Nippon Telegraph and Telephone Corporation

Nec Corporation

Meidensha Corporation

Takanori Hayashi

Kazuhisa Yamagishi

Jun Okamoto

Noritsugu Egi

Makoto Niwakawa

Toshitaka Ishii

Seiji Tabayashi

This invention provides a video quality estimation apparatus () including a packet analysis unit () that derives the bit rate of an encoded video packet contained in an input packet, and the bit amount of the encoded video packet for each encoded video frame type, a video subset frame characteristic estimation unit () that derives the frame characteristic of each video frame type from the bit rate derived by the packet analysis unit (), and an encoding quality estimation unit () that derives, based on the bit rate and the bit amount of each video frame type, a video quality value quantitatively representing the quality of encoded video data that is affected by encoding degradation. The video quality estimation apparatus performs more accurate video quality estimation by taking account of the bit amount of each video frame type.

Video quality estimation apparatus, video quality estimation method, and program

An audio quality estimation apparatus includes an audio packet loss frequency calculation unit () which, when at least one audio packet to be assessed exists in singly or continuously generated IP packet losses, calculates an audio packet loss frequency based on information of received IP packets by counting the packet losses as an audio packet loss of one time regardless of the continuous length, an average influence time calculation unit () which calculates, based on information of received IP packets, an average influence time serving as an average time during which audio quality is influenced when the audio packet loss frequency is 1, and a subjective quality assessment value estimation unit () which estimates a subjective quality assessment value based on the audio packet loss frequency and average influence time.

Audio quality estimation method, audio quality estimation apparatus, and computer readable recording medium recording a program

A multi-modal quality estimation unit () estimates a multi-modal quality value (A) on the basis of an audio quality evaluation value (A) and a video quality evaluation value (). In addition, a delay quality degradation amount estimation unit () estimates a delay quality degradation amount (B) on the basis of an audio delay time (A) and a video delay time (B). A video communication quality estimation unit () estimates a video communication quality value () on the basis of a multi-modal quality value (A) and a delay quality degradation amount (B).

Video communication quality estimation apparatus, method, and program

A packet loss frequency calculation unit () which counts, from an extracted packet loss pattern, packet losses generated in a predetermined interval representing the interval of a plurality of continuous IP packets as a packet loss of one time, thereby calculating the value as a packet loss frequency. The packet loss frequency calculation unit () also calculates a burst packet loss length representing the number of continuously lost packets from the packet loss pattern. An average burst packet loss length within a quality estimation interval is calculated from the burst packet loss length. A packet loss variation index calculation unit () derives a packet loss variation index from the average burst packet loss length. On the other hand, an encoding quality calculation unit () calculates an encoded video quality value based on the extracted encoding bit rate and frame rate. A video quality estimation unit () calculates a video quality value based on the encoded video quality value, packet loss frequency, and packet loss variation index. This allows to properly estimate the quality of a video in which a burst packet loss has occurred.

Video quality estimation apparatus, method, and program

In estimating subjective video quality corresponding to main parameters which are input as an input frame rate representing the number of frames per unit time, an input coding bit rate representing the number of coding bits per unit time, and an input packet loss rate representing a packet loss occurrence probability of an audiovisual medium, a degradation model specifying unit specifies a degradation model representing the relationship between the packet loss rate and the degradation in reference subjective video quality on the basis of the input frame rate and input coding bit rate. A desired subjective video quality estimation value is calculated by correcting the reference subjective video quality on the basis of a video quality degradation ratio corresponding to the input packet loss rate calculated by using the degradation model.

In estimating subjective video quality corresponding to main parameters () which are input as an input coding bit rate (B/B) representing the number of coding bit rates per unit time and an input frame rate (A/A) representing the number of frames per unit time of an audiovisual medium, an estimation model specifying unit specifies, on the basis of the input coding bit rate (B/input frame rate (A)), an estimation model () representing the relationship between subjective video quality and the frame rate (/coding bit rate) of the audiovisual medium. Subjective video quality corresponding to the input frame rate (A/input coding bit rateB) is estimated by using the specified estimation model () and output as an estimation value ().

A system for avoiding congestion in mobile terminal communication, includes (a) a plurality of mobile stations, (b) a plurality of base stations, and (c) a base station controller connected to the base stations through a common communication line. The base station controller (a) monitors an activity ratio of a down common communication line, (b) when it is judged that the activity ratio of a down common communication line may be congested, assigns an order of precedence to each of the mobile stations using the common communication line, based on the number of base stations to which each of the mobile stations concurrently makes communication, and (c) abandons low-rate voice frames at a constant ratio among voice frames of a mobile station to which a low order of precedence is assigned.

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Tokyo, Japan

Takanori Hayashi