&lt;title&gt;Performance of real-time software-only H.261 codec on the Power Macintosh&lt;/title&gt;

Wu, Hsi-Jung; Wang, Katherine S.; Normile, J.; Ponceleón, Dulce; Chu, Ken; Sung, K.

doi:10.1117/12.206389

Cited by 2 publications

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“…There are currently known a few software-only solutions for H.261 videoconferencing and MPEG playing back on the Power Mac and PC platforms. For example, video codec [1] is capable of delivering real-time, full-duplex QCIF (176x144) connections between two Power Macintosh 8100s. This paper describes a software implementation of the fast computational algorithms for video codecs exploiting DCI technique, which have been presented by the author at the February's 1995 SPIETIS&T meeting [2].…”

Section: Introductionmentioning

confidence: 99%

<title>High-performance software-only H.261 video compression on PC</title>

Kasperovich

1996

Digital Video Compression: Algorithms and Technologies 1996

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This paper describes an implementation of a software H.261 codec for PC, that takes an advantage of the fast computational algorithms for DCT-based video compression, which have been presented by the author at the February's 1995 SPIEI'IS&T meeting. The motivation for developing the H.261 prototype system is to demonstrate a feasibility of real time software-only videoconferencing solution to operate across a wide range of network bandwidth, frame rate, and resolution ofthe input video. As the bandwidths ofcurrent network technology will be increased, the higher frame rate and resolution of video to be transmitted is allowed, that requires, in turn, a software codec to be able to compress pictures of CIF (352x288) resolution at up to 30 frame/sec. Running on Pentium 133 MHz PC the codec presented is capable to compress video in CIF format at 21-23 frame/sec. This result is comparable to the known hardware-based H.261 solutions, but it doesn't require any specific hardware. The methods to achieve high performance, the program optimization technique for Pentium microprocessor along with the performance profile, showing the actual contribution of the different encoding/decoding stages to the overall computational process, are presented.

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Section: Introductionmentioning

confidence: 99%

<title>High-performance software-only H.261 video compression on PC</title>

Kasperovich

1996

Digital Video Compression: Algorithms and Technologies 1996

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A real time software-only H.261 codec

Wang

Normile

et al.

1995 International Conference on Acoustics, Speech, and Signal Processing

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Video and audio conferencing over networks is becoming increasingly popular due to the availability of video and audio I/O as standard equipment on many computer systems. So far, many algorithms have concentrated on playback only capability [ 11. This generally results in unacceptable real-time performance with respect to latency and encoder complexity. We describe a software-only system that allows full duplex video communication. For our analysis and implementation we chose a DCT based method that uses motion estimation and is modelled on the CCITT H.261 standard.We begin with a brief discussion of the algorithm and follow with an analysis of the computational requirements for each major block. The results presented show the effect of computational simplifications on signal to noise ratio and image quality. In our conclusion, we examine the processing needs for full resolution coding and project when this will become available. INTRODUCTIONThe conventional approach to teleconferencing has been to use dedicated hardware for compression and decompression. This viewpoint assumes that the computational requirements are beyond the capabilities of general purpose processors. Some of our earlier work [2] showed how a small number of specialized signal processors could be used to achieve real-time compression and decompression. Since then there has been a four to eight fold increase in the performance of general processors. Our goal is to provide real-time simultaneous encode and decode on a single general purpose processor.We chose to implement the CCITT H.26 1 [3] video codec because of its widespread acceptance as a video conferencing standard and its ability to deliver good quality video at low bit rates. Undoubtedly, higher quality compression techniques will be developed in the future; however, in our opinion the H.26 1 standard offers the best overall performance at present. The target characteristics of our codec are 10 frames/sec of QCIF 176x144 sized frames simultaneously encoded and decoded at bit rates from 64 kbits/s to 384 kbits/s. The size and frame rate are near the lower threshold for acceptable visual performance.The H.261 encoder consists of a forward path comprised of motion compensated error computation, followed by DCT, scalar quantization and lossless coding and a feed-

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<title>Performance of real-time software-only H.261 codec on the Power Macintosh</title>

Cited by 2 publications

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<title>High-performance software-only H.261 video compression on PC</title>

<title>High-performance software-only H.261 video compression on PC</title>

A real time software-only H.261 codec

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