HD video in teaching environment Eva Hladká, Ludek Matyska CESNET, Prague, and Masaryk University, Brno Czech Republic

Overview Two Collaborative Concepts Virtual Classroom Concept Collaborative Technologies HD Video Introduction to HPC class Participating institutions Network setup Site Setup Time-Shift Problem and its Mitigation Lessons Learned San Diego, October 9th 2007 I2

Two Collaborative Concepts “In” and “Out” “In” – collaborate in a virtual world (on line games, Second Life etc.) System (virtual world) explicit and important part “Out” – bridge the physical distance (classical videoconferences) Invisible system San Diego, October 9th 2007 I2

The Learning Process The teacher as the focal point Verbal expression Non-verbal expression Empathy, … We should not “hide” the teacher Virtual classroom – implementation of the “Out” concept San Diego, October 9th 2007 I2

Virtual Classroom Concept “In” concept: strictly digital classroom, avatars “Out” concept: several physical classrooms sharing one teacher The problem: To make teacher’s presence as natural as possible in all “instances” Use of advanced collaborative technologies San Diego, October 9th 2007 I2

Collaborative Environment High Definition (HD) Video High picture quality Able to record and display classical screen without any distortion Both a screen/blackboard and a teacher as seen in a single classroom Huge amount of data, difficult to process (compress/decompress) in real time Use of uncompressed video Accompanied with uncompressed audio San Diego, October 9th 2007 I2

HD Video Formats San Diego, October 9th 2007 I2

HD Video Parameters Used Basic parameters Effective resolution 1920x1080 pixels 60 interlaced fields per second 4:2:2 color space sampling with 10b per color plane Packetizing 8500 B Jumbo Ethernet frames Data rate of 1.5 Gbps one stream Processing: UltraGrid software San Diego, October 9th 2007 I2

Actual Class Taught Introduction to High Performance Computing Prof. Thomas Sterling, LSU, LA, USA Five participating institutions Masaryk University, Czech Republic (Europe) University of Arkansas Louisiana Technical University MCNC, North Carolina North Carolina State University Spring semester 2007 (January till June) San Diego, October 9th 2007 I2

Data Distribution San Diego, October 9th 2007 I2

Data Distribution II Based on a set of packet reflectors Located in appropriate places in the network Create a logical overlay network Used instead of Multicast (higher reliability) Minimizing the data actually transmitted over any physical link 1:N and N:1 video distribution Only teach sees everybody N:N audio distribution San Diego, October 9th 2007 I2

Data Distribution III San Diego, October 9th 2007 I2

Site Setup HD camera Plus processing hardware/software Only LSU (Johnston) needed several projection screens LCD/Plasma or full HD projectors Stream capture (MU) RAID0 disk array (needs >200MB/s) 1TB per 1.5hour lecture San Diego, October 9th 2007 I2

Audio Using RAT from MBone Tools Uncompressed stream 16 b quantization, 48 kHz sampling rate Data rate 1.6 Mbps N:N distribution Most important—the microphone quality Changes several times during the semester Bad audio could cancel the lecture San Diego, October 9th 2007 I2

LSU Setup San Diego, October 9th 2007 I2

MU Web Pages (Materials) San Diego, October 9th 2007 I2

MU Web Pages (Videos) San Diego, October 9th 2007 I2

Problems Time-shift problem Different time zones Different beginnings of a semester Actual interaction among different students’ groups Problem sets and homework Similar environment is necessary Computing cluster, high performance network, batch system, compilers, … San Diego, October 9th 2007 I2

Time Shift Mitigation Different time zones Negotiations Did not work for this case LSU started at 3pm  MU at 10pm With truly global collaboration always somebody “out of usual working hours” Different start of a semester Those starting later must catch the delay Necessity—access to stored lectures San Diego, October 9th 2007 I2

Time Shift Mitigation II MU started to capture HD video stream when the lectures at LSU started TA time intensive, twice a week, 10pm till midnight Students agreed to watch more than two lectures per week However, problem with homework Hints in “future” lectures Lesser time available (overlap of problem sets) Actual lectures started at 7pm When delay removed, students invited to stay for the real time lectures San Diego, October 9th 2007 I2

Lessons Learned Lot of manual work Setting/tearing networks Both recording time and the re-play Setting local environment and adapting problem sets to it Sharing the evaluation process (points) San Diego, October 9th 2007 I2

Lessons Learned II Adaptation to problems Not so hot for recorded lectures Real time adaptation very difficult We run a back up solution using AccessGrid and Webcasting in Quick Time format Need to develop more detailed monitoring of the network and automatic reaction to any problems (including change of the collaborative environment) See CoUniverse information sheet San Diego, October 9th 2007 I2

Lessons Learned III Students and teacher interaction Must be directly incorporated in the materials Interactive feedback required Some mitigation for delayed groups Problem sets to be solved by group of students (from different institutions) General enough not to be thwarted by the time shift (esp. different start of semester) San Diego, October 9th 2007 I2

Conclusion The Introduction to HPC class ran during the Spring semester 2007 Using collaborative environment based on uncompressed HD video and audio At 5 institutions, almost 100 students attended and passed the class Including all the homework, projects, … We plan to repeat the experience next Spring for some 15 institutions round the globe San Diego, October 9th 2007 I2

Thank you for your attention Questions? San Diego, October 9th 2007 I2