JPS62116087A - Animation picture transmitter - Google Patents

Abstract

PURPOSE:To reproduce a frame dropping picture as a smooth picture without deteriorating a transmission efficiency by controlling the number of a repetitive reading of the same frame in an output buffer correspondingly to the same writing time of a receiving buffer as a reading time of a preceding frame read according to the state of a transmission path of a transmission buffer. CONSTITUTION:In a transmission side, digital picture data 2 successively inputted in an interval of a camera synchronization from a camera 1 is repetitively written in one side A of an input DB (double buffer) 3. The previously written data is erased and updated. The input DB3 is changed over at a break time of a next camera input when a writing and a reading of a transmission DB4 are completed and at the same time, in an opposite side B, the writing is started and the same operation is repeated. In the receiving side, the data decoded by a variable length detector 7 is written in one side G of an output DB8 and in the opposite side H, the data of the frame is repetitively read synchronously with a monitor 9 and outputted. At this time, the number of readings corresponding to a receiving time (writing time of a receipt DB6) of a preceding frame is previously stored and only the number is outputted. Thereafter, the reading and the writing of the output DB8 are changed over and the same operation is repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a moving image transmission device, and particularly relates to frame drop control in the device.

[Conventional technology]

FIG. 3 is a block diagram showing a conventional moving image transmission device. In the figure, 1 is a camera, 2 is digital image input data, 3 is an input double buffer, 4 is a transmission double buffer, and 5 is a variable length encoder. , 6 is a reception double buffer, 7 is a variable length decoder, 8 is an output double buffer, 9 is a monitor, 10 is image output data, 11 is a transmission path, 12 is a camera synchronization signal, 13 is a transmission double buffer switching signal , 14 are monitor synchronization signals, 3 to 5 are provided in the image transmitter 20, and 6 to 8 are provided in the image receiver 21.

On the other hand, FIG. 4 is a timing chart for explaining the operation of the above-mentioned conventional device, and in the figure, W indicates buffer writing;
R indicates reading from the buffer, ..., (n-
1), (n), (n+1), . . . indicate the numbers of frames to be transmitted.

Next, the operation will be explained. On the sending side, one frame worth of digital image data 2, which is continuously input from camera 1 at camera synchronization intervals, is placed on one side (referred to as ■ side) of input double buffer 3 (hereinafter referred to as DB). only write. At this time, the sending DB 4 writes the previous frame data and reads the frame data before the previous one, and as soon as these are completed, the input DB 3 is switched between reading and writing.
The image data is read for encoding. Note that the input 2 from the camera 1 during this period is not written to the input buffer 3 and is omitted. After that, image data for one frame from the next camera 1 is written to the input DB 3 on the opposite side (■ side), and the same operation is repeated thereafter.

Next, the data read from the input DB 3 is encoded by the variable length encoder 5, and the data on the side (
side). Opposed (111 (■01.!3 )
During this time, the image data of the previous frame is read out and transmitted to the transmission line 11. As soon as the reading and writing of the transmission DB 4 is completed, the reading and writing are switched, and the written data is read and transmitted. Repeat the same action below. If the encoding is variable length and the transmission time changes, the time from the start of reading from the input DB3 until the end of writing to the transmission DB4 is set to be smaller than the minimum value of the transmission time, so that transmission can be performed without reducing transmission efficiency. It can be performed.

On the other hand, on the receiving side, the received data is written to one side (referred to as the ■ side) of the receiving DB 6. On the opposite side (C side), the data of the previous frame is read out for decoding, and the reading is finished first. When writing is completed, reading and writing of the receiving DB 6 is switched, reading of the written data and writing of the next data are started. Repeat the same action below. Next, the data read from the reception DB 6 is decoded by the variable length decoder 7 and written to one side (defined as the @ side) of the output DB 8. Opposite side (
On the side (3), the previous frame data is read out repeatedly in synchronization with the monitor 9, and the image output is 1°. The output DB 8 switches between reading and writing at the end of the next monitor output after writing, reads the written data, and outputs it to the monitor 9.

Writing to the output DB 8 starts when the next decoded data arrives. Repeat the same action below.

In the conventional moving image transmission device as described above, as shown in FIG.
The time until the first frame) is approximately equal to the sum of the transmission time of the previous frame and the frame before the previous frame (R(n-1) and R(n-2) of the transmission DB4) minus one power synchronization time, The frame drop interval (interval from W(n) to W(n+1) of input DB3) is equal to the transmission time of the frame before the previous frame (R(n-2) of transmitter DB4).
)). Also, monitor 9 on the receiving side
The time of the frame played back (the repetition time of R(n) of the output DB8) is the reception time of the next frame (the W of the receiving DBS).
(n+1) time).

[Problem that the invention seeks to solve]

Conventional video transmission devices are configured as described above, so that each frame is adaptively dropped at a different time interval depending on the state of the transmission path on the transmitting side, and the same frame is displayed on the receiving side monitor. There were problems such as the playback times were generally different and the movements became awkward.

This invention was made to solve the above-mentioned problems, and it is possible to adaptively drop frames depending on the transmission path condition without reducing transmission efficiency, and to reproduce the dropped-frame image as a smooth image. The purpose of this invention is to obtain a moving image transmission device that can transmit images.

[Means for solving problems]

The moving image transmission device according to the present invention controls read/write and switching of the input buffer based on the camera synchronization signal and the transmission buffer switching signal, updates and writes image data from the camera frame by frame, and transmits the image data. An input buffer control means that switches reading and writing from the next frame after the buffer has been switched, and controls reading and writing and switching of the output buffer based on a monitor synchronization signal and a reception buffer switching signal, and repeatedly reads the same frame in the output buffer. and output buffer control means for making the number of times correspond to the writing time of the previous frame to the reception buffer.

[Effect]

In this invention, since a different time interval for each frame dropped in the input buffer corresponds to the read time of the previous frame read from the transmit buffer depending on the state of the transmission path, the receive buffer By controlling the number of times the same frame is repeatedly read out in the output buffer in accordance with the write time, a frame-dropped image can be reproduced as a smooth image without reducing transmission efficiency.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Note that the same reference numerals are used for the same or equivalent parts as in the conventional example,
The explanation will be omitted.

FIG. 1 is a block diagram showing the configuration of an embodiment, and in the figure,
Reference numeral 15 denotes an input double buffer control device provided on the transmitter 20 side, which corresponds to the input buffer control means of the present application and outputs an input double buffer control signal 16 based on the camera synchronization signal 12 and the transmission double buffer switching signal 13. The input double buffer 3 controls read/write and switching thereof. On the other hand, 17 is an output double buffer control device provided on the receiver 21 side, which corresponds to the output buffer control means of the present invention, and outputs an output double buffer control signal 19 based on the monitor synchronization signal 14 and the reception double buffer switching signal 18. is output to control the reading/writing and switching of the output double bar 7/8.

Next, the operation of the embodiment configured as described above will be explained with reference to the timing chart shown in FIG.

On the transmitting side, digital image data 2 that is continuously input from camera 1 at camera synchronization intervals is input every frame D.
Repeatedly write to one side of B3 (referred to as 91). Previously written data is erased and updated during the next write.

The input DB 3 is switched at the end of the next camera input after writing and reading of the transmission DB 4 is completed, and reads the last written data. At the same time, writing starts on the opposite side (■ side), and the same operation is repeated thereafter. The data read from the input DB 3 is thereafter transmitted in the same manner as in the conventional example.

In this case, start reading from input DB3 and then send
By making the time obtained by adding one frame time of the camera to the time required to finish writing to B4 smaller than the minimum value of the transmission time, transmission can be performed without reducing transmission efficiency.

On the receiving side, the operation of the receiving DB 6 is the same as in the conventional example.

Output the data decoded by variable length decoder 7 to DB
Write on one side of 8 (assumed to be 0 rule), and write on the other side ([phase]
(rule), the data of the previous frame is repeatedly read out in synchronization with the monitor 9 and output as image output data 10. At this time, the reception time of the previous frame, that is, the write time of the reception DBS (the transmission time, that is, the transmission DB4
(equivalent to the readout time of ) is stored, and only that number is output. Thereafter, reading and writing of the output DB 8 is switched, and the same operation is repeated thereafter. However, even if the number of reads of the output DB8 is exceeded, the output DB of the next frame
If the writing to 8 does not finish, increase the number of reads, and conversely, even though the number of reads is not reached, frames are received one after another from the receiving DB.
6, the reading from the receiving DB 6 is delayed, the number of readings from the output DB 8 is reduced, and the image output 10 is adaptively output continuously.

In the moving image transmission device of the embodiment as described above, the second
From the figure, it can be seen that the time from the image input from the camera 1 to the start of transmission on the transmitting side and the frame drop interval are about the same as the transmission time of the previous frame (R(n-1) of the transmission DB 4). Also, the time of the frame played back on the monitor 9 on the receiving side is the reception time of the previous frame (W(n-1 of reception DB 6)
), it can be seen that these are approximately equal (transmission time 2 reception time). Therefore,
Frame-dropped images can be reproduced as smooth images without reducing transmission efficiency.

In the above embodiment, a double buffer is provided as the output buffer, but if it is difficult to time the write and read timings, control may be performed using three or more buffers. The same applies to other buffers.

〔Effect of the invention〕

As described above, according to the present invention, the reading/writing and switching of input buffers are controlled based on the synchronization signal of the camera and the switching signal of the transmission buffer, and the image data from the camera is updated and written frame by frame. An input buffer control means that switches reading and writing from the next frame after the transmission buffer is switched, and an input buffer control means that controls reading and writing and switching of the output buffer based on a synchronization signal of the monitor and a switching signal of the reception buffer, and repeats the same frame in the output buffer. By including an output buffer control means that makes the number of reads correspond to the writing time of the previous frame to the reception buffer, a moving image transmission device is provided that can reproduce a frame-dropped image as a smooth image without reducing transmission efficiency. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a moving image transmission device according to an embodiment of the present invention, FIG. 2 is a timing chart thereof, FIG. 3 is a block diagram showing a conventional moving image transmission device, and FIG. 4 is a timing chart thereof. It is. 1 is a camera, 2 is digital image input data, 3 is an input double buffer, 4 is a transmitting double buffer, 5 is a variable length encoder, 6 is a receiving double buffer, 7 is a variable length decoder, 8 is an output double buffer Buffer, 9 monitor, 10 image output data, 11 transmission path, 12 camera synchronization signal, 1
3 is a transmission double buffer switching signal, 14 is a monitor synchronization signal, 15 is an input double buffer control device (input buffer control means), 16 is an input double buffer control signal, 17
18 is a receiving double buffer switching signal, 19 is an output double buffer control signal, 20 is an image transmitter, and 21 is an image receiver. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] The input section from the camera and the transmission section to the transmission path are equipped with an input buffer and a transmission buffer in which a storage area for one frame of digital image data from the camera is multiplexed, and the image data is variable-length coded and sent to the transmission path. It is equipped with an image transmitter for transmitting data to the computer, a reception buffer and an output buffer similar to those described above in the reception section from the transmission path and the output section to the monitor, and variable length decoding is performed on the variable length encoded image data to be sent to the monitor. and an image receiver for outputting images, the moving image transmission device is configured to alternately switch between reading and writing each storage area of each of the buffers according to the state of the transmission path, and drop frames of image data from the camera. In this step, the reading/writing and switching of the input buffer is controlled based on the synchronization signal of the camera and the switching signal of the transmission buffer, and the image data from the camera is updated and written for each frame, and the next data after the transmission buffer is switched is controlled. An input buffer control means for switching between reading and writing from a frame, and controlling reading and writing and switching of the output buffer based on a synchronization signal of the monitor and a switching signal of the receiving buffer, and controlling the number of times the same frame is repeatedly read from the output buffer to the receiving buffer. 1. A moving image transmission device comprising: output buffer control means that corresponds to the writing time of the previous frame.