1. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Modern Trends in Audio Compression presented by Ognen Paunovski Andon Dragomanov 2 nd International Student Spring Symposium in Contemporary Topics in IT

2. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Agenda  Idea Behind the Compression  Lossy and Lossless Compressions  Key Terms  Compression Algorithms  MP3 - Format  Ogg Vorbis -Format  WMA – Format  Format Comparison

3. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 In general Compression refers to a variety of ways (algorithms) to reduce the size of a data file. IMPORTANT Compression makes downloading quicker and lessens the amount of storage space needed on a hard drive. The Idea Behind the Compression

4. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Lossy - Lossless - Lossy vs. Lossless Compression After one applies lossy data compression to a file, the file can never be recovered exactly as it was before it was compressed. In a lossless data compression file after the operation of compression and decompression will be restored to its original format.

5. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Key Terms  Wave Form  Sample  Bit Rate (CBR, VBR)  Sample Rate  Code Word  Quantization  Digitalization

6. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03  Dictionary Methods  Huffman Coding  PCM Pulse Code Modulation  DPCM Differential PCM Compression Algorithms

7. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03  Creation Process Stages:  Separation into Frames  Spectral Analysis  “Masking” ( Psychoacoustic Models )  Processing ~ Bit Rate & Joint Stereo  Compressing ( Hoffman ZIP )  CBR & VBR  Most Popular  Many codec's and players Specific Audio Formats – MP3

8. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Specific Audio Formats – Ogg Vorbis  Creation Process Stages:  Same as those in MP3  Improvements over MP3  Designed for Streaming Connection  Real Stereo ~ No Multiplexing  Multi-Channel Support (more than Mono & Stereo)  Bit Rate Scaling  Preferred VBR  New Codec  Free Source Code  One codec and few players

9. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Specific Audio Formats – WMA  Advanced System Format (ASF) including:  Support for Meta Data  Scripting  Security Features  CBR & VBR (only after version 9)  Industrial Support  Free Codec  Few Players

10. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Comparison WAV

11. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Comparison MP3

12. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Comparison OGG

13. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Comparison WMA

14. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Comparison WAVMP3OGGWMA

15. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 Comparison (Cont.) From a WAV File with size 3,85 MB KB

16. Mar 2003 Ognen Paunovski :: Andon Dragomanov S3CTIT03 THANK YOU!