We are presenting a wavelet based video conferencing system. Openphone. Dirac Wavelet based video codec
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(2) Investigating Wavelet Based Video Conferencing We are presenting a wavelet based video conferencing. system. Openphone Peer to peer video conferencing system Dirac Wavelet based video codec. 2.
(3) Outline Introduction Video Conferencing system Openphone. Wavelet based video codec Dirac. . Embedding Process Improvements in Openphone Improvements in Dirac Scalability Summary 3.
(4) Video Conferencing – System Overview. 4.
(5) Open Phone in Video Conferencing System What is Openphone? PWLIB SIP RTP. 5.
(6) Outline Introduction Video Conferencing system Openphone. Wavelet based video codec Dirac. . Embedding Process Improvements in Openphone Improvements in Dirac Scalability Summary 6.
(7) Dirac: Wavelet Based Video Codec What is Dirac? Open Source technology High Performance, simple and Modular Design Video. Codec Support Multiple Picture Formats Good Subjective quality due to Psycho Visual property of wavelet. 7.
(8) Dirac Encoder Architecture. 8.
(9) Outline Introduction Video Conferencing system Openphone. Wavelet based video codec Dirac. . Embedding Process Improvements in Openphone Improvements in Dirac Scalability Summary 9.
(10) Dirac Integration In Openphone Dirac version 0.9.1 has successfully embedded in. Openphone.. Methods Source Code Integration Dirac Library PlugPlug-in. Support in Openphone Registration of Dirac in Openphone Dirac Bridging Classes 10.
(11) Outline Introduction Video Conferencing system Openphone. Wavelet based video codec Dirac. . Embedding Process Improvements in Openphone Improvements in Dirac Scalability. Summary 11.
(12) Buffer I/O Sender Side. Take video from the camera Encodes it using the Dirac encoder and directs the output. bitbit-stream to a buffer. buffer. The output bitbit-stream buffer is then handled by Openphone Transmits the bitbit-stream over network in order to send it to the receiver side side.. Receiver Side Openphone receives the bitbit-stream, Decodes it using Dirac decoder and Displays the video on the local display window window... 12.
(13) Parameter passing from Openphone We have modified Dirac encoder / decoder to get the. parameter list from Openphone instead of acquiring it through console input. input. Width Height Frame rate BitBit-rate Video format Quality etc. etc. whereas Dirac encoder/decoder uses this list to encode/decode as appropriate appropriate.. 13.
(14) Bit Bit--stream Fragmentation . Divide the bit-stream into network supported size packets.. 14.
(15) Size Up gradation (CIF) We have added support for CIF size (352x288) as well. as for QCIF (176x144) size. Practical issues involved were increase in encoding time and size of bitbit-stream. Frame rate reduced to 2,3 fps. 15.
(16) Frame Rate Optimization Dirac usually generates a bitbit-stream of 5 to 75. kilobytes modified the Openphone architecture to transmit the whole bitbit-stream of one frame before grabbing the next frame. Increased the frame rate to 12 fps.. 16.
(17) INTER Mode Motion Estimation Support BitBit-stream size reduction Maintaining the starting and ending sequence of the. frame Maintaining the initialization and rere-initialization of Dirac encoder. Also, some buffers are introduced for maintaining the bitbit-stream before transmission.. 17.
(18) GUI Support The user can configure video conferencing options as. desired Dial / Listen Video Size CIF or QCIF. Quality Encoding mode (INTER / INTRA). 18.
(19) GUI Main Window. 19.
(20) Crashing Problem Video conferencing lasted only a couple of hours Memory leakages and bugs have been removed from. the code by extensive debugging. Tested for 50 hours.. 20.
(21) Discrete Wavelet Transform Old DWT filter DD9_7 10 frames per second. Experimentations have been done over all the available. wavelet filters Replaced with HAAR0 Performance gain 25 % Frame rate increased to 15 frames per second 21.
(22) Dirac 1.0.2 Latest release of Dirac video codec version 1.0.2 has. been successfully implemented in Openphone. Frame rate is around 15 frames per second. 22.
(23) Client / Server Configurations Quality and Size To be set from both sides. Now only Dialer has the option and whatever he. selects becomes the communication size for video conferencing.. 23.
(24) Experiments and Results (Cont.) Comparison of Dirac and other video codec Comparison of Openphone Codecs. Average PSNR (dB). 50 45 40. H263-Intra. 35. H261-Intra Dirac-Intra. 30 25 20 50 100 150 200 250 300 350 400 450 500 Bitrate. . Bit rate Vs PSNR of Openphone Codec 24.
(25) Experiments and Results (Cont.) Subjective Quality Difference in H.261,H.263 and Dirac. at 300 Kbps. H.261. H.263. Dirac 25.
(26) Outline Introduction Video Conferencing system Openphone. Wavelet based video codec Dirac. . Embedding Process Improvements in Openphone Improvements in Dirac Scalability Summary 26.
(27) Improvements in Dirac Improvement in Motion Estimation 3D Recursive Search Algorithm Reduced Computational Complexity Performance. Scalability Three Different Bit Streams. Base Layer, Enhancement Layer1, Enhancement Layer2 Three Types SNR, Spatial, Temporal . 27.
(28) Improvements in Motion Estimation Existing Motion Estimation Algorithm: Three Stages Motion vectors are found for each block of 1 pixel accuracy using Hierarchical Motion Estimation. Vectors are refined to sub pixel accuracy. Mode Decision 28.
(29) Continued… Process of down conversion in hierarchical motion. estimation. 29.
(30) Continued… In lowest level, two candidate vector lists are generated , one is. centered at zero motion vector and the other spatially predicted motion vector. In all other levels, there candidate vector lists are generated, two above and one guide vector list ,which is the best motion vector of the block at the immediate lower level.. Sum of absolute difference is used as a cost function. 30.
(31) Continued… Complexity of Existing. Algorithm Using Hierarchical Motion Estimation Huge amount of SAD calculations, taking 80% of total encoding time 3DRS Algorithm Spatial Predictor Temporal Predictor. A. B MB in current frame. C. X. MB in previous frame Current MB. E. 31.
(32) Continued… Proposed ME Scheme Based on 3DRS. 32.
(33) Experiments and Results The Comparison of Motion Estimation (ME) Results for CIF with GOP Size = 36, B Frames = 18 Sequence. Foreman. Container. News. Highway. Algorithm File Size (KB). PSNR-Y (dB). Avg(SAD) /Frame. Original 1316. 37.9834. 122871. 3DRS. 1281. 37.7774. 47285. Original. 825. 35.8540. 142651. 3DRS. 769. 35.5432. 58371. Original 791. 39.8091. 76566. 3DRS. 781. 39.7951. 27965. Original. 7231. 39.2548. 107357. 3DRS. 6732. 39.0925. 46962. %SAD %ME Time Reduction of Reduction of 3DRS 3DRS. %Total Time Reduction of 3DRS. 62%. 61%. 49%. 59%. 59%. 46%. 63%. 60%. 43%. 57%. 55%. 42%. 33.
(34) Experiments and Results The Comparison of Motion Estimation (ME) Results for CIF with GOP Size = 54, B Frames = 36 Sequence. Foreman. Container. Algorithm File Size (KB). 1129. 37.3678. 126498. 3DRS. 1075. 37.1229. 48095. Original. 697 635. 37.7331 37.7676. 681 656 6050 4692. 3DRS. 3DRS Original. Highway. Avg(SAD) /Frame. Original. Original News. PSNR-Y (dB). 3DRS. %SAD %ME Time Reduction of Reduction of 3DRS 3DRS. %Total Time Reduction of 3DRS. 62%. 62%. 49%. 79323 30872. 61%. 59%. 43%. 39.4961 39.4300. 78479 28453. 64%. 60%. 44%. 38.7711 38.5662. 110046 48299. 56%. 57%. 43%. 34.
(35) Conclusion Implemented modified adaptive 3DRS algorithm by. using temporal and spatial block motion vectors. Reduces the average number of SAD calculations per block by 50% to 65%. Reduces the motion estimation time from 50% to 60%. Reduces the total encoding time from 30% to 50%. Average PSNR and bit stream size does not show significant variations.. 35.
(36) Outline Introduction Video Conferencing system Openphone. Wavelet based video codec Dirac. . Embedding Process Improvements in Openphone Improvements in Dirac Scalability Summary 36.
(37) Scalability Three different bitbit-streams Base Layer (7(7-16) Enhancement Layer 1 (4(4-6) Enhancement Layer 2 (1(1-3). Three types SNR Spatial Temporal ( In progress). 37.
(38) Dirac Bit Stream Syntax. 38.
(39) Dirac Bit Stream Syntax. 39.
(40) Dirac Architecture For Scalability. 40.
(41) Dirac Bit stream Splitter. 41.
(42) Bit Stream Layers After Splitting Bit Stream Layers After Splitting for Inter Frame. 42.
(43) Dirac Bit stream Joiner. 43.
(44) Bit Stream After joining Bit Stream After Joining for Inter Frame. 44.
(45) Scalability In Openphone Three different bitbit-streams Base Layer (7(7-16) Enhancement Layer 1 (4(4-6) Enhancement Layer 2 (1(1-3 ). Three types Spatial SNR Temporal (Not completed). 45.
(46) Scalability in Openphone • User receive video depending on his capabilities.. 46.
(47) Outline Introduction Video Conferencing system Openphone. Wavelet based video codec Dirac. . Embedding Process Improvements in Openphone Improvements in Dirac Scalability Summary 47.
(48) Tasks Completed Understanding the code of different modules of Dirac. video codec Documenting the algorithmic details Improvement in encoding time of Dirac 3DRS implementation, Comp complexity reduction , wavelet transform improvement Implementing SNR and Spatial scalability in Dirac Integrating Dirac in Open phone Implementing Multi-streaming in open phone Providing Graphical User Interface support Support up till CIF format Improvement Dirac to real time Extended frame rate from 3 to 15 48.
(49) Ongoing and Future Work Addressing other modules regarding performance. perspective Implementing Wavelet coefficient parent child relationship for scalable video performance improvement Implementing Temporal scalability Support extended for HDTV. Multi-user support for scalability in open phone Association of audio stream Improvement of GUI according to new developments Chat, File sharing. 49.
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