1. Department of Computer Science and Engineering, CUHK 1 Final Year Project 2003/2004 LYU0302 PVCAIS – Personal Video Conference Archives Indexing System Supervisor: Prof Michael Lyu Presented by: Lewis Ng, Philip Chan 2 December 2003

2. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 2 Outline Introduction Motivation Architecture of PVCAIS - Media Acquisition Module - Archive Indexing Module - Videoconference Accessing Module Implementation in First Term Conclusions Future Work

3. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 3 Introduction PVCAIS stands for Personal Video Conference Archives Indexing System A system that provides the convenient searching and browsing support for videoconferencing users on past videoconference archives

4. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 4 Introduction What is video conference? A real-time communication technology which combines different media: audio, video, text chat, file transfer, whiteboard and shared applications - More precisely is “multimedia conference” - Standard of video conference : ITU-T H.323

5. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 5 Motivation – Videoconference is becoming popular in education, business and personal communication – Participants wish to keep videoconference archives for later references – Normal video and audio files are neither searchable nor helpful to recall their contents – Indexing of videoconference archives has not been investigated till now

6. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 6 Architecture of PVCAIS Consists of 3 modules: - Media Acquisition Module - Archive Indexing Module - Videoconference Accessing Module

7. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 7 Architecture of PVCAIS

8. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 8 Extracts channel data and forms media files Videoconferencing physically contains 4 types of channels: Audio, Video, Data and Control Audio and Video channels: transmit incoming/ outgoing audio and video information Data channel: carries information for user application such as Text Chat, Whiteboard and File Transfer Control channel: transmits system control information such as Member Information Architecture Media Acquisition Module

9. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 9 Architecture Media Acquisition Module Video-in and Video-out channel – Reduce redundancy : just store key-frames – Detect scene change in real time – Each key frame picture is stored with a timestamp

10. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 10 Architecture Media Acquisition Module Audio-in and Audio-out channel – Mixed into one stream after videoconference – Will be used for Speech Recognition

11. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 11 Architecture Media Acquisition Module Text Chat channel – sender / receiver – message – store with timestamp

12. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 12 Architecture Media Acquisition Module Whiteboard channel – Consists of a text-based index file and a number of snapshot pictures – Index file records timestamp for each whiteboard update event and the path of the corresponding snapshot picture – Update of this channel happens in a period of time -> need to detect when update begins and ends by monitoring data transfer in this channel

13. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 13 Architecture Media Acquisition Module File Transfer channel – Make a copy of the sent/received files to the directory of archive – Index file includes sender’s / recipient’s user names and the path of the files

14. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 14 Architecture Media Acquisition Module Control channel – Contains timestamp and information of each event such as member joined and member left

15. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 15 Architecture Media Acquisition Module Paradigm of storing the videoconference archives. Video_in Video_out Audio_in Audio_out Text_chat Whiteboard File_in File_ out Control Time 0:00:00 One line Two lines One line Two lines Three lines One line Two lines Three lines Four lines One line Two lines Three lines Four lines Five lines i iii Video_in archive Audio archive Text chat archive Whiteboard archive Document archive Control archive Video_out archive

16. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 16 Architecture Archive Indexing Module 7 raw files are extracted in Media Acquisition Module Need to implement some multimedia indexing functions to retrieve more information These includes: Face Detection, Face Recognition, Speech Recognition, OCR, Time-based Text Merging, Keyword Selection, Title Generation

17. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 17 Architecture Archive Indexing Module Face Detection - Distinguish between Slides and Faces - If face is detected, find out the face region Slide Face

18. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 18 Architecture Archive Indexing Module Face Recognition - Associate human faces in Video-in with name - Need to keep a face base - If no match in the face base, ask remote user to enter the name

19. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 19 Architecture Archive Indexing Module Speech Recognition - Generate speech script from audio archive - Speech of a videoconferencing contains the most information - Can use commercial library: Microsoft SAPI, IBM Via Voice OCR - Take the slide archive as input and recognizes text from them - Need to identify and localize text on the complex background

20. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 20 Architecture Archive Indexing Module Time-based Text Merging - Merge the Speech transcript, Chat script, Whiteboard script and slide text archive into the Text Source according to their timestamp Keyword Selection - Take the Text Source as input - Generate keyword for the videoconference

21. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 21 Architecture Archive Indexing Module Generate XML index file - Integrate all the archives - Store all the related files of a videoconference into a single directory Title Generation - Take the Text source as input - Automatically generate a title for the videoconference

22. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 22 Architecture Videoconference Accessing Module Provides an interface for user to manage, search and review all indexed conference archives. Allows user to modify the content of a conference, such as editing title or keywords, or delete a conference. Allows user to search for a conference by different criteria, such as period of meeting, member name or keyword. Allows user to review a conference by playing back different media in a synchronized way.

23. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 23 Implementation NetMeeting 3.0 – A Windows feature that provide Internet conferencing function. – Support video, audio and data conferencing including application sharing, chat, whiteboard and file transfer. – Other features include remote desktop sharing.

24. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 24 Implemetation NetMeeting 3.0 SDK – An extension of NetMeeting, provides an interface for programmers and Web developers to integrate conferencing capabilities into their applications. – API is in the form of COM interfaces and functions.

25. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 25 Implementation A simple NetMeeting compatible videoconference program built on top of the NetMeeting 3.0 SDK. Support: – Video – Audio – Text message – File Transfer – Whiteboard

27. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 27 Implementation Media Acquisition Module By directly using the functions of the API, the following raw data can be obtained: – the members information – file transfer record – text messages record Video, audio and whiteboard data cannot be directly obtained.

28. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 28 Implementation Media Acquisition Module Video – create a thread to check the display of the video windows – if scene change is detected, the video will be captured and stored as a still image. – the stored images are key frames of the conference.

29. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 29 Implementation Media Acquisition Module Audio – create a thread to record the local audio from the microphone. – members of the conference will continuously exchange the audio data. – all the received audio files and locally recorded audio files will be combined to generate a single audio file.

30. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 30 Whiteboard – cannot capture the NetMeeting whiteboard information because the format of the data is not stated in the API. – solution: create our own whiteboard function and data format. Implementation Media Acquisition Module

31. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 31 Implementation Archive Indexing Module The stored key-frames will be used for face detection and recognition after the conference. The final audio file will be used for voice recognition, the voice engine used is Microsoft SAPI.

32. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 32 Implementation Videoconference Accessing Module An interface for conferences management. --- search conference by member name or chatting content. --- review conference by playing back the content of the conference, including audio, key-frames, member information, file exchange record and chatting content.

33. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 33 Conclusions We developed a videoconferencing agent All channel data except whiteboard can be collected. Speech Recognition and Face Detection & Recognition is integrated into the system but accuracy needs to be improved Simple searching can be performed on stored archives

34. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 34 Future Work Whiteboard Improve accuracy of Voice Recognition Improve performance of Face Detection XML Better searching method OCR for slide in video Improve User Interface

35. LYU0302 : PVCAIS – Personal Video Conference Archives Indexing System 35 Q & A Session