CODECS AND COMPRESSION          An overview of main concepts and standards          Marco Venanzi            @marcovenamar...
Run through most common                compression standards and formats                Images • Audio • Video            ...
Codecs vs File Formats                              Image          File Formats                             JPEG GIF      ...
Loseless Lossymartedì 18 ottobre 2011                    4
Imagesmartedì 18 ottobre 2011   5
BMP, TIFF                          Almost uncompressed formats                          Not used on the web, large dimensi...
JPEG                Most common lossy compression                format for photography                10:1 compression wi...
GIF               Popular file format, especially for               little images, logos, animations               max 256 ...
PNG       Born as improvement on GIF       Better compression for graphics       and vectors       Loseless format, 8-bit ...
full transparency                          no transparency   Just 1 bit transparencymartedì 18 ottobre 2011               ...
Pixel • Resolution • dpi • ppi                      A lot of          Monitors display pixels, and                     con...
Pixel • Resolution • dpi • ppi                             I want a 30x40 cm print                      12”x16” inches at ...
Audiomartedì 18 ottobre 2011   13
Loseless                Best Quality                Audiophile, Archive, Editing, Hi-Fi                FLAC, WMA Loseless,...
AAC                             AMR-NB                          AAC+            MP3             AMR-WB                    ...
martedì 18 ottobre 2011   16
martedì 18 ottobre 2011   16
Bitrate                          320 kbps       Channels                                         Mono, Stereo, 5.1        ...
MP3                          Most common lossy compression                          format                          128kbp...
AAC                          Default audio format for                          iTunes, iPod, PS3                          ...
AAC+                                Enhanced AAC+     Spectral Band Replication                    Parametric Stereo     c...
AMR-NB                Low quality for speech - Based on ACELP®                Sampling frequency 8 kHz                8 so...
AMR-WB                          Sampling frequency 16 kHz                          9 configurations with bitrates          ...
Videomartedì 18 ottobre 2011           23
Frame rate                    25 fps                                                   Bit Rate                           ...
RESOLUTIONmartedì 18 ottobre 2011   25
FRAME RATE               Number of still images in a time unit               10 fps is the minimum frame rate to          ...
Deinterlace             Due to old TVs and technology limits             Not possible to shoot fluid full frame videos     ...
Chroma Subsampling                               Human eye is less sensitive to color than luminance                      ...
Common codecs            MJPEG                       MPEG2          Sequence of JPEG frames       Widespread codec for man...
H.264        Blu-ray Discs        Streaming (Vimeo, YouTube, and the iTunes Store)        Web software (Adobe Flash Player...
H.264   High efficiency (50% compared to MPEG-2)   Lot of tools and algorithms that can be combined in   different profiles ...
Other codecs          VC-1          Started by Microsoft as a proprietary protocol and released in          2006 as a SMTP...
The Futuremartedì 18 ottobre 2011   33
WebP                                  H.265                                    JpegMini          WebM                     ...
martedì 18 ottobre 2011   35
H.265                          High Efficiency Video Coding (HEVC)                 50 percent increase in efficiency and 3 ti...
H.265 - Timeline                          2013: coding standard published       2012: draft version of                    ...
Higher Resolutionsmartedì 18 ottobre 2011                        38
Focus is not on encoding but on delivery            Dull scene for codecs lately            Adaptive Bit Rate Streaming   ...
Questions?martedì 18 ottobre 2011                40
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Codecs and multimedia formats

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An overview of most common multimedia codecs and relative file formats. Some clarification on common terms and mistakes.

Some hints on future trends.
Follow me at http://twitter.com/marcovena

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Codecs and multimedia formats

  1. 1. CODECS AND COMPRESSION An overview of main concepts and standards Marco Venanzi @marcovenamartedì 18 ottobre 2011 1
  2. 2. Run through most common compression standards and formats Images • Audio • Video Pros and cons of each format Clarification on some confusing terminologiesmartedì 18 ottobre 2011 2
  3. 3. Codecs vs File Formats Image File Formats JPEG GIF .3gp .mov .mp4 PNG BMP TIFF .avi .mp3 .mpg Audio Video WAV FLAC H.264 MPEG4 MP3 AAC MPEG2 DivX AMR Vorbis MIDI VP8 WebMmartedì 18 ottobre 2011 3
  4. 4. Loseless Lossymartedì 18 ottobre 2011 4
  5. 5. Imagesmartedì 18 ottobre 2011 5
  6. 6. BMP, TIFF Almost uncompressed formats Not used on the web, large dimensions Allow multiple edits Hi-quality processing .bmp, .tiff filesmartedì 18 ottobre 2011 6
  7. 7. JPEG Most common lossy compression format for photography 10:1 compression with minimum degradation Not suitable for file editing, vector shapes and text drawing (artifacts) No transparency File Format: JPEG/Exif , .jpeg filesmartedì 18 ottobre 2011 7
  8. 8. GIF Popular file format, especially for little images, logos, animations max 256 colors - dithering Limited transparency (only 1 color) Best replaced by PNG Still the most used format for simple animationsmartedì 18 ottobre 2011 8
  9. 9. PNG Born as improvement on GIF Better compression for graphics and vectors Loseless format, 8-bit alpha blending Not fully supported by old browsers .png filesmartedì 18 ottobre 2011 9
  10. 10. full transparency no transparency Just 1 bit transparencymartedì 18 ottobre 2011 10
  11. 11. Pixel • Resolution • dpi • ppi A lot of Monitors display pixels, and confusion printers produce dots Screen 72 ppi, Print 300 ppi PPI is the bridge between Fine Art 600 ppi digital and physical worldmartedì 18 ottobre 2011 11
  12. 12. Pixel • Resolution • dpi • ppi I want a 30x40 cm print 12”x16” inches at 300 ppi is 3600x4800martedì 18 ottobre 2011 12
  13. 13. Audiomartedì 18 ottobre 2011 13
  14. 14. Loseless Best Quality Audiophile, Archive, Editing, Hi-Fi FLAC, WMA Loseless, Dolby TrueHD Lossy Psycoacoustics Some info not perceived by the auditory system High frequencies, tones covered by a louder sound (masking)martedì 18 ottobre 2011 14
  15. 15. AAC AMR-NB AAC+ MP3 AMR-WB E-AAC+ AMR-WB+ Vorbis WAV MIDI WMA File formats .3gp, .mp4, .m4a, .3ga, .mp3, .aac, .amr, .oggmartedì 18 ottobre 2011 15
  16. 16. martedì 18 ottobre 2011 16
  17. 17. martedì 18 ottobre 2011 16
  18. 18. Bitrate 320 kbps Channels Mono, Stereo, 5.1 Sampling Rate 44kHzmartedì 18 ottobre 2011 17
  19. 19. MP3 Most common lossy compression format 128kbps(Radio Quality) 192kbps(CD) 320kbps(Hi-Quality) Lots of songs in your pocket File Format: only .mp3 filesmartedì 18 ottobre 2011 18
  20. 20. AAC Default audio format for iTunes, iPod, PS3 Improvement on mp3 (~20% gain) especially at lower bitrates from 8 to 96 kHz (MP3:16 to 48 kHz) Up to 48 channels Lots of tools and configuration that define different profiles. AAC 128kbps ~ MP3 160kbps File Format: .mp4, .m4a, .3gp, .aacmartedì 18 ottobre 2011 19
  21. 21. AAC+ Enhanced AAC+ Spectral Band Replication Parametric Stereo creation of higher frequences by an Downmix of 2 stereo channels into a mono approx. of lower armonies (psycoacoustics) channel along with PS info Works at low bitrates (~24kbps) AAC 60kbps = AAC+ 48kbps > 48kbps is transparent AAC+ 32kbps >> AAC 48kbps Backward compatiblemartedì 18 ottobre 2011 20
  22. 22. AMR-NB Low quality for speech - Based on ACELP® Sampling frequency 8 kHz 8 source codecs with bit-rates range 4kbps~12kbps Link adaptation on low signal condition the codec switches to lower bitrate AMR utilizes Discontinuous Transmission (DTX), with Voice Activity Detection (VAD) and Comfort Noise Generation (CNG) to reduce bandwidth usage during silence periodsmartedì 18 ottobre 2011 21
  23. 23. AMR-WB Sampling frequency 16 kHz 9 configurations with bitrates 6~23kbps File Format: .3gp, .amrmartedì 18 ottobre 2011 22
  24. 24. Videomartedì 18 ottobre 2011 23
  25. 25. Frame rate 25 fps Bit Rate Variable, Constant Resolution QVGA, VGA, 720p, 1080pmartedì 18 ottobre 2011 24
  26. 26. RESOLUTIONmartedì 18 ottobre 2011 25
  27. 27. FRAME RATE Number of still images in a time unit 10 fps is the minimum frame rate to achieve motion illusion.martedì 18 ottobre 2011 26
  28. 28. Deinterlace Due to old TVs and technology limits Not possible to shoot fluid full frame videos (max 25fps) Half the frame in two subsequent instants Progressive displays have to reconstruct the full frame but the result is not pleasant DEINTERLACE ALGORITHMSmartedì 18 ottobre 2011 27
  29. 29. Chroma Subsampling Human eye is less sensitive to color than luminance Bandwidth can be optimized by storing more luminance detail than color detail (cones are two times rods)martedì 18 ottobre 2011 28
  30. 30. Common codecs MJPEG MPEG2 Sequence of JPEG frames Widespread codec for many years Easy to process On DVD, DVB, Satellite MJPEG Highly inefficient Not suitable for low bitrates .avi files .mpg files MPEG2 (used in DVD) MPEG4 H.263 h.263 Improvements on MPEG2 developed by ITU-T in 1995 Used in DivX, Quicktime Low bit rate encoding .mp4, .m4v, .mov .divx .avi H.323 (RTP/IP video conf RTP/IP), H.320 (ISDN video conf), RTSP (Streaming) and SIP.martedì 18 ottobre 2011 29
  31. 31. H.264 Blu-ray Discs Streaming (Vimeo, YouTube, and the iTunes Store) Web software (Adobe Flash Player, Microsoft Silverlight) Broadcast services for DVB Direct-broadcast, cable television services Real-time videoconferencingmartedì 18 ottobre 2011 30
  32. 32. H.264 High efficiency (50% compared to MPEG-2) Lot of tools and algorithms that can be combined in different profiles and levels Quality depends also on the encoder implementation. H264 defines the structure and the tools but the intrinsic algorithms are open for improvement.martedì 18 ottobre 2011 31
  33. 33. Other codecs VC-1 Started by Microsoft as a proprietary protocol and released in 2006 as a SMTPE standard Used In HD-DVD, BlueRay, Silverlight, Windows Media (.wmv) Theora Open Codec Developed By Xiph.org OGG Container And Matroska (.mkv) Same Performance As MPEG4 Part 2 Codecmartedì 18 ottobre 2011 32
  34. 34. The Futuremartedì 18 ottobre 2011 33
  35. 35. WebP H.265 JpegMini WebM JpegXR AMR-WB+martedì 18 ottobre 2011 34
  36. 36. martedì 18 ottobre 2011 35
  37. 37. H.265 High Efficiency Video Coding (HEVC) 50 percent increase in efficiency and 3 times complexitymartedì 18 ottobre 2011 36
  38. 38. H.265 - Timeline 2013: coding standard published 2012: draft version of 3-5 years before commercial the standard expected productsmartedì 18 ottobre 2011 37
  39. 39. Higher Resolutionsmartedì 18 ottobre 2011 38
  40. 40. Focus is not on encoding but on delivery Dull scene for codecs lately Adaptive Bit Rate Streaming HTTP Live Streaming Apple HTTP Dynamic Streaming Adobemartedì 18 ottobre 2011 39
  41. 41. Questions?martedì 18 ottobre 2011 40
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