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Hybrid Bit-Stream Models (September 2008 Ghent)

Detailed guidelines and specifications for testing hybrid bit-stream models, focusing on rebuffering, freezing, and subjective testing methods. Proposals, model inputs, proponents, and reference decoders are discussed.

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Hybrid Bit-Stream Models (September 2008 Ghent)

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  1. Hybrid Bit-Stream Models (September 2008 Ghent)

  2. Test conditions • PVS length: SD/HD => 16 • Rebuffering is NOT allowed • PVS length: QCIF/QVGA • Variable for rebuffering: 16(SRC)/upto24(PVS) • Fixed: 10 sec • Rebuffering is allowed • Definition: Rebuffering is freezing longer than 0.5s without skipping • Issue: the maximum time limit for freezing or rebuffering is 8 seconds (QCIF/QVGA)? • Minimum length of SRC present in PVS? (+/1 0.5 sec)?

  3. Subjective Test • ACR w/ HRR (tentatively) for both QVGA/VGA and SD/HD • Graphical, continuous ACR version may be also used. • Numbers will be used along with semantic terms unless P.910rev is approved. • Decision: Tentatively accepted • Proposal. • (1) Vittorio: Some concerns about ACR-HR, new subjective testing method. • (2) Silvio • Propose to use a scale from 1 to 5 with steps of 1/10. • Propose to use MOS (or MOS_adj) as a target value

  4. Model Inputs • Model A (P.NAMS): TS, RTP, UDP, IP headers & (optional) longer freezing Model B (P.NBAMS): TS, RTP, UDP, IP headers, ES information & (optional) longer freezing • Hybrid models (FR/RR/NR): bit stream data (TS, RTP, UDP, IP headers, ES information) & PVS (SRC if required)

  5. Proponents & Preferred input types (1) Hybrid models

  6. Proponents & Preferred input types (2)P.NAMS: Use only IP, UDP, RTP and TS headers

  7. Proponents & Preferred input types (3)P.NBAMS

  8. ILGs • CRC • INTEL • Acreo • IRCCyN • Nortel

  9. Reference Decoder • Reference decoder to ensure error-free bit stream compliance to the standard (open source) • Open-source H.264 codec (JM) –Agreed • Alternative: x264 • Open-source MPEG2 (FFMPEG) - Agreed • Open-source MPEG4 - TBD • momusys, Xvid??

  10. Capturing bit stream data [TBD] • File format: PCAP, RTP dump, MS Network Analyzer format (.cap). • Capturing programs: Wireshark, Tcpdump, MS Network Analyzer format • Protocol: TCP/IP, UDP??

  11. Streaming Server [TBD] • Representative streaming server • Live555: working for MPEG2 • VLC: working for H.264 and MPEG4 • Dvbstream: working for ??? • Helix: working for ??? • Darwin: working for H.264 and MPEG4

  12. Inputs to the model • Text file (Hybrid) • Bit stream data (Bitstream/Hybrid)

  13. Inputs to the model

  14. Issues with Inputs to the model [TBD] • If bit-stream data which contains transmission errors can’t be interpreted by some models, what will we do about the models?

  15. IP analyzer: converter & decoder • We need to convert the captured bit stream data so that the reference decoder can decode it. • programs??? • Free or open-source SW?? • Hire professional developer??

  16. IP analyzer • Any bit stream data which can be understood by the reference IP analyzer will be admissible. Models are required to handle the bit stream data. • Bottom Line: We need working programs for reference encoder, container, server, packet capturer, extractor and reference decoder so that the reference decoder can decode the captured bit stream data. Also the transmission error information should be outputted.

  17. Data Analysis • Same as the multimedia project?

  18. Schedule • Reference decoder for each codec: TBD • Reference IP analyzer: TBD • Finalization of test plan: VQEG meeting after the reference IP analyzer is available • Model submission: Six months after the test plan is finalized.

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