Uploaded byIain Richardson
Iain Richardson: An Introduction to Video Compression
The document provides an overview of video compression, covering its definition, how codecs operate, and specific standards such as H.264 and HEVC. It explains the processes involved in video compression, including prediction, transform, quantization, and coding. Additionally, the document discusses video compression patents and resources for further exploration.
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Iain Richardson: An Introduction to Video Compression
- 1. An introduction to VideoCompression Iain Richardson 20 June 2012 Slide 1
- 2. Agenda • 1. Whatis 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. Agenda • 1. Whatis 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. Video compression MPEG-2 H.264 HEVC …… Broadcast DVD / IPTV Web Mobile Digital TV Blu-Ray Video Video …… Slide 4
- 5. The need forvideo compression Original 2 hour movie: 1,800,000,000,000 bits =53 DVD disks COMPRESS =1 DVD disk Slide 5
- 6. Video Source Video Display Compress Transmi Decompress (Encode) t or (Decode) Store Slide 6
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- 10. Agenda • 1. Whatis 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. Digital video Luma (Y) Displayed frame Chroma (Cr) Chroma (Cb) Slide 11
- 12. Macroblock Slide 12
- 13. Video Encoder Slide 13
- 14. Video decoder Slide 14
- 15. Prediction Slide 15
- 16. Prediction Slide 16
- 17. Intra prediction Slide 17
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- 19. Inter prediction Slide 19
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- 21. Types of predictedpicture I : Intra prediction only P : Inter prediction (one reference frame) or Intra prediction B : Biprediction (two reference frames), Inter (one reference) or Intra prediction Slide 21
- 22. Transform + Quantization Slide 22
- 23. Video Encoder Slide 23
- 24. Forward Transform Slide 24
- 25. Inverse Transform Slide 25
- 26. Forward Quantize Slide 26
- 27. Forward Transform +Quantize 58 64 51 58 961 -41 15 -48 48 -1 0 -1 52 64 56 66 -34 72 -30 -104 -1 1 -1 -2 62 63 61 64 -15 3 15 24 0 0 0 0 59 51 63 69 13 81 -5 8 0 1 0 0 Block of samples After transform Quantized, QP=18 Slide 27
- 28. Inverse Quantize Slide 28
- 29. Inverse Transform Slide 29
- 30. 58 64 51 58 48 -1 0 -1 55 66 54 58 52 64 56 66 -1 1 -1 -2 54 62 58 63 62 63 61 64 0 0 0 0 61 59 61 62 59 51 63 69 0 1 0 0 60 55 65 67 Block of samples Quantized, QP=18 Rescaled + inverse transformed Slide 30
- 31. Entropy coding Slide 31
- 32. Video Encoder Slide 32
- 33. Entropy coding Fixed length codes Variable length Headers codes Prediction parameters Context Adaptive Quantized coefficients Variable Length Codes Context Adaptive Binary Arithmetic Codes Slide 33
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- 37. Examples Slide 37
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- 42. ……etc Slide 42
- 43. Agenda • 1. Whatis 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. H.264 Advanced VideoCompression Slide 44
- 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
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- 47. High Efficiency VideoCompression (HEVC) Slide 47
- 48. HEVC • Under developmentby ISO MPEG and ITU-T VCEG • Roughly 2x compression efficiency of H.264 • Due for publication in 2013 Slide 48
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- 50. Agenda • 1. Whatis 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. Source: USPTO database Slide 51
- 52. Types of videocompression patent • Encoder • Decoder • Transport Slide 52
- 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. Agenda • 1. Whatis 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. To find outmore • http://www.itu.int - Download the H.264 standard • http://www.vcodex.com - Free tutorials • Follow me on Twitter: @onecodec Slide 55