Abstract:
This invention comprise a connection call processing unit for exchanging settings of encoded data and redundant data stored in each packet, and a setting of at least any one of encoding bit rates of a sound encoding unit and a redundant data generating unit, between the media transmitting/receiving apparatus, and a sound decoding unit for decoding at least any one of the encoded data and the redundant data based on the setting of the encoding bit rate exchanged between the media transmitting/receiving apparatuses, wherein the encoded data and the redundant data are separated from each packet based on the setting of the data stored in the packets exchanged between the media transmitting/receiving apparatuses, and lost encoded data is compensated with the redundant data, and thereby degradation of the media quality is prevented even when the packet loss occurs in transferring media encoded data in the packets via an IP network.
Abstract:
A conversion server and a plurality of clients are connected via a transmission line. The conversion server that receives image coded data from the clients converts the image coding system in accordance with the coding system available to each client, the coding setting, and the status of the transmission line, and transmits the converted image coded data. For a client where the number of images that can be displayed is limited, the conversion server decodes a selected plurality items of image coded data, re-encodes the selected pieces into one composite image, and transmits the re-encoded image. The conversion server also comprises decoding processing units, one for each connected client, for decoding image coded data from each client. In response to a display image switching request from a client, the conversion server intraframe-codes the decoded image data of an image that will be used after the switching and transmits the intraframe-coded data. This enables an image to be switched quickly independently of the intraframe time of received image coded data that will be used after the switching.
Abstract:
When an error is detected in coded data in the current frame, data separation section 201 separates the data into coding parameters first. Then, mode information decoding section 202 outputs decoding mode information in the previous frame and uses this as the mode information of the current frame. Furthermore, using the lag parameter code and gain parameter code of the current frame obtained at data separation section 201 and the mode information, lag parameter decoding section 204 and gain parameter decoding section 205 adaptively calculate a lag parameter and gain parameter to be used in the current frame according to the mode information.
Abstract:
A system and a method of suppressing outstanding degradation of decoded audio quality due to a transmission error of audio coded data are provided without feedback information from a receiver, thereby reducing the increase of the number of necessary transmission bands and the arithmetic complexity on the receiving side. A code conversion and transmission apparatus 100 for inputting audio coded data includes first to N-th code conversion and transmission units 102 and 104 to 106 for converting audio data to N pieces of coded data, and transmitting the data at predetermined or adaptively variable time intervals to M transmission lines 130. The second to N-th audio code conversion and transmission units 104 to 106 codes a frame at a compression rate equal to or higher than the rate of input coded data. The code conversion and reception apparatus 120 selects a transmission line using a selection unit 107, and selecting data from correctly received coded data in a frame or packet unit, thereby reconfiguring the coded data using a coded data reconfiguration unit 112.
Abstract:
When media communication is relayed through a circuit switching network and a packet switching network, packet congestion and packet loss is inhibited by limiting the bandwidth and the number of packets on the packet switching network. Audio packets received from the packet switching network are stored in a buffer for absorbing fluctuation on the packet switching network, and it is determined whether an encoded audio stream is acquirable from the buffer. If no acquisition, an encoded audio stream representing either silence or noise information is generated and multiplexed, and the multiplexed data is output to the circuit switching network. Multiplexed data constituted by a plurality of multiplexed encoded streams received from the circuit switching network is separated into respective encoded streams, and only encoded audio streams representing sound or noise information are packetized based on the frame information for the encoded audio streams and sent to the packet switching network.
Abstract:
An apparatus and a method in which, even in case the transmitted speed on a transmission channel is low and hence it is not possible to provide a sufficient number of frames, a receiving side is able to restore a picture, which has not been received, with the use of a characteristic parameter, in such a manner that motion can be expressed sufficiently satisfactorily on the receiving side to improve the quality of a moving picture. The apparatus includes a decoder 200 for receiving a bitstream, obtained on compression/encoding of a moving picture, and for decoding a picture image from the bitstream; a characteristic parameter extractor 210 for extracting a characteristic parameter from a picture image restored, a moving picture reconstructor 212 for carrying out preset processing, using one or both of a temporally past characteristic parameter and a temporally future characteristic parameter, for restoring a picture image which has not been received.
Abstract:
In the transmission and reception of a medium signal, a device in accordance with the present invention reduces a medium signal deterioration generated by a data loss, caused by a bandwidth fluctuation in a wired IP network or a wireless network or by a wireless handover, and minimizes an increase in the amount of processing that is required for the signal deterioration. In a bidirectional medium transmission and reception, the reception side has a control unit 108 that monitors a storage amount of a buffer 111 in which a medium signal obtained by decoding a stream by a decoder 112 is stored, and transmits a control signal to a transmission line if the storage amount of the buffer exceeds or falls below a predetermined threshold, and the transmission side has a control unit 102 that encodes a medium signal and outputs a stream and, if a control signal is received from the transmission line, changes the compression rate of an encoder 104.
Abstract:
In response to a coded speech signal output from a speech coder, a speech decoder decodes the coded speech signal into a reproduction speech signal. If the reproduction speech signal meets predetermined conditions, for example, “silence”, “unvoiced sound”, and the like, the speech decoder further operates as the following. The speech decoder calculates spectral parameters based on the reproduction speech signal, and calculates an excitation signal on the basis of the reproduction speech signal and the spectral parameters. In the calculation, a level of the excitation signal is also obtained. The speech decoder smoothes in time at least one of the spectral parameters and the level of the excitation signal. The speech decoder synthesizes the excitation signal by using the synthesis filter constructed with the spectrum parameters, so as to reproduce the speech signal. The speech signal has an excellent quality even if a bit rate is low.
Abstract:
It is an object of the invention to excellently code a speech and music signal over all of bands in a speech and music signal code decoding apparatus having a band divided constitution. In order to achieve the object, a residue vector is generated by using an inverse filter (230 of FIG. 3) from a difference vector outputted from a first differencer (180 of FIG. 3). A band selecting circuit (250 of FIG. 3) generates n pieces of subvectors by using a component included in an arbitrary band in the residue vector subjected to orthogonal transformation. An orthogonal transformation coefficient quantizing circuit (260 of FIG. 3) quantizes n pieces of the subvectors.
Abstract:
In this speech encoding system, the limiter circuit is input with the delay of adaptive codebook obtained for the previous subframe, and the pitch cycle search range is limited so that the delay of adaptive codebook obtained for the previous subframe is not discontinuous to the delay of adaptive codebook to be obtained for the current subframe, and the pitch cycle search range limited is output to the pitch calculation circuit. The pitch calculation circuit is input with output signal Xw(n) of the perceptual weighting circuit and the pitch cycle search range output from the limiter, calculating the pitch cycle Top, then outputting at least one pitch cycle Top to the adaptive codebook circuit. The adaptive codebook circuit is input with the perceptual weighting signal x′w(n), the past excitation signal v(n) output from the gain quantization circuit, the perceptual weighting impulse response hw(n) output from the impulse response calculation circuit, and the pitch cycle Top from the pitch calculation circuit, searching near the pitch cycle, calculating the delay of adaptive codebook. With the above composition, the delay of adaptive codebook obtained for each subframe can be prevented from being discontinuous in the process of time.