IBM Computer, Laptops and Servers

FILE FORMATS There are several audio file formats in common use. There are fewer video file formats, but audio video file extensions can be confusing. This is just a brief description of what the more commonly used audio and video file formats and systems are.

Laptop Battery AAC:Advanced Audio Coding This is the audio file format used by Apple for the iTunes Music Store, and it may appear with the M4A filename extension. It is better than MP3 for sound quality. It was developed as part of the MPEG4 group owned by Dolby (see below).

Any kind of file can contain a learning activity—Word documents, Excel spreadsheets, image files of all formats, video or audio files, and more.

Thinkpad AU: This audio file format is the standard used by Java, Sun and Unix.

"Computers today are capable of handling images, video and audio, " said Alice H. Chang, CEO of CyberLink Corp. "Unfortunately, there are lots of file formats for video, audio and images, and the end users might find it difficult to identify its type. Hence, CDWizard is created as an intelligent, audio files and to view image files as well."

Microsoft MPEG: Moving Pictures Expert Group There are a number of MPEG types now, described below.

Video recording Yes does the camera have a video recording option Video Recording data 640x480, 320x240, 30fps, 15fps the amount of time, resolution, etc. when the camera is recording video. Audio Inbuilt microphone Yes Enables the camera to record audio. Audio recording Yes indicates if the camera has the ability to record audio. File formats Image format JPEG (EXIF v. 2.2) the type of files your pictures are taken as (i.e. jpeg, tiff)

Laptop Computers MPEG-1: This is used in digital cameras and camcorders for small video clips. VHS quality playback can be expected from MPEG-1.

Laptop Computer MPEG-2: Used for digital satellite TV, professional movie recording and recording of home DVD recordings. Provides provision for multi-channel surround sound recordings.

Both .wav format and .mp3 format files are audio files, and to the best of our knowledge these audio file formats cannot contain viruses. Even if one did, streaming audio file formats such as wav and mp3. It appears that the virus check software is confused by what it finds in the audio file and is therefore incorrectly reporting this as an infected file. We are confident that these reports are false alarms.

Desktop Computer MPEG-3: MPEG-3 was propose as an entity, but eventually merged into MPEG-2.

Notebooks MPEG-4: This is the newest MPEG system and is used for streaming internet content. It is also used in portable video recorders and for internet downloads. Required for DivX. It improves digital broadcasting and interactive graphics and multimedia.

Lenovo MP3: Digital audio files, most commonly used to store and playback music. It compresses the files to about 10% of a normal audio file, and a normal music track will be about 5 -6 MB in size. MP3 stands for MPEG-1 Audio Layer 3, not MPEG-3 as many people think. A typical MP3 audio file is near CD quality.

Hard Drive OGG: An audio file format supporting a variety of codecs, the most popular of which is the audio codec Vorbis. However, MP3 files are much more broadly supported than Vorbis.

Travelstar RA: Real Audio This format is designed for streaming audio over the Internet. It is a self-contained file format with all the audio information stored within the file itself.

Gateway WAV: The simplest of the audio file formats, developed by Microsoft and IBM, and built into Windows 95. It is an uncompressed audio file format with large file sizes (10 x MP3), and does not need further processing to play. The WAV file consists of three blocks of information: The RIFF block which identifies the file as a WAV file, The FORMAT block which identifies parameters such as sample rate and the DATA block which contains the actual data, or music sample.

Laptop Parts WMA: Windows Media Audio A digital system invented by Microsoft, and is used in portable digital audio players. Using WMA, a file can be programmed so that it cannot be copied, and can be used to protect copyright.

Software WMF: Windows Media Format These are audio-video files comprising WMA and video codecs. They provide high quality and media security for streaming and download and play applications on computers.

Hard Drives WMV: Windows Media Video Used in the Windows media Player, this is used to stream and download and play audio and video content.

Electronics When dealing with audio and video file formats, you will sometimes notice the term 'codec'. A codec is simply short for encoder-decoder (or compressor - decompressor). A main function of a codec is to compress audio or video data streams so that transmission of digital audio samples and video frames can be speeded up and storage space reduced.

Canon The objective of all codecs is to reduce the file size to a minimum while maintaining audio and video quality. A quick indication of the codec's place in the path of transmission and reception is:

Desktop Pc Video device (e.g. camcorder) - video capture card - video digitized - codec (compresses digital info) - result (MPEG2, AVI, WMV etc) - codec (decompress) - video frames - display device.

Desktop Computers Between the two codecs the compressed result is transferred to the display device transmitted, stored on file, etc). So to condense the flow even further, we could basically describe it as:

Think Pad Raw data - codec - transmit - codec - play

Repair This is simplistic, but it shows where the codecs are used. Therefore, in order to play a movie, video or piece of music of a certain format, you need a codec in your computer to allow you to decompress the file and play it.

Data Recovery Peter Nisbet has written many articles on audio and video file formats and their transmission. decoding, playback and conversion. More info on his websites http://www.legalandfree.com and http://www.online-free-movies.com

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