Iain Richardson: An Introduction to Video Compression

7,059 views

Published on

Slides to accompany a talk I gave in June 2012. These are an updated version of my H.264/video compression slides.

1 Comment
29 Likes
Statistics
Notes
No Downloads
Views
Total views
7,059
On SlideShare
0
From Embeds
0
Number of Embeds
22
Actions
Shares
0
Downloads
0
Comments
1
Likes
29
Embeds 0
No embeds

No notes for slide

Iain Richardson: An Introduction to Video Compression

  1. 1. An introduction toVideo Compression Iain Richardson 20 June 2012 Slide 1
  2. 2. Agenda• 1. What is Video Compression?• 2. How does a video codec work? – - prediction – - transform + quantization – - coding – - examples• 3. Video compression standards – - H.264 – - HEVC• 4. Video compression patents• 5. Going further Slide 2
  3. 3. Agenda• 1. What is Video Compression?• 2. How does a video codec work? – - prediction – - transform + quantization – - coding – - examples• 3. Video compression standards – - H.264 – - HEVC• 4. Video compression patents• 5. Going further Slide 3
  4. 4. Video compression MPEG-2 H.264 HEVC ……Broadcast DVD / IPTV Web MobileDigital TV Blu-Ray Video Video …… Slide 4
  5. 5. The need for video compression Original 2 hour movie: 1,800,000,000,000 bits =53 DVD disks COMPRESS =1 DVD disk Slide 5
  6. 6. Video Source Video Display Compress Transmi Decompress (Encode) t or (Decode) Store Slide 6
  7. 7. Slide 7
  8. 8. Slide 8
  9. 9. Slide 9
  10. 10. Agenda• 1. What is Video Compression?• 2. How does a video codec work? – - prediction – - transform + quantization – - coding – - examples• 3. Video compression standards – - H.264 – - HEVC• 4. Video compression patents• 5. Going deeper Slide 10
  11. 11. Digital video Luma (Y) Displayed frame Chroma (Cr) Chroma (Cb) Slide 11
  12. 12. Macroblock Slide 12
  13. 13. Video Encoder Slide 13
  14. 14. Video decoder Slide 14
  15. 15. Prediction Slide 15
  16. 16. Prediction Slide 16
  17. 17. Intra prediction Slide 17
  18. 18. Slide 18
  19. 19. Inter prediction Slide 19
  20. 20. Slide 20
  21. 21. Types of predicted pictureI : Intra prediction onlyP : Inter prediction (one reference frame) or Intra predictionB : Biprediction (two reference frames), Inter (one reference) or Intra prediction Slide 21
  22. 22. Transform + Quantization Slide 22
  23. 23. Video Encoder Slide 23
  24. 24. Forward Transform Slide 24
  25. 25. Inverse Transform Slide 25
  26. 26. Forward Quantize Slide 26
  27. 27. Forward Transform + Quantize58 64 51 58 961 -41 15 -48 48 -1 0 -152 64 56 66 -34 72 -30 -104 -1 1 -1 -262 63 61 64 -15 3 15 24 0 0 0 059 51 63 69 13 81 -5 8 0 1 0 0Block of samples After transform Quantized, QP=18 Slide 27
  28. 28. Inverse Quantize Slide 28
  29. 29. Inverse Transform Slide 29
  30. 30. 58 64 51 58 48 -1 0 -1 55 66 54 5852 64 56 66 -1 1 -1 -2 54 62 58 6362 63 61 64 0 0 0 0 61 59 61 6259 51 63 69 0 1 0 0 60 55 65 67Block of samples Quantized, QP=18 Rescaled + inverse transformed Slide 30
  31. 31. Entropy coding Slide 31
  32. 32. Video Encoder Slide 32
  33. 33. Entropy coding Fixed length codes Variable length Headers codesPrediction parameters Context AdaptiveQuantized coefficients Variable Length Codes Context Adaptive Binary Arithmetic Codes Slide 33
  34. 34. Slide 34
  35. 35. Slide 35
  36. 36. Slide 36
  37. 37. Examples Slide 37
  38. 38. Slide 38
  39. 39. Slide 39
  40. 40. Slide 40
  41. 41. Slide 41
  42. 42. ……etc Slide 42
  43. 43. Agenda• 1. What is Video Compression?• 2. How does a video codec work? – - prediction – - transform + quantization – - coding – - examples• 3. Video compression standards – - H.264 – - HEVC• 4. Video compression patents• 5. Going deeper Slide 43
  44. 44. H.264 Advanced Video Compression Slide 44
  45. 45. H.264/AVC• First released in 2003• Published by ISO MPEG and ITU-T VCEG• Roughly 2x compression efficiency of MPEG-2• Used for: – Blu-Ray Disks – High Definition TV broadcasting – Internet video – …… Slide 45
  46. 46. Slide 46
  47. 47. High Efficiency Video Compression (HEVC) Slide 47
  48. 48. HEVC• Under development by ISO MPEG and ITU-T VCEG• Roughly 2x compression efficiency of H.264• Due for publication in 2013 Slide 48
  49. 49. Slide 49
  50. 50. Agenda• 1. What is Video Compression?• 2. How does a video codec work? – - prediction – - transform + quantization – - coding – - examples• 3. Video compression standards – - H.264 – - HEVC• 4. Video compression patents• 5. Going deeper Slide 50
  51. 51. Source: USPTO database Slide 51
  52. 52. Types of video compression patent• Encoder• Decoder• Transport Slide 52
  53. 53. Patent Pools• E.g. MPEG-LA, H.264/AVC patent pool: – Licenses patents on behalf of patent holders – Unrelated to ISO/IEC MPEG – Accepts patents based on determination of “essentiality” – 250+ US patents – 900+ licensees Slide 53
  54. 54. Agenda• 1. What is Video Compression?• 2. How does a video codec work? – - prediction – - transform + quantization – - coding – - examples• 3. Video compression standards – - H.264 – - HEVC• 4. Video compression patents• 5. Going further Slide 54
  55. 55. To find out more• http://www.itu.int - Download the H.264 standard• http://www.vcodex.com - Free tutorials• Follow me on Twitter: @onecodec Slide 55

×