JP2005204054A - Image encoding and transmitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image encoding and transmitting device capable of selecting an encoding system matching the format of a video signal and encoding the signal without inputting a mode select signal and a synchronizing signal in addition to the video signal. <P>SOLUTION: The device includes a format decision part 3 which decides the format of the video signal by monitoring the video signal received by a video reception part 2 and a control part 4 which selects the encoding system corresponding to the format decided by the format decision part 3, and encodes the video signal by the encoding system selected by the control part 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image encoding / transmission apparatus that encodes and transmits a video signal.

  2. Description of the Related Art Conventional image encoding and transmission apparatuses include an input terminal for inputting a high definition television (HDTV) digital serial signal, which is a high-definition video signal, and a standard serialization television (SDTV) digital serial signal, which is a standard display video signal. When an input terminal for inputting a signal and an input terminal for inputting a mode selection signal for designating a video signal encoding method are provided, and an HDTV or SDTV digital serial signal is input from any of the input terminals, the mode selection signal The encoding method is selected according to the encoding method, and an HDTV or SDTV digital serial signal is encoded and transmitted by the encoding method (see, for example, Patent Document 1).

  In addition, another image coding and transmission apparatus includes an input terminal for inputting a video signal and an input terminal for inputting a synchronization signal accompanying the video signal. When a video signal is input from the input terminal, the synchronization signal Based on the period, the format of the video signal is determined, an encoding method is selected, and the video signal is encoded and transmitted by the encoding method (see, for example, Patent Document 2).

JP-A-10-210478 (paragraph numbers [0028] to [0050], FIG. 1) JP-A-6-315142 (paragraph numbers [0010] to [0017], FIG. 1)

Since the conventional image encoding and transmitting apparatus is configured as described above, it is possible to automatically select an encoding method suitable for the format of the video signal and encode the video signal. However, there is a problem that it is necessary to provide an input terminal for inputting a mode selection signal and a synchronization signal in addition to an input terminal for inputting a video signal.
In addition, an external device that supplies a video signal to an image encoding transmission device has a problem that it is necessary to generate a mode selection signal and a synchronization signal.

  The present invention has been made to solve the above-described problems, and selects a coding method suitable for the format of the video signal without inputting a mode selection signal or a synchronization signal in addition to the video signal. It is an object of the present invention to obtain an image encoding transmission device that can be converted into an image.

  The image coding and transmitting apparatus according to the present invention monitors the video signal received by the video signal receiving means, and determines the format of the video signal, and corresponds to the format determined by the format determining means. Selection means for selecting an encoding method is provided, and the video signal is encoded by the encoding method selected by the selection means.

  According to the present invention, the video signal received by the video signal receiving means is monitored, the format discriminating means for discriminating the format of the video signal, and the encoding method corresponding to the format discriminated by the format discriminating means are selected. And the video signal is encoded by the encoding method selected by the selection means, so that the video signal can be input without inputting a mode selection signal or a synchronization signal in addition to the video signal. There is an effect that it is possible to select and encode an encoding method suitable for the format.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing an image encoding / transmission apparatus according to Embodiment 1 of the present invention. In the figure, a video input terminal 1 is a terminal for inputting an HDTV or SDTV digital serial signal (video signal).
The video receiver 2 is equipped with a receiver that receives an HDTV or SDTV digital serial signal input from the video input terminal 1. The video encoder 5 converts the video data and audio data contained in the digital serial signal. And the clock included in the digital serial signal is supplied to the video encoding unit 5, the system multiplexing unit 6 and the transmission path conversion unit 7. Needless to say, the receiver installed in the video receiver 2 may be a digital serial signal input from the video input terminal 1, whether it is an HDTV digital serial signal or an SDTV digital serial signal. It can respond. The video receiver 2 constitutes video signal receiving means.

The format determining unit 3 constitutes format determining means for monitoring the HDTV or SDTV digital serial signal received by the video receiving unit 2 and determining the format of the digital serial signal.
The control unit 4 constitutes selection means for selecting an encoding method, a multiplexing method, and a transmission method corresponding to the format determined by the format determination unit 3.
The video encoding unit 5 encodes the video data and audio data output from the video receiving unit 2 by the encoding method selected by the control unit 4, and outputs the encoded data to the system multiplexing unit 6. The video encoding unit 5 constitutes video encoding means.

The system multiplexing unit 6 converts the encoded data output from the video encoding unit 5 into a TS (Transport Stream) by the multiplexing method selected by the control unit 4 and outputs the TS data to the transmission path conversion unit 7. The transmission path conversion unit 7 outputs the TS data output from the system multiplexing unit 6 to the output terminal 8 by the transmission method selected by the control unit 4. The system multiplexing unit 6 and the transmission path conversion unit 7 constitute transmission means.
The output terminal 8 outputs TS data output from the transmission line conversion unit 7 to the outside.

Next, the operation will be described.
First, when an HDTV or SDTV digital serial signal is supplied to the video input terminal 1 from an external device, the video receiver 2 receives the HDTV or SDTV digital serial signal input from the video input terminal 1.
The video reception unit 2 outputs the HDTV or SDTV digital serial signal to the format determination unit 3, while separating the video data and audio data and the clock included in the digital serial signal, and the video data and audio data. Is output to the video encoding unit 5. The clock is supplied to the video encoding unit 5, the system multiplexing unit 6, and the transmission path conversion unit 7.

The format determination unit 3 monitors the HDTV or SDTV digital serial signal received by the video reception unit 2 and determines the format of the digital serial signal.
Specifically, the format determination unit 3 detects the frequency of the digital serial signal output from the video reception unit 2, and if the frequency is about 1.5 GHz, the format of the digital serial signal is HDTV. If the frequency is about 270 MHz, the digital serial signal format is recognized as SDTV.

When the format determination unit 3 specifies the format of the digital serial signal as described above, the format determination unit 3 specifies the field frequency of the digital serial signal.
That is, the format determination unit 3 measures the frequency of one frame by counting the number of data for one frame of the digital serial signal using the internal clock.
Usually, the frequency of one frame, which is the field frequency measured by the format determination unit 3, is 59 Hz or 60 Hz.

In the first embodiment, the format determination unit 3 detects the frequency of the digital serial signal output from the video reception unit 2 to recognize whether the format of the digital serial signal is HDTV or SDTV, Although what has specified the field frequency of the digital serial signal has been shown, when the receiver mounted on the video receiver 2 has a function of identifying the format of the digital serial signal, the receiver of the video receiver 2 The format identification result may be transmitted to the format determination unit 3.
Further, if the receiver of the video receiving unit 2 outputs the horizontal synchronization signal included in the digital serial signal to the format determining unit 3, the format determining unit 3 uses the internal clock to output 1 of the digital serial signal. The frequency of one frame can be measured from the horizontal synchronizing signal without counting the number of data for the frame.

When the format determination unit 3 specifies the format and field frequency of the digital serial signal, the control unit 4 selects an encoding method according to the format and field frequency of the digital serial signal.
Specifically, if the format of the digital serial signal is HDTV and the field frequency is 59 Hz, the control unit 4 selects, for example, MP @ HL as the encoding method, and sets the number of frames per second. Assume that encoding processing is performed on 29.97 sheets. If the field frequency is 60 Hz, for example, MP @ HL is selected as the encoding method, and the encoding process is performed with 30 frames per second.
Also, if the digital serial signal format is SDTV and the field frequency is 59 Hz, for example, MP @ ML is selected as the encoding method, and the encoding process is performed with 29.97 frames per second. Shall be performed. If the field frequency is 60 Hz, for example, MP @ ML is selected as the encoding method, and the encoding process is performed with 30 frames per second.

Next, the control unit 4 selects a multiplexing method corresponding to the format of the digital serial signal determined by the format determination unit 3.
Specifically, if the digital serial signal format is HDTV, the control unit 4 sets the video data transmission rate to 40 MHz and the audio data transmission rate to 1.5 MHz, for example, as a multiplexing method. Set.
If the format of the digital serial signal is SDTV, for example, the video data transmission rate is set to 20 MHz and the audio data transmission rate is set to 512 KHz.

Next, the control unit 4 selects a transmission method corresponding to the format of the digital serial signal determined by the format determination unit 3.
Specifically, if the digital serial signal format is HDTV, the control unit 4 sets the transmission clock to 50 MHz, for example, and if the digital serial signal format is SDTV, the transmission scheme is used. For example, the transmission clock is set to 25 MHz.

When receiving a clock from the video receiver 2, the video encoder 5 starts an encoding process in accordance with the MPEG-2 (ISO / IEC13818-2) standard in synchronization with the clock.
That is, the video encoding unit 5 encodes the video data and audio data output from the video receiving unit 2 by the encoding method selected by the control unit 4 and outputs the encoded data to the system multiplexing unit 6. .

When receiving a clock from the video receiver 2, the system multiplexer 6 starts multiplexing processing in synchronization with the clock.
That is, the system multiplexing unit 6 converts the encoded data output from the video encoding unit 5 into a TS (multiplexing) by the multiplexing method selected by the control unit 4, and converts the TS data into the transmission path conversion unit 7. Output to.

When receiving a clock from the video receiver 2, the transmission path converter 7 starts TS data transmission processing in synchronization with the clock.
That is, the transmission path conversion unit 7 outputs the TS data output from the system multiplexing unit 6 to the output terminal 8 by the transmission method selected by the control unit 4 and outputs the TS data to the outside.

  As is apparent from the above, according to the first embodiment, the video signal received by the video receiver 2 is monitored, and the format determination unit 3 that determines the format of the video signal, and the format determination unit 3 And a control unit 4 for selecting an encoding method corresponding to the determined format, and the video data and the audio data are encoded by the encoding method selected by the control unit 4. In addition, there is an effect that the video data and audio data can be encoded by selecting an encoding method suitable for the format of the video signal without inputting a mode selection signal or a synchronization signal.

  Further, according to the first embodiment, since the multiplexing method corresponding to the format determined by the format determination unit 3 is selected and the encoded data is multiplexed by the multiplexing method, the video signal In addition, there is an effect that the encoded data can be multiplexed by selecting a multiplexing method suitable for the format of the video signal without inputting a mode selection signal or a synchronization signal.

  In addition, according to the first embodiment, the transmission method corresponding to the format determined by the format determination unit 3 is selected, and the TS data is transmitted by the transmission method. There is an effect that TS data can be transmitted by selecting a transmission method suitable for the format of the video signal without inputting a selection signal or a synchronization signal.

Embodiment 2. FIG.
In the first embodiment, the control unit 4 selects an encoding method, a multiplexing method, and a transmission method corresponding to the format of the digital serial signal determined by the format determination unit 3, and the selection result is used as the video encoding unit 5. , What is notified to the system multiplexing unit 6 and the transmission path conversion unit 7 has been described. Since the operation of the video receiving unit 2 is not stable immediately after the switching of the digital serial signal format, video encoding is performed even immediately after the switching. If the processing of the unit 5, the system multiplexing unit 6 and the transmission path conversion unit 7 is continued, TS data representing an abnormal image may be output from the output terminal 8.

Therefore, in the second embodiment, when the control unit 4 detects the switching of the format of the digital serial signal determined by the format determination unit 3, the video encoding unit 5, the system multiplexing unit 6, and the transmission path conversion unit 7 are used. To temporarily stop the process.
The control unit 4 restarts the processing of the video encoding unit 5, the system multiplexing unit 6, and the transmission path conversion unit 7 when a predetermined time has elapsed and the operation of the video reception unit 2 is stabilized.
At this time, the control unit 4 selects an encoding method, a multiplexing method, and a transmission method corresponding to the new format, and the encoding method, the multiplexing method, and the transmission method are selected as the video encoding unit 5, the system multiplexing unit 6. And notifies the transmission path converter 7.

  As is apparent from the above, according to the second embodiment, when the switching of the format of the digital serial signal determined by the format determination unit 3 is detected, the video encoding unit 5, the system multiplexing unit 6, and the transmission path conversion are detected. Since the processing of the video encoding unit 5, the system multiplexing unit 6 and the transmission path conversion unit 7 is resumed after the processing of the unit 7 is temporarily stopped, immediately after switching the format of the digital serial signal, There is an effect that it is possible to avoid a situation in which TS data representing an abnormal image is output from the output terminal 8.

Embodiment 3 FIG.
2 is a block diagram showing an image encoding / transmission apparatus according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG.
The video reception buffer 11 stores the video data and audio data output from the video reception unit 2.
Similar to the control unit 4 in FIG. 1, the control unit 12 constitutes a selection unit that selects an encoding method, a multiplexing method, and a transmission method corresponding to the format determined by the format determination unit 3. When the control unit 12 detects the switching of the format determined by the format determination unit 3, the control unit 12 temporarily stops the storage of the video data and audio data in the video reception buffer 11 in the video reception unit 2, and then The storage process of the video receiver 2 is resumed.

  The clock generation unit 13 generates a clock synchronized with the video signal received by the video reception unit 2, and uses the clock as a video reception buffer 11, a video encoding unit 5, a system multiplexing unit 6, and a transmission path conversion unit 7. When the clock generation unit 13 detects the switching of the format determined by the format determination unit 3, the clock generation unit 13 temporarily continues the clock having the same frequency as the clock generated immediately before the format switching. And supply.

  FIG. 3 is a block diagram showing the clock generation unit 13 of the image encoding / transmission apparatus according to the third embodiment of the present invention. In the figure, the PLL circuits 21 and 22 indicate the frequency of the video signal received by the video reception unit 2. Follow-up processing (for example, the phase of the clock output from the internal oscillation circuit is compared with the phase of the video signal received by the video receiver 2, and the phase of the clock is adjusted and output so that the phases of both coincide. ) To generate a clock synchronized with the video signal.

The SEL 23 selects the clock generated by the PLL circuit 21 from among the clocks generated by the PLL circuits 21 and 22, and switches the format determined by the format determination unit 3 when the clock is output to the PLL circuit 24. Is detected, the frequency tracking process in the PLL circuit 21 is stopped, and the clock immediately before the tracking process is stopped is continuously output to the PLL circuit 24. After that, when the operation of the video receiving unit 2 is stabilized, the PLL circuit The clock generated by 22 is selected and output to the PLL circuit 24.
The PLL circuit 24 performs frequency tracking processing on the clock output from the SEL 23 to generate a clock synchronized with the clock, and the clock is received by the video reception buffer 11, the video encoding unit 5, the system multiplexing unit 6. And supplied to the transmission path converter 7.

Next, the operation will be described.
First, when an HDTV or SDTV digital serial signal is supplied from an external device to the video input terminal 1, the video receiver 2 receives the HDTV or SDTV digital signal input from the video input terminal 1 as in the first embodiment. Receive serial signal.
The video reception unit 2 outputs the HDTV or SDTV digital serial signal to the format determination unit 3, while separating the video data and audio data and the clock included in the digital serial signal, and the video data and audio data. Is stored in the video reception buffer 11. The clock is output to the clock generation unit 13.

When receiving the HDTV or SDTV digital serial signal from the video receiver 2, the format determination unit 3 monitors the digital serial signal and determines the format of the digital serial signal in the same manner as in the first embodiment. The field frequency of the digital serial signal is specified.
When the format determination unit 3 specifies the format and field frequency of the digital serial signal, the control unit 12 performs encoding according to the format and field frequency of the digital serial signal in the same manner as the control unit 4 of the first embodiment. Select a method. Also, a multiplexing method and a transmission method are selected according to the format of the digital serial signal.

When receiving a clock from the clock generation unit 13 (details will be described later), the video encoding unit 5 starts an encoding process according to the MPEG-2 (ISO / IEC13818-2) standard in synchronization with the clock. .
That is, the video encoding unit 5 encodes the video data and audio data stored in the video reception buffer 11 by the encoding method selected by the control unit 12 and outputs the encoded data to the system multiplexing unit 6. To do.

When receiving a clock from the clock generation unit 13, the system multiplexing unit 6 starts multiplexing processing in synchronization with the clock.
That is, the system multiplexing unit 6 converts the encoded data output from the video encoding unit 5 into a TS using the multiplexing method selected by the control unit 12 and outputs the TS data to the transmission path conversion unit 7.

When receiving a clock from the clock generation unit 13, the transmission path conversion unit 7 starts transmission processing of TS data in synchronization with the clock.
That is, the transmission path conversion unit 7 outputs the TS data output from the system multiplexing unit 6 to the output terminal 8 by the transmission method selected by the control unit 4 and outputs the TS data to the outside.

Here, immediately after the switching of the format of the digital serial signal, as described above, the operation of the video receiving unit 2 is not stable. If the above process is continued, TS data representing an abnormal image may be output from the output terminal 8.
Therefore, in the third embodiment, in order to prevent TS data representing an abnormal image from being output from the output terminal 8, the format is changed until the operation of the video receiver 2 is stabilized. The TS data immediately before the switching is continuously output from the output terminal 8 so that the freeze image is displayed.

Specifically, when the control unit 12 detects the switching of the format determined by the format determination unit 3, the video data and audio data included in the video signal received by the video reception unit 2 are thereafter converted into video. Processing to be stored in the reception buffer 11 is temporarily stopped.
Further, the control unit 12 continuously notifies the video encoding unit 5, the system multiplexing unit 6 and the transmission path conversion unit 7 of the selection result before the format is switched.

As a result, the video encoding unit 5 encodes the same video data and audio data as before the format switching in the same encoding method as before the format switching, and outputs the encoded data to the system multiplexing unit 6. .
The system multiplexing unit 6 converts the encoded data output from the video encoding unit 5 into a TS using the same multiplexing method as before the format is switched, and outputs the TS data to the transmission path conversion unit 7.
The transmission path conversion unit 7 outputs the TS data output from the system multiplexing unit 6 to the output terminal 8 by the same transmission method as before the format is switched, and outputs the TS data to the outside.

  However, if the clock frequency supplied to the video encoding unit 5, the system multiplexing unit 6 and the transmission path conversion unit 7 is different before and after the format switching, different TS data is output before and after the format switching. When the generation unit 13 detects the switching of the format determined by the format determination unit 3, the generation unit 13 temporarily supplies a clock having the same frequency as that of the clock generated immediately before the format is switched.

Specifically, the PLL circuits 21 and 22 of the clock generation unit 13 perform frequency tracking processing on the video signal received by the video reception unit 2 to generate a clock synchronized with the video signal. For example, when the SEL 23 selects the clock generated by the PLL circuit 21 and outputs the selected clock to the PLL circuit 24, if the switching of the format determined by the format determination unit 3 is detected, the frequency tracking in the PLL circuit 21 is detected. The processing is stopped, and the clock immediately before the follow-up processing is stopped is continuously output to the PLL circuit 24.
As a result, the PLL circuit 24 of the clock generation unit 13 performs a frequency tracking process on the clock having the same frequency as before the format is switched, generates a clock synchronized with the clock, and receives the clock as a video. The data is supplied to the buffer 11, the video encoding unit 5, the system multiplexing unit 6, and the transmission path conversion unit 7.

Thereafter, when the operation of the video reception unit 2 is stabilized, the SEL 23 of the clock generation unit 13 selects the clock generated by the PLL circuit 22 and outputs it to the PLL circuit 24.
As a result, the PLL circuit 24 of the clock generation unit 13 supplies a clock synchronized with the video signal after the format change to the video reception buffer 11, the video encoding unit 5, the system multiplexing unit 6, and the transmission path conversion unit 7. Will be.

  When the operation of the video reception unit 2 is stabilized, the control unit 12 resets the video data and audio data stored in the video reception buffer 11, and then performs the video data and audio data storage processing in the video reception unit 2. The encoding method, the multiplexing method, and the transmission method are selected according to the format and field frequency of the digital serial signal newly specified by the format determination unit 3, and the selection result is selected as the video encoding unit 5, This is notified to the system multiplexing unit 6 and the transmission path conversion unit 7.

  As apparent from the above, according to the third embodiment, when the switching of the format determined by the format determination unit 3 is detected, the video data and audio data are stored in the video reception buffer 11 in the video reception unit 2. Is temporarily stopped and then the storage process of the video receiver 2 is resumed. Therefore, immediately after the digital serial signal format is switched, TS data representing an abnormal image is output from the output terminal 8. There is an effect that can avoid the situation.

  Further, according to the third embodiment, a clock synchronized with the video signal received by the video receiving unit 2 is generated, and the clock is received by the video receiving buffer 11, the video encoding unit 5, the system multiplexing unit 6. And a clock generation unit 13 to be supplied to the transmission path conversion unit 7, and when the clock generation unit 13 detects the switching of the format determined by the format determination unit 3, it is the same as the clock generated immediately before the format is switched. Since the configuration is such that the clock of the frequency is continuously supplied, it is possible to avoid the situation where different TS data is output before and after the format switching.

It is a block diagram which shows the image coding transmission apparatus by Embodiment 1 of this invention. It is a block diagram which shows the image coding transmission apparatus by Embodiment 3 of this invention. It is a block diagram which shows the clock generation part of the image coding transmission apparatus by Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Video input terminal, 2 Video receiving part (Video signal receiving means), 3 Format determination part (Format discrimination means), 4 Control part (Selection means), 5 Video encoding part (Video encoding means), 6 System multiplexing part (Transmission means), 7 transmission path conversion section (transmission means), 8 output terminal, 11 video reception buffer, 12 control section (selection means), 13 clock generation section (clock generation means), 21 PLL circuit, 22 PLL circuit, 23 SEL, 24 PLL circuit.

Claims (7)

  Corresponding to the format discriminated by the format discriminating means, the video signal receiving means for receiving the video signal, the format discriminating means for monitoring the video signal received by the video signal receiving means and discriminating the format of the video signal Selection means for selecting the encoding method to be performed, video encoding means for encoding the video signal in the encoding method selected by the selection means, and the video signal encoded by the video encoding means are multiplexed. An image encoding transmission apparatus comprising:   A video signal receiving means for receiving the video signal and storing the video signal in a reception buffer; a format determining means for monitoring the video signal received by the video signal receiving means; and determining the format of the video signal; Selection means for selecting an encoding method corresponding to the format determined by the format determination means, and video encoding for encoding the video signal stored in the reception buffer by the encoding method selected by the selection means And a transmission means for multiplexing and transmitting the video signal encoded by the video encoding means.   The selection means selects a multiplexing method corresponding to the format determined by the format determination means, and the transmission means multiplexes the video signal by the multiplexing method selected by the selection means. The image encoding transmission apparatus according to claim 2.   4. The transmission apparatus according to claim 1, wherein the selection means selects a transmission method corresponding to the format determined by the format determination means, and the transmission means transmits the video signal by the transmission method selected by the selection means. The image encoding transmission apparatus of any one of these.   Upon detecting the switching of the format determined by the format determination unit, the selection unit temporarily stops the processing of the video encoding unit and the transmission unit, and then restarts the processing of the video encoding unit and the transmission unit. The image encoding transmission apparatus according to claim 1.   When the selector detects the switching of the format determined by the format determiner, the selector temporarily stops the storage of the video signal in the reception buffer in the video signal receiver, and then performs the storage of the video signal receiver. The image encoding transmission apparatus according to claim 2, wherein the image encoding transmission apparatus is restarted.   A clock generating means for generating a clock synchronized with the video signal received by the video signal receiving means and supplying the clock to the video encoding means and the transmitting means is provided, and the clock generating means is discriminated by the format discriminating means. 7. The image encoding / transmission apparatus according to claim 6, wherein when the switching of the generated format is detected, a clock having the same frequency as that of the clock generated immediately before the switching of the format is continuously supplied.

Images