This slides explains about multimedia data types and the types of compression techniques

1. Chapter2:
MultimediaDataFormatsandBasic
Compression
Dr
.RuzianaBintiMohamadRasli

2. OverviewofMultimedia
DataTypes
• Multimedia encompasses various forms of content,
including text, images, audio, and video.
• Each type of multimedia data can be stored and
transmitted in different formats, each optimized for
specific uses, devices, or platforms.
• Understanding these formats is essential for working
with multimedia in different contexts, whether in
media production, web development, or general
digital communication.

3. OverviewofMultimedia
DataTypes
Multimedia data types include:
1) Text: Characters, numbers, and symbols used for
communication.
2) Images: Visual representations of data, such as
photographs, graphics, or illustrations.
3) Audio: Sound, including music, speech, and sound
effects.
4) Video: Moving images, often accompanied by sound.
This subject focuses on the most common formats for
audio, video, and image data types.

4. CommonAudioFormats
Audio formats encode sound into a digital form, preserving the quality while managing file size.
The primary categories are uncompressed, lossless, and lossy formats.
- Uncompressed Audio Formats:
- WAV (Waveform Audio File Format):
- Developed by Microsoft and IBM, WAV is a widely used format for raw, uncompressed
audio.
- High-quality sound, suitable for professional audio editing, but large file sizes.
- AIFF (Audio Interchange File Format):
- Developed by Apple, AIFF is similar to WAV but primarily used on macOS.
- High-quality sound with large file sizes.

5. CommonAudioFormats
- Lossless Compressed Audio Formats:
- FLAC (Free Lossless Audio Codec):
- Compresses audio without losing any data, making it ideal for audiophiles.
- Smaller file sizes than uncompressed formats, while maintaining original quality.
- ALAC (Apple Lossless Audio Codec):
- Apple’s version of lossless compression, used in iTunes and compatible devices.
- Retains original quality with reduced file sizes.

6. CommonAudioFormats
- Lossy Compressed Audio Formats:
- MP3 (MPEG Audio Layer III):
- The most popular audio format, widely used for music and online streaming.
- Balances sound quality and file size, making it ideal for storage and distribution.
- AAC (Advanced Audio Coding):
- Developed as a successor to MP3, offering better sound quality at similar bit rates.
- Commonly used in Apple devices, YouTube, and streaming services.

7. CommonVideoFormats
Video formats consist of a container (file type) and codec (compression technology) that
store and manage both video and audio data.
- MP4 (MPEG-4 Part 14):
- A widely used format that supports high-quality video and audio.
- Compatible with almost all devices and platforms, making it ideal for sharing and
streaming.
- Uses the H.264 or H.265 codec for compression.
- AVI (Audio Video Interleave):
- An older format developed by Microsoft, offering high-quality video.
- Larger file sizes compared to modern formats; not as commonly used today.
- Compatible with most Windows-based devices and software.

8. CommonVideoFormats
- MKV (Matroska Video):
- An open-source format supporting multiple audio tracks, subtitles, and metadata.
- Popular for HD video content and streaming; offers flexibility and high-quality storage.
- Supports various codecs like H.264, H.265, and VP9.
- MOV (QuickTime Movie):
- Developed by Apple for QuickTime, commonly used for video editing and production.
- High-quality video, often used in professional environments.
- Supported on macOS and iOS devices, with some cross-platform compatibility.
- WMV (Windows Media Video):
- Developed by Microsoft, optimized for Windows-based applications.
- Used for streaming and online video; offers good compression with decent quality.
- Less compatible with non-Windows devices.

9. CommonImageFormats
Image formats store visual data in various ways, depending on their intended use, whether for photography,
web design, or graphic arts.
- JPEG (Joint Photographic Experts Group):
- The most common image format, widely used for photographs and web images.
- Uses lossy compression, balancing image quality and file size.
- Best suited for images with gradients and a wide range of colors.
- PNG (Portable Network Graphics):
- A lossless compression format, ideal for web graphics, logos, and images requiring transparency.
- Retains image quality without data loss, but larger file sizes compared to JPEG.
- Supports transparency, making it useful for overlays and icons.

10. CommonImageFormats
- GIF (Graphics Interchange Format):
- Popular for simple animations and short looping videos.
- Limited to 256 colors, making it suitable for simple graphics, icons, and short animations.
- Supports transparency and small file sizes.
- BMP (Bitmap Image File):
- An uncompressed format that stores detailed image data.
- Produces large file sizes with high-quality images, often used in printing.
- Less common today due to its large file size and lack of compression.
- TIFF (Tagged Image File Format):
- A lossless format, commonly used in professional photography and publishing.
- Supports high-quality images with extensive detail, ideal for editing and printing.
- Larger file sizes, often used when quality is a priority over file size.

11. Selectingtherightformat
• Audio: For music distribution, MP3 or AAC are preferred due to their balance
of quality and size. For archiving or professional editing, FLAC or WAV are
better choices.
• Video: MP4 is the most versatile, suitable for streaming, sharing, and storage.
For high-quality or multi-track needs, MKV or MOV might be appropriate.
• Image: JPEG is ideal for photos on the web, PNG for images requiring
transparency, and TIFF for print-quality images.

12. IntroductiontoCompression
Compression involves encoding information using fewer bits than the original representation. The primary
goals are to reduce file size, conserve storage space, and improve transmission speed. Compression
algorithms work by identifying and eliminating redundancies, either by removing repeated patterns (in
lossless compression) or by approximating data (in lossy compression).
- Compression Ratio: A key metric in compression, representing the ratio of the original data size to the
compressed data size. A higher compression ratio indicates more efficient compression.
- Redundancy: Refers to the repetitive or unnecessary data within a file that can be reduced or eliminated
without losing essential information.
- Entropy: The measure of unpredictability or randomness in data. High entropy means less redundancy,
making it harder to compress.
- Bitrate: Often used in multimedia, it represents the number of bits processed per unit of time. Lower
bitrates typically result in smaller file sizes, though they may reduce quality in lossy compression.

13. TypesofCompression:Losslessvs.Lossy
Compression techniques can be broadly categorized into two types: lossless and lossy. Each has distinct characteristics and applications.
a. Lossless Compression
Lossless compression reduces file size without losing any data. The original data can be perfectly reconstructed from the compressed data.
This method is ideal for scenarios where data integrity is crucial, such as text files, software, and some image formats.
- How It Works: Lossless compression algorithms work by finding and eliminating redundancy within the data. Common techniques include:
- Run-Length Encoding (RLE): Compresses data by replacing sequences of repeated elements with a single element and a count. For
example, "AAAABBBCCDAA" becomes "4A3B2C1D2A".
- Huffman Coding: Uses variable-length codes to represent more frequent elements with shorter codes, reducing the overall number of
bits.
- Lempel-Ziv-Welch (LZW): Builds a dictionary of patterns found in the data and replaces repeating patterns with shorter codes.
- Examples:
- ZIP: A widely used format for compressing files and folders, often combining multiple files into a single archive.
- PNG (Portable Network Graphics): An image format that uses lossless compression, making it ideal for graphics that require transparency
and sharp edges.
- FLAC (Free Lossless Audio Codec): An audio format that compresses sound without losing quality, often used by audiophiles for high-
fidelity music storage.

14. TypesofCompression:Losslessvs.Lossy
b. Lossy Compression
Lossy compression reduces file size by removing some data, typically those considered less important or less
perceptible to the user. The original data cannot be perfectly reconstructed, as some information is
permanently lost. This method is used where a balance between file size and quality is acceptable, such as in
multimedia applications.
- How It Works: Lossy compression algorithms work by discarding parts of the data that are deemed less critical
or that have minimal impact on the perceived quality. Techniques include:
- Transform Coding: Converts data into another domain (like frequency) and discards less significant parts. For
example, in JPEG compression, the image is transformed using the Discrete Cosine Transform (DCT), and less
critical frequencies are removed.
- Quantization: Reduces the precision of data, grouping similar values together. This is common in audio and
image compression, where similar tones or colors are approximated.

15. TypesofCompression:Losslessvs.Lossy
- Examples:
- JPEG (Joint Photographic Experts Group): A popular image format that reduces file size by approximating
colors and discarding less noticeable details, making it ideal for photographs.
- MP3 (MPEG Audio Layer III): An audio format that compresses sound by removing frequencies less audible to
the human ear, widely used for music files.
- MP4 (MPEG-4 Part 14): A video format that uses lossy compression to reduce file size while maintaining
acceptable visual and audio quality, commonly used for streaming and online videos.

16. SimpleExamplesofLossyandLosslessCompression
a. Example of Lossless Compression: Text Compression with Huffman Coding
Consider the text: "BANANA". A simple lossless compression using Huffman coding might
assign shorter codes to the more frequent letters:
- B: 00
- A: 01
- N: 10
The original binary representation might be: "BANANA" = "0001101010", but after
compression using Huffman coding, it might be "000101010". The original text can be
perfectly reconstructed from this compressed data.

17. SimpleExamplesofLossyandLosslessCompression
b. Example of Lossy Compression: Image Compression with JPEG
Consider an image with subtle color variations across a sky. In lossy compression, similar blue
shades might be averaged or reduced in detail. The compressed JPEG image might appear
slightly blocky or blurred in those areas, but the overall visual impact remains similar to the
uncompressed version. The exact original data cannot be recovered, but the image is
significantly smaller in size.

18. ApplicationsofCompression
Compression is used in various fields:
- Web Development: To reduce load times by compressing images, scripts, and videos.
- Multimedia: To store and transmit audio and video efficiently, balancing quality and file
size.
- Data Storage: To save space on storage devices by compressing files and folders.
- Communication: To transmit data faster over networks, especially in limited bandwidth
environments.

19. Conclusion
• Understanding multimedia data types and their formats is crucial for effectively managing
and delivering digital content.
• Each format serves a specific purpose, balancing factors like quality, file size, compatibility,
and functionality.
• By selecting the right format for each application, users can optimize their multimedia
content for both performance and user experience.
• Compression is an essential tool in managing and transmitting digital data efficiently.
• Understanding the difference between lossy and lossless compression, along with their
respective use cases, helps in selecting the right approach for a given application.0
• Lossless compression ensures data integrity, while lossy compression offers greater size
reduction at the cost of some quality, making both methods indispensable in the digital
world.

20. THANKYOUVERY
MUCH!