A review over multimedia and how to share multimedia data between clients and servers. Find me on: AFCIT http://www.afcit.xyz YouTube https://www.youtube.com/channel/UCuewOYbBXH5gwhfOrQOZOdw Google Plus https://plus.google.com/u/0/+AhmedGadIT SlideShare https://www.slideshare.net/AhmedGadFCIT LinkedIn https://www.linkedin.com/in/ahmedfgad/ ResearchGate https://www.researchgate.net/profile/Ahmed_Gad13 Academia https://www.academia.edu/ Google Scholar https://scholar.google.com.eg/citations?user=r07tjocAAAAJ&hl=en Mendelay https://www.mendeley.com/profiles/ahmed-gad12/ ORCID https://orcid.org/0000-0003-1978-8574 StackOverFlow http://stackoverflow.com/users/5426539/ahmed-gad Twitter https://twitter.com/ahmedfgad Facebook https://www.facebook.com/ahmed.f.gadd Pinterest https://www.pinterest.com/ahmedfgad/

1. Multimedia
Networking
Pre-Master

2. Digital Media

3. Multimedia Application

4. Video Characteristics
Bit Rate
100kbps 8Mbps
Popular

5. Video - Compression
Spatial redundancy

6. Video - Compression
Temporal redundancy

7. Video – Compress to
multiple versions
High Quality Low Quality
On-the-fly Compression
Video Conference Application

8. Audio - Characteristics
PCM
Analog
Speech
8000 sample/sec
Sample
8 bit/sample
64 kbps
Audio size < Video size

9. Audio - Compression
MPEG 1 layer 3 MP3
128 kbps
Advanced Audio
Coding (AAC)

10. Types of Multimedia
Network Applications
Streaming stored audio/video
Conversational voice/VoIP
Streaming live audio/video

11. Streaming Stored Audio
and Video

12. Client-Server Operation -
Data Stream
Request
Response

13. Interactivity
Request
Response
Pause Reposition

14. Continuous playout
Request
Response

15. Performance Measure of
video streaming
Average Throughput CDN
Prefetch &
Buffering
Adapt Quality

16. Conversational
Voice/VoIP
Time
Delay-Sensitive
Data Loss
Loss-Tolerant

17. Streaming Live Audio and
Video

18. Streaming Stored Video
UDP streaming
HTTP streaming
Adaptive HTTP streaming

19. Client Buffering
Variations in server-to-client
delay (Jitter).
Bandwidth Drops

20. UDP Streaming
Fixed Server Transmission Rate
= Client Video Consumption Rate
Real-Time Transport Protocol
(RTP) – Audio/Video
RTP/UDP
Control Mechanism - “Real-
Time Streaming Protocol
(RTSP)”

21. UDP Streaming
Drawbacks
Constant Data Rate
Require Control – RTSP
Play - Pause
Many Firewalls Block UDP
Traffic

22. HTTP Streaming
GET URL HTTP/1.1TCP HTTP/1.1 200 OK

23. HTTP Streaming Benefits
Built-in Congestion Control Mechanism -
No RTSP
Traverse Firewalls

24. TCP Prefetching Video
UDP
Fixed to Client Video Consumption Rate
Rate at which video is played out.
TCP Supports
Higher Rates than Consumption Rate
+
Client Buffering

25. Example
UDP Consumption Rate = 1Mbps
Client & Server can support 1.5Mbps
TCP use .5Mbps to prefetch data
What if data rate drops less than 1Mbps?
TCP has prefetched data
UPD has not

26. Repositioning the Video
HTTP streaming systems use the HTTP byte-range
header in the HTTP GET request message range of bytes
the client currently wants to retrieve from the desired video.
Prefetching makes repositioning easier.

27. HTTP Streaming
Drawbacks
All clients use same bit rate
despite bandwidth variations

28. Dynamic Adaptive Streaming
over HTTP (DASH)
2.5Mbps
1Mbps
5Mbps
Manifest File 1, 2.5, 5GET 1Mbps
Bandwidth
Increased /
Much Buffered
GET 2.5MbpsGET 5Mbps
Bandwidth
Decreased /
Few Buffered
GET 1Mbps
Rate Determination
Algorithm
Sudden Data Rate Change
5Mbps (720p)
To
1Mbps (320p)

29. DASH Benefits
Client maintains the intelligence
Saving server time
Maintains HTTP Byte-Range

30. Single Server Drawbacks
Data go through multiple links.
What if one link data rate < consumption rate?
If many clients access a video in the same
server?
Single data center = Single point of failure

31. Content Distribution
Networks (CDNs)

33. Server Selection Strategies
Geographically closest
Real-time measurements