Evaluate the coding artifacts in mpeg encoding
Computer Engineering
Question 1
(a) Calculate the binary values of the following decimals. The integer part of the converted binary numbers has a bit length of 8 bits.
(i) 11 (ii) -12 (iii) 3.141 (iv) -5.252
(b) Differentiate between the advantages and disadvantages of digital signals over that of analogue signals.
(c) Describe the phenomenon of persistence of vision and its importance in the creation of the illusion of motion in a movie?
(d) When setting up or tuning your MIO TV system provided by SINGTEL, you may often come across the video specification resolution settings of 1080p and 1080i respectively. Discuss with relevant illustrations the significance of “1080”, “p” and “i” to the video quality expected from these selections.
Question 2
(a)
(i) Describe in brief the process of Chroma subsampling as a useful tool in analogue video encoding process.
(ii) Explain the difference in the Chroma sampling process between the 4:4:4 and 4:2:2 standards used in the current video industry. Cite two high-end digital video formats and interfaces that uses the 4:2:2 sampling scheme.
(b)
(i) Use appropriate diagrams to demonstrate how a NTSC Video signal can be digitized.
(ii) If a PAL Video signal is to be digitized, briefly appraise the changes in system specifications that must be made when compared to the digitization of the NTSC signal.
(c) Differentiate the different video format specifications by completing Table Q2(c).
Active Resolution
(H x V)
Definition of TV
Signal Quality
(eg SDTV, HDTV,
UHDTV etc)
Frame Rate Used
(also indicate “I” or “P” scanning mode)
Screen Aspect Ratio
720 x 480
720 x 576
1920 x 1080
3840 x 2160
7680 x 4320
Question 3
(a) Relate to appropriate illustrations from the Study Guide, to show Photopic and Scotopic Vision are achieved in the human eye. Keep your answer concise.
(b) Write down equations that enable us to generate Chroma value and Luminance signals from Colour Component inputs. Illustrate with a suitable block diagram to show the signal generation process.
(c) Explain the terms, “Visual Acuity” and “Spatio-Temporal Response” of the human eye. Use appropriate diagrams to support your presentation.
(d) Critique the role of human eye saccade in the role of resolution improvement in tracking video scenes.
Question 4
(a) Produce a sketch of the Inter-frame Coding algorithm. Briefly describe the roles of the blocks performing motion estimation/motion compensation, inverse discrete cosine transform and frame store respectively.
(b) Evaluate the coding artifacts (showing up as video noise) in MPEG encoding. Provide the following details:
(i) the signal characteristics of video noise (ii) the causes of the video noise, and, (iii) suggest methods to reduce the video noise.
Note that the discussions presented here should be open-ended.
(c) Calculate the uncompressed video file size of a UHD (2160p/60p) video clip from an hour long recording session for the following formats with data rates given below:
(i) BluRay H.264 (ii) MPEG2 High (iii) PRORes422 (iv) RAW RGB 3×8 bit (v) RAW RGB 3×16 bit
Use an appropriate video file size calculator from the internet to determine the file sizes above such as:
http://toolstud.io/video/filesize.php?imagewidth=1920&imageheight=1080&framerat e=25&timeduration=60&timeunit=seconds
(d) Table Q4(d) shows the different video formats and compression types. You have been tasked to produce a short 5 minute overview of your understanding of the course MTD207eVideo Technology which will be streamed later via the YouTube channel. Apply justifiable reasons to support your selections of the recording format to be used and also provide the suitable export file format to be uploaded to YouTube taking into considerations internet bandwidth limitations as well as retention of adequate audio and video quality.
Format
Resolution
Compression Type
Data Rate
Applications
MJPEG
720×486
Intra-frame
0.5-25
MB/sec
General
MPFG-1
352-240
Intra-frame
0.01-0.06
MB/sec
Video CD, CD- Rom, Web
MPEG-2
720×480
Infra- and
Inter-frame
0.01-2 MB/sec
DVD, Satellite TV
H264
720×480
1080P
720P
Intra-frame
Inter-frame
0.01-30
MB/sec
Consumer,
Industrial,
Broadcast
