Video and animation involve capturing and displaying sequences of images to depict motion. Video uses real-world images while animation uses drawn or computer-generated images. MPEG standards like MPEG-1, 2, and 4 are used to compress digital video for storage and transmission by removing spatial and temporal redundancies between frames. MPEG compression involves three frame types - I, P, and B frames. I-frames are independent while P and B frames use motion prediction from previous and following frames. Grouping frames into GOPs allows efficient compression. The MPEG encoding and decoding process reconstructs frames using motion vectors and compensating for prediction errors.

1. Video and Animation
By
Dr. R. Manjula Devi
Assistant Professor(SRG) / CSE

2. Video and Animation
• “A Picture is worth a thousand words”
• Video: images are of real world objects
• Animation: drawn or computer generated
images
• Video camera: to capture events, thoughts,
sounds while recording
• Eye is not good at rapidly changing scenes.
• Need for high refresh rate: to reduce flicker Eg.
25 to 30 frames / sec

3. Phases and activities
• Techonologies: provides flexibility to create,
capture, edit, store, transmit, distribute & deliver
visual media

4. Digital Video
• TV Std: International
Telecommunication Union
Recommendation 601 -ITU
BR.601(CCIR 601)– 1981 – 116MB/sec
– Not practical to transmit through
100Mbs n/w – thus compression is
essential
• Compression: make use of
similarities between neighbouring
images.

5. Motion JPEG
• Motion JPEG(MJPEG):
– guranteed quality – flexibility to use lower/higher
compression for high /lower image quality
– Frame rate – can be controlled
– Limited delay between capturing, encoding, transferring,
decoding and displaying
• Spatial redundancies (similarities within the picture
frame) are removed
• Temporal redundancies ( similarities between
frames) are not.

6. Moving Picture Experts Group (MPEG)
Stds
• MPEG1 : 1993 – digital video on CD – 1.5Mbs – audio
compression MP3 is a part of MPEG1
• MPEG2: 1994 – 1.5 to 15Mbs – very high image
quality - Applications: DVD, HDTV, interactive storage
media, digital broadcast video, cable TV - lower
compression ratio and high bit rate
• MPEG4: 2000 – many tools to lower bit rate – used for
interactive multimedia and web applications –
– Object based compression – individual objects(text, img,
video, animation, button, etc) within a scene are tracked
separately and compressed together – developers can control
objects independently –
– Large no. of profiles and profile levels – for defining subset
of tools used in MPEG4

7. Scope of MPEG4

8. Moving Picture Experts Group (MPEG)
Stds
• MPEG7 : meta data – represent information about
content – called as Multimedia Content Description
Interface – provides set of rules and tools for
describing content, allowing content manipulation,
filtering and personalization, integrity and security of
the content – uses XML based Description Definition
Language
• MPEG21: called as Multimedia framework – describe
elements & the relationships among them for
multimedia delivery through different networks and
devices – “Adaptation” feature helps to interact with
specific items in the file.
• DRM (Digital Rights / Restrictions) : control over
dissemination and usage of digital content for any
purpose on any device or network.

9. Guidelines for choosing suitable
video compression method
• MJPEG: < 5frames/sec; robust, flexible, low
latency, more image quality – surveillance
• MPEG1: high img quality (CD), limited bandwidth
– viewing and recording applications
• MPEG2: very high img quality, 25/30 fps, high
available bandwidth - viewing and recording
• MPEG4: >10fps, higher latency,limited but
guaranteed bandwidth – wide range of viewing
and recording applications

10. MPEG Video Compression
• To achieve high rates of compression by
exploiting the redundancy in video
• It removes both spatial and temporal
redundancies
• Variable bit rate – not suitable for transmission
which requires fixed rate
• Through away most detailed information while
preserving less detailed picture content
• To ensure overall bit rate and minimal loss of
picture quality

11. MPEG Compression (contd.)

12. Basic Operations of an MPEG Encoder

13. Spatial Redundancy
• Also termed intra-frame redundancy
• Occurs when parts of the picture are replicated
within a single frame of video

14. Temporal Redundancy
• Also termed inter-frame redundancy
• Occurs when successive frames of video display
images of the same scene
Note: Not always possible to compress every frame of a video clip to the
same extent
• Some parts of a clip may have low spatial redundancy
• Other parts may have low temporal redundancy

15. Types of Frames
MPEG compression technique uses three kinds of
frames
– I frame
– P frame
– B frame
• Used for
– Redundancy reduction
– Subsequent motion estimation processing

16. I Frame
 I stands for Intra
 I-Frame is treated as a still process
 Reconstructed without any reference to other frames
 Provides a known staring point
 Usually the first frame to be sent
 Used for internal reference and provide the ability to fast
forward through a picture

17. P Frame
• P stands for Predicted
• Uses the preceding I frame as its reference and
for motion estimation processing
• Forward predicted from the last I-frame or P-
frame
– Not possible to reconstruct them without the data of
another frame ( I or P)

18. B Frame
• B stands for Bidirectional
• Uses both forward predicted and backward
predicted from the last / next I-frame or P-frame
– P-frames and B-frames are referred as inter
coded frames

19. Group of Pictures (GOP)
Decoder Task :
Reorder the
reconstructed
frames

20. MPEG Compression -
Grouping of Frames
• Three frames: 1 for forward prediction, 1 for
backward prediction, 3rd contains frame coming into
being.
• Display order is not the coding order; referred
frames precede referring frames; ascending
frame number comes with each frame

21. Decoder
• Decoder: to reorder the reconstructed frames
• Motion Prediction: Motion vector declares how
to move the object on I-frame to obtain the
object in P-frame –
• it has horizontal & vertical part –
– can be +ve (motion to the right/downwards)
– can be –ve (motion to the left/upwards)
– changes are expressed as displacement of pixels

22. MPEG Compression - Prediction
Error
• In actual – motion (right shifted/ rotated) – cause
prediction error – to compensate this, matrix
used in MPEG stream
• Steps for Reconstruction of inter coded
frames: (i) application of the motion vector to
the referred frame (ii) adding the prediction error
compensation to the result
• Prediction compensation error : requires less
bytes than whole frame(white parts are
discarded); DCT compression is applied to it,
which decreases its memory size.

23. MPEG Compression -
Reconstructing Picture

24. Creating Digital Video
• Basic Steps:
(i)capturing digital video,
(ii)editing video out of a no. of video clips, pictures &
audio clips
(iii)saving final video in required format
• Capturing: digital video camera directly used – if
analog camera, video capture card needed to
digitised – webcams also used – several options
available for controlling capture quality

25. Creating Digital Video
• Editing: order the clips, add animations, text
subtitles, audio narrations, music; sometimes
transition effects, etc.
Eg. Adobe’s Premiere, Pinnacle Studio, Roxio Creator, Corel’s
VideoStudio, VideoWave, Dazzle Digital Video Creator,
Windows MovieMaker

26. Creating Digital Video
• Editing : Individual files are placed on timeline using
drag & drop method –unwanted segments removed –
tested – finally add transition effects, titles, subtitles,
etc.
• High end Video editing tool: allow multiple layers for
the timeline – better control and flexibility
• Saving: required format and size depends on
application; (.wmv for web; .avi, .mpeg, etc)
• Convertion needed : based on platforms, software
used - Video editing software has convertion option

27. Animation
• Animation of an object is created when
snapshots of the object during various intervals
of time of its motion are displayed rapidly
• Initially – hand drawn objects used;
• later 2D and 3D animations have been
developed using softwares – Adobe’s Flash,
Director, Autodesk’s 3Ds Max and Maya

28. Animation
• 3 Principles:
1. By adding motion dynamics properties to the
object ( moving from point A to point B)
2. By adding dynamics of object properties –
dynamically changing its shape, color, structure,
texture, etc.
3. By changing viewing dynamics of object –
changing viewing angle, lighting, orientation,
focus, etc.

29. Guidelines for Animation
• Motion meaningful
• Direct connection with idea
• To convey feelings and emotions
• Finishing touches enhance the appeal of
animations
• Real life simulation of life characters is a major
factor
• Adding sounds and speeches improves effect of
animation
• Lip-syncing is often essential

30. File formats for Animation
• Windows Media File (.avi, .asf, .asx, .wma, .wmv)- cannot be
streamed
• Quicktime ( .mov, .qt) – supports synchronised graphics,
sound, video, text, music, VR and 3D media
• RealMedia(.rm, .ra) – streaming media, audio and video –
supports several types
• MPEG(.mpg, .mp4) – std – converted from AVI – streaming is
possible
• Animation (.flc, .fli) – main animation format
• Adobe Flash Animation(.swf, .fla, .flv)- SWF are derived
from FLA file – swf are popular for web

31. THANK
YOU