|
TYPES OF VIDEO FORMATS AND THEIR
DIFFERENCES AND QUALITY
Jurayev Suhrobjon Salohiddin o'g'li
Tashkent University of Information Technologies named
after Muhammad Al-Khorazmiy Faculty of "Computer Engineering"
Department of
"Information and Multimedia
Technologies"
1st course Student of Master deegre
Mirzayeva Faxriya Shavkat qizi
Karshi branch of the Tashkent University of
Information Technologies named after Muhammad Al-Khorazmiy 2nd
year student
Shoniyozova
Yulduz Qahramon qizi
Karshi
branch of Tashkent University of Information Technologies named after
Mohammed
al-Khwarizmi Uzbekistan, Karshi 3rd
year student
Annotation: The progenitor of this format - MPEG-1, can not
hesitate to call it truly revolutionary, because nothing like it existed
before. The first video discs and satellite TV broadcasts in MPEG-1 format
seemed like a miracle - such quality at such a relatively low bitrate.
Compressed digital video had a quality comparable to that of a home VCR and had
a lot of advantages over analog media. But time passed, progress in the field
of digital technologies marched by leaps and bounds, and now the old man MPEG-1
needed a significant revision to keep up with the wonders of science and
technology.
Key words : MPEG-1 format, MPEG-2 format, DVD-discs, video
formats.
The result was the MPEG-2 format, which is not revolutionary, but rather
an evolutionary format, resulting from the rework of MPEG-1 for the needs of
customers. And the customers of this format were the largest mass media
companies, which relied on satellite television and nonlinear digital video
editing. This is now the MPEG-2 format is associated primarily with DVD-discs,
and in 1992, when work on the creation of this format began, there were no
widely available media on which it would be possible to record compressed
MPEG-2 video information, but most importantly, computer equipment of that time
could not provide the required bandwidth - from 2 to 9 Mbit per second. But
this channel could provide satellite television with the latest equipment for
those times. Such high requirements for the channel did not mean that the
compression ratio of MPEG-2 is lower than that of MPEG-1, on the contrary, it
is much higher! But the image resolution and the number of frames per second
are much higher, since it was the high quality with a reasonable bit rate that
was the main goal that the customers set for the MPEG committee. It is thanks
to MPEG-2 that the emergence of high-definition television - HDTV, in which the
image is much clearer than that of conventional television, became possible.
Several years after the start of work, in October 1995, the first
20-channel TV broadcast using the MPEG-2 standard was carried out via the Pan
Am Sat satellite television. The satellite has carried out and still carries
out broadcasting in Scandinavia, Belgium, the Netherlands, Luxembourg, the
Middle East and Africa. HDTV is currently undergoing extensive expansion in the
Far East in Japan and China. Compressed MPEG-2 video streams with a bit rate of
9 Mbps are used for studio recording and high-quality digital video editing.
With the advent of the first DVD-players with colossal storage capacity and
relatively affordable price, MPEG-2 was naturally chosen as the main video
compression format for its high quality and high compression ratio. It is films
that use MPEG-2 that are still the main argument in favor of DVD. Let's finish
with a retrospective review of MPEG-2 and try to delve into its internals. As
already mentioned, the MPEG-2 format is evolutionary, which is why it is
appropriate to consider it, comparing it with its eminent progenitor MPEG-1,
indicating what was new in the original format.
It must be said that the MPEG-2 developers approached the solution of
the problem in a creative way. The brainstorming session unleashed on the
search for the possibility of removing extra bits and bytes from an already
compressed image (remember, MPEG-1 already existed, now it was necessary to
shrink it) was started from three sides at once. In addition to improving the
compression algorithms for video (one side) and audio (other), an alternative
way to reduce the size of the final file was found, which had not been used
before.
As it became known from the studies of the MPEG committee, over 95% of
the video data, one way or another, is repeated in different frames, and more
than once. This data is ballast or, to use the term proposed by the MPEG
committee, redundant. Redundant data is removed with little or no damage to the
image; a single original fragment is substituted in place of the repetitive
sections during playback. Along with the already known algorithms for
compressing and removing redundant information, which we met in the MPEG-1
format, one more, apparently the most effective, has been added. After
splitting the video stream into frames, this algorithm analyzes the contents of
the next frame for duplicate, redundant data. A list of original parcels and a
table of duplicate parcels are compiled.
It
is also possible to load a separate quantization matrix just before each frame,
which allows for very high image quality, albeit quite time consuming. How can
I improve image quality using a quantization matrix? It's no secret that fast
moving areas are traditionally a weak point for the MPEG family, while static
areas of the image are encoded very well. From this it follows that it is
impossible to encode statics and areas with movement in the same way. Since the
image quality depends on the quantization stage, which largely depends on the
used quantization matrix, changing these matrices for different parts of the
video can improve the image quality.
REFERENCES
1.
Developing
a video game on the unity 3D platform ст 3-5 / FE Kodirov, FK Achilova - ФИЗИКО-МАТЕМАТИЧЕСКИЕ И ТЕХНИЧЕСКИЕ …, 2019.
2.
Производство компьютерных компонентов
промышленного видео производства ст – 270-272 / ФЭ Кодиров, ФК Ачилова, С Ахматова -
Инновации в технологиях и образовании, 2019.
3.
Adobe photoshop программа разработка
видео руководство по эксплуатации ст 237-240 / ФК Ачилова, ФЭ Кодиров, СЗ
Ахматова - Инновации в технологиях и образовании, 2019.
|
