1. How video works
Atsunori Tezuka s1180026
The common understood that it is difficult for the
specification of the video file. This time, I want to
introduce the video files.

2. Special mechanism for video files
● A video file is a file that different from the
character information file and image files in
general. You can open the file in notepad.
● On the PC, scheme called mark that
represents the software that can play and edit¨
can be established in this way. But movie file
may this schema does not hold.

3. Configuration of the video file
● When you play in the GOM PLAYER software
such as video files, the audio will be played at
the same time in addition to the video. If video
files, two types of data referred to as "audio
data" and "image data" is basically a
combination, it may be played simultaneously
by being seen as "normal video".
● Is due to this mechanism is that there is a
screen called "black only" sound to flow
"sound is not in the video are seen."

4. Configuration of the video file
● When playing a video file, you may not have
to judge absolute reference software to play
the "Can I play, I can not," the video file to the
[extension].
● Video in extension is made of two on the
judgment of "Can I play audio" "Can I play a
video portion", based on rough.
● This point is part of a general document and
video files, image files and still images is
significantly different.

5. Compression and decompression of
audio part1
● Video data of the video file is a collection of
still images in fact.
● Still images are displayed one by one in
sequence and picture cards, as fluently
cartoon being played as a moving image.
● Therefore, video data pieces thousands of
video, it is a mechanism that is still even tens
of thousands of copies are stored.

6. part2
● n the intact state (uncompressed), video data
is a collection of still images is, it becomes a
very large file size. There will also be
hundreds of GB of video data, such as an
hour was allowed to set a still image of a
single 500KB becomes, for example.
● Are treated in a state therefore, the video file
is "compressed" in principle. We can handle
the file size of 1/1000 and 1/100 the
uncompressed file size than by
"compression".

7. part3
● Video data that has been "compressed", as
well as comparison with the data of
uncompressed state, becomes assumed that
the quality of the image quality falls
compression to reduce the quality degradation
of image quality even when compressed by
technology advances far have been
developed one after another way.

8. part4
● Be reduced to 1/100 the file size by
compression, and compression method
almost does not degrade the image quality
compared to the non-compressed state is
widespread, for example.
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● end