Abstract: A packet compressor 12 operates under a reliable mode or an optimistic mode. A mode determination unit 31 counts the number of ACK packets or NACK packets received by a unit time X by an ACK/NACK packet receiver 14. When the counted number of NACK packets is larger than a predetermined value Y, the mode determination unit 31 switches the operation mode of the packet compressor 12 to the reliable mode. When the counted number of ACK packets is larger than a predetermined value Z, the mode determination unit 31 switches the operation mode of the packet compressor 12 to the optimistic mode.

Abstract: The present invention provides a reproduction apparatus that is capable of suppressing a flicker or a picture distortion caused when an interpolation frame in which a false interpolation occurred is reproduced and output, by specifying effectively the interpolation frame in which the false interpolation might occur. A reproduction apparatus of the present invention includes a moving vector calculating section 103 for calculating a moving vector based on pixels configuring a first frame and a second frame, an interpolation frame generating section 104 for generating an interpolation frame to interpolate the first frame and the second frame based on the moving vector, and an interpolation frame output deciding section 106 for deciding whether the interpolation frame should be output or not, based on a change between the first frame and the second frame.

Abstract: A moving image reproduction device which can display a list of contents by an image at an early stage without variation in time even when reproduction is interrupted. A moving image reproduction part (120) decodes coded image data and reproduces the moving image. A monitor (130) displays the reproduced moving image and displays the list of the contents by image. A reproduction position information generation part (140) intra-codes display image data on images to be displayed within a predetermined period including the time of having interrupted the reproduction when the reproduction is interrupted. A list information creation part (150) instructs a reproduction start position image data storage section (113) to output reproduction start position image data to the moving image reproduction part (120), obtains decoded reproduction start position image data from the moving image reproduction part (120), and generates the list of the contents in image.

Abstract: A packet compressor 12 operates under a reliable mode or an optimistic mode. A mode determination unit 31 counts the number of ACK packets or NACK packets received by a unit time X by an ACK/NACK packet receiver 14. When the counted number of NACK packets is larger than a predetermined value Y, the mode determination unit 31 switches the operation mode of the packet compressor 12 to the reliable mode. When the counted number of ACK packets is larger than a predetermined value Z, the mode determination unit 31 switches the operation mode of the packet compressor 12 to the optimistic mode.

Abstract: A packet compressor 12 operates under a reliable mode or an optimistic mode. A mode determination unit 31 counts the number of ACK packets or NACK packets received by a unit time X by an ACK/NACK packet receiver 14. When the counted number of NACK packets is larger than a predetermined value Y, the mode determination unit 31 switches the operation mode of the packet compressor 12 to the reliable mode. When the counted number of ACK packets is larger than a predetermined value Z, the mode determination unit 31 switches the operation mode of the packet compressor 12 to the optimistic mode.

Abstract: A demultiplexing apparatus includes a data obtainment unit to obtain the MP4 file data, and a decoding unit to demultiplex the MP4 file data obtained by the data obtainment unit into pairs of a moov and a mdat and pairs of a moof and a mdat, and decode those pairs pair-by-pair. A content duration specification unit specifies the content total duration based on the content total duration information contained in the moov of the MP4 file data obtained by the data obtainment unit and a playback unit displays the content total duration specified by the content duration specification unit.

Abstract: A packet transmission apparatus and method may divide data into a plurality of packets and transmit the packets. At a transmitting end, a context identifying number, identifying a data stream, is selected based on a relationship between a sequence number of a packet that is to be transmitted and a sequence number in an immediately preceding packet. A sequence number denoting an order of a packet divided on a per context basis is compressed, and transmission data assigned to the context identifying number with the compressed sequence number is transmitted on a per packet basis. At the receiving end, the compressed sequence number is decompressed on a per context basis. The context is separated based on the context identifying number, and data is combined by reassembling a packet into the order of a decompressed sequence number.

Abstract: A packet receiving method may include receiving a packet having either a compressed header or a noncompressed header. A packet received with a compressed header is decompressed to regenerate a non-compressed header for the packet. Error detection is performed to detect the presence of an error in a packet: (1) received with a noncompressed header, (2) having a regenerated non-compressed header, or (3) having a replacement non-compressed header. Part of the non-compressed header, in a packet having a regenerated non-compressed header, is replaced with previously stored non-compressed header information, which is known to be correct, when an error is detected in the packet so as to produce a replacement non-compressed header. A packet is output as a correctly received packet when no error is detected in the packet.

Abstract: Received packets are preserved in a receiving buffer 102; a playback decision section 103 decides whether the preserved packets are in time for the playback time or not; the playback orders and the preservation addresses of the preserved packets which have been decided to be in time are memorized in a pointer 104 for playback; the preserved packets are read and played back according to the pointer 104 for playback. And, the playback orders and the preservation addresses of the preserved packets are memorized in a pointer 106 for preservation; and a media conversion section 107 reads the preserved packets according to the pointer 106 for preservation, and memorizes them after conversion into packets with a form by which the packets may be memorized in a preservation memory 108.

Abstract: Received packets are preserved in a receiving buffer 102; a playback decision section 103 decides whether the preserved packets are in time for the playback time or not; the playback orders and the preservation addresses of the preserved packets which have been decided to be in time are memorized in a pointer 104 for playback; the preserved packets are read and played back according to the pointer 104 for playback. And, the playback orders and the preservation addresses of the preserved packets are memorized in a pointer 106 for preservation; and a media conversion section 107 reads the preserved packets according to the pointer 106 for preservation, and memorizes them after conversion into packets with a form by which the packets may be memorized in a preservation memory 108.

Abstract: When an error is detected in a received header, in estimating reference information while assuming an error in a packet receiving interval, a header is decompressed using at least one value of another candidate sequence numbers used in correcting an erroneous sequence number, corresponding to a time that elapses between previously receiving a packet correctly and receiving a current packet and to the packet receiving internal. It is thereby possible to increase a possibility of estimating the reference information correctly and suppress the number of discarded packets at a receiving side, while suppressing increases in introduced processing amount in data transmission with header compression.

Abstract: A data transmitting apparatus and a data receiving apparatus, which are capable of retransmitting a packet even when a retransmission request is made by a client after transmitting a session close notice packet to the client. A session is closed by a session closing means 105 when a predetermined period of time has passed after transmitting the session close notice packet, which is generated by a control command generating means 102 as the session close notice packet, from a packet transmitting means 103 to the client.

Abstract: In a bit counter 214, an amount of codes included in one transmission unit is counted; in a significance decision section 217, the amount of codes counted in the bit counter 214 is divided by the number of coded macroblocks included in the one transmission unit to calculate an average amount of codes per one coded macroblocks; and in a threshold comparing section 220, the significance of the pertinent transmission unit is decided by comparing the average amount of codes to the calculated threshold based on a frame rate and a bit rate.

Abstract: A transmission end (header compression end) and a reception end (header decompression end) share the same timestamp calculation information which is previously prepared. At the transmission end, in the case that the timestamp of the current packet to be subjected to header compression cannot be compressed with the current timestamp calculation information, the history record which covers timestamp calculation information previously transmitted is referred to for determining whether to transmit a packet header carrying the timestamp without updating the current timestamp calculation information, or a packet header carrying the timestamp by updating the current timestamp calculation information.

Abstract: In a header decompression apparatus 709, a header decompressor 703 refers to reference information stored in a reference information manager 707 to decompress a compressed header of a packet received by a packet receiver 704. An error detector 702 detects a CRC error in the packet with its header decompressed by the packet receiver 704, and outputs only a correct packet. A successive error counter 705 counts the number of successive errors detected by the error detector 702. A successive decompression success counter 706 counts the number of decompression successes that successively appear. By referring to these counted numbers, an update request unit 708 transmits an update request to a transmitting side as required. A reference information manager 707 manages the reference information for header decompression. With this structure, the header decompression apparatus can request update of the reference information based on the state of the error.

Abstract: A data transmitter 10 transmits packets each with a sequence number and a priority added. A data receiver 20 detects any packet loss by referring to the sequence numbers added to the packets, and if detecting any packet of high priority as having been lost, requests for packet retransmission. Based on information about thus detected packet loss, the data receiver 20 generates and transmits an RR packet 110 indicating the packet reception state. The data transmitter 10 extracts from the RR packet 110 a packet loss ratio 200, and therewith, changes manners of priority assignment. The manners are so changed that the packet of high priority is found with a lower ratio when the packet loss ratio 200 is high, and when the packet loss ratio 200 is low, found with a higher ratio.

Abstract: An image encoding apparatus having a transmission side capable of preventing generation of pseudo-synchronization and a reception side capable of restoring an image as intended al the transmission side. In the image encoding apparatus; a synchronous word containing possibility detection unit (212) decides whether a quantized DCT coefficient can be a bit string to become a synchronous word. When the possibility is detected, a control signal is output to an image information modification unit (213). Upon reception of the control signal, the image information modification unit (213) modifies image information (quantized DCT coefficient), is output to a variable length encoding unit (208), and output to a reverse quantization unit (209). When the possibility of containing a synchronous word is not detected, the quantized DCT coefficient is output to the variable length encoding unit (208) and output to the reverse quantization unit (209).

Abstract: In a header decompression apparatus 709, a header decompressor 703 refers to reference information stored in a reference information manager 707 to decompress a compressed header of a packet received by a packet receiver 704. An error detector 702 detects a CRC error in the packet with its header decompressed by the packet receiver 704, and outputs only a correct packet. A successive error counter 705 counts the number of successive errors detected by the error detector 702. A successive decompression success counter 706 counts the number of decompression successes that successively appear. By referring to these counted numbers, an update request unit 708 transmits an update request to a transmitting side as required. A reference information manager 707 manages the reference information for header decompression. With this structure, the header decompression apparatus can request update of the reference information based on the state of the error.

Abstract: The demultiplexing apparatus 200 comprises a data obtainment unit 210 operable to obtain the MP4 file data 100, a decoding unit 213 operable to demultiplex the MP4 file data 100 obtained by the data obtainment unit 210 into pairs of a moov 110 and a mdat 110 and pairs of a moof 130 and a mdat 140, and decode those pairs pair by pair, a content duration specification unit 211a operable to specify the content total duration based on the content total duration information contained in the moov 110 of the MP4 file data 100 obtained by the data obtainment unit 210 and a playback unit 214 operable to display content total duration specified by the content duration specification unit 211a.

Abstract: In a header decompression apparatus 709, a header decompressor 703 refers to reference information stored in a reference information manager 707 to decompress a compressed header of a packet received by a packet receiver 704. An error detector 702 detects a CRC error in the packet with its header decompressed by the packet receiver 704, and outputs only a correct packet. A successive error counter 705 counts the number of successive errors detected by the error detector 702. A successive decompression success counter 706 counts the number of decompression successes that successively appear. By referring to these counted numbers, an update request unit 708 transmits an update request to a transmitting side as required. The reference information manager 707 manages the reference information for header decompression. With this structure, the header decompression apparatus can request update of the reference information based on the state of the error.