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Progress Update on VC Recommendations

Progress Update on VC Recommendations. PPNCG report by Geoff Fayers available: http://ppewww.ph.gla.ac.uk/vcrec These are Entry-Level Products. MBone Tools on the LAN. 10Mbit Ethernet. LAN Analyzer. No. packets/s Kbytes/s. Simulate a VC on a private LAN - act as a baseline

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Progress Update on VC Recommendations

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  1. Progress Update on VC Recommendations PPNCG report by Geoff Fayers available: http://ppewww.ph.gla.ac.uk/vcrec These are Entry-Level Products R. Hughes-Jones Sep 1998

  2. MBone Tools on the LAN 10Mbit Ethernet LAN Analyzer No. packets/s Kbytes/s • Simulate a VC on a private LAN - act as a baseline • Two 350 MHz Pentium II with the Winnov Videum pro cards and camera ( 350 MHz Pentium II ensure CPU power not an issue >166MHz is fine ) • vic (video) & rat (audio) Get the kit from http://www.video.ja.net/mice • Two way Video, One way Audio • Change Compression methods and parameters R. Hughes-Jones Sep 1998

  3. rat on the LAN Prim GSM GSM GSM GSM GSM LCP LCP Sec none GSM GSM GSM GSM none LCP Duration ms 20 20 40 80 160 20 20 The amount of audio in the packet R. Hughes-Jones Sep 1998

  4. rat Encoding • Suppress Silence • Audio sent one way • dvi, gsm, lcp have sec. encoding • Piggy back audio recovery • no. packets same • size increase ~20-30 bytes • All send ~ 800ms data per sec • Network load agrees with rule-of thumb bit rates • RTP overhead 96 bits • Win with more ms / packet • gsm sounds OK R. Hughes-Jones Sep 1998

  5. Packet rates & Kbytes depend on movement • No large & small packet sizes • CIF ie ~10cm video pictures vic on the LAN Action : adjust talking move head rub eye talk clap write Frames/s : 16 20 20 30 30 R. Hughes-Jones Sep 1998

  6. vic LAN Analysis • Used H261 and CIF in the tests • Traffic VERY dependent on movement • sudden action ~100 kB/s • moving 50-60 kB/s • just talking 40-50 kB/s • no movement <10 kB/s • Packet size: • little movement 600-700 bytes • general movement 800-900 bytes • Did not see an increase in pkts/s as no. frame/s was increased • ( Claimed to be due to WinNT OS calls - we should try with Win95 to see ) TOTAL network load: 40kByte/s video 3 kByte/s audio Say ~400 kbit/s total R. Hughes-Jones Sep 1998

  7. First London to Manchester TestsRemember this is Entry Level Kit • Used the production network: LAN-Campus-SuperJANET-Campus-LAN • vic : H261 and CIF ( Man 25 - 75 % load on ethernet ) • rat : gsm+gsm, suppress silence, full duplex and Net mutes mike • Video quality good when cameras tuned, but its NOT full screen! • Set the white level • Have plenty of light and adjust the contrast - don’t point at a window • Check the focus • Audio Manchester -> London very good • Audio London -> Manchester lost second section of sentence • Had speakers at Manchester, Headphones at London • First report from PPNCG is ready. Further work in progress! R. Hughes-Jones Sep 1998

  8. Stop Press - More Tests • Tried : Man - IC as reported above • Man - UCL Man - Gla Gla - UCL • Video : Worked fine “out of the box” in all cases. • Audio : This is more difficult : • Man to UCL 1 Octv. Lower • UCL to Man 1 Octv. Higher • Wanted to run the system • hands free • use speakers not headset Could be a problem with the interface clocks. • Used rat options : • net mutes mike • suppress silence • mikes un-muted R. Hughes-Jones Sep 1998

  9. London talks Encode Encode Decode Decode Manc. Speakers send send Cut off Manc. mike • What might be happening to cut off sentences : • Find with “push to talk” “suppress silence” blanks out parts of the dialogue.( Probably the input audio drops below the send threshold. ) • Conclude (so far) we should use : • full duplex • no suppress silence • push to talk • care with mike volume. Keep it low to prevent clicks in the sound. • Further work : • Test head sets • Test with CERN Virtual Room Do you want / have to buy now? R. Hughes-Jones Sep 1998

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