Part A Multimedia Production

Rico Yu

Part A Multimedia Production

Ch.1 Text Ch.2 Graphics Ch.3 Sound Ch.4 Animations Ch.5 Video

Video

Properties of Video Video Sources Size of Video file Compression of video Video Streaming

1. Properties of Video

Full motion of recording Video player is needed Video vs Animation Quality of Video

Video vs Animation

Video– Continuous motion breaks up into still pictures

Animation– Still pictures combined to become a movie

Quality of Video

Information Description Typical value

Frame rate # of image / sec. 30 fps

Image size # of pixels / image 320 x 240 (VCD)

640 x 480 (DVD)

Color depth # of possible color / pixel

24-bit

Sound information Sampling rate and sampling size

44.1kHz 16-bit

2. Video Sources

Digital– From digital video camera (DV camcorder) and web

cam.

Analogue– From TV, Video Cassette Recorder (VCR) and

analogue camcorder

2. Video Sources

Video capture card– Digital

IEEE1394 or USB

– Analogue Composite cable (RWY)

3. Size of Video file

File size (uncompressed)= Image size x color depth in bit x Frame rate

x Duration / 8 bytes

3. Size of Video file

e.g. a 1 minute adv. recorded in 320 x 240 pixels, 24-bit color and 30 fps would have an uncompressed file size at least

= 320 x 240 x 24 x 30 x 60 /8

= 4.1472 x 108B

= 395.5MB

4. Compression of Video

Reasons for compression– reduce file size– enable live broadcast on Internet

Moving Picture Expert Groups (MPEG) Compression and Decompression (CODEC)

CODEC

Codec Application Year Resolution

DV Hardware-encoded consumer video 720 x 480

MPEG-1 Primarily VCDs 1992 NTSC: 352 x 240PAL: 352 x 288

MPEG-2 DVDs and VCDs 1994 720 x 480

MPEG-4 High-quality Web video 1998

Real Media Real-time streaming Web video

Windows Media Video

Real-time streaming Web video

Cinepak High-motion video, works on older computers

Varies

5. Video Streaming

Start displaying the data before entire file has been transmitted.

CODEC: MPEG-4 e.g. ASF, WMV, RM Can only view, can’t store