mpeg-2 music videos :-) alan crosswell [email protected]

MPEG-2 MusicVideos :-)

Alan [email protected]

mailto:[email protected]





May, 2001 Columbia University Academic Information Systems

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Outline

• The Content• Network Issues• Production Issues• Show and Tell• CODEC Issues and Requirements


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Outline



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The Content

• Violin Master Class – December 8, 2000• Student: Wu Jie, at CANARIE in Ottawa.• Teachers: Pinchas Zukerman and Patinka

Copec (of MSM) in New York (at Columbia).• Manhattan School of Music, CANARIE,

National Research Centre, Natl Arts Centre.• Pt-to-Pt Litton CV2 MPEG2 & mcast MPEG1.


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The Content

• Dance Rehearsal/Conference – Jan 6, 01• Peter Sparling Dance Company in Ann

Arbor.• Association for Performing Arts

Presenters conference in New York.• Demonstration/discussion of an in-

progress commissioned work involving dances, costumes, set designs.


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The Content

• Cello Master Class – May 10, 2001• David Geber of MSM in New York (at

CU).• Erin Dunn at University of Oklahoma• YAML (Yet Another Music Lesson:-)


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Outline



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• Campus network• 1% packet loss is not good enough

w/CV2.• CV2 at 15.4 Mbps sends 16K PDUs via

UDP:• 11 IP fragment Ethernet packets.• 352 ATM cells.

• Drop one cell and the whole PDU's lost.• ATM issues - cell loss, policing, bursts.

Network Issues


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Network Issues

• Abilene/CANARIE ATM issues• Getting clobbered by QoS (shaping,

policing). • ATM cell loss on NYCM OC-12 intf

• Several sub-rate VCs.• OC-12 was not oversubscribed.• One 24 Mbps VC was heavily congested (JANET).• Caused head of line problems for other VCs.

• Brent made it go away.


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Network Issues

• Some things to look for on campus:• 100-full duplex negotiated correctly? • Router ATM interface CRC errors?

• ATM cell loss (policing, default burst length)?

• Cisco PA-A3 (OC3 ATM) SAR HW 1.0?

• Analog video causing Codec resets that convince you there’s a network problem.


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Outline



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Production Issues

• Demos Harder than the “real thing.”• A large audience for a one-on-one

event.• Added sound amplification adds echo.• Complicates echo cancellation.• Video monitors/projection screens.• Lighting for two-way video at the same

time as projecting is goofy.


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Production Issues

• Audio• Emphasize audio over video quality.• Pops, squeals, screeches, drop-outs,

echoes.• Audience will accept a few video

artifacts.• Room-filling "rich" audio compensated

for poor video in one event.


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Production Issues

• Audio engineers dealt with:• Room acoustics at both ends.

• Drapes and foam where hung.• Gobos used to isolate codec fan noise.

• Some echo is a good thing: room was too dead, so...

• Remote echo was used to liven the room.


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Production Issues

• Audio echo avoidance• Can't use a voice-grade echo canceller

for music.• Off-axis speaker/mic placement.• Gobos isolating mics from speakers.• Masking the backs of mics to control

echo.• Muting ruins spontaneity.


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Production Issues

• Audio for world-class musicians• Doing audio for people who can hear

the difference.• Frustrating not being able to directly

monitor the remote room.• Maintaining a natural listening level.• Shaping of the audio by codec, etc.


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Production Issues

• Video (bush league)• Switching sources *must* have a time

base corrector (e.g. video mixer).• A simple video switch causes a ~5

second CV2 encoder reset.• Which also kills the audio.• Bad video (loose connector) causes

encoder resets which manifest as audio dropout.


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Production Issues

• Video• A prosumer mixer boasts 500 effects.• Don’t <BLINK>have</BLINK> to use them.• Prosumer mixer quality is just that.• PIP may show annoying artifacts.• Good lighting, camera quality and operator

skill (get a pro video crew if it is important).• Plug a $200 camera into a $20,000

codec….


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Production Issues

• “How do you get to Carnegie Hall?”• “Practice, Practice, Practice”

• In a new campus location, begin testing one month beforehand to have plenty of time to deal issues that will come up.

• When dealing with a new partner, there will be new routes and performance issues.

• Both ends need to rehearse from the actual location of the event.


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Outline



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The Road Show

• SKB portable rack


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The Road Show

• SKB portable rack• Flat panel drawer


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The Road Show

• SKB portable rack• Flat panel drawer• Keyboard/mouse

drawer


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The Road Show


drawer• Video proc amp


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The Road Show


drawer• Video proc amp• Stereo mic/line mixer


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The Road Show


drawer• Video proc amp• Stereo mic/line mixer• Stereo VU meter


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The Road Show


drawer• Video proc amp• Stereo mic/line mixer• Stereo VU meter• Litton CV2 MPEG-2

codec


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The Road Show


drawer• Video proc amp• Stereo mic/line mixer• Stereo VU meter• Litton CV2 MPEG-2

codec• PC w/Z360 H.323 codec


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The Road Show

• SKB portable rack• Flat panel drawer• Keyboard/mouse drawer• Video proc amp• Stereo mic/line mixer• Stereo VU meter• Litton CV2 MPEG-2 codec• PC w/Z360 H.323 codec• PC w/IPTV MPEG-1/2


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The Road Show

• Belkin PC switcher (remoted to kbd drawer)

• Video & Audio DAs


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The Road Show


• Video & Audio Das• Audio/Video patch bay


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The Road Show


• Video & Audio Das• Audio/Video patch bay• Biamp echo canceller


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The Road Show


• Video & Audio Das• Audio/Video patch bay• Biamp echo canceller• UPS


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The Road Show


• Video & Audio Das• Audio/Video patch bay• Biamp echo canceller• UPS• Still missing/unfinished:

• Headphone monitor• DV capture• Echo canceller + bypass


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The Road Show

• Videonics MXPro DV :-(

• Canon GL1 camera.• Tripod.• Powerbook w/PPT for

title slides (use S-video out).

• 2 SM57 mics.• 2 Samsung VGA/Video

15" TFT monitors.

• 2 DELVCAM 5.6" TFT monitors.

• test generators (SMPTE bars, tone).

• miniDV recorder.• 2 S-Video to S+Comp

DA. • lots and lots of cables. • adapters.• gaffers tape.


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The Road Show

• Interfacing with the pros(umers)• Balanced vs. unbalanced audio (the audio

engineers will get over it:-)• mic/line mixer with balanced XLR, TRS,

mic and line jacks makes it easy.• Composite vs. S-video vs. component vs.

firewire. • Chose S-video throughout the rack.• DV->analog conversion in the Videonics.


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Outline



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CODEC issues/reqs

• Why are we using analog audio/video?• Audio requires better than CD quality:

• 6 or more channels (e.g. Dolby 5.1, 7.1).• 96 kHz sampling.

• "Perfect" audio/video synchronization.• Better than MP@ML (SDTV)• HD 1280p would be nice.• Firewire capture instead of analog?


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CODEC issues/reqs

• CODECs have to work with IP networks.

• QoS-enabled.• RTP.• Dynamically adjust based on

changing conditions.• Oh, and, by the way, deliver

extremely low latency:-)


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DV capture -> MPEG with Linux on a VAIO

http://www.schirmacher.de/arne/dvgrab/http://linux1394.sourceforge.net/# modprobe ieee1394# modprobe ohci1394# modprobe raw1394# modprobe sbp2_1394# rescan-scsi-bus.sh# mount /dev/sda1 /mnt/disk# cd /mnt/disk# dvgrab --autosplit --format dv2 file

http://www.schirmacher.de/arne/dvgrab/

http://linux1394.sourceforge.net/


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DV capture -> MPEG with Linux on a VAIO

$ lav2yuv -I 1 file*.avi | mpeg2enc –o video.mpg$ lav2wav file*.avi | mp2enc -s -b 384 -r 48000 -o

audio.mp3$ mplex -o final.mpg video.mpg audio.mp3$ gtv final.mpg


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c:\program files\sony\digital media park\mediabar d:\mpeg\a007.avi


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Thanks….

• Lou Brown & Christianne Orto, Manhattan School of Music

• Brent Sweeny, Grover Browning, Matt Davies & co., Abilene

• Marc Boulerice, Jane Hermanson, Thomas Tam, CANARIE

• Brian Shepard, Oklahoma University• Bill Owens, NYSERnet


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Performance Copyright (p) 2000 Pinchas Zukerman, Manhattan School of Music, National Arts Centre of Canada

www.columbia.edu/acis/networks/advanced

[email protected]

mpeg-2 music videos :-) alan crosswell [email protected]

Documents

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content violin master