IT152_Lecture_2_Multimedia_delivery_2013a Flashcards
Currently Internet for multimedia on NZ is less suitable than DVD - why?
- Relatively slow connections
- No guarantee that site visitors have multimedia capable computers.
- Plug-ins usually required - problematic
- Security issues
- Data integrity
- Legal ownership of media.
Large files can be unusable through modem connections because…?
- Modem: 56 Kbps
- CDROM (single speed) transfers data to 150Kbps
- 1x speed rating for DVDs is 1.32 Mbps
- To put bandwidth in perspective, most broadband users surf at less than the speed of a single-speed CD-ROM drive.
- Faster Broadband AND technologies such as streaming / compression needed.
Dealing with Slow Transfer Times - What can you do to solve this?
- Compress files using different format GIF, JPEG, MPEG.
- Use a Codec (= ‘Co’mpression ‘Dec’ompression) to reduce file up to 90% but also reduces quality.
- Use lower-quality elements to reduce sizes.
- Reduce bit-depth/physical size. - Combine Optical Disk and Internet delivery.
Browsers don’t natively support…?
Audio, Video, or Sophisticated animation.
(Additional programs are often needed to view Multimedia elements such as helpers and plug-ins, some organisations don’t allow plug-ins, plug-ins often don’t work due to version/ OS issues)
How is a helper different to a plug-in?
Helper applications display the element in a separate window, Plug-ins display the element in the browser window. (Fortunately, more than 90% of current browsers view Flash and the Swf or Shockwave format.
Some common viewers-helpers and plug-ins include…?
- Windows Media Player for a range of files such as .avi
- Mpgeplay for .mpg movie files
- QuickTime Viewer 32 for .mov movie files
- RAplayer for RealAudio .rm and .ra files
- Viewer32 for Adobe postscript .pdf files
- Shockwave for Flash .swf files
- Neuron for Asymmetric Toolbook .tbk files
Flash is an authoring tool used in…?
Multimedia mainly for animation. (Can create very small files for Internet playback)
Director, is industry standard optical disk authoring tool and creates…?
Shockwave content for Internet, current browsers have the Shockwave Flash plug-in
Most browsers read only…?
Bitmapped, JPG, GIF, and PNG image files.
PNG is an…?
Open format supported by most image creation programs.
Joint Photographic Experts Group (JPEG) uses lossy compression to …?
Produce files of small size from natural images.
GIF is useful for..?
Solid blocks of colour limited to 256 colours.
Plug-ins that enable viewing of vector formats (such as Flash) are…?
Useful.
Vector graphics are…?
Device-independent. (An image is displayed at the correct size and with colors supported by the computer.)
When creating images bound for the Web, use a resolution of…?
72 pixels per inch.
Animated text can be done through…?
XHTML
DHTML allows for…?
animation effects.
Animated GIFs are…?
small and efficient.
Directory or Flash (SWF format) movie usually require…?
plug-ins
3-D environments (VRML, Quick Time VR) require…?
plug-ins
Formats are…?
SWF, GIF89a, MOV, MPEG, AVI, MNG
GIF89a format specification creates…?
Simple animations. (It integrates multiple images, or frames, into a single GIF89a file and displays them with programmable delays between them.
Internet is not suitable for high quality video due to…?
low bandwidth.
Webcam can record at…?
56kbps but poor quality. Needs 128k+
Broadcast video …?
384k min needed for watchable quality but ideally 512k needed for smaller screaps and 1Mbps for larger screens.
Formats developed for web include…?
ASF, AVI, MPEG, MP4, MOV, RM and WMV.
Codecs are…?
Indeo, MPEG (incl. divX), Sorenson, DVI, H264)
Kbps stands for…?
kilobits per second transfer (1000 bits)
WMV is used by…?
Windows Movie Maker
MPEG-1 Part 2: Used for…?
Video CDs, and also sometimes for online video. (The quality is roughly comparable to that of VHS. Almost every computer in the world can play this codec, and very few DVD players do not support it.)
MPEG-2 Used on…?
DVD and in another for for SVCD and used in most digital video broadcasting and cable distribution systems. (When used on a standard DVD, it offers good picture quality and supports widescreen. Will also be used on HD-DVD and Blu-Ray. In terms of technical design, the most significant enhancement in MPEG-2 relative to MPEG-1 was the addition of support for interlaced video. MPEG-2 is now considered an aging codec, but has tremendous market acceptance and a very large installed base.
MPEG-4 Part 2: An MPEG standard that can be used for…?
Internet, broadcast, and on storage media. It offers improved quality relative to MPEG-2. Like MPEG-2, it supports both progressive scan and interlaced video.
MPEG-4 Part 10. This emerging new standard is the current state of the art and is rapidly gaining adoption into a wide variety of applications. It contains…?
a number of significant advances in compression capability, and it has recently been adopted into a number of company products, including for example the Playstation Portable, the Nero Digital product suite, Mac OS X v10.4, as well as HD-DVD/Blu-Ray.
DivX, XviD and 3ivx are…?
Video codec packages basically using MPEG-4 Part 2 video codec, with the *.avi, *.mp4, *.ogm, or *.mkv file container formats.
High quality music is not suitable for the Internet because…?
- Is encoded at 256-384+kbps which is ok for CD player (reads at 300kbps) but not general Web.
MIDI sound files are more…?
compact, but they depend upon the computer’s MID setup for quality.
Sound elements may also…?
Be embedded into projects made with various authoring tools.
Digitized sound files in MP3, WAV, AIF, or AU formats may be send and played on a users computer from…?
Internet.
Plug-ins allows embedding of…?
sounds into HTML documents.
Internet Explorer offers the tag to play…?
an AU, WAV, or MIDI sound track in a document background.
Netscape and Internet Explorer offer the QuickTime plug-in for…?
Playing AIFF, MIDI, WAV, and AU formats. (Streaming audio is more useful for the Web, where a sound file can start playing as soon as data begins to download.)