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 InformationDescriptionTypical value Frame rate# of image / sec.30 fps Image size# of pixels / image320 x 240 (VCD) 640 x 480 (DVD) Color depth# of possible color / pixel 24-bit Sound informationSampling 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 = x 10 8 B = 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 CodecApplication YearResolution DVHardware-encoded consumer video720 x 480 MPEG-1Primarily VCDs1992NTSC: 352 x 240 PAL: 352 x 288 MPEG-2DVDs and VCDs x 480 MPEG-4High-quality Web video1998 Real MediaReal-time streaming Web video Windows Media Video Real-time streaming Web video CinepakHigh-motion video, works on older computersVaries

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