2. 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.
4. How Actually Video Compression Works ?
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
5. LOSSLESS COMPRESSION:
SUM OF ABSOLUTE DIFFRENCES
The pixels of House is steady, So
not included in transmitted
video
6. SUM OF ABSOLUTE DIFFRENCES
A,B are the memory elements which 1 byte long and
256 element deep.
SAD
A
256-byte array
32-bits
B
Sad_Out
256-byte array
Go
CLOCK
By using Matlab R2012, we generate hex file which can be used for reading
hexadecimal numbers to initialize memories i.e. A & B
9. VERILOG IMPLEMENTATION
Sum = 0
I=0
!Go
S0
Go
S1
S2
I < 256
I > 256
SAD_Reg = Sum
S4
S3
Sum=Sum+ABS(A[I]-B[I])
I=I+1
10. 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
11. 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;
begin
ABS = (IntVal>=0)?IntVal:-IntVal;
end
endfunction
15. 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
Notes de l'éditeur
Good morning friends, as my friend said, 5d == 1 byte, 1byte * 256 == 256 byte