Ayuko Takagi

A method of inserting binary data into MPEG bitstreams for video index labeling

We propose a method for inserting optional binary data into MPEG bitstreams. By inserting additional information like index label effectively into video database, we can deal the additional information with video data itself easily. The proposed method allows us to extract the inserted data perfectly though the MPEG video is a lossy algorithm, and the quality of the decoded images after extracting additional information is almost the same as that of the ordinary MPEG bitstreams. Moreover, the standard MPEG decoder can be used for decoding the bitstreams with inserted binary data. In that case, the additional binary data remains in bitstreams but can decode images without obvious image degradation. To verify the effectiveness of our method, we show simulation results for binary data insertion.

Motion estimation with power scalability and its VHDL model

In the MPEG standard, motion estimation (ME) is used to eliminate the temporal redundancy of video frames. This ME is the most time-consuming task in the encoding of video sequences and is also the one using the most power. Using low-bit images can save the power of ME and a conventional architecture fixed to a certain bit width is used for low-bit motion estimation. It is known that there is a trade-off between power and image quality. ME may be used in various situations, and the relation between demands for power or image quality will depend on those circumstances. We therefore develop an architecture for a low-bit motion estimator with adjustable power consumption. In this architecture, we can select the bit width for the input image and adjust the amount of power for ME. To evaluate its effectiveness, we designed the motion estimator by VHDL and used the synthesis results to estimate the performance.

A method of inserting binary data into MPEG bitstreams

We propose a method for inserting binary data into MPEG bitstreams. The proposed method allows us to extract the inserted data perfectly eventhough the MPEG video is a lossy algorithm, and the quality of the decoded images after extracting additional information is almost the same as that of the ordinary MPEG bitstreams. Moreover, the standard MPEG decoder can be used for decoding the bitstreams with inserted binary data. In that case, the additional binary data remains in bitstreams but can decode images without obvious image degradation. To verify the effectiveness of our method, we show simulation results using BIFS (BInary Format for Scenes) data for MPEG-4 as an example of the binary data for insertion.

Low-bit motion estimation with edge enhanced images for lowpower MPEG encoder

This paper proposes a method for improving the image quality when we use low-bit motion estimation (ME) using linear quantization. By using edge enhanced images for quantization, we can increase the accuracy of the low-bit ME and improve the image quality. It is known that using low-bit images for ME is effective on saving power but it slightly degrades image quality. The quality of the encoded image depends on the thresholds for data quantization, and algorithms for determining thresholds are studied. The proposed method uses linear quantization, which simply truncates the least significant bits. This method is simple without any complicated threshold calculations, and the image quality improves as much as the methods with threshold calculations. To evaluate the effectiveness, we simulate results for image quality and estimate the power consumption using synthesis results from a VHDL model motion estimator.