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 subjecti

ve 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)

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

NTT

BT

KDDI

Psytechnics

SQ

(1) Hybrid models

6

Proponents & Preferred input types

Bit-stream (trace dump with arrival

time)

Don’t know

Telchemy

Tektronix

NTIA

Ericsson

DT

Ghent Univ

Symmetricom

BT

KDDI

NTT

Psytechnics

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

7

Proponents & Preferred input types

Text Bitstream Don’t know

Ericsson

Ghent Univ

DT

Symmetricom

NTT

BT

KDDI

Psytechnics

(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)

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 da

ta so that the reference decoder can decode it.• programs???• Free or open-source SW??• Hire professional developer??

refererenceencoder

bit stream data

playerchannel

packetcapturer

container server

extracterrefererencedecoder

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.