Image processing using software packages

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COMPARISON & EVALUATION BENCHMARKS BETWEEN
DIFFERENT VIDEO COMPRESSION FORMATS
REPORT [3]
LAMA MAHMOUD
Khalifa University of Science, Technology and Research
Electronics and Computer Engineering Department (ECE)
ELCE 491: Independent Study
Fall Semester / 2013-2014
A report submitted to Dr. Andrzej Sluzek as a one of the independent study course reports
Note:
A DVD disc which contains some
relevant files related to this report is
required in order to be able to fully
understand the report contents.

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CONTENTS
ABSTRACT.................................................................................................................................... 3
CHAPTER [1]: Experiment [1] ...................................................................................................... 4
CHAPTER [2]: Results and Analysis............................................................................................. 4
CHAPTER [3]: Experiment [2] ...................................................................................................... 6
CHAPTER [4]: RESULT & ANALYSIS....................................................................................... 6
Experiment [1]: .avi Format........................................................................................................ 7
Experiment [2]: .wma Format..................................................................................................... 8
Experiment [3]: .mpeg Format.................................................................................................... 9
Experiment [4]: .mov Format.................................................................................................... 10
CHAPTER [5]: Experiment [3] .................................................................................................... 10
CHAPTER [6]: CONCLUSION................................................................................................... 10
REFERENCE................................................................................................................................ 11
LIST OF FIGURES AND TABLES
Figure 1: Original image for experiment 1 ..................................................................................... 4
Table 1: The tested image with the most three different degradations in the image quality .......... 5
Table 2: The 4 experiments for testing the effect of video format standards on the video quality…….. ...7

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ABSTRACT
Having already understood the motivation and objectives behind both image and video
compressions concepts, got familiarized with the mostly used video compression formats and
finally discussed the properties, advantages & disadvantages of different video compression
algorithms; this report aims to compare between the different video compression algorithms
using a practical approach.
In fact, this report comprises two practical experiments & both experiments were
conducted by using some of the online available image/video compression tools. Technically, the
first experiment aims to test the effect of having a lossy versus a lossless image format.
Consequently, the second experiment aims to clarify the importance of choosing a suitable video
file format along with the desired application. Clearly, this depends mainly on the desired
resolution, bandwidth and storage. From both experiments, it could be concluded that an image
or a video file format might be selected depending mainly on the desired application in which the
resolution, file storage, bandwidth and bitrate matter.

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CHAPTER [1]: Experiment [1]
There are two basic categories of compression; lossless and lossy. Lossless compression is a
class of algorithms that will allow for the exact original data to be reconstructed from the
compressed data. That means that a limited amount of techniques are made available for the data
reduction, and the result is limited reduction of data. GIF is an example of lossless images
compression. Lossy compression on the contrary means that through the compression data is
reduced to an extent where the original information cannot be obtained when the video is
decompressed. The difference is called the artifacts. PNG format is an example of the lossless
compression and JPEG format is an example of the lossy compression.
In this experiment, an image (see figure 1) with a resolution of 1920 x 1080 and size of
211 KB in JPEG was used to test the effect of choosing a lossless versus a lossy image format
experiment. Simply, the experiment was started by alternatively changing the original image
format from JPEG (i.e. lossy format) to PNG (i.e. lossless format).
CHAPTER [2]: Results and Analysis
Every time the image is converted from JPEG format to PENG format, some of the image
information will be lost which will be obviously reflected in a degraded resolution and a smaller
image size. In order to compare with, the altering from one format to another was altered for
approximately 100 times.
Table (1) below shows how the original image resolution was degraded as well as the size was
reduced. It could be concluded from this experiment that PNG format would be more useful for
the applications in which an image could be modified. For example, adding a watermark and
hiding information inside the image’s least significant bits would cause changing in the image’s
special domain. So that, using PNG format will give some flexibility of retrieving the original
image without needing the initial image file.
Original Image
Size: 211 KB
Resolution: 1920 x 1080
Format: JPEG
Figure 1: Original image for experiment 1

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Table 1: The tested image with the most three different degradations in the image quality
No. Image Format Description
1 JPEG 211 KB
2 PNG 64 KB
3
PNG 38 KB

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CHAPTER [3]: Experiment [2]
Ultimately, each video format algorithm has its own advantages and disadvantages. Henceforth
and similarly to the image compression case described in the earlier sections of this report, the
choice of choosing a video format depends mainly on the desired application. Consequently, the
aim of this experiment is to examine how different video compression format algorithms will
result in different interpretations in terms of the compression ratio, frame rate, resolution and
data rate. Namely, with the aid of one online available software called “Prism”, a certain video
file was converted to the four most commonly used video formats which are .avi, .wma, .mpag,
.mov and .3gpp. Furthermore, in order to conduct a more informative comparison, within each
video format algorithm, the sub-properties of the video format itself were changed for the worst
case scenario and for the best case scenario respectively.
Tip: The reader may review the original video file that is used for this experiment. In order to be
able to have a distinct comparison, it is advised to carefully observe the video’s sound and
frames quality.
CHAPTER [4]: RESULT & ANALYSIS
In this section, observations and analysis of each video compression format will be discussed.
Table 2 below shows the details of every experiment along with the video/sound compression
format and the resultant compression ratio. It should be noted that all the video files in this
experiment are included in the attached DVD disc to this report.

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Experiment[1]Experiment[2]Experiment[3]Experiment[4]
Table 2: The 4 experiments for testing the effect of video format standards on the video quality
Experiment [1]: .avi Format
To begin with, the “avi” format stands for Audio-Video Interleave & it was first introduced by
Microsoft in 1992. AVI files can contain both audio and video data in a file container that allows
synchronous audio-with-video playback. Like the DVD video format, AVI files support multiple
streaming audio and video, although these features are seldom used. Most AVI files also use the
file format extensions developed by the Matrox OpenDML group in February 1996.
In this experiment, the original video file was converted into the avi format & some video
and audio encoder settings were altered for the sake of testing. In the first avi formatted video,
Exp. # Format Frame
Rate/
Second
Sound Format File Size Video
Format
(Data Rate)
Compression
Ratio
1
1. .avi
Format
.avi 5 8000Hz
8kbps
mono
589 KB 72 kbps
13.7 %
2
2. Avi
Format
.avi 5 48000Hz
320kbps
stereo
2716 KB 49kbps
2.97 %
1
1. wma
Format
.wma 5 8kHz
4kbps
mono
3030 KB 512 kbps
2.66 %
2
2. wma
Format
.wma 5 32kHz
32kbps
2 channels
16 CBR
3912 KB 16384 kbps
2.06 %
1 1. mpeg .mpeg 23 32 kHz
32kbps
7572 KB 1150 kbps 1.065 %
2
2. mpeg .mpeg 23
38kHz
384Kbps
13650 KB 9000 Kbps
0.6 %
1 1. mov .mov 5 4 kbps 699 KB 34 kbps
11.54%
2
2. mov .mov 5 320Kbps 37476 KB 4962 kbps
0.22%

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the sound format was changed to a relatively poor sampling frequency which is 8 KHz, bit rate
was also changed to a poor bit rate about 8k bit/second and finally sound quality was changed to
mono ( a single channel). As a result, it could be observed that the sound quality of the video was
degraded. On the other hand, in the second avi formatted, the sound quality was generally much
higher than the first avi formatted file. Mainly, the following parameters where changed; the
sampling frequency was set to 48 KHz, bit rate was set to be 321 K bit/second and the sound
quality was stereo (two channels). Clearly, when comparing the sound in both avi files, it could
be easily observed that second video got a higher sound quality than the first video.
With respect to the video format, both files were set to a relatively very low frame rate;
typically 5 frames/second. However, the video data rate was 72 K bit/second & 49 K bits/second
for the first and second videos respectively. In fact, the difference in the video data rate was not
really observed when watching both videos. However, it could be clearly noticed that the video
quality of both avi formatted files was low due to the low frame rate.
Needless to say, the degradation of the both the sound and video quality of both the avi
formatted files is reflected upon their sides. The video sizes were reduced to 589 KB and 2716
KB for the first and second avi formatted files respectively. Hereafter, the compression ratio is
about 13.7% and 2.97% respectively. The high compression ratio of the first video could be
referred to the high degradation in the sound quality compared to the second video.
Experiment [2]: .wma Format
To begin with the history of the .wma format, Windows Media Audio (WMA) is an audio data
compression technology developed by Microsoft. The name can be used to refer to its audio file
format or its audio codecs. It is a proprietary technology that forms part of the Windows
Media framework. WMA consists of four distinct codecs. The original WMA codec, known
simply as WMA, was conceived as a competitor to the popular MP3 and Real Audio
codecs. WMA Pro, a newer and more advanced codec, supports multichannel and
high resolution audio. A lossless codec, WMA Lossless, compresses audio data without loss of
audio fidelity (the regular WMA format is lossy). WMA Voice, targeted at voice content, applies
compression using a range of low bit rates.

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Similarly to the previous avi experiment, in this experiment, the sound quality of the first
wma formatted file was lowered down and in contrary, the sound quality was better for the
second wma formatted video file. For the first wma file, sound quality was 8 KHz for the
sampling frequency, 4 K bit/second for the bit rate and mono sound quality. While, for the
second wma video, the sampling frequency was 32 KHz, same bit rate as the first video and 2
sound channels with 16 CBR. When watching both video and comparing the sound quality of
both, it could be noticed that the first video’s sound quality is really bad and even it disturbs. The
second video file sound quality was much better and actually very close to the original un-
formatted file.
In regard with the video quality, both videos had same frame rate (5 frames/ second).
However, the video data rate was512 K bits/second and 16384 K bits/second for the first and
second wma formatted files. As a result, the video quality for the first file is better than the
second one.
With respect to the file sizes of both files, the first file was compressed around 2.66% and
the second file was compressed for around 2.06%. Both files have had almost the same
compression percentage which means that reducing the sound or video quality will have low
impact on the size of a video file if it was in wma format.
Experiment [3]: .mpeg Format
MPEG format is one of the most famous video formats. In fact, The Moving Picture Experts
Group (MPEG) is a working group of experts that was formed by ISO and IEC to set standards
for audio and video compression and transmission.
Having already altered the sound quality in the last two experiments (i.e. .avi and .wma
formats), in this experiment, the sound sampling frequency format was almost the same for both
of the mpeg-formatted files; typically, 32 kHz versus 28 KHz for the first and second videos
respectively. However, the sound bit rate was 32 Kbits/second and 384Kbit/second for the first
and second mpeg formatted files respectively. On the other hand, the frame rate was 23
frames/seconds for both files. Finally, compression ratio for the first file was only 1.065% and
0.6% for first and second files respectively. It could be concluded that the sizes of both files were
not really affected by the degradation in the sound and video qualities of both files.

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Experiment [4]: .mov Format
MOV video file is a common multimedia format often used for saving movies and other video
files, using a proprietary compression algorithm developed byApple Computer, compatible with
both Macintosh and Windows platforms. The format specifies a multimedia container file that
contains one or more tracks, each of which stores a particular type of data: audio, video, effects,
or text (e.g. for subtitles). Each track either contains a digitally-encoded media stream (using a
specific format) or a data reference to the media stream located in another file. Tracks are
maintained in a hierarchical data structure consisting of objects called atoms. An atom can be a
parent to other atoms or it can contain media or edit data, but it cannot do both. Because both the
MOV and MP4 container formats can use the same MPEG-4formats, they are mostly
interchangeable in a QuickTime-only environment.
To compare with, in this experiment, the sound format was only 4 Kbits/ second for the
first mov file while it was 320 Kbits/second for the second file. The video data rate was 34
Kbits/second for the first file and 4962 Kbits/second for the second file. As a result, the first
video had a very low video quality in which the edges of the objectives on the video are totally
blurry. However, the second video seemed to be better than the first one but still not as good
video quality as the original video.
With respect to the compression ratio, since the first video had a degraded quality, its
compression ratio was 11.54% while it was only 0.22% for the second video (higher quality).
CHAPTER [5]: Experiment [3]
In this experiment, the aim was to check the effect of changing the sound frequency. Definitely,
it is know the higher frequencies will give an indication of a more-like female singer while the
lower frequency will give an indication of a more like male singer. This result was exactly the
same for the two tested file (please refer to the attached DVD file to this report to watch both
videos).
CHAPTER [6]: CONCLUSION
Finally, it could be concluded that even though compression techniques will serve in reducing
the memory needed to store the video files, the overall quality might suffer. As was shown in the
earlier sections of this report, the degradation in the video quality depends on the choice of the

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compression algorithm. Hereafter, the best solution is to compress the video and having an
unnoticeable degradation in the desired video quality such as the resolution, bit rate,
frames/second & sound quality.
REFERENCE
[1] “PRISM video convertor” Software. Free download online:
http://www.nchsoftware.com/prism/