1 Hybrid Bit-Stream Models (September 25, 2008 Ghent) FINAL.

1

Hybrid Bit-Stream Models(September 25, 2008 Ghent)

FINAL

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

• Maximum delay/advance in PVS? (+/- 0.25 sec): other conditions will be identical as in the multimedia project [TBD]

• Decision: the maximum time limit for freezing or rebuffering is 8 seconds forQCIF/QVGA.

3

Subjective Test • ACR HR (tentatively) for both QVGA/VGA

and SD/HD • Graphical, continuous ACR version may be

also used.• Numbers will be used along with semantic ter

ms unless P.910rev is approved.• Proposal.• (1) Vittorio: Some concerns about ACR-HR, new subjecti

ve testing method. => prefer DSCQS, DSIS, at least 10 steps

• (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

• Decision: 11 scale ACR-HR(P.910)=10, DSCQS=1

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)

headerextractor

bit-stream data(trace dump with arrival time) P.NAMS

5

Proponents & Preferred input types

Text Bit-stream (trace dump with arrival time)

Don’t know

OPTICOM

Yonsei

NEC

Tektronix

Ghent Univ.

Symmetricom

NTTLancaster Univ

BT

KDDI

Psytechnics

SQ

(1) Hybrid models

6


Bit-stream (trace dump with arrival

time)

Don’t know

NTT

Telchemy

Tektronix

Ericsson

DT

Ghent Univ

Symmetricom

BT

KDDI

Psytechnics

NEC

(2) P.NAMS: Use only IP, UDP, RTP and TS headers

Note: Potential proponents should declare their intensions to SG12 by Sep. 30.

7


Text Bitstream Don’t know

Ericsson

Ghent Univ

DT

Symmetricom

NTT

BT

KDDI

Psytechnics

(3) P.NBAMS

8

ILGs

• CRC

• INTEL

• Acreo

• IRCCyN

• Nortel

• FUB

• NTIA

9

Reference Decoder [TBD]

• Reference decoder to ensure error-free bit stream compliance to the standard (open source)

– Open-source H.264 codec (JM) • Alternative: x264

– Open-source MPEG2 (FFMPEG)– Open-source MPEG4 -

• momusys, Xvid??

NOTE: Proponents should provide a working system of entire chains (encoder, container, server, capture program, decoder, etc)

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 ???– Ffserver: MPEG2 and MPEG4, H.264(?)

12

Inputs to the model

• Text file (Hybrid)

• Bit stream data (Bitstream/Hybrid)

network decoder

bit-streamcapture

DISPLAY

bit-stream data(trace dump with arrival time)

videocapture

PVS

13

Inputs to the model

Hybrid modelsbit-stream data(trace dump with arrival time)

PVS

headerextractor

bit-stream data(trace dump with arrival time)

P.NBAMSbit-stream data(trace dump with arrival time)

P.NAMS

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?

referencedecoder

bit-stream datawithout transmission errors

reference IPanalyzer &decoder

bit-stream datawith transmission errors

15

IP analyzer: converter & decoder • We need to convert the captured bit stream data so that the ref

erence decoder can decode it.• programs??? (TCP replay, off-line simulator)• Free or open-source SW??• Hire professional developer??

refererenceencoder

bit stream data

player

channel

packetcapturer

container server

extracterrefererencedecoderPVS

network emulator

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 – tentatively agreed.

18

Target usage (PLR): TBD

• SD/HD: (information from Broadband forum may be useful)

• QCIF/VGA - internet: - mobile: 0-15%

19

Drafting test plan

• A draft of the hybrid test plan will be done by the co-chairs (JB, CL) and editors (David Hands, Nicolas Staelens, Vittorio Baroncini, Yves Dhondt) by borrowing heavily from the multimedia and HD test plans.

• The draft will be presented to VQEG for approval.

20

Schedule

• Proposal for a working system (encoder, server, capturing program, decoder): next VQEG meeting (Jan, 2009)

• Finalization of test plan: VQEG meeting after the reference IP analyzer is available: VQEG meeting (July, 2009)

• Model submission: Six months after the test plan is finalized.

21

Remaining issues [TBD]

• Subjective test – Multimedia project approach: proven,

but delays may happen (about 6 month delay after model submission). Easy to correct errors

– HDTV project approach: Fast, but there can be impasse if serious PVS problems occur. Difficult to correct errors.

22

Number of subjective tests (Proponents)

BT 1Ericson1DT 1Ghent Univ. 1KDDI 2Lancaster Univ 1NEC 1NTT 1Opticom 1Psytechnics 1Symmetricom 1SQ 1TektronixYonsei 3

Total: 16

23

Number of subjective tests (ILG)

• CRC 0• INTEL 0• Acreo 0 or possibly 1• IRCCyN 1• Nortel • FUB 1• NTIA 1?

• NOTE: ATIS option may be considered.

24


• Calibration limit: currently same as HDTV & Multimedia (will be decided over the reflector)

25


• Bit-stream models– P.NAMS (audio/video, video only)– P.NBAMS (audio/video, video only)– P.NBAMS with some additional information from decoder such

as freeze frames (audio/video, video only)

• audio/video(P.NAMS) vs. Hybrid (video only)

• Decision: Initially video only. If enough audio(with video) subjective data is available, models for audio and audio/video will be also validated.

1 Hybrid Bit-Stream Models (September 25, 2008 Ghent) FINAL.

Documents