multimedia entertainment and security1 multimedia entertainment and security submitted by:...
TRANSCRIPT
Multimedia entertainment and security 1
Multimedia Entertainment and Security
Submitted by:
Sravanthi. Y
Multimedia entertainment and security 2
Outline : Introduction Services of multimedia Challenges of MM over wireless Multimedia Security Image Security Video Security Audio Security Audio Video Mixing Conclusion References
Multimedia entertainment and security 3
What is Multimedia?????
The term multi-media means that there are more than one media type involved in the communication, e.g. text and graphics, voice animations, video and audio.
Multimedia entertainment and security 4
Multimedia Services
2,000
0
32
64
9.6
128
144
384
1G 2G 3G
VoiceVoice
Text MessagingText Messaging
Video StreamingVideo Streaming
Still Still ImagingImaging
Audio StreamingAudio Streaming
Da
ta T
ran
sm
iss
ion
Sp
ee
d -
k b
ps
ElectronicNewspaper
RemoteMedical Service(Medical image)
Video Conference(High quality)
Telephone (Voice)
Voice Mail
E-MailFax
ElectronicPublishing
Karaoke
Video Conference(Lower quality)
JPEG Still Photos
Mobile Radio
Video Surveillance,Video Mail, Travel
Image
Audio
Voice-driven Web PagesStreaming Audio
DataWeather, Traffic, News,Sports, Stock updates
Mobile TV
E-Commerce
Video on Demand:Sports, News Weather
Reference:http://www.cse.fau.edu/~borko/PP,ChallengesWireless%20MM.ppt
Multimedia entertainment and security 5
Challenges of MM over wireless:MM applications over a wireless channel require:
High data rates Reliable connection More memory High resolution displays High processing units Quality of service factors Problem of portability with wireless Security
Multimedia entertainment and security 9
SENDER RECEIVER
THIRD PARTY INTERRUPTION
Multimedia security for : Content Protection, Protecting copy rights of sender
Is the data
credible
Multimedia entertainment and security 10
Security in MMDigital Watermarking: Digital water marking is a process that
embeds an imperceptible signature or watermark in digital file containing audio, image, text or voice data.
Watermark can be a binary data, a logo or random numbers with a certain distribution.
Watermarking Algorithm
WatermarkedImage Ì
Stego-Image I
Watermark W
Secret / public key K
Multimedia entertainment and security 12
Advantages: Watermark is invisible Easy to detect and hard to remove Combats fraudulent use of wireless communications Authenticating the identity of cell phones and
transmission stations Secured delivery of mm applications (audio, video
and images);Disadvantages: Expensive Adds to the drain of the available energy in handheld
devices.
Multimedia entertainment and security 13
Issues:
Security in Image transfer
Security in Video transfer
Security in Audio transfer
Multimedia entertainment and security 14
Issue 1: Image Security
Reference: http://www.ics.uci.edu/~forge/papers/dac04.pdf
Issue :It is very easy to reproduce multimedia image with out damage, crop images and change the content of images.
Multimedia entertainment and security 18
Components :
Mobile or hand-held device Content Server ( stores multimedia and
data base content and stream data (say images) to a client as per requests.
Proxy servers – compress/decompress images, transcode video in real-time, provide/access directory services.
Multimedia entertainment and security 19
Implementation Step 1:There are three basic tasks in watermarking
with respect to imaging: Embedding:
Multimedia entertainment and security 20
DWTOriginal image
watermark
Watermarked image
Insertion procedure:
Multimedia entertainment and security 21
Steps 2 & 3: Detection and Extraction: Detecting
whether an image has a watermark and extracting watermark from the image by applying the reverse process of embedding.
Authentication : refers comparing the extracted watermark with the orginal watermark.
Multimedia entertainment and security 23
Wavelet- based Watermarking
Insertion and extraction procedure
Multimedia entertainment and security 24
Issue 2: Audio Security
Reference: www.fxpal.com/publications/FXPAL-PR-03-212.pdf
Unauthorized tapping, copying, redistribution, removal or embedding of data –Audio piracy
Multimedia entertainment and security 25
According to IFPI…… The water mark should not degrade the
perception of audio. The algorithm must offer more than 20dB
of SNR for water mark audio and 20 bps data payload for watermark.
The watermark must resist most common audio processing operations.
Watermark must prevent unauthorized copying, redistribution, removal or embedding of data –data piracy
Multimedia entertainment and security 27
Audio Watermarking Changing the time duration of an audio
sample with out changing the pitch or other spectral characteristics
These small amounts of time scale modifications are not noticeable.
Short time regions of the signal are either compressed or expanded by an imperceptible amount - “time base modulation”
Multimedia entertainment and security 29
How is it done??? Time-alignment of the watermarked and
reference audio produces a “tempo map” that indicates how the time base of the watermarked audio has been altered.
In regions of compression or expansion, the tempo map will deviate from a straight line and the embedded watermark data may be recovered from these deviations. Though this method will not work on audio with undetectable spectral change, such as silence,
Multimedia entertainment and security 32
Signal x(t) expressed as the concatenation of K non-overlapping blocks,x1…..k, with concatenation denoted by C.
The watermarked signal, xw(t)..
Multimedia entertainment and security 34
Issue 3: Video Security
Unlimited duplication, piracy and unauthorized access and distribution of video.
Reference: http://www.cse.cuhk.edu.hk/~lyu/paper_pdf/icdat05.pdf
Solution : Video Watermarking
Multimedia entertainment and security 35
Solution: Video Watermarking
Watermark remains intact even when the decrypted signal is converted from digital to analog.
Transparency : Invisibility of water mark with out affecting the video quality.
Robustness: watermark is not removable by any attacks, including frame dropping, compression, cropping, resampling.....
Multimedia entertainment and security 36
Implementation of Video watermarking Step 1: Video is taken as input , perform
scene change detection by histogram difference method.
Video divided into frames.
Multimedia entertainment and security 37
GOP - Frames 3 types of frames: I-frames (frames independent of other
frames). P-frames (frames predicted from I-frames). B-frames ( Between P-frames &i-frames for
motion compensation).
Multimedia entertainment and security 38
Watermark PreprocessIf size of image = 64.2p X 64.2q
p + q = n ; p, q<0; 2n≦m,
Divide the image into 2n small images with size 64 X 64
Multimedia entertainment and security 40
Implementation (contd..) Step 2: Applying DWT to video &
watermark.
Step 3: Embedding Algorithm :
Multimedia entertainment and security 41
Watermark embedding Some applications require real-time
watermark embedding. Frames with high degree of similarity
cannot have different watermarks. Embedding the same watermark in all
frames may be insecure. Embedding a watermark must not
significantly increase the data rate of the watermarked video stream.
Multimedia entertainment and security 44
Experimental results
Extracted watermark from different attacks
Dropping and averaging
Compression
Increase brightness
Cropping some regions
Dropping all frames with the 5th part of watermark
Multimedia entertainment and security 45
Is this a good approach????
Watermarked Video Frames
Watermarked Audio
Multimedia entertainment and security 46
Is this a good approach??? (contd..)
Difference in delays
Missing frames or audio packets
Attack against integrity
Lip synchronization
Multimedia entertainment and security 47
Combined Audio Video
watermarking
Synchronization based approach
Multimedia entertainment and security 48
Synchronization based approach: Inserts a time code as a watermark into
multimedia data in a efficient manner. time code format : hh:mm:ss:ff (f-frame) Well known synchronization time code is
SMPTE
Each position in a multimedia stream would include a complete timing information;
Multimedia entertainment and security 49
Implementation:Step 1: Inserting an absolute time code into
a/v streams.Absolute time
code
Relative time code
Multimedia entertainment and security 50
Range of time code {0-12},{0-59}, {0-59}
This can be encoded with 4+6+6 = 16 bits
01: 35: 45 = 00 01 11 101 100 101
Multimedia entertainment and security 51
Time code transferred to a Watermark
01:35:45 0001 011101 100101
Time
Secret key
Watermarking patternBit vector
Multimedia entertainment and security 52
Loop hole:
The features of audio/video content extraction are a subject to further research.
(The reliability of audio signal varies with different audio categories).
Multimedia entertainment and security 53
Conclusion & Future Direction: Watermarking is a good solution for
transfer of multimedia through an unsecured wireless channel and with out effecting the quality of data.
Watermarking can be improved with error coding and compression techniques.
Multimedia entertainment and security 54
References:[1]. Borko Furht, ”Challenges in Wireless Multimedia” CSE Department Seminar
Series, September 2003
[2]. Arun Kejrariwal, Sumit Gupta, Alexanderu Nicolau, Nikil Dutt, Rajesh, “Proxy based task Partitioning of watermarking Algorithms for reducing Energy
Consumption in Mobile Devices” October 2004
[3]. Jonathan Foote, John Adcock and Andreas Girgensohn, “Time Based Modulation: A new Approach to Watermarking”, July 2005
[4]. Pik-Wah Chan, Michael R.Lyu, “ Digital Video Watermarking with a genetic Algorithm”, computer science and Engineering Department, the Chineese University of Hongkong, March 2004
[5]. Jana Dittman, Martin Steinebach, Ivica Rimac, Stephan Fischer, and Ralf Steinmetz, “Combined video and audio watermarking: Embedding content information in multimedia data” GMD- German national research Center for Information Technology,