VIdeo Compression using sum of Absolute Difference
-
Upload
dhaval-kaneria -
Category
Technology
-
view
462 -
download
4
description
Transcript of VIdeo Compression using sum of Absolute Difference
VIDEO COMPRESSION: SUM OF ABSOLUTE DIFFRENCES
PRESENTED BY:
1. NIKUNJ HINSU2. DHAVAL KANERIA
What is VIDEO ? The technique in which images are recorded, manipulated and
displayed in a motion.
Persistence of Vision Plays an vital Role
An image shown to any human persists for 1/25th second on the retina, So if images are shown at a rate of 25 pictures per second then we wouldn’t be able to perceive the blank spaces.
A Cinema Film Roll comprises of Pictures or Frames only
Roll is projected onto screen at very high rateWhich gives feeling of Motion Picture
WHAT IS DIGITAL VIDEO?
Digital Video refers to the capturing, manipulation and storage of video in digital formats (MPEG, .avi, .mkv, etc.).
A digital video camcorder (Sony Handi-Cam ©), for example, is a video camera that captures and stores images on a digital medium
When Digital Video are transferred & modified over INTERNET the size of video really matters in terms of accessibility. So video compression is required to reduce the size upto reasonable extent
How Actually Video Compression Works ?
Compression
Lossless (Intra-Frame) Lossy (Inter-Frame)
No lose of information
Compression is comparatively low
Redundancy in consecutive frames is removed by SAD
Lose of information Occurs
Compression is comparatively high
Size compression occurs by discarding the data of frames in a video, it will ultimately reduce the quality of video.
It is used in internet telephony, video conference
LOSSLESS COMPRESSION: SUM OF ABSOLUTE DIFFRENCES
The pixels of House is steady, So not included in transmitted video
SUM OF ABSOLUTE DIFFRENCES
B
A
Go
SAD
Sad_Out
256-byte array
256-byte array
32-bits
CLOCK
A,B are the memory elements which 1 byte long and256 element deep.
By using Matlab R2012, we generate hex file which can be used for reading hexadecimal numbers to initialize memories i.e. A & B
VERILOG IMPLEMENTATION
module SADSAD(Go, outp, Clk, Rst);input Go;output reg [31:0] outp;input Clk, Rst;
reg [7:0]A [0:255];reg [7:0]B [0:255];reg [2:0]State;integer Sum, SAD_Reg;integer I;
S0 S1 S2
S4 S3
I = 0!Go
Go
VERILOG IMPLEMENTATION
I > 256
Sum=Sum+ABS(A[I]-B[I])I=I+1
I < 256
SAD_Reg = Sum
Sum = 0
VERILOG IMPLEMENTATION
initial $readmemh ("lenaorignal.txt", A);initial $readmemh ( "distorted.txt", B);
Program will start taking SAD when “GO” Pulse is being Provided
S3: begin
Sum <=Sum +ABS(A[I]-B[I]); I<= I+ 1; State <=S2;end
VERILOG IMPLEMENTATION
Function ABS depicts the Absolute Value for converting a negative difference of A & B into positive difference
function integer ABS;input integer IntVal;beginABS = (IntVal>=0)?IntVal:-IntVal;endendfunction
Xilinx Waveform
Xilinx Waveform
Xilinx Waveform
Conclusion:
Thus we successfully implemented VIDEO COMPRESSION ALGORITHM by using SUM of Absolute Differences
By using this algorithm we would be able to significantly reduce the size of VIDEO
Applications:1. Video Conferencing like Skype, Cisco WebEx
2. Video Streaming Websites like YouTube
3. Video-on-demand, Video surveillance
4. Digital storage media CD-ROM, DVD, BluRay