signals, using compression, reduces the required capacity of storage media, and it is directly
proportional to the size of compression. For archival purposes that significantly reduces the
required space and cost of the archive.
Techniques for accomplishing a reduction in the video size are mostly confined to compress
individual frames of content and techniques of writing changes and differences between
frames. Videos are usually composed of three types of frames: I-frames (
intra-
frames), P-
frames (
predicted-
frames) and B-frames (
bidirectional-
frames). The difference between different
types of frames is only in the write mode and read mode (the interpretation). During the
playing (displaying), each frame is shown as a normal image regardless of recording technique
of the video format. Intraframe or spatial compression is technique in the video compression
for reducing the size of individual frames. Interframe or temporal compression is a video
compression technique that achieves a reduction in size of similar series of frames [3].
The development of digital telecommunications allows the use of high-definition television
(HDTV) besides standard-definition television (SDTV). HDTV is a technology that offers
significantly higher quality of picture and sound than the traditional display technology did
(analog PAL, NTSC, SECAM, SDTV and digital). Since the resolution is higher, the image is
sharper, less blurry and the content is closer to reality. HDTV offers smoother movement,
detailed and more vibrant colors, and there is a very high-quality multichannel sound that
makes viewing experience even better.
Table 1 shows the basic characteristics of the primary
digital TV standards.
