ENCODING STORED VIDEO FOR STREMMING APPLICATIONS

Presented By:Navin Kumar09EAXEC075

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 11, NO. 2, FEBRUARY 2001

I.-MING PAOMING-TING SUN

Outline

Introduction

Background Study

Problem Statement

Contribution of Paper

Sliding-Window Encoding Scheme

DCT Coefficient Selection

Simulation Result

Conclusion

References

Introduction

Digital video applications have become increasingly popular.

There are several video standards established for different purposes.

e.g, MPEG-1, MPEG-2, H.263…

Delay is an important issue in real-time communication.

Background Study

Streaming video applications

Video sequences are Encoded off-line Stored in a server

Pre-load before playback

E.g, VOD

Problem Statement

Bit allocation and video quality

Minimum distortion under the rate constraint

Contribution of this paper

1. Propose a sliding-window rate-control scheme.

2. A quantized DCT coefficient selection scheme.

3. Improve video quality for video streaming.

Sliding-Window Encoding Scheme

Use future frames to improve video quality.

Set window size W to encode video frame. frames : i, i+1, …, i+W-1 let frame i be the current frame

This proposed encoder better than real-time’s for the same bitrate.

Buffer-size and Pre-loading Time Requirement

Why need buffer? Store the excess bit waiting to be decodede.g, bits of future frames

Why need pre-loading time? The delay before playback

DCT Coefficient Selection

Quantize the DCT coefficients rate-distortion sense and macroblock level. quantizer step-sizes(Q) largely determine the rate-distortion

tradeoff.

There are not optimal for all video sequences by limited quantizer selections and predetermined run-length codeword.

The encoder can adjust the quantized coefficient’s level. a marginal distortion increase but a significant bit-rate reduction.

Simulation Result

Different bitrates: 32, 64, and 128 kbits/s

Different types of video sequences:

large facial movement head and shoulder camera panning

Compare with TMN8

CONCLUSION

Better video quality than TMN8 in high motion-activity frames and scene-change frames.

Require more buffer size and pre-loading time than TMN8.

References

[1] Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s, ISO/IEC 11 172, Aug. 1993.

[2] Generic coding of moving pictures and associated audio information, ISO/IEC 13 818, 1995.

[3] Video coding for low bit rate communication, ITU-T Recommendation H.263, March 1996.

[4] G. Cote, B. Erol, M. Gallant, and F. Kossentini, “H.263+: Video coding at low bit rates,” IEEE Trans. Circuits Syst. Video Technol., vol. 8, pp. 849–866, Nov. 1998.

[5] Test model 5, JTC1/SC29/WG11 coding of moving pictures and associated audio MPEG 96/1260, ISO-IEC/JTC1/SC29/WG11, Mar. 1996.

[6] Video codec test model, TMN8, ITU-T/SG15, Jun. 1997.

[7] Encoding Stored Video For Stremming Applications, IEEE Transactions On Circuits And Systems For Video Technology, Vol. 11, No. 2, February 2001