The different formats of codec stream carried in the radio access network and the core network make the double speech encoding/decoding necessary, which degrades the speech quality. Accordingly, codec negotiation tech...The different formats of codec stream carried in the radio access network and the core network make the double speech encoding/decoding necessary, which degrades the speech quality. Accordingly, codec negotiation technologies are necessary for unifying encoding/ decoding in the whole process. Transcoder Free Operation (TrFO), Tandem Free Operation (TFO), and network quality deciding technology are the leading codec negotiation technologies. The TrFO is a mechanism for optimum selection during the establishment of a call. It tries to establish connection between User Equipment (UE) without Transcoder (TC). Its successful fulfillment enables the efficient utilization of bandwidth. The TFO, a standby technology of TrFO, is the negotiation technology of an in-band codec. With it, the user codec stream is free from the compression and decompression by the voice codec, and the quality of voice can accordingly be improved. The network-quantity deciding technology adopts G.711 or G.729 flexibly according to the number of accessed calls. This allows the access of new calls while won’t increase the load of network too much.展开更多
Aiming at improving rate flexibility of the enhanced voice services (EVS) channel-aware mode for various VoIP applications, two new bit-rate channel-aware modes are proposed in this paper in addition to the existing 1...Aiming at improving rate flexibility of the enhanced voice services (EVS) channel-aware mode for various VoIP applications, two new bit-rate channel-aware modes are proposed in this paper in addition to the existing 13.2 kbit/s mode. Channel-aware mode uses forward error correction by transmitting re-encoded information redundantly for use when the original information is lost or discarded due to late arrival to the receiver. The primary frame bit rate is reduced for the redundant accommodation. A modified quantization scheme is proposed for core encoding regarding the quality degradation. Partial redundant coding is a simplification of that in the existing 13.2 kbit/s channel-aware mode due to the bit constraint. The objective evaluation results of PESQ show that the additional channel-aware modes achieve similar performance in improving the error robustness against missing packets as that of the existing 13.2 kbit/s mode. Multiple bit-rate modes can be dynamically selected in the communication system for more voice services in different bandwidths. On the other hand, optimal allocation based on real-time feedback can adapt to the rapidly-changing network environment as well as possible.展开更多
ITU-T G. 729 is the primarily recommended speech codec by H. 323 standard. This paper describes how to implement G. 729 codec in IP telephony gateway, and goes deep into the programming skills on TMS320C6201 DSP and o...ITU-T G. 729 is the primarily recommended speech codec by H. 323 standard. This paper describes how to implement G. 729 codec in IP telephony gateway, and goes deep into the programming skills on TMS320C6201 DSP and optimizing methods of program code to reduce the speech processing delay time of G. 729 codec. Due to adopting these optimizing methods and programming skills, we have implemented a high-speed speech codec that can process concurrently 20 voice channels with single TMS320C6201 chip in IP telephony gateway. Finally, the paper analyzes the performance results of ITU-T G. 729 codec based on TMS320C6201.展开更多
In this paper, we present a method using video codec technology to compress ECG signals. This method exploits both intra-beat and inter-beat correlations of the ECG signals to achieve high compression ratios (CR) and ...In this paper, we present a method using video codec technology to compress ECG signals. This method exploits both intra-beat and inter-beat correlations of the ECG signals to achieve high compression ratios (CR) and a low percent root mean square difference (PRD). Since ECG signals have both intra-beat and inter-beat redundancies like video signals, which have both intra-frame and inter-frame correlation, video codec technology can be used for ECG compression. In order to do this, some pre-process will be needed. The ECG signals should firstly be segmented and normalized to a sequence of beat cycles with the same length, and then these beat cycles can be treated as picture frames and compressed with video codec technology. We have used records from MIT-BIH arrhythmia database to evaluate our algorithm. Results show that, besides compression efficiently, this algorithm has the advantages of resolution adjustable, random access and flexibility for irregular period and QRS false detection.展开更多
Nowadays, from home monitoring to large airport security, a lot of digital video surveillance systems have been used. Digital surveillance system usually requires streaming video processing abilities. As an advanced v...Nowadays, from home monitoring to large airport security, a lot of digital video surveillance systems have been used. Digital surveillance system usually requires streaming video processing abilities. As an advanced video coding method, H.264 is introduced to reduce the large video data dramatically (usually by 70X or more). However, computational overhead occurs when coding and decoding H.264 video. In this paper, a System-on-a-Chip (SoC) based hardware acceleration solution for video codec is proposed, which can also be used for other software applications. The characteristics of the video codec are analyzed by using the profiling tool. The Hadamard function, which is the bottleneck of H.264, is identified not only by execution time but also another two attributes, such as cycle per loop and loop round. The Co-processor approach is applied to accelerate the Hadamard function by transforming it to hardware. Performance improvement, resource costs and energy consumption are compared and analyzed. Experimental results indicate that 76.5% energy deduction and 8.09X speedup can be reached after balancing these three key factors.展开更多
由于数字静态照相机等仪器也搭载有高画质的视频摄像功能，在视频质量提供的同时，对录音音质提升的需求也在提高。OKI开发了行业内第一款内置自动降风噪过滤器的16bit单声道Audio CODEC IC ML26127，自动降风噪过滤器具有自动抑制麦克...由于数字静态照相机等仪器也搭载有高画质的视频摄像功能，在视频质量提供的同时，对录音音质提升的需求也在提高。OKI开发了行业内第一款内置自动降风噪过滤器的16bit单声道Audio CODEC IC ML26127，自动降风噪过滤器具有自动抑制麦克风录音时混入风噪．提高录音音质的功能，是为带播放录音功能的便携式设备而开发的最佳产品。展开更多
文摘The different formats of codec stream carried in the radio access network and the core network make the double speech encoding/decoding necessary, which degrades the speech quality. Accordingly, codec negotiation technologies are necessary for unifying encoding/ decoding in the whole process. Transcoder Free Operation (TrFO), Tandem Free Operation (TFO), and network quality deciding technology are the leading codec negotiation technologies. The TrFO is a mechanism for optimum selection during the establishment of a call. It tries to establish connection between User Equipment (UE) without Transcoder (TC). Its successful fulfillment enables the efficient utilization of bandwidth. The TFO, a standby technology of TrFO, is the negotiation technology of an in-band codec. With it, the user codec stream is free from the compression and decompression by the voice codec, and the quality of voice can accordingly be improved. The network-quantity deciding technology adopts G.711 or G.729 flexibly according to the number of accessed calls. This allows the access of new calls while won’t increase the load of network too much.
基金Supported by the International Cooperation Research Project between Ericsson(Sweden) and BIT
文摘Aiming at improving rate flexibility of the enhanced voice services (EVS) channel-aware mode for various VoIP applications, two new bit-rate channel-aware modes are proposed in this paper in addition to the existing 13.2 kbit/s mode. Channel-aware mode uses forward error correction by transmitting re-encoded information redundantly for use when the original information is lost or discarded due to late arrival to the receiver. The primary frame bit rate is reduced for the redundant accommodation. A modified quantization scheme is proposed for core encoding regarding the quality degradation. Partial redundant coding is a simplification of that in the existing 13.2 kbit/s channel-aware mode due to the bit constraint. The objective evaluation results of PESQ show that the additional channel-aware modes achieve similar performance in improving the error robustness against missing packets as that of the existing 13.2 kbit/s mode. Multiple bit-rate modes can be dynamically selected in the communication system for more voice services in different bandwidths. On the other hand, optimal allocation based on real-time feedback can adapt to the rapidly-changing network environment as well as possible.
基金Supported by the National Natural Science Foundation of China under grant!69773046
文摘ITU-T G. 729 is the primarily recommended speech codec by H. 323 standard. This paper describes how to implement G. 729 codec in IP telephony gateway, and goes deep into the programming skills on TMS320C6201 DSP and optimizing methods of program code to reduce the speech processing delay time of G. 729 codec. Due to adopting these optimizing methods and programming skills, we have implemented a high-speed speech codec that can process concurrently 20 voice channels with single TMS320C6201 chip in IP telephony gateway. Finally, the paper analyzes the performance results of ITU-T G. 729 codec based on TMS320C6201.
文摘In this paper, we present a method using video codec technology to compress ECG signals. This method exploits both intra-beat and inter-beat correlations of the ECG signals to achieve high compression ratios (CR) and a low percent root mean square difference (PRD). Since ECG signals have both intra-beat and inter-beat redundancies like video signals, which have both intra-frame and inter-frame correlation, video codec technology can be used for ECG compression. In order to do this, some pre-process will be needed. The ECG signals should firstly be segmented and normalized to a sequence of beat cycles with the same length, and then these beat cycles can be treated as picture frames and compressed with video codec technology. We have used records from MIT-BIH arrhythmia database to evaluate our algorithm. Results show that, besides compression efficiently, this algorithm has the advantages of resolution adjustable, random access and flexibility for irregular period and QRS false detection.
文摘Nowadays, from home monitoring to large airport security, a lot of digital video surveillance systems have been used. Digital surveillance system usually requires streaming video processing abilities. As an advanced video coding method, H.264 is introduced to reduce the large video data dramatically (usually by 70X or more). However, computational overhead occurs when coding and decoding H.264 video. In this paper, a System-on-a-Chip (SoC) based hardware acceleration solution for video codec is proposed, which can also be used for other software applications. The characteristics of the video codec are analyzed by using the profiling tool. The Hadamard function, which is the bottleneck of H.264, is identified not only by execution time but also another two attributes, such as cycle per loop and loop round. The Co-processor approach is applied to accelerate the Hadamard function by transforming it to hardware. Performance improvement, resource costs and energy consumption are compared and analyzed. Experimental results indicate that 76.5% energy deduction and 8.09X speedup can be reached after balancing these three key factors.
文摘由于数字静态照相机等仪器也搭载有高画质的视频摄像功能，在视频质量提供的同时，对录音音质提升的需求也在提高。OKI开发了行业内第一款内置自动降风噪过滤器的16bit单声道Audio CODEC IC ML26127，自动降风噪过滤器具有自动抑制麦克风录音时混入风噪．提高录音音质的功能，是为带播放录音功能的便携式设备而开发的最佳产品。
