Subrate multi-media data transmission system

Abstract

A substrate sub-rate multimedia data transmission control system in which transmission frame bits set in a unit of a transmission frame having a repeating cycle of 8 KHz according to the present invention enables it to effect a realtime multiplexed bit allocation in the 8 kbps unit in a variable fashion such that an automatic matching of a transmission frame is achieved at an initiation of a transmission and error check bits of the error correction code are contained in a transmission frame with a satisfactory matching. In addition, the multiframe configuration according to the present invention enables it to handle in an integrated fashion the synchronizations of the voice data frame, the error correction frame, and the video data packet, which as a result minimizes the size of the buffer memories disposed to send and/or to receive motion video and which enables the transmission speed smoothing operation to be accomplished in a simple configuration through an easy control.

Description

Recommendations G.704 and information such as the frame synchronization, the multiframe synchronization, the data link, and the CRC-6 are subjected to a time-sharing operation. The information bits of a transmission frame 17 are subdivided into items motion video data, the voice data 105, the external data 108, and the control data 110, a transmission frame configure section 112 to form a transmission frame with a variable transmission speed of 64/128 kbps, a control signal 113 outputted from the transmission controller 109 to control the operation of the transmission frame configure section 112, a control signal 114 delivered from the transmission controller 109 to control the operation of the error correction encoder 102, and a transmission frame 115 outputted from the transmission frame configure section 112 at a variable transmission speed of 64/128 kbps.

FIG. 2 is a diagram showing a transmission frame configuration in a case where the transmission frame 115 of FIG. 1 can be changed over between 64 kbps and 128 kbps in which the configuration includes a transmission frame 120 having a frame repeating cycle of 8 KHz, contents 121 of an odd-numbered frame corresponding to the #16 bit, and contents 122 of an even-numbered frame associated with the #16 bit. The odd-numbered frame and the even-numbered frame constitute a multiframe including, for example, 80 transmission frames.

FIG. 3 is a diagram illustrating a utilization example of transmission frame format information BA contained in an area ranging from the 17th frame to the 31st frame in the contents 121 of the odd-numbered frame corresponding to the #16 bit of FIG. 2. The configuration includes transmission frame format information BA (123) indicated in a unit of k multiframes (k is an integer at least equal to one) and a transmission frame 124 of which the format is changed after a delay of kpbs/16 bits=8 KHzdata in the FEC frame. The flag F_f 133 indicating the presence/absence of the filler is added as the first item to the motionCorrection Codemotion video data frame 160 according to a unit of the motion video data packet 132.

Moreover, although the 16/8 kbps voice data frames 150-151 are described in conjunction with the embodiment above, the present invention may also be applicable to other transmission speeds such as 64 kbps.

In addition, although the 64/128 kbps accesses with variable rates have been described for the embodiment above, even if the rate is expressed as 64 kbps×N₁ (N₁ is an integer at least equal to one), the transmission frame 115 need only be expanded in a unit of the octet so as to attain the same effect as the embodiment above.

Furthermore, although the embodiment has been described in case of a transparent communication line, two 64 kbps lines may also be used to obtain the same effect as the embodiment above.

Moreover, although the code length of the BCH code is fixed for each multiframe in the embodiment described above, the code length of the BCH code may be set to be identical to that of the video data packet so as to change the word length depending on the number of allocated bits, which also leads to the same effect as that of the embodiment above.

According to configuration of the present invention, as described above, bits are allocated for a unit of a transmission frame having a frame cycle of 8 KHz, the multiframe cycle is matched with the error correction frame and the voice data frame, the bit allocation and access rate are adaptively variable based on the transmission frame bits, and the video data frame is transmitted in a unit of the video packet; consequently, an apparatus accessing the communication route in a complicated fashion can be configured in a simple structure. Moreover, there are attained effects, for example, a movie image transmission can be implemented with a high picture quality even through a low-bit-rate transmission line.

While the present invention has been described with reference to the particular illustrative embodiments, it is not restricted by those embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change and modify the embodiments without departing from the scope and spirit of the present invention.

Claims

1. A sub-rate, multi-media data transmission control system in which multi-media data series, including motion video data, voice data, and external digital data are multiplexed and transmitted through a transmission line having a maximum transmission speed of 64 kbps×N₁, N₁ being an integer at least equal to one, at a variable speed of 64 kbps×N₂, N₁ ≧N₂ ≧1, comprising:

means for setting a basic transmission frame to N₁ ×8 bits at a frequency of 8 kHz in which a subframe of N₂ ×8 bits is used at said variable speed of 64 kbps×N₂ with a dummy subframe of (N₁ -N₂)×8 bits;

multiplexing means for multiplexing said multi-media data series into said transmission frame by allocating 1/8 bits for each data type of said series in said transmission frame, wherein 1 is the transmission speed of each data type in kbps;

transmission speed matching means for setting the number of data bits in a transmission frame to 8 bits×N₁ for a transmission speed of 64 kbps×N₁, and to 8 bits×N₂ for a transmission speed of 64 kbps×N₂, forming a multiframe of j transmission framed frames divided into even and odd numbered frames, j being an integer at least greater than one, and assigning particular frame synchronization data, transmission speed/bit allocation data and control data to a particular bit in each frame of said multiframe in a timesharing fashion thus establishing a frame/multiframe synchronization autonomously matching the transmission speed;

frame synchronization means for setting an integral ratio between the number of bits of voice data allocated in a multiflame and the length of a voice data transmission frame to establish an integrated frame synchronization with respect to synchronization of said transmission frame;

correction encoding means for performing error correction encoding on predetermined bits in a unit of said multiflame;

identification information adding means for subdividing said video data into each unit of said error correction encoding operation and adding information thereto identifying the type of motion video data contained therein; and

transmitting means for transmitting multiplexed information attained from said multiplexing means at intervals of K multiframes in a real time fashion, K being an integer at least equal to one.

2. A system in accordance with claim 1 wherein said correction encoding means effects an error correction encoding by use of Bose-Chaudhuri-Hocquenghem (BCH) code as an error correction code, said code matching with a bit length of said multiframe so as to arrange error correction bits of said BCH code at predetermined bit positions of said frame bits, thereby achieving the error correction encoding only on said motion video data.

3. A system in accordance with claim 1 wherein said correction encoding means adds information identifying an invalid data contained in the motion video data obtained through the subdivision in the error correction encoding unit and motion video data types including a first item, an intermediate item, and a last item of the video frame to transmission data and transmits a resultant transmission data therefrom.

4. A system in accordance with claim 1 wherein only in a case where said digital data is transmitted in a predetermined period of successive time during an ordinary transmission, a transmission speed of an integral multiple of 8 kbps is allocated for a transmission according to a predetermined procedure, and in the other cases, the transmission speed is allocated to the video data.

5. A system in accordance with claim 1 wherein said identification information adding means effects a voice activation, in case the multiframe is set to an integral multiple of the voice data frame, to identify an interval with a voice and an interval without a voice in a unit of k multiframes, transmits only a voice data frame associated with the interval with a voice, and employs a control increasing the allocation to the voice data in case of the interval without a voice, which is identified depending on bit allocation information in said frame bits in a unit of said k multiframes.

6. A system in accordance with claim 1 wherein when said transmission line has a transmission speed of 64 kbps×2=128 kbps at the maximum and is capable of a variable-transmission-speed connection for 64/128 kbps, the bits speed is fixed to 128 kbps, the transmission frame length is fixed to 16 bits, all 16 bits of said transmission frame are utilized for a 128 kbps operation, eight bits of said transmission frame are used for a 64 kbps operation, the frame bit of said transmission frame is set to one bit, and the multiframe configuration includes 80 frames.

7. A system in accordance with claim 1 wherein said correction encoding means utilizes as an error correction code a (320, 302, 5) shortened BCH code, a (640, 620, 5) shortened BCH code, or a (1280, 1258, 5) shortened BCH code so as to establish a matching with said multiframe including 80 frames.

8. A system in accordance with claim 1 wherein said transmission speed matching means sets the voice data frame to 160 bits for an 8 kbps operation and to 320 bits for a 16 kbps operation so as to match said voice data frame with a cycle of said multiframe including 80 frames.

9. A system in accordance with claim 6 wherein said correction encoding means utilizes as an error correction code a (320, 302, 5) shortened BCH code, a (640, 620, 5) shortened BCH code, or a (1280, 1258, 5) shortened BCH code so as to establish a matching with said multiframe including 80 frames.

10. A system in accordance with claim 6 wherein said transmission speed matching means sets the voice data frame to 160 bits for an 8 kbps operation and to 320 bits for a 16 kbps operation so as to match said voice data frame with a cycle of said multiframe including 80 frames.

11. A sub-rate, multi-media data transmission control system in which multi-media data series, including video data, voice data, and external digital data are multiplexed and transmitted through a transmission line having a maximum transmission speed of a predetermined value, at a variable speed less than or equal to said maximum transmission speed, comprising:

means for setting a basic transmission frame to a predetermined number of bits at a predetermined frame cycle frequency such that the product of said predetermined number of bits and said predetermined frame cycle frequency is equal to said maximum transmission speed, in which a subframe of less than said predetermined number of bits is used at said variable speed with a dummy subframe having a number of bits equal to the difference between the bits of said basic transmission frame and said subframe;

multiplexing means for multiplexing said multi-media data series into said transmission frame by allocating a specific amount of bits for each data type of said series in said transmission frame in accordance with the transmission speed of each data type;

transmission speed matching means for variably setting the number of data bits in a transmission frame in accordance with said variable speed, forming a multiframe of j transmission frames, j being an integer at least greater than one, and assigning particular frame synchronization data, transmission speed/bit allocation data and control data to a particular bit in each frame of sai multiframe in a timesharing fashion thus establishing a frame/multiframe synchronization matching the transmission speed;

frame synchronization means for setting an integral ratio between the number of bits of voice data allocated in a multiframe and the length of a voice data transmission frame to establish an integrated frame synchronization with respect to synchronization of said transmission frame;

correction encoding means for performing error correction encoding on predetermined bits in a unit of said multiframe;

identification information adding means for subdividing said video data into each unit of said error correction encoding operation and adding information thereto identifying the type of video data contained therein; and

transmitting means for transmitting multiplexed information attained from said multiplexing means at intervals of K multiframes in a real time fashion, K being an integer at least equal to one. 12. A sub-rate, multi-media data transmission control system in which multi-media data series, including video data, voice data, and external digital data are multiplexed and transmitted through a transmission line having a maximum transmission speed of 8M kbps×N₁, M being an integer greater than or equal to one, N₁ being an integer at least equal to one, at a variable speed of 8M kbps×N₂, N₁ ≧N₂ ≧1, comprising:

means for setting a basic transmission frame to N₁ ×M bits at a frame cycle frequency of 8kHz, in which a subframe of N₂ ×M bits is used at said variable speed with a dummy subframe of (N₁ -N₂)×M bits;

multiplexing means for multiplexing said multi-media data series into said transmission frame by allocating l/M bits for each data type of said series in said transmission frame, wherein l is the transmission speed of each data type in kbps;

transmission speed matching means for setting the number of data bits in a transmission frame to M bits×N₁ for a transmission spee of 8M kbps×N₁, and to M bis×N₂ for a transmission speed of 8M kbps×N₂, forming a multiframe of j transmission frames, j being an integer at least greater than one, and assigning particular frame synchronization data, transmission speed/bit allocation data and control data to a particular bit in each frame of said multiframe in a timesharing fashion thus establishing a frame/multiframe synchronization matching the transmission speed;

frame synchronization means for setting an integral ratio between the number of bits of voice data allocated in a multiframe and the length of a voice data transmission frame to establish an integrated frame synchronization with respect to synchronization of said transmission frame;

correction encoding means for performing error correction encoding on predetermined bits in a unit of said multiframe;

identification information adding means for subdividing said video data into each unit of said error correction encoding operation and adding information thereto identifying the type of video data contained therein; and

transmitting means for transmitting multiplexed information attained from said multiplexing means at intervals of K multiframes in a real time

fashion, K being an integer at least equal to one. 13. A sub-rate, multi-media data transmission control system in which multi-media data series, including video data, voice data, and external digital data are multiplexed and transmitted through a transmission line having a maximum transmission speed of 8 kbps×N₁, N₁ being an integer at least equal to one, at a variable speed of 8 kbps×N₂, N₁ ≧N₂ ≧1, comprising:

means for setting a basic transmission frame to 1×N₁ bits at a frame cycle frequency of 8kHz, in which a subframe of 1×N₂ bits is used at said variable speed with a dummy subframe of 1×(N₁ -N₂) bits;

multiplexing means for multiplexing said multi-media data series into said transmission frame by allocating l bits for each data type of said series in said transmission frame, wherein l is the transmission speed of each data type in kbps;

transmission speed matching means for setting the number of data bits in a transmission frame to 1×N₁ bits for a transmission speed of 8 kbps×N₁, and to 1×N₂ bits for a transmission speed of 8 kbps×N₂, forming a multiframe of j transmission frames, j being an integer at least greater than one, and assigning particular frame synchronization data, transmission speed/bit allocation data and control data to a particular bit in each frame of said multiframe in a timesharing fashion thus establishing a frame/multiframe synchronization matching the transmission speed;

frame synchronization means for setting an integral ratio between the number of bits of voice data allocated in a multiframe and the length of a voice data transmission frame to establish an integrated frame synchronization with respect to synchronization of said transmission frame;

correction encoding means for performing error correction encoding on predetermined bits in a unit of said multiframe;

identification information adding means for subdividing said video data into each unit of said error correction encoding operation and adding information thereto identifying the type of video data contained therein; and

transmitting means for transmitting multiplexed information attained from said multiplexing means at intervals of K multiframes in a real time

fashion, K being an integer at least equal to one. 14. A multimedia data transmission control system for multiplexing and transmitting various types of media data, including video data, audio data and external digital data, comprising:

transmission control means for allocating transmission frame bits, aligning transmission frame patterns, and setting transmission rates adaptively according to said various types of media data presented for transmission;

multiplexing means for multiplexing said various types of media data according to transmission frame bit allocation information from said transmission control means; and

transmission frame configuring means for configuring multiplexed data from said multiplexing means, and bit allocation and frame alignment pattern information from said transmission control means into transmission frames, and generating multiframes consisting of a plurality of transmission

frames, for transmission over a transmission medium. 15. A multimedia data transmission control system for multiplexing and transmitting various types of media data, including video data, audio data and external digital data, comprising:

transmission control means for allocating transmission frame bits, aligning transmission frame patterns, and setting transmission rates adaptively according to said various types of media data presented for transmission;

multiplexing means for multiplexing said various types of media data according to transmission frame bit allocation information from said transmission control means;

transmission frame configuring means for configuring multiplexed data from said multiplexing means, and bit allocation and frame alignment pattern information from said transmission control means into transmission frames, and generating multiframes consisting of a plurality of transmission frames, for transmission over a transmission medium; and

error correction encoding means for performing error correction encoding on predetermined bits of said multimedia data, and adding synchronization bits to said data as a result of error correction encoding.