JPS63252083A - Picture coding transmitter - Google Patents

Abstract

PURPOSE:To improve the picture quality by multiplexing a voice and a picture data on an assigned time slot in the presence of a voice signal and multiplexing a picture data onto a voice time slot in the absence of sound. CONSTITUTION:A digital picture signal from an input terminal 1 is coded and given to a transmission buffer memory 3, a coded mode is controlled in response to the occupied quantity (a) in the memory 3, the band is compressed and stored in the memory 3. The memory 3 stores the controlled data and sends the read data (c) to a multiplexer 4 by a signal (b) from the multiplexer 4. A digital voice data (d) from a terminal 5 is fed to a multiplex control circuit 6 to check the level and outputs a signal (e) after discriminating the presence or absence of the voice signal. In the pressure of voice, the data (d) is multiplexed onto a prescribed slot of the multiplexer 4. In the absence of voice, the video data (c) is assigned to the voice slot of the multiplexer 4. An output (f) of the multiplexer 4 is interfaced (7) and outputted (8). Thus, the quality of picture is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an image encoding and transmitting device that encodes and transmits an image signal with high efficiency.

[Conventional technology]

Conventionally, in this type of image coding and transmission apparatus, a method has been adopted in which image signals and audio signals are always allocated to predetermined time slots or a necessary number of bits, and are multiplexed and transmitted.

[Problem that the invention seeks to solve]

With the conventional image encoding and transmitting device described above, when you are listening to the other party during a video conference but are not speaking,
There is no particular need to transmit audio, but since a predetermined time slot or number of pits is assigned to the audio signal, there is a problem in that useless information is transmitted as the audio signal.

[Means for solving problems]

The image encoding and transmitting apparatus of the present invention includes an encoder that converts an image signal into a digital signal and performs high-efficiency encoding using predictive encoding or orthogonal transform encoding; A multiplexer for multiplexing a transmission buffer memory to output, image data output from the transmission buffer memory, and digital audio data input from an input terminal different from the at least one image signal, and this multiplexing. a transmitting section consisting of a transmitting line interface circuit that outputs the output of the device to the transmission line according to the transmission line format; a receiving line interface circuit that frames the input data from the transmission line; and the receiving line interface circuit of the receiving line interface circuit. A separator that separates and outputs digital audio data and image data from the output, a reception pack memory that temporarily stores and reads out the image data output from this separator, and a reception buffer memory that decodes the output data of the reception buffer memory and outputs it as an analog image. In an image encoding/transmission device having a receiving section comprising a decoder for converting into a signal, a multiplex control circuit is provided in the transmitting section, and the presence or absence of an audio signal is constantly detected from the input level of input digital audio data. ,
The detection output is multiplexed on the time slot determined as the audio presence/absence information, and if there is an audio signal based on the audio presence/absence information, the digital audio data is added to the respective time slots assigned to the audio signal and the image signal. and the image data, and if there is no audio signal, control the image data to be multiplexed also on the time slot assigned to the audio signal, while providing a separation control circuit in the receiving section, The audio presence/absence information multiplexed by the transmitter is separated from the data input to the separator by a predetermined time slot, and if the audio presence/absence information indicates that an audio signal is present, the audio data and image data are If the audio signal is shown as absent, it is determined that image data is also multiplexed in the time slot assigned to the audio signal, and control is performed to separate only the image data. It is.

[For production]

In the present invention, the presence or absence of an audio signal is detected from the input level of the input audio signal, and when it is detected that audio is present, image data and audio data are multiplexed on their respective assigned time slots. When detecting that there is no audio data, the multiplexing of audio data is stopped and the image data is also multiplexed on the time slot assigned to audio.
Increase the amount of image information in the image signal to be transmitted.

〔Example〕

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In FIG. 1, (a) shows a transmitting section, and (b) shows a receiving section.

In FIG. 1 (&), 1 is an input terminal, 2 is an encoder that converts the image signal from the input terminal 1 into a digital signal and encodes it with high efficiency by predictive encoding or orthogonal transform encoding; 4 is a transmitting buffer memory which temporarily stores the output of this encoder 2 and outputs it at a constant speed, and 4 is a separate input terminal 5 from which the image data outputted from this transmitting buffer memory 3 and at least one or more of the above image signals are received. A multiplexer that multiplexes input digital audio data, etc., 6 is a multiplex control circuit,
This multiplex control circuit 6 constantly detects the presence or absence of an audio signal from the input level of input digital audio data, multiplexes the detection output on a predetermined time slot as audio presence information, and also outputs an audio signal from the audio presence information. If there is, the digital audio data and the image data are multiplexed onto the respective time slots allocated to the audio signal and image signal, and if there is no audio signal, the digital audio data and the image data are multiplexed onto the time slot allocated to the audio signal. is also configured to control the image data to be multiplexed. 7 is a transmission line/interface circuit that outputs the output of the multiplexer 4 to the transmission line in accordance with the transmission line format, and 8 is a transmission line output end.

On the other hand, in FIG. 1 6), 9 is a transmission line input terminal, 10 is a reception line interface circuit that frames input data from the transmission line, and 11 is a reception line interface circuit that outputs digital audio and image data from the output of this reception line interface circuit 10. 12 is a separation control circuit, and this separation control circuit 12 separates and outputs the audio presence/absence information multiplexed by the transmitter from the data input to the separator 11 on a predetermined time slot. If the audio presence/absence information indicates that the audio signal is present, the audio data and image data are separated, and if the audio signal is not present, the image data is also included in the time slot assigned to the audio signal. It is configured to determine that the image data is multiplexed and control to separate only the image data. 13 is a reception buffer memory that temporarily stores and reads out the image data output from the separator 11; 14 is a decoder that decodes the output data of the reception buffer memory 13 and converts it into an analog image signal;
15 and 16 are output ends.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

First, the digital image signal from the input terminal 1 is input to the encoder 2, and the amount of generated information is controlled by controlling the encoding mode according to the occupied amount a from the transmission buffer memory 3. and outputs it to the transmission buffer memory 3. In this transmission buffer memory 3, the input data is temporarily stored, and the image data C is read out and output to the multiplexer 4 in response to the image readout signal from the multiplexer 4, and overflow and under 70- do not occur in the transmission buffer memory 3. The occupied amount a is output to the encoder 2 in order to control the generated amount of input data to be stored.

On the other hand, the digital audio data d from the input terminal 5 is input to the multiplexer 4 and the multiplex control circuit 6, and the multiplex control port 6 detects the presence or absence of an audio signal from the input level of the parallel audio data d, and outputs the detection result. It is output to the multiplexer 4 as audio presence/absence information. The multiplexer 4 multiplexes the audio presence/absence information e onto a predetermined time slot, and also multiplexes the image data C and digital audio data d according to the audio presence/absence information e.
Output to the transmission line interface circuit T.

The transmission line interface circuit 7 forms the frame format of the transmission line and outputs it to the transmission line output end 8.
Send to.

Next, the transmission line data inputted through the transmission line input end 9 is framed by a reception line interface circuit 10 and multiplexed data g is outputted to a demultiplexer 11 and a separation control circuit 12. The separation control circuit 12 separates the audio presence/absence information e multiplexed by the transmitter from the input data, and outputs the separated output signal to the separator 11 as the audio presence/absence signal. This separator 11 separates the image data 1 and the parallel audio data k by controlling the input audio presence/absence signal.
The image data 1 is output to the reception buffer memory 13 at the same time as the image write signal j, the image data l is stored by the image write signal j, and the parallel audio data is output to the output terminal 16. .

Further, the image data read out from the reception buffer memory 13 is input to the decoder 14, where it is subjected to band compression decoding.
It is outputted to the output end 15 as a digital image signal.

FIG. 2 is a block diagram showing an extracted portion of the multiplexer 4 and multiplex control circuit 6 in FIG.

In FIG. 2, the same symbols as in FIG. 1 indicate corresponding parts, 4-1 is a pulse generator, 4-2 is a switch, 4-
3 is a parallel-to-serial converter, which constitutes a multiplexer 4. 6-1 is a fixed level generator; 6-2 is a comparator that compares the output of the fixed level generator 6-1 with the digital audio data d from the input terminal 5; these constitute a multiplex control circuit 6; ing.

Next, referring to FIG. 2, we will explain the multiplexer 4 and the multiplex control circuit 6.
The operation will be explained in detail.

In this FIG. 2, 8-bit digital audio data d input to the multiplexer 4 and the multiplex control circuit 6 is converted into serial audio data t by the parallel-to-serial converter 4-3 of the multiplexer 4, and then converted to serial audio data t. 4-2.

On the other hand, since the 8-bit digital audio data d input to the multiplex control circuit 6 is detected by the comparator 6-2 as to the presence or absence of an audio signal, the output of the fixed level generator 6-1 is set to an inaudible level. If the level value of the digital audio data d is larger than the level value of the fixed level signal, it is valid audio. It determines that a signal is being input and sets the audio presence/absence information e to the "1" level, and if it is small, it determines that an invalid audio signal is being input and sets the audio presence/absence information e to the "0" level and sends it to the multiplexer 4. Output each. The audio presence/absence information e input to the multiplexer 4 is input to the switch 4-2 and the pulse generator 4-1, and the pulse generator 4-1 performs image reading controlled by the audio presence/absence information e. Outputs the signal m to the transmission buffer memory 3, and outputs the switching signals m and n to the switch 4-2.
Output to.

The image data C read out from the transmission buffer memory 3 by the image readout signal is inputted to the switch 4-2 of the multiplexer 4, and is combined with the serial audio data t from the parallel-to-serial converter 4-3 to the comparator 6. -2 and the audio presence/absence information e and the switching signal m
, n, and outputs the multiplexed data f to the transmission line interface circuit 7.

3 and 4, the audio presence/absence information 62 image data C and the serial audio data t when the audio presence/absence information e input to the multiplexer 4 is "H" and when it is "L" are shown as switching signals. An operational waveform diagram is shown in which signals m and n are switched by the switch 4-2 and are multiplexed.

In the third factor and FIG. 4, (a) shows the audio presence/absence information e, and (b) shows the image readout signal b) (
e) is image data c1 (d) is serial audio data t1 (,
) indicates the switching signal m1(f) indicates the switching signal 1, and (X) indicates the multiplexed data f.

FIG. 5 is a block diagram showing extracted portions related to the separator 11 and separation control circuit 12 in FIG. 1.

In FIG. 5, the same reference numerals as in FIG.
It consists of 12-1 is a flag detection circuit, and this flag detection circuit 12-1 constitutes the separation control circuit 12.

Next, referring to this fifth factor, we will discuss the separator 4 and the separation control circuit 1.
The operation of step 2 will be explained in detail.

First, the multiplexed data g output from the reception line interface circuit 10 is input to the switch 11-1 of the separator 11 and the flag detection circuit 12-1 of the separation control circuit 12. The transmitter detects the multiplexed audio presence/absence information from g and sends the separated audio presence/absence signal to the pulse generating circuit 11-2 of the separator 11.

Next, in this pulse generating circuit 11-2, a switching signal ('+p) controlled by the audio presence/absence signal hK is input to the switching device 11-2.
1 and outputs the image write signal j to the reception buffer memory 13. Then, the switch 11-1 performs switching control of the switching signals o and p, and separates the image data 5 and the serial audio data q from the multiplexed data g, and the image data i is input to the reception buffer memory 13, and the image data is written. It is written into the reception buffer memory 13 by the signal j.

On the other hand, serial audio data q is input to a serial-parallel converter 11-3, converted into 8-bit parallel audio data k, and output.

FIGS. 6 and 7 show operation waveforms from detecting audio presence/absence information from multiplexed data g to controlling switching of the switch 11-1 by switching signal '+P to separating image data 1 and serial audio data q. Show the diagram.

6 and 7, (a) shows the multiplexed data g, and (b) shows the audio presence/absence signal h1 (c
) shows the switching signal 0%, (d) shows the switching signal ps, e) shows the serial audio data q%, (f) shows the image data 1, and (g) shows the image writing signal j.

In the above embodiment, the case where the presence or absence of an audio signal is detected and multiplexed into an image signal has been described as an example, but it is also possible to detect the presence or absence of data such as a facsimile or an electronic blackboard and multiplex it.

〔Effect of the invention〕

As explained above, according to the present invention, the presence or absence of an audio signal is detected from the input level of the input audio signal, and when the presence of audio is detected, the image data and the audio data are transferred to the respective assigned time slots. Also, when it detects that there is no audio, the multiplexing of the audio data is stopped and the image data of the image signal to be transmitted is controlled to be multiplexed on the time slot assigned to the audio as well. Increasing the amount of information has the effect of improving the quality of the image displayed on the television monitor. For example, when a 64 kb/s digital audio signal is assigned to an image in a 384 kb/s image coded transmission, the number of bits of the image signal can be increased by about 20 bits.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram extracting parts related to the multiplexer and multiplex control circuit in FIG. 1, and FIGS. Figure 2 is an operational waveform diagram for explaining the operation; Figure 5 is a block diagram extracting the portions related to the separator and separation control circuit in Figure 1;
FIG. 7 and FIG. 7 are operation waveform diagrams for explaining the operation of FIG. 5. 2...Encoder, 3...Transmission buffer memory, 4
...Multiplexer, 6...Multiple control circuit, 7...
・Transmission line interface circuit, 10...Reception line interface circuit, 11...Separator, 1
2...Separation control circuit, 13...Reception buffer memory, 14...Decoder. Figure 2 Figure 4 Person? ! Island 1 Atonement Figure 5

Claims (1)

[Claims] An encoder that converts an image signal into a digital signal and performs high-efficiency encoding using predictive encoding or orthogonal transform encoding; a transmission buffer memory that temporarily stores the output of this encoder and outputs it at a constant speed; A multiplexer that multiplexes image data to be output and digital audio data input from an input terminal other than at least one of the image signals, and outputs the output of this multiplexer to a transmission line in accordance with a transmission line format. a transmitting section consisting of a transmitting line interface circuit that frames input data from the transmission line; a receiving line interface circuit that frames input data from the transmission line; and separating digital audio data and image data from the output of the receiving line interface circuit. a receiving section comprising a separator for outputting, a receiving buffer memory for temporarily storing and reading image data output from the separator, and a decoder for decoding the output data of the receiving buffer memory and converting it into an analog image signal; In the image encoding and transmitting device, the transmitting section is provided with a multiplex control circuit, the presence or absence of an audio signal is always detected from the input level of the input digital audio data, and the detection output is used as audio presence/absence information in a predetermined time slot. and multiplexing the digital audio data and the image data onto respective time slots allocated to the audio signal and the image signal, if there is an audio signal based on the audio presence/absence information,
If there is no audio signal, the image data is controlled to be multiplexed also on the time slot assigned to the audio signal, and a separation control circuit is provided in the receiving section, and the transmission is performed from the data input to the separator. The audio presence/absence information multiplexed in the section is separated from a predetermined time slot, and if the audio presence/absence information indicates that an audio signal is present, audio data and image data are separated, and the audio signal is indicated as absent. If the image data is multiplexed in the time slot assigned to the audio signal, it is determined that the image data is also multiplexed, and control is performed to separate only the image data.