JP6483176B2 - Video transmission device - Google Patents

Description

  The present invention relates to a video transmission apparatus.

A conventional video transmission apparatus will be described with reference to FIGS. 4 and 5. FIG.
FIG. 4 is a block diagram for explaining a conventional video transmission apparatus. FIG. 5 is a timing chart for explaining the operation of the conventional video transmission apparatus.
In FIG. 4, the video transmission device 400 includes an encoding device 410, a transmission device 420, a transmission antenna 430, a reception antenna 450, and a reception device 460.

The encoding device 410 includes a control unit 411, an I (Intra-coded Picture) processing unit 412, a P (Predictive-coded Picture) processing unit 413, a selection unit 414, a decoding unit 416, and a buffer memory 1 unit 417. .
The control unit 411 inputs SUM and outputs a comp control signal and an I / P1 control signal.
Further, I / P1 output from the control unit 411 is a signal that changes while shifting the target range downward for each frame from the upper part of the screen.

  The encoding apparatus 410 generates compressed data I-CD from the input video signal SI-VID by the I processing unit 412, generates compressed data P-CD by the P processing unit 413, and selects the compressed data I by the selection unit 414. -CD or P-CD is selected, the selected data S-CD is output to the buffer memory 1 unit 417, and the compressed data BF-CD is output from the buffer memory 1 unit 417. The decoding unit 416 decodes the S-CD and outputs the decoded video signal V-DEM to the P processing unit 413.

The comp control signal (encoding target) output from the control unit 411 is a control signal for increasing or decreasing the generated code amount of the I processing and the P processing, and the I processing unit and the P processing unit change the quantization roughness. The generated code amount is increased or decreased.
The I / P1 control signal output from the control unit 411 selects a control signal to the selection unit 414, which is a code by I processing or a code by P processing. If the number of scanning lines is 1280 as selected in order from the top of the screen, the period of 1 to 64 is selected for the first frame, and the period of 65 to 128 is selected for the second frame.
The SUM input to the control unit 411 is a signal related to the amount of compressed data stored in the buffer memory unit 134.
The control unit 411 controls the quantization roughness, that is, the amount of newly generated data, with the comp control signal (encoding target) while checking the amount of SUM.

The transmission apparatus 420 includes a buffer memory 2 unit 421, a correction code unit 422, a modulation unit 423, an interleaving unit 424, a TMCC switch unit 424b, an IFFT (Inverse Fast Fourier Transform) unit 425, and a D / A (Digital-to-Analog Converter). Part 426, frequency conversion part 427, and power amplification part 428.
The transmitting apparatus 420 writes the input compressed data BF-CD into the buffer memory 2 unit 421, adds the error correction code to the TD-M read from the buffer memory 2 unit 421, and adds the error correction code to the error correction code. The added TD-P is subjected to, for example, QPSK (Quadrature Phase Shift Keying) by the modulation unit 423, and the data order after the error correction coding is performed on the modulated TD-QM by the interleaving unit 424. The TD-Qi in which the data order is changed is inserted in the TMCC switch unit 424b at intervals of a predetermined period by the TMCC switch unit 424b, and a TMCC value indicating the setting of the correction coding is inserted. The D / A unit 426 analog-converts the MOD that has been subjected to inverse fast Fourier transform, and the analog-converted AM is converted to the frequency converter 427. Predetermined frequency (e.g., 800 MHz band) is converted into the RF-M obtained by frequency conversion amplified to a predetermined power by the power amplifier unit 428, and outputs the amplified RF-P to the transmission antenna 430 (transmission output).
The transmission antenna 430 transmits a radio wave (OFDM (Orthogonal Frequency Division Multiplexing) signal) 440 to the reception antenna 450.

The reception device 460 includes a reception high-frequency unit 461, an A / D (Analog-to-Digital Converter) unit 462, an FFT (Fast Fourier Transform) unit 463, a deinterleave unit 464, a demodulation unit 465, and a decoding unit 466. .
The reception device 460 converts the frequency of the signal (OFDM signal) received by the reception antenna 450 into a baseband signal by the reception high frequency unit 461, converts it to an analog signal by the A / D unit 462, and converts frequency axis data ( Transmission frame), the order of the bit strings is changed by the deinterleaver 464, demodulated by the demodulator 465, error corrected by the decoder 466, and the video signal SI-VID is output to the outside.

As a prior art document, for example, Patent Document 1 discloses an invention of an image encoding method and apparatus that can encode a randomly accessible moving image with low delay and high compression.
Further, Patent Document 2 discloses an invention for preventing image quality deterioration at the time of switching accompanied with video signal encoding.
As Patent Document 3, the encoding unit includes an I processing unit, a P processing unit, a selection unit, a buffer memory unit, a decoding unit, a motion correlation unit, a weighting unit, and a determination unit, and the weighting unit corresponds to the state information. An invention is disclosed in which the weighting is changed and the selection unit selects one of the output of the I processing unit, the output of the P processing unit, and the output of the determination unit.
Non-Patent Document 1 includes ARIB STD-B33, which is a standard for a portable OFDM digital wireless transmission system for transmitting television broadcast program material.

JP 2010-45857 A Japanese Patent Laid-Open No. 2006-158185 JP 2006-184912 A

ARIB STD-B33 version 1.2, “Portable OFDM digital wireless transmission system for transmitting television broadcast program material”, The Japan Radio Industry Association

Video transmission has a delay time due to compression processing + transmission, and a reduction in delay is desired.
In the compression process itself, data can be reduced by making the required data amount somewhat according to the complexity of the video content, but in order to smooth the amount of data generation, a process of storing in the buffer memory is commonly used.
In the image compression processing of a conventional encoding device, the “a little” of the data generation amount depends on the design, and is stored and written in the buffer memory for data continuation, and the encoded output (compressed data) is output from the buffer memory after a predetermined time has elapsed. ).
For this reason, the encoded output (compressed data) has a delay time at the time of image compression processing.
An object of the present invention is to achieve low-delay transmission of a video signal.

  The video transmission apparatus according to the present invention is a video transmission apparatus including an encoding apparatus, a transmission apparatus, and a reception apparatus, and the encoding apparatus generates compressed data from an input video signal and generates data according to a picture pattern. TMCC information including the amount of generated data is generated, and the compressed data and the TMCC information are output to the transmission device. The transmission device modulates the compressed data input from the encoding device based on the input TMCC information, The TMCC information is superimposed on the transmitted signal and transmitted, and the receiving apparatus detects TMCC information from the signal received from the transmitting apparatus, and performs demodulation and decoding processing using the TMCC information.

  The encoding device also performs an I process on the input video signal to generate I compressed data, a P processor to perform a P process on the input video signal to generate P compressed data, and I A selection unit that selects compressed data or P compression data and intermittently outputs it, a generation amount counter unit that counts the data generation amount of I compression data or P compression data selected by the selection unit, and a generation amount counter unit that counts It is preferable to provide a control unit that generates TMCC information based on the value, and to output the I compressed data or the P compressed data selected by the selection unit and the TMCC information to the outside.

  In addition, the transmission apparatus includes a modulation unit that modulates the data into a predetermined modulation scheme based on the input compressed data and TMCC information, a TMCC switch unit that adds TMCC information to the data modulated by the modulation unit, and a signal that includes TMCC information. Is preferably provided with a signal processing unit for transmitting the signal using an OFDM signal and a power amplifier for amplifying the power of the signal from the signal processing unit, and the OFDM signal amplified by the power amplifier is transmitted via a transmission antenna.

  Further, the receiving device is a receiving device of a video transmission device that receives an OFDM signal to which TMCC information is added, and includes a control unit that detects TMCC information from the OFDM signal, a demodulation unit that demodulates the OFDM signal, and a demodulation unit. A decoding unit that decodes the demodulated signal, the control unit controls the demodulation unit and the decoding unit using the detected TMCC information, and the decoding unit outputs the restored pre-encoded video signal to the outside Is preferred.

According to the present invention, it is possible to perform low-delay transmission of a video signal.
In addition, the buffer memory capacity associated with encoding can be reduced.

It is a block diagram for demonstrating the video transmission apparatus which concerns on one Example of this invention. 6 is a timing chart for explaining the operation of the video transmission apparatus according to the embodiment of the present invention. It is a figure for demonstrating the structure of the OFDM modulation wave which concerns on one Example of this invention. It is a block diagram for demonstrating the conventional video transmission apparatus. It is a timing chart for demonstrating operation | movement of the conventional video transmission apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram for explaining a video transmission apparatus according to an embodiment of the present invention.
In FIG. 1, the video transmission device 100 includes an encoding device 110, a transmission device 120, a transmission antenna 130, a reception antenna 150, and a reception device 160.

The encoding device 110 includes a control unit 111, an I (Intra-coded Picture) processing unit 112, a P (Predictive-coded Picture) processing unit 113, a selection unit 114, a generation amount counting unit 115, and a decoding unit 116. .
The control unit 111 receives the SUM and outputs a comp control signal and an I / P1 control signal.
The I / P1 output from the control unit 111 is a signal that changes while shifting the target range downward for each frame from the upper part of the screen.
Furthermore, the control unit 111 outputs TMCC (Transmission and Multiplexing Configuration and Control) information, which is a signal related to transmission control of modulated waves, to the transmission device 120.
The TMCC information is a transmission parameter in which transmission parameters such as a modulation scheme and an inner code coding rate can be set in segment units.

The encoding device 110 generates the compressed data I-CD from the input video signal SI-VID by the I processing unit 112, the compressed data P-CD by the P processing unit 113, and the compressed data I by the selection unit 114. -Select CD or P-CD and output the selected compressed data S-CD to the transmitter 120.
Since the compressed data S-CD is output from the encoding device 110 in an intermittent state in terms of time, the delay for the buffer memory is reduced.
The decoding unit 116 decodes the S-CD and outputs the decoded video signal V-DEM to the P processing unit 113.
The SUM is a value obtained by counting the compressed data S-CD by the generation amount counting unit 115, and the generation amount increases / decreases (changes) according to the picture pattern.

The comp control signal (encoding target) output from the control unit 111 is a control signal for increasing / decreasing the generated code amount of the I processing and the P processing, and the I processing unit and the P processing unit change the quantization roughness, The generated code amount is increased or decreased.
The I / P1 control signal output from the control unit 111 selects a control signal to the selection unit 114, which is a code by I processing or a code by P processing. If the number of scanning lines is 1280 as selected in order from the top of the screen, the period of 1 to 64 is selected for the first frame, and the period of 65 to 128 is selected for the second frame.
In addition, the control unit 111 controls the quantization roughness, that is, the amount of newly generated data, with the comp control signal (encoding target) while watching the amount of SUM.

  The transmission apparatus 120 includes a buffer memory 2 unit 121, a correction code unit 122, a modulation unit 123, an interleaving unit 124, a TMCC switch unit 124b, an IFFT (Inverse Fast Fourier Transform) unit 125, and a D / A (Digital-to-Analog Converter). Unit 126, frequency conversion unit 127, and power amplification unit 128.

  The transmission device 120 sequentially writes the compressed data S-CD input to the buffer memory 2 unit 121. The TM-M correction code unit 122 adds an error correction code corresponding to the error correction variable processing to the data read from the buffer memory 2 unit 121, and the TM-P to which the error correction code is added is converted by the modulation unit 123. For example, the modulation number variable processing such as QPSK (Quadrature Phase Shift Keying) or 64QAM (64 Quadrature Amplitude Modulation) is performed and the modulation signal TM-QM is output. The modulated TM-QM is subjected to a data order change after error correction coding by the interleave unit 124, and the TMCC switch unit 124b receives the TMCC information from the TMCC information every fixed period for the TM-Qi whose data order has been changed. TMCC information related to modulation and correction coding settings is inserted into the TM-F, the IFFT unit 125 performs IFFT (Inverse Fast Fourier Transform) on the TM-F, and MMOD on which the inverse Fast Fourier Transform has been performed is converted to D / D. The A unit 126 performs analog conversion, and the analog-converted A-MM is converted into a predetermined frequency (for example, 800 MHz band) by the frequency conversion unit 127. Here, the IFFT unit 125, the D / A unit 126, and the frequency conversion unit 127 are referred to as a signal processing unit. In the signal processing unit, the frequency-converted RF-MM is amplified to a predetermined power by the power amplification unit 128, and the amplified RF-PM is output (transmission output) to the transmission antenna 130.

  The transmitting antenna 130 transmits a radio wave (OFDM (Orthogonal Frequency Division Multiplexing) signal) 140 to the receiving antenna 150.

  The reception device 160 includes a reception high-frequency unit 161, an A / D (Analog-to-Digital Converter) unit 162, an FFT (Fast Fourier Transform) unit 163, a deinterleave unit 164, a demodulation unit 165, a decoding unit 166, and a control unit 167. It is configured.

  The receiving device 160 converts the frequency of the signal (OFDM signal) received by the receiving antenna 150 into a baseband signal by the reception high frequency unit 161, converts it to an analog signal by the A / D unit 162, and converts frequency axis data ( Transmission frame), the order of the bit strings is changed by the deinterleaver 164, demodulated by the demodulator 165, error corrected by the decoder 166, and the video signal SI-VID is output to the outside.

  The control unit 167 detects TMCC information from the received signal (OFDM signal), outputs a demodulation method corresponding to the modulation number variable processing to the demodulation unit 165, and varies the error correction to the decoding unit 166. A control signal corresponding to the process is output.

Next, the operation of the video transmission apparatus according to an embodiment of the present invention will be described with reference to FIG.
FIG. 2 is a timing chart for explaining the operation of the video transmission apparatus according to the embodiment of the present invention.
The generated data amount S-CD in FIG. 2 is 16 ms per frame, the first 1 ms (1 ms) is 40 k, the next 1 ms (2 ms) is 120 k, and the last 1 ms (16 ms) is This is the case for 40k.

  TM-M, which is the output of the buffer memory 2 unit 121 in FIG. 1, has a delay time 1 shorter than the output TD-M of the buffer memory 2 unit 421 in FIG. Low latency).

  TM-P, which is the output of the correction code unit 122, is obtained by reading the first ms of one frame (16 ms) from the buffer memory 2 unit 121 at the normal speed (2 bits), and performing QPSK modulation (2 bits) by the modulation unit 133. TM-QM is output, and the remaining time is output as empty data (0 bits).

  TM-P, which is the output of the correction coding unit 122, has a large data generation amount of 120k at the second ms, so it is read from the buffer memory 2 unit 121 at a triple speed (6 bits), and the modulation unit 133 codes 6 bits. The remaining time is output as empty data (0 bits). In addition, you may modulate by 16QAM according to data generation amount.

  The TM-P output from the correction code unit 122 is the 16th ms read out from the buffer memory 2 unit 121 at the normal speed (2 bits), and outputs TM-QM QPSK modulated (2 bits) by the modulation unit 133. The remaining time is output as empty data (0 bits).

  The transmission output RF-PM of the transmission device 120 becomes intermittent output by the above-described processing.

Next, the configuration (data carrier, TMCC carrier) of the OFDM modulated wave of the present invention will be described with reference to FIG.
FIG. 3 is a diagram for explaining the configuration of an OFDM modulated wave according to an embodiment of the present invention.
The TM-QM output from the modulation unit 133 is QPSK, QPSK (empty data), 64QAM, QPSK (empty data),..., QPSK, QPSK.

The OFDM modulation wave adds TMCC information indicating a modulation scheme to the modulation multi-level number of each data carrier.
The control unit 167 of the receiving device 160 can restore the video signal SI-VID by controlling the demodulation unit 165 and the decoding unit 166 based on the TMCC information.

  The video transmission apparatus according to the embodiment of the present invention can perform low-delay transmission of video signals. In addition, the buffer memory capacity associated with encoding can be reduced.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, switching between I processing and P processing can be applied to switching in the horizontal direction instead of the vertical direction of the screen.

  By changing the modulation method according to the amount of video data, the present invention can be applied to a purpose of performing low-delay transmission of a video signal.

  100: Video transmission device, 110: Encoding device, 111: Control unit, 112: I processing unit, 113: P processing unit, 114: Selection unit, 115: Generation amount counting unit, 116: Decoding unit, 120: Transmission device 121: buffer memory 2 units, 122: correction code unit, 123: modulation unit, 124: interleave unit, 124b: TMCC switch unit, 125: IFFT unit, 126: D / A unit, 127: frequency conversion unit, 128: Power amplification unit, 130: transmission antenna, 150: reception antenna, 160: reception device, 161: reception high frequency unit, 162: A / D unit, 163: FFT unit, 164: deinterleave unit, 165: demodulation unit, 166: Decoding unit, 167: Control unit, 400: Video transmission device, 410: Coding device, 411: Control unit, 412: I processing unit, 413: P processing unit, 414: Selection 416: Decoding unit 417: Buffer memory 1 unit 420: Transmission device 421: Buffer memory 2 unit 422: Correction code unit 423: Modulation unit 424: Interleaving unit 424b: TMCC switch unit 425: IFFT unit, 426: D / A unit, 427: frequency conversion unit, 428: power amplification unit, 430: transmission antenna, 450: reception antenna, 460: reception device, 461: reception high frequency unit, 462: A / D unit, 463: FFT unit, 464: deinterleave unit, 465: demodulation unit, 466: decoding unit.

Claims (2)

A video transmission device comprising an encoding device, a transmission device, and a reception device,
The encoding device generates compressed data from an input video signal, generates a signal related to transmission control of a modulated wave, and outputs the compressed data and a signal related to transmission control of the modulated wave to a transmission device,
The transmitting device modulates the compressed data input from the encoding device based on the input signal related to transmission control of the modulated wave, and superimposes the signal related to transmission control of the modulated wave on the modulated signal. Send
The receiver detects a signal related to transmission control of a modulated wave from a signal received from the transmitter, performs demodulation and decoding using the signal related to transmission control of the modulated wave ,
Furthermore, the encoding device comprises:
An I processing unit that performs I processing of the input video signal to generate I compressed data;
A P processing unit that performs P processing on the input video signal to generate P compressed data;
A selection unit that selects and intermittently outputs the I compressed data or the P compressed data;
A generation amount counter unit that counts the data generation amount of the I compression data or the P compression data selected by the selection unit;
A control unit that generates a signal related to transmission control of a modulated wave based on the value counted by the generation amount counter unit,
Outputs the I-compressed data or the P-compressed data selected by the selector and a signal related to transmission control of the modulated wave to the outside.
A video transmission apparatus characterized by that.   A video transmission device comprising an encoding device, a transmission device, and a reception device,
  The encoding device generates compressed data from an input video signal, generates a signal related to transmission control of a modulated wave, and outputs the compressed data and a signal related to transmission control of the modulated wave to a transmission device,
  The transmitting apparatus modulates the compressed data input from the encoding apparatus based on the input signal related to transmission control of the modulated wave, and superimposes the signal related to transmission control of the modulated wave on the modulated signal. Send
  The receiver detects a signal related to transmission control of a modulated wave from a signal received from the transmitter, performs demodulation and decoding using the signal related to transmission control of the modulated wave,
  Furthermore, the transmission device includes:
  A modulation unit that modulates a predetermined modulation method based on the input compressed data and a signal related to transmission control of the modulated wave;
  A TMCC switch unit for adding a signal related to transmission control of the modulated wave to the data modulated by the modulation unit;
  A signal processing unit for transmitting a signal to which a signal related to transmission control of the modulated wave is added as an OFDM signal;
  A power amplifier that amplifies the power of the signal from the signal processing unit,
  The OFDM signal amplified by the power amplifier is transmitted through a transmission antenna.
  A video transmission apparatus characterized by that.

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