JPH04368030A - Picture transmitter - Google Patents

Abstract

PURPOSE:To set a voice delay automatically to synchronize a picture output and a voice output with respect to a delay of the picture signal sent by the picture transmitter. CONSTITUTION:The transmitter consists of a picture signal processing section 2 to code/decode a picture signal, a voice signal processing section 3 coding/ decoding a voice signal, a data multiplexer/demultiplexer section 9 multiplexing/ demultiplexing a picture voice data, and a line interface section 10 interfacing a line of a transmission reception data. The voice signal processing section 3 consists of a pseudo voice signal transmission section 11 to set a delay, a delay measurement section 12, and a delay calculation section 13.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio delay processing function for synchronizing the output of image data and audio data in the transmission of both data by an image transmission apparatus.

0002

2. Description of the Related Art FIG. 2 is a functional block diagram showing a conventional image transmission device disclosed in, for example, Japanese Unexamined Patent Application Publication No. 1-265795. 3 is an audio signal processing section; 4 is a part of 3 and is a preprocessing section that performs A/D conversion of the transmitted analog signal; 5 is an encoding section that encodes the output signal of 4; 6 is an audio delay processing unit that performs audio delay processing; 7 is a decoding unit that decodes the encoded received signal; 8 is a post-processing unit that converts the digital signal decoded in 7 into an analog signal; 9 10 is a data multiplexing/demultiplexing unit that multiplexes and demultiplexes data such as image signals and audio signals, and 10 is a line interface unit that performs interface processing with a line.

Next, the operation will be explained with reference to FIG. In the figure, the analog audio signal to be transmitted is processed by the preprocessing unit 4.
The signal is subjected to processing such as amplification, filtering, and A/D conversion, and then input to the encoding section 5. The encoded signal is held for a preset delay time in the audio delay processing section 6 and output to the data multiplexing/separating section 9. The delay time is set manually using a switch or the like provided in the image transmission device 1. Data multiplex/separator 9
The transmission audio data inputted to is multiplexed with data such as image data, and sent to the line via the line interface section 10. On the other hand, received data inputted from the line is passed through the line interface unit 10 and separated into data such as audio and image data by the data multiplexing/demultiplexing unit 9, and the audio data is processed by the audio delay processing unit 6, similar to the above-mentioned transmission system. After being held for the delay time set in , it is output to the decoding section 7. The data decoded by the decoding section 7 is subjected to processing such as D/A conversion in the post-processing section 8, and then outputted to the outside of the image transmission device 1 as an analog reception signal.

0004

[Problem to be Solved by the Invention] Since the conventional device is configured as described above, it is difficult to see the image actually received.
The audio delay amount must be set manually while listening to the audio, and setting requires as many adjusters as there are image transmission devices to be connected. When changing the method or changing the capacity of the line to be connected, there were problems such as the adjuster having to make manual adjustments each time.

[0005] This invention was made to solve the above-mentioned problems, and by automatically setting the audio delay amount, the adjustment operation can be omitted, and it can also be adjusted according to the line speed and encoding method. It is an object of the present invention to provide a device that saves the effort of changing audio delay amount settings.

[0006]

[Means for Solving the Problems] An image transmission device according to the present invention is configured to transmit a pseudo audio signal to another station, return it from the other station to its own station, and measure and set the amount of audio signal delay. It is.

[0007]

[Operation] The setting of the audio delay amount in this invention is instantaneously calculated with high precision using the actually measured value as a parameter as described above, and can be easily reset even if the line speed or encoding method is changed. and synchronize images and audio.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the same or corresponding parts as in FIG. 2 are given the same reference numerals. Reference numeral 11 denotes a pseudo audio signal generating section that outputs pseudo audio for measuring the amount of delay. Reference numeral 12 denotes a delay amount measuring section that measures the amount of delay from the time when the pseudo voice signal is output and the time when the signal returned from the partner station is decoded. Reference numeral 13 denotes a delay amount calculating section that calculates an audio delay amount based on the measured value of the delay amount measuring section 12 and the separately measured image delay amount.

Next, the operation will be explained. In FIG. 1, the analog audio signal transmitted is subjected to processing such as amplification, filtering, and A/D conversion in a preprocessing section 4, and then input to an encoding section 5 and encoded. The encoded signal is held in the audio delay processing section 6 for a preset delay amount time and is output to the data multiplexing/demultiplexing section 9. The time delayed by the audio delay processing section 6 is set as follows.

[0010] First, when the own station turns on the power supply or changes the settings of the encoding method or line speed, the pseudo speech generation section 11 outputs a pseudo speech signal to the preprocessing section 4 and the delay amount measuring section 12. . The pseudo audio signal preprocessed by the preprocessing unit 4 is encoded by the encoding unit 5 and then passed through the audio delay processing unit 6.
The data is sent to the data multiplexing/demultiplexing section 9. Here, the pseudo audio signal is multiplexed with image data encoded by the image processing section 2 and sent to the line via the line interface section 10. At this time, the amount of delay in the audio delay processing section 6 is 0.
shall be. Further, the delay amount measuring unit 12 detects the received pseudo audio signal and holds the transmission time.

[0011] The data sent to the line is received and decoded by the image transmission device 1 of the partner station, converted into an analog signal, and then preprocessed and encoded again as a transmission signal to the partner station and sent to the line. . This loop is set by the local station.

The signal sent to the line is received by the image transmission device 1 of the local station via the line interface section 10, separated from image data etc. by the data multiplexing/demultiplexing section 9, and then sent via the audio delay processing section 6. After being decoded by the decoding section 7 and subjected to post-processing by the post-processing section 8, it is input to the delay amount measuring section 12. The delay amount measurement unit 12 outputs the transmitted analog audio signal inputted to the image transmission device 1 as the received analog audio signal of the other station from the time when the transmitted pseudo audio signal is detected and the time when the received pseudo audio signal is detected. The value is approximately twice as long as the time it takes to complete the test.

[0013] Then, using the above-mentioned measured value as one of the parameters, and other parameters such as the delay amount of the image signal due to image signal processing, the delay amount calculating section 13 determines and sets the audio delay amount. The audio delay amount measuring and setting means according to the present invention described above can be realized without adding a significant circuit to an image transmission apparatus that does not have these.

[0014] In the above embodiment, the pseudo speech signal is an analog signal and is output to the preprocessing section 4, but the pseudo speech signal may be a digital signal and may be output to the encoding section 5. In this case, the received pseudo-speech signal is often detected from the output of the decoding section 7, and the decoded signal is immediately encoded while the signal returned by the other station is still a digital signal.

The audio data delay processing may be performed by the audio delay processing section 6 on either or both of the transmitting side and the receiving side.

Furthermore, although the above embodiment has been described for the purpose of synchronizing images and audio, it can also be used for other purposes such as measuring audio delay.

[0017]

[Effects of the Invention] As described above, according to the present invention, the amount of audio delay is measured and set by generating a pseudo audio signal and returning it at the other party's station, so it takes no time to manually set it. can be omitted.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing an image transmission device according to an embodiment of the present invention.

FIG. 2 is a functional block diagram showing a conventional image transmission device.

[Explanation of symbols]

1 Image transmission device 2 Image signal processing section 3 Audio signal processing section 6 Audio delay processing section 11 Pseudo audio signal generator 12 Delay measurement section 13 Delay amount calculation unit

Claims (1)

[Claims] Claim 1: When image data and audio data are digitally encoded and transmitted, and the image data and audio data are decoded on the receiving side, the audio data is delayed by an audio delay processing unit provided in the image transmission device. In the synchronous output of image data and audio data, the audio delay processing unit includes a circuit for measuring an amount of audio delay and a circuit for calculating and setting the amount of delay based on the measurement result. image transmission device.