Introduction to Digital Video

An Introduction to Digital Video: Processing, Coding and Format

A brief introduction to digital video processing, coding and formats are presented here. The discussion contains:

- Introduction to analog and digital signals

- Introduction to video signals

- Digital video signals

- Digital video compression and compression standards

- Digital video standards: MPEG

- Frame formation

- Group of pictures (GOP)

- Temporal redundancy (Motion prediction)

The discussion is limited to basic information only.

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Selected parts of the presentation:

Necessity of video coding:

For high definition un-coded raw video at 1.3 Gb/s, a 90 minute movie will take storage space of:

(90 x 60) x 1.3 = 7020 Gbits = 877.5 G Bytes !!

Even a 90 minute movie at 30 frames per second at resolution 720 x 480 will take a storage space of 167.96 G Bytes !! So, raw digital video takes a very large storage.

The transmission of un-coded raw video requires very high bit rate ( for HD, up to 1.3 Gb/s ). But a even a high definition video channel is limited to 20 Mb/s bandwidth. So, the signal is 65 times the available bandwidth. For these reasons, un-coded transmission is not practical. Therefore, digital video coding is used to compress the signal and reduce the bit rate.

Bandwidth reduction by digital video compression:

Some digital video compression standards: