audio and video compression and it’s importance on the internet
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Audio and Video Compression and it’s importance on the internet. Brian Dillinger May 3, 2010. What is compression?. A reversible conversion of data that requires fewer bits using codecs. Audio and Video Codecs. - PowerPoint PPT PresentationTRANSCRIPT
AUDIO AND VIDEO COMPRESSION AND IT’S IMPORTANCEON THE INTERNETBrian DillingerMay 3, 2010
What is compression?
A reversible conversion of data that requires fewer bits using codecs
Audio and Video Codecs
A codec is a device or software that allows for COmpression and DECompression of video and audio
Common Audio Codecs
• MP3 (MPEG-1 Audio Layer 3)• FLAC (Free Lossless Audio Codec)• AAC (Advanced Audio Coding)• Ogg (Ogg Vorbis)
Common Video Codecs
• DivX (MPEG-4 Part 2)• XviD (MPEG-4 Part 2)• H.264/x264 (MPEG Part 10)• WMV (Windows Media Video)
Audio Standards MP3
MP3 file format is the most common With increased quality
comes increased file size CBR vs VBR ID3 tagging through
metadata
Switch
Target Kbit/s
Bitrate Range Kbit/s
320 320 320 CBR
V0 245 220-260 VBR
V1 225 190-250 VBR
192 192 192 CBR
V2 190 170-210 VBR
Audio Standards FLAC
FLAC file format is most commonly used for lossless compression
High bitrate 768 kBit/s Large file size
Song length of 4:31 MP3 V0 9.12MB FLAC 32.3MB
Audio Compression Software Exact Audio Copy (Powerful Accurate and
FREE) FLAC, WMV, MP3 and Ogg support MP3 ripping capable of both VBR and CBR
using Lame 3.98 Free CD lookup
iTunes MP3 and Apple Lossless Apple Lossless has limited
playback
VIDEO Standards XviD
Standard Definition standard Follows MPEG-4 part 2 standards Lossy encoding PAL video requires ~100GB per hour
Compressed at 200:1 XviD requires ~500MB per hour
Video Standards H.264/x264 Standard for High Definition video Follows MPEG-4 part 10 standards Allows for half the file size for the same
video as XviD standards
Video Compression Software bitRipper
Very simple way to convert DVD video using the XviD codec and avi container
Adobe Encore Expensive Professional Suite Extremely fast and efficient Voice to text for adding subtitles
Why use compression?
Disc space is increasing but not infinite Online streaming for both audio and video is a
growing trend Video conferencing and video chats
References
www.xvid.org www.hydrogenaudio.com www.id3.org www.flac.sourceforge.net www.matroska.org/