bit rate (carrier frequency) is determined by the clock rate of the digital
data: 143 Mbits/s for NTSC, 177 Mbits/s for PAL, and 270 Mbits/s for Rec. 601
component digital. The widescreen (16 × 9) component system defined in SMPTE 267
will produce a bit rate of 360 Mbits/s. This serial interface may be used with
normal video coaxial cable or fiber optic cable, with the appropriate interface
adapters.
11.04.14
CAMERA CONTROL
Parlama (Flare) ayarý: Kamera objektiflerinden kaynaklanan, görüntünün siyah
14. seviyesindeki bozulmalarý düzeltmek için yapýlýr
14.04.14
If any channel of R', G', B' signal exceeds either the upper limit or lower
limit, it is out of gamut, or out of range. The violation of the gamut limits
makes the signal illegal.
The targets for red, blue, and green form a triangle. In between each of these
primary colors are the colors formed by mixing those primaries. So the color
between red and blue is magenta. The color between blue and green is cyan, and
the color between red and green is yellow. These secondary colors form another
triangle. The other interesting relationship that is formed on the vectorscope
is that complementary colors are directly opposite each other. Red is opposite
cyan, magenta is opposite green, and yellow is opposite blue. These
relationships will play a pivotal role as you begin to manipulate colors. For
example, if you are trying to eliminate a magenta cast in an image, a glance at
the vectorscope will tell you that you need to add green, which is opposite
magenta. Or you could reduce red and blue in equal amounts (the two colors that
make magenta). If an image has yellows that are too cyan, then adding red will
begin to
solve the problem. Eventually, you should not even need the graticule (the
graphic part of the vectorscope that identifies color targets) to know where the
colors lie on the face of the vectorscope.
they all should sit neatly in the center of the vectorscope. While most video
images will have a range of colors, they also usually have some amount of
whites, blacks, and neutral grays. The key is to be able to see where these
parts of the picture sit on the vectorscope and then use the color correction
tools at your disposal to move them toward the center of the vectorscope.
For nearly all professional colorists, the various waveform displays “ Flat, Low
Pass, Luma only, RGB Parade, and YCbCr Parade “ plus the vectorscope are the
main methods for analyzing your image. While experienced colorists often rely on
their eyes, they use these scopes to provide an unchanging reference to guide
them as they spend hours color correcting.
HARRIS TVM WAveform
To store a preset in bank A, press and hold the desired preset number button (1
to 8) for three seconds. The number button is high tally upon release after
holding the button for three seconds. Also, a beep will sound if the Aural alert
is enabled in the SYSTEM SETUP menu.
Hold MLT button to enter pane selection part. Press and hold CURS button for
three seconds. Use the NAVIGATION buttons or knobs to select Amplitude or Time.
Once selected, press the ENT button to enable it. Once one or both cursors are
selected, press the EXIT button to exit the CURS pane menu.
21.04.14
LIGHTING(PLACING SHADOWS LIGHTING TECHNIQUES BOOK PAGE 44
Infrared light is the longer of the two wavelengths, and far more of these rays
penetrate the atmosphere because of their wavelength. They are not easily broken
up by the particulate matter in the atmosphere.We cannot see them, but we feel
them in the form of heat. In fact, as some of the incoming ultraviolet rays pass
through the upper atmosphere, their short wavelengths bounce around the
particles and are converted to heat energy or infrared radiation. Like
ultraviolet radiation, infrared waves also affect photographic film and
television cameras.
08.05.14
15. GHOSTING
Digital ghostinG :
Ghosting is not specific to analog transmission. It may appear in digital
television when interlaced video is incorrectly deinterlaced for display on
progressive-scan output devices.
23.07.14
SCRAMBLER
a scrambler is a device that transposes or inverts signals or otherwise encodes
a message at the transmitter to make the message unintelligible at a receiver
not equipped with an appropriately set descrambling device. Whereas encryption
usually refers to operations carried out in the digital domain, scrambling
usually refers to operations carried out in the analog domain.
GATEWAY
Roughly, it refers to systems called as protocol converter!!
PROXY SERVER
In computer networks, a proxy server is a server (a computer system or an
application) that acts as an intermediary for requests from clients seeking
resources from other servers.
-Alice : Ask Bob what the current time is
-Proxy : what is the current time Bob?
-Bob : The time is 7pm.
-proxy : Time is 7pm.
01.08.14
SDI STANDARDS
SMPTE 292M - HD-SDI - 1998[2] - 1.485 Gbit/s, and 1.485/1.001 Gbit/s - 720p,
1080i
SMPTE 372M - Dual Link HD-SDI - 2002[2] - 2.970 Gbit/s, and 2.970/1.001 Gbit/s
1080p
SMPTE 424M - 3G-SDI - 2006[2] - 2.970 Gbit/s, and 2.970/1.001 Gbit/s
1080p
composite-encoded (NTSC or PAL)!!!!!
LTC
LTC care:
Avoid percussive sounds close to LTC
Never process an LTC with noise reduction, eq or compressor
Allow pre roll and post roll
To create negative time code add one hour to time (avoid midnight effect)
Always put slowest device as a master
05.08.14
ANCILLARY DATA(SDI)
Like SMPTE 259M, SMPTE 292M supports the SMPTE 291M standard for ancillary data.
16. Ancillary data is provided as a standardized transport for non-video payload
within a serial digital signal; it is used for things such as embedded audio,
closed captions, timecode, and other sorts of metadata. Ancillary data is
indicated by a 3-word packet consisting of 0, 3FF, 3FF (the opposite of the
synchronization packet header), followed by a two-word identification code, a
data count word (indicating 0 - 255 words of payload), the actual payload, and a
one-word checksum. Other than in their use in the header, the codes prohibited
to video payload are also prohibited to ancillary data payload.
Specific applications of ancillary data include embedded audio, EDH, VPID and
SDTI.
17.10.14
ENCODING and SDI
Kodlama, x9 + x4 + 1 þeklinde kodlanýr. Çünkü, arka arkaya 4 sýfýr ya da 4 bir
gelirse, DC voltaj seviyesi olarak algýlanabilir. Ayrýca, belli bir bant
geniþliðine sýðdýrmak için de arka arkaya 4 bir gelmez. Beyaz, FF diye gelir,
siyah 00 diye gelir.
SDI'da, satýr baþlarken 4 byte olarak satýr bilgisi, neyim, nerdeyim bilgisi vs.
sinyalin baþýnda gönderilir. Hiç bir sesin bilgisi 00 ya da FF gelmiyo. Bu
alanda kontrol bilgileri yollanýyor. 8 bit tanýmlandýðý için SDI monitör
bilgileri 8 bittir genelde. SDI'da her aletin içinde 27 MHz'lik dahili bir
jeneratör vardýr sinyale kilitlenir.
In SDI, or all serial digital interfaces (excluding the obsolete composite
encodings), the native color encoding is 4:2:2 YCbCr format. The luminance
channel (Y) is encoded at full bandwidth (13.5 MHz in 270 Mbit/s SD, ~75 MHz in
HD), and the two chrominance channels (Cb and Cr) are subsampled horizontally,
and encoded at half bandwidth (6.75 MHz or 37.5 MHz).
Gamut, renk skalasý, üretebildiði dalga boyu cihazlarýn.
QPSK, daha az güç(daha az güçle tekiklenir) ister QAM'a göre.
10845MHz H. 30000 5/6 8 PSK... Hata düzeltme az, video fazla daha fazla güç
ister.
Dijitalde bant geniþliðini ayarlayabiliyosun analogta ayarlanamýyor.
04.11.14
COMPRESSION
Sayýsal TV yayýnlarýnýn iletilebilmesi için en az 50 kere sýkýþtýrýlmasý
gerekir. MPEG-2 ile STV yayýnlarý 4 ila 8 Mbitps, HDTV yayýnlarý da 18-20 Mbitps
ile iletilebiliyor.
Bir çerçevedeki gereksiz bilgileri atmak intra frame.
Zaman içindeki tekrarlaran kaynaklanan gereksiz bilgileri atmak inter frame.
MODÜLASYON
QAM = QUADRATURE AMPLITUDE MODULATION(UYDU)
QPSK = QUADRATURE PHASE SHIFT KEYING(KABLO)
AUDIO
MPEG-2 = AVRUPA
17. DOLBY AC-3 = AMERÝKA
SAYISAL TV ALICILARI
Sayýsal TV alýcýsý normal bir analog TV alýcýsýna sayýsal kod çözücünün
eklenmesi ile elde edilebilir. Nitekim sayýsal TV sistemlerine geçiþte ilk aþama
eski analog TV alýcýlarýna Set-Üstü-Cihaz (Set-Top-Box) adý verilen
sayýsal/analog dönüþtürücü cihazlarýn dýþardan eklenmesi #þeklinde olmuþtur.
(Þekil-6). Yeni nesil sayýsal TV alýcýlarýnda kod çözücü de cihazýn içine
konacaktýr.
DISPERSION
1. The optical phenomenon where the refractive index of a transparent media
varies with the wavelength of light. This effect is most visible in a prism,
where white light enters but a rainbow of colored light emerges because each
color is bent by a different amount as it passes through the prism. 2. The
spreading of sound waves as they leave a loudspeaker. 3. Refraction.
REFERENCE SIGNAL CONTROL
Find the switch on the cameras (or the CCUs) that turn on the camera's internal
color bars. When you flick that switch to bars, you should see color bars on the
monitor for each camera as you press the corresponding numbered button in the
PROGRAM bus (row of buttons). The picture will jump a little as you punch the
buttons. iki kamerada dahili olarak color bar üretilince cameralarý pgme
seçerken geçiþler sýrasýnda atlama yapýyosa referanslarý senkronize deðildir.
EXPOSURE VALUE
In photography, exposure value (EV) is a number that represents a combination of
a camera's shutter speed and f-number, such that all combinations that yield the
same exposure have the same EV value (for any fixed scene luminance). Exposure
value is also used to indicate an interval on the photographic exposure scale,
with 1 EV corresponding to a standard power-of-2 exposure step, commonly
referred to as a stop.
F-STOP
The f-number N is given by
N = f/D where f is the focal length, and D is the diameter of the entrance pupil
(effective aperture). It is customary to write f-numbers preceded by f/, which
forms a mathematical expression of the entrance pupil diameter in terms of f and
N. For example, if a lens's focal length is 10 mm and its entrance pupil
diameter is 5 mm, the f-number is 2 and the aperture diameter is f/2.
Ignoring differences in light transmission efficiency, a lens with a greater f-number
projects darker images. The brightness of the projected image
(illuminance) relative to the brightness of the scene in the lens's field of
view (luminance) decreases with the square of the f-number. Doubling the f-number
decreases the relative brightness by a factor of four. To maintain the
same photographic exposure when doubling the f-number, the exposure time would
need to be four times as long.
26.11.14
PAL and NTSC = They are systems of single-channel composite transmission. PAL-B
is used for VHF band. PAL-G is used for UHF band.
04.11.14
18. Alex Barwell
System Specialist at BBC
Agree with Fred that the starting point for 4K+ is not difficult, but gets
complicated with other systems and infrastructure. As with early HD and some 3G
arrangements, one scheme uses multiple connections for a single 4K feed - as one
instance, 4 SDI connections run in parallel for a 4K run, so depending on your
existing technology just jumping to 4K could conceptually cut your router down
to 1/4 the effective ins and outs.
Then at about this point film houses reportedly are struggling with the
increased data workload for a film - not just storage but inevitable render
efforts similarly effectively shrinking the capability of their render farms.
I would challenge whether production values are sufficient to justify these
increased efforts - before now I have made the observation that shooting with
the latest camera with bad shot composition, lighting, focus etc completely
defeats the object - if it's out of focus it doesn't really matter what
definition. If you are doing a good job then go ahead!
08.12.14
GENERATOR LOCKING
Tricaster make it easy to synchronise each camera with a little latency.
TRI-LEVEL SYNC
Tri-level sync is becoming a required part of HD system timing.
One reason is that tri-level sync can be created to exactly match any of the
standard formats. Black burst only comes in two flavors 29.97 fps (525 line) and
25 fps (625 line).
Another reason is that black burst (gen-lock) is measured at the halfway point
of the leading (falling) edge of the pulse. Tri-Level sync uses the halfway
point of the trailing (rising) edge of the pulse. These points are used to time
the digital video. They are determined by means of a sync separator and voltage
comparator.
Usually determining the 50% point of the falling edge entails measuring the
total height and divide by two. Unfortunately, the trigger point has past by
that time. Another method is to infer the total height from previous sync
pulses. This involves some averaging process. In addition, the amplitude of the
pulse can vary due to attenuation in the cables. These effects cause some
uncertainty in the final positioning. This uncertainty leads to jitter in the
output of the sync separator / comparator.
Tri-level sync was created to avoid this uncertainty. The target 50% point is on
the rising edge of the pulse. This point corresponds to the original blanking
level. This means that the 50% voltage level is a known voltage. There is no
integration or averaging involved. This leads to lower jitter from the sync
separator / comparator.
CONCLUSION
Tri-level sync has advantages and should be used whenever possible in all
digital facilities. But that workhorse ‘Black Burst‘ will be around as long as
standard definition analog equipment is in use and requires timing.