Digital Media: Voice, Video, Images, Quantities and Text

The converged network carries all media: voice, video, text and images in packets. An essential first step is digitizing the media, representing it using 1s and 0s, to be carried in said packets.

We’ll first understand analog vs. digital, how voice is digitized and reconstructed, the G.711 64 kb/s and AMR codec standards. The same principles apply to images and video in formats like jpg and mp4 video.

We’ll make sure you are up to speed on binary and hexadecimal for quantities, and finish with ASCII and unicode for coding keystrokes and emojis.

Telecom Module 6

Detailed Outline

6 Digital Media: Voice, Video, Images, Quantities, Text

6.1 Analog and Digital: What do we really mean?

..... 6.1.1 Analog Signal

..... 6.1.2 Analog Circuit

..... 6.1.3 Digital Signal

..... 6.1.4 Digital Circuit

..... 6.1.5 Bandwidth

6.2 Continuous vsDiscrete Signals

..... 6.2.1 Continuous Signals

..... 6.2.2 Discrete Signals

6.3 Voice Digitization (Analog-Digital Conversion)

..... 6.3.1 Quantization

..... 6.3.2 Sampling

..... 6.3.3 Coding

6.4 Voice Reconstruction (Digital - Analog Conversion)

..... 6.4.1 Reconstruction

..... 6.4.2 Quantization Error

..... 6.4.3 Aliasing Error

6.5 Voice Digitization: 64 kb/s G.711 Standard

..... 6.5.1 256 Quantization Levels

..... 6.5.2 8,000 Samples per Second

..... 6.5.3 8-bit Coding

..... 6.5.4 64 kb/s G.711 Codec Standard

..... 6.5.5 64 kb/s DS0 Channels

..... 6.5.6 64 kb/s Packetized Voice

..... 6.5.7 AMR Codec for Cellular

..... 6.5.8 mu-law and a-law

6.6 Digital Video, H.264 and MPEG-4

..... 6.6.1 Digital Video Cameras

..... 6.6.2 Factors Affecting Video Quality

..... 6.6.3 Definition vsResolution

..... 6.6.4 Standard Definition, Interlaced and 480i

..... 6.6.5 High Definition, Progressive and 720p

..... 6.6.6 Full HD 1080 and 2K

..... 6.6.7 Ultra HD, 4K, 8K, … 4M

..... 6.6.8 Compression

..... 6.6.9 MPEG

..... 6.6.10 MPEG-4 and H.264

6.7 Digital Images: JPEGs and GIFs

..... 6.7.1 Lossless Compression: PNG

..... 6.7.2 Lossy Compression: JPEG and GIF

6.8 Digital Images in Email: MIME

..... 6.8.1 UUENCODE, Quoted-Printable and Base-64 Encoding

6.9 Digital Quantities: Number Systems

6.10 Digital Quantities: Binary

6.11 Digital Quantities: Hexadecimal

..... 6.11.1 Common Use for Hexadecimal

6.12 Digital Text

..... 6.12.1 ASCII

..... 6.12.2 Unicode