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Audio Visual archiving : User requirements and challenges on infrastructure (AVATAR-m view)

Audio Visual archiving : User requirements and challenges on infrastructure (AVATAR-m view). Rajitha Weerakkody 22 Nov 2010. Outline. Audio visual archiving challenges Obsolescence Scalability Degradation Digitisation Avatar-m approaches Storage Management

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Audio Visual archiving : User requirements and challenges on infrastructure (AVATAR-m view)

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  1. Audio Visual archiving: User requirements and challenges on infrastructure (AVATAR-m view) Rajitha Weerakkody 22 Nov 2010

  2. Outline • Audio visual archiving challenges • Obsolescence • Scalability • Degradation • Digitisation • Avatar-m approaches • Storage Management • Scalable storage technologies • Video coding for graceful degradation

  3. The challenge: in perspective.. • BBC Archive has 650K hrs of video and 350K hrs of audio • (Estimated 100M hrs of film, video, audio in Europe, 200M worldwide!!) • Stored in various media types (2” tapes, 1” tapes, Betacam, Digibeta, D3, LTO, VCD, DVD, disk storage,……) • In both analog and digital …

  4. Obsolescence is a significant factor • Formats, media, .. • Long lasting media is not a solution • If no equipment to playback.. • New technologies are emerging • Migration is a must • Migration cycles getting shorter (4 years!!)

  5. They keep degrading.. • From physical degradation of storage media – to digital data corruptions..

  6. But we want to keep them in perpetuity!!

  7. Digitisation efforts • Digitisation is theway for long term (perpetual) preservation • Not all collections will ever be digitised – choices will have to be made • BBC currently runs a mass digitisation project for D3 tapes • Uncompressed video and audio in MXF files • Stored in LTO3 tapes-on-shelves • Generate up to 2 peta bytes per year!! • “Preservation factory” • File-based production and Archive workflows • Born-digital material also need to be preserved

  8. To recap, there are challenges around: • Digital storage system scalability and management • Constant migration cycles • Content degradation • Supporting file-based production workflows • Access to the archives • With HD material coming in, and SHV (16xHD) in the horizon, the pressure on the infrastructure is more ..

  9. What is AVATAR-m project.. • British government (Technology Strategy Board) funded industrial and academic collaboration • Completion November 2010 • Key research areas • Intelligent storage Management • Scalable storage technologies • Video coding for graceful degradation

  10. Intelligent Storage Management • Archive storage planning and management • Tools for planning for the archive growth, obsolescence and automating migration • Avatar archive storage manager • Some of the key features: • Centralised management of heterogeneous storage systems • Intelligent data handling, integrity checking and recovery with data chunking • Policy based management • Open file system interfaces • Seamless migration of data

  11. Avatar aggregated storage

  12. Scalable Storage Technology • Why digital storage doesn’t scale infinitely? • Interconnection fabric limitations – particularly with distributed storage technologies • I/O request handling • Indexing, metadata servers and databases • What we did.. • Detailed investigation of the state-of-the art, and various commercial products • Produce scalable architectures, with prototypes • Key recommendations • Ring architectures with high speed interconnectivity of nodes • Hierarchical grouping of I/O requests • Networked metadata server clusters • Parity declustering techniques to supersede RAID

  13. Archive Coding • Rationale: • AV files are subjected to data corruptions when retained for long periods in digital storage systems • Encoded video streams are made of a number of distinct components of varying “significance” (e.g. headers, various coding parameter blocks, sub band coefficient data etc.) • Thus the sensitivity of video files to data corruptions depends on the location of errors on the bit stream. E.g.: • Could be even worse! Files could be unreadable. Errors on a DC sub band data (Dirac Pro coding) Errors on a high freq. sub band data (Dirac Pro coding)

  14. Archive Coding • Proposal: • Significance classification for the bit stream elements • E.g.: • “Graded” protection based on Significance index • Split the video file into multiple sub streams • Use tiered storage for variable protection

  15. Archive Coding • Encoder process:

  16. Archive Coding • Retrieval process: • Combine multiple sub streams • Exploit redundancies to recover from data corruptions

  17. Archive Coding • Benefits: • Enables graceful degradation in the face of storage system errors • Significantly less bit rate overhead (1~10%) compared to keeping multiple copies (>100%) of the video files • Reduced total cost of storage • Enhanced value for the stored video content

  18. Demonstration • Demo • Dirac Pro coding • 10:1 compression • BER: 1E-6 • Error type: random bit errors

  19. Conclusions • Digital preservation of AV archives is a challenging task • Creates significant stress on the digital infrastructures • AVATAR-m project addressed some of these challenges • Intelligent storage management • Ultra scale storage technology • Video encoding for graceful degradation.

  20. Questions ? www.Avatar-m.org.uk Rajitha.Weerakkody@bbc.co.uk

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