JP6102332B2 - Video stream switching system, video stream switching method and program - Google Patents

Description

  The present invention relates to a video stream switching system, a video stream switching method, and a program, and more particularly to a video stream switching system and the like that can suppress deterioration in image quality when switching video.

  In Japan, as terrestrial television broadcasting has completely shifted to digital broadcasting, almost all of the transmission facilities of television broadcasting stations have also shifted to devices that handle digital video stream signals. Of course, not only terrestrial television broadcasts but also satellite broadcasts, cable television broadcasts, IPTV broadcasts via optical fiber lines, etc., their transmission facilities are devices that handle video stream signals.

  As a general rule, such broadcasting cannot be stopped, so for example, when maintenance of transmission facilities (including regular and urgent ones) is required, there are two systems, an active system and a standby system prepared in advance. It is absolutely necessary to switch the active system in operation to the standby system. This switching must be done seamlessly so that the viewer does not notice that it has been done.

  For analog video signals, this switching does not cause a problem. In addition, when a digital video signal is uncompressed, the switching is performed according to the frame period of the synchronization signal as long as all devices and signals related to the switching are synchronized by the synchronization signal indicating the frame period. By doing so, it is possible to easily switch seamlessly from the active system to the standby system without causing synchronization disturbance on the receiver side.

  However, in digital broadcasting that has recently become widespread, MPEG-2 and H.264 have been used. An encoder device that performs compression processing of a video signal in accordance with a standard such as H.264 is used. In this compression processing, data compression is performed based on the motion of the image between the frames constituting the moving image and the previous and subsequent frames. Therefore, when the compressed video signal is switched as it is, the receiver side Mosaic noise or the like due to synchronization disturbance occurs in the video.

  When compression processing such as MPEG-2 is required and a high compression rate used in broadcasting is required, data constituting a GOP (Group Of Picture) with I / P / B pictures having different data structures It is common to do. GOP indicates a data structure in compression.

  In order to seamlessly switch the encoded video signal data, it is necessary to make the data before and after the switching a closed GOP that is completed in GOP units so that the data is not destroyed. . In addition, it is necessary to set the timing for switching between the last data of the GOP before switching and the top data of the GOP after switching.

  In the compressed video signal data, the code amount for each picture varies depending on the intensity of the motion of the video to be encoded, the complexity of the video, and the like. In particular, the amount of code varies greatly depending on video signal data composed of I / P / B pictures and differences in picture types. Here, a picture is data in which one frame of video is generally compressed.

  Further, an encoder that performs compression processing generally employs a method for obtaining a code amount of a frame to be encoded next based on a code amount of a video frame that has been encoded. In this system, the same result cannot be obtained unless the apparatus is turned on at exactly the same timing and encoding is started with exactly the same video.

  In addition, data compression generally used in digital broadcasting or the like is a CBR (Constant Bit Rate) method in which the amount of data per time is constant. In this method, unless the video has almost no motion such as a color bar (test pattern) for broadcasting test, it is common to adjust the code amount within the range of the MPEG standard VBV buffer to improve the image quality. In this case, data is output without interruption between GOPs. Therefore, the GOP is not “intermittent data”, and even if data is switched here, seamless switching is not achieved.

  Due to the above factors, it is difficult to create a GOP break synchronized with each other with two encoders in video signal data compressed by a normal encoding process. “Seamless switching” is difficult. Therefore, the method described in FIG. 8 described below is used in the existing video stream switching system.

  FIG. 8 is an explanatory diagram showing a configuration of an existing video stream switching system 910. The video stream switching system 910 includes two systems of encoders as an active system and a standby system that perform a coding process on an externally input video signal and output a transport stream (TS). These are respectively referred to as an encoder 911a as an active system and an encoder 911b as a backup system.

  Then, the video stream switching system 910 selects and switches one of the TSs output from the encoders 911a and 911b, and outputs TS to the outside. Control means 913 for controlling the switching operation.

  The control means 913 is a processor that is a computer program implementation body, and functions as an encoder control function for controlling the encoders 911a and 911b and a TS switching control function for controlling the TS switching means 912 by the control program.

  When a system switching command is input from the outside to the control means 913, first, the TS code amount is smaller than the total bit rate set from the start to the end of the GOP for the encoders 911a and 911b. A control signal for suppressing the image quality is issued. The encoders 911a and 911b operate according to the control signal so as to suppress the image quality and reduce the TS code amount.

  With this operation, a space between the GOP and the next GOP can be a blank portion where no valid encoded data exists. In this state, even if the encoded data is not exactly the same between the encoders 911a and 911b, there is no deterioration in image quality that can be seen by human eyes, so there is a particular problem in switching. Thus, the data can be seamlessly switched between these encoders.

  After this state, the control unit 913 operates the TS switching unit 912 so that the TS is switched between GOPs that have become blank portions.

  In this connection, the following technical documents exist. Among them, Patent Document 1 describes a system switching system in which an active encoder transmits state parameter information to a standby encoder to enable seamless switching. Patent Document 2 describes a switching device that holds a packet of a video signal in a buffer and performs switching control by changing a reading position to a switchable packet.

  Patent Document 3 describes a switching system that enables seamless switching without degrading the image quality by thinning out frames and adjusting the phase when switching between a plurality of encoders of the active system and the standby system. ing. Patent Document 4 describes a switching device that selects a switching method according to conditions. Patent Document 5 describes an encoder device and a switching control method for shortening the IDR cycle immediately before switching.

  Patent Document 6 describes a video encoding device including a two-pass encoder that performs encoding in two stages of preliminary encoding and main encoding. Patent Document 7 describes a video encoding apparatus that detects a scene change in a GOP and uses a point with little deterioration in image quality as an editing point.

JP 2000-269864 A JP 2001-217753 A JP 2012-049594 A Japanese Patent No. 4464727 Japanese Patent No. 4492518 JP 2003-018593 A JP 2006-121415 A

  In the existing video stream switching system 910 shown in FIG. 8, if the input video signal is a normal video, the encoder can be operated to “suppress image quality” in order to create this blank portion. No degradation of image quality that humans can see with eyes. Therefore, no particular problem occurs when the TS is switched between GOPs that have become blank portions.

  However, for video that changes rapidly between frames, such as scene changes (scene changes) or some sports broadcasts, for example, in normal encoding, the amount of code is temporarily increased only in the areas where the change is significant. Need to be maintained.

  Therefore, when a TS switching command overlaps a GOP including such an image, the encoder enters an operation of “suppressing image quality”, so an operation of “temporarily increasing the code amount and maintaining the image quality” can be performed. Disappear. Therefore, visible image quality degradation such as generation of mosaic noise occurs.

  Techniques that can solve this problem are not described in the aforementioned Patent Documents 1-7. Patent Document 3 describes a technique such as thinning out a frame or adjusting a phase when switching between a plurality of systems of an active system and a standby system. However, none of these documents mentions the above-mentioned problem associated with scene changes, and therefore, this problem cannot be solved by a combination of the techniques described in these documents.

  An object of the present invention is to provide a video stream switching system, a video stream switching method, and a program capable of seamlessly switching between an active system and a standby system even for a video including a frame in which an image changes drastically. There is.

  In order to achieve the above object, a video stream switching system according to the present invention performs encoding processing on a video signal input from the outside and outputs a transport stream and a plurality of encoders output from each encoder. TS switching means for selecting and switching one of the transport streams to be output and outputting to the outside. When each TS switching means performs transport stream switching in each encoder, image quality deterioration may be caused. Pre-analysis means for determining whether a state frame is included in a GOP (Group Of Picture) of a video signal is provided, and a video signal at the time when the system switching command is input from the outside and the system switching command is performed If the GOP contains a frame that can cause image quality degradation, When it is determined, it has a control means for causing the TS switching means to switch the transport stream at the GOP immediately after the GOP.

In order to achieve the above object, a video stream switching method according to the present invention performs encoding processing on a video signal input from outside and outputs a transport stream, and outputs from each encoder. When a system switching command is input from the outside, the video stream switching system includes TS switching means for selecting and switching one of the transport streams to be output to the outside. The pre-analysis control function issues a control signal to the pre-analysis means provided in each encoder, and the pre-analysis means that receives the control signal may cause image quality degradation when the TS switching means performs transport stream switching. Judgment whether the state frame is included in the GOP (Group Of Picture) of the video signal However, when the pre-analyzing unit determines that a frame that can cause image quality degradation is included, the image quality is maintained during the GOP, and the transport stream can be switched at the end of the GOP immediately after the GOP. encoder control function operation to suppress image quality by reducing the amount of code instructs the encoder, last TS switching control function of the GOP that suppresses image quality by reducing the code amount to switch the transport stream TS switching means Generating a control signal to be performed.

In order to achieve the above object, a video stream switching program according to the present invention performs a coding process on an externally input video signal and outputs a transport stream, and is output from each encoder. A video stream switching system including TS switching means for selecting and switching one of the transport streams to be output to the outside. When a switching command is input, when the TS switching unit switches the transport stream with respect to the pre-analyzing unit provided in each encoder, a frame in a state that may cause image quality degradation is converted into a GOP (Group Of Picture) of the video signal. ) Control signal to determine whether or not When the pre-analyzing unit determines that a frame that can cause image quality degradation is included, the image quality is maintained during the GOP, and the transport stream is switched at the end of the GOP immediately after the GOP. procedure for instructing the operation to suppress the smaller to the picture quality code amount to perform, and the code amount less to the last TS switching means of the GOP that suppresses image quality procedures that emits a control signal for switching the transport stream It is made to perform.

  As described above, in the present invention, when a GOP of a video signal includes a frame in a state that can cause image quality degradation when switching of a transport stream is performed, switching is performed at the end of the GOP immediately after the GOP. Since it is configured, a video stream switching system and a video stream switching method having an excellent feature that it is possible to seamlessly switch between the active system and the standby system even for a video including a frame in which the image changes drastically. And to provide a program.

It is explanatory drawing shown about the structure of the video stream switching system which concerns on the basic form of this invention. It is explanatory drawing shown about the structure of the video stream switching system which concerns on the 1st Embodiment of this invention. 3 is a timing chart for explaining an operation of TS switching performed in the video stream switching system shown in FIG. 2. The case where the image quality information is “not in a state that can cause image quality degradation” will be described. 3 is a timing chart for explaining an operation of TS switching performed in the video stream switching system shown in FIG. 2. A case where the image quality information is “a state that can cause image quality degradation” will be described. 5 is a flowchart for explaining an operation of TS switching shown in FIGS. 3 to 4 performed in the video stream switching system shown in FIG. 2. It is explanatory drawing shown about the structure of the video stream switching system which concerns on the 2nd Embodiment of this invention. It is explanatory drawing shown about the structure of the video stream switching system which concerns on the expansion of embodiment of this invention. It is explanatory drawing shown about the structure of the existing video stream switching system.

(Basic form)
Hereinafter, the basic configuration of the present invention will be described with reference to FIG.
First, the basic contents of the basic form will be described, and then more specific contents will be described.
The video stream switching system 1 according to the basic mode includes a plurality of systems of encoders 2a to 2b that perform encoding processing on an externally input video signal and output a transport stream, and transports output from the encoders. TS switching means 3 for selecting and switching any one of the streams and outputting to the outside. Each encoder has a state that can cause image quality degradation when the TS switching means executes switching of the transport stream. Pre-analysis means 4a-b for determining whether or not a frame is included in a GOP (Group Of Picture) of a video signal is provided, and a video at the time when the system switching command is input from the outside and the system switching command is performed If the GOP of the signal contains a frame that can cause image quality degradation, the prior analysis means will determine. In the case of disconnection, the control unit 5 is configured to cause the TS switching unit to switch the transport stream at the GOP immediately after the GOP.

As a result, the video stream switching system 1 can seamlessly switch between the active system and the standby system even for a video including a frame in which the image changes drastically.
A more detailed configuration of each of these means will be described as the first embodiment.

(First embodiment)
Next, the configuration of the first embodiment of the present invention will be described with reference to FIG.
First, the basic content of the present embodiment will be described, and then more specific content will be described.
The video stream switching system 10 according to the present embodiment includes a plurality of systems of encoders 11a and 11b that perform encoding processing on a video signal input from the outside and output a transport stream, and transformers output from the encoders. A state in which any one of the port streams is selected and switched, and TS switching means 12 for outputting to the outside is provided. When each TS switching means performs transport stream switching in each encoder, the image quality may be deteriorated. Pre-analysis means 15a-b for determining whether or not the frame is included in the GOP (Group Of Picture) of the video signal is provided, and a system switching command is input from the outside, and at the time when the system switching command is performed. If the GOP of the video signal contains frames that can cause image quality degradation, When the analysis unit determines, the control unit 13 causes the TS switching unit to switch the transport stream at the GOP immediately after the GOP.

  In addition, each encoder 11a-b is provided with delay means 14a-b that delay the video signal by a time required for processing by the pre-analyzing means and input it to the TS switching means. Further, when the system switching command is input from the outside, the control means 13 determines whether or not the GOP of the video signal at the time when the system switching command is performed includes a frame in a state that can cause image quality degradation. The pre-analysis control function 13a for controlling the pre-analysis means to determine, and the pre-analysis means that the pre-analysis means determines that a frame in a state that can cause image quality deterioration is included, the operation for maintaining the image quality during the GOP An encoder control function 13b for instructing and a TS switching control function 13c for causing the TS switching means to switch the transport stream at the GOP immediately after the GOP.

  When the pre-analysis unit determines that the encoder control function 13b of the control unit 13 does not include a frame in a state that can cause image quality degradation, the code amount is set so that the transport stream can be switched at the end of the GOP. The encoder is instructed to perform the adjustment, and if the pre-analysis unit determines that a frame that can cause image quality degradation is included, the code amount is set so that the transport stream can be switched at the end of the GOP immediately after the GOP. The encoder is instructed to perform the adjustment.

With the above configuration, the video stream switching system 10 can detect and detect even a video including a frame in which the image changes rapidly, and can seamlessly switch between the active system and the standby system.
Hereinafter, this will be described in more detail.

  FIG. 2 is an explanatory diagram showing the configuration of the video stream switching system 10 according to the first embodiment of the present invention. The video stream switching system 10 includes two systems of encoders as an active system and a standby system that perform encoding processing on video signals and synchronization signals input from the outside and output a transport stream (TS). These are respectively referred to as an encoder 11a (ENC-A) as an active system and an encoder 11b (ENC-B) as a standby system.

  The video stream switching system 10 selects and switches any one of the TSs output from the encoders 11a and 11b, and outputs the TS to the outside. And a control means 13 for controlling the switching operation.

  Further, the video stream switching system 10 performs delay processing for delaying the video signal for each of the active system and the standby system, and performs a pre-analysis described later on the video signal input from the outside. Pre-analysis means for outputting the result to the control means 13. For each of these, the working system, that is, the encoder 11a (ENC-A) side is referred to as delay means 14a and pre-analysis means 15a. The spare system, that is, the encoder 11b (ENC-B) side is referred to as delay means 14b and pre-analysis means 15b.

  The pre-analyzing means 15a and 15b receive video signals and synchronization signals from the outside, and operate in synchronization with each other. The video signal is analyzed for characteristics of the input video, the difficulty of encoding, and the like, and image quality information described later is output to the control means 13 as the analysis result. Further, it receives a switching control signal from the control means 13 and operates according to it. The image quality information here is information indicating whether or not the GOP of the video signal includes a frame of “a state in which image quality deterioration can be caused during execution of switching control”.

  The “state that can cause image quality degradation” detected by the pre-analyzing means 15a and 15b refers to a state of a video in which an image change between frames is severe, such as a scene change (scene change) or some sports broadcast. Say. A technique for detecting whether or not such a state exists in the GOP of the video signal is known, for example, from the aforementioned Patent Document 7. The delay means 14a and 14b delay the video signal for the time required for processing by the pre-analysis means 15a and 15b and output the delayed video signal.

  The encoders 11a and 11b operate synchronously according to a synchronization signal input from the outside, and MPEG-2 or H.264 is applied to the video signals output from the delay means 14a and 14b. An encoding process is performed according to a known standard such as H.264, and a TS is output. At that time, it receives the switching control signal and the image quality control signal from the control means 13 and operates in accordance therewith.

  The switching control signal is a control signal that suppresses the image quality so that the TS can be switched at the end of the GOP, as described in the background art section. The image quality control signal is a control signal that is changed to an encoding process that retains the image quality (performs an operation equivalent to normal encoding) after switching control, and will be described in detail later.

  A synchronization signal is also input to the TS switching means 12 from the outside, and at the same timing as the encoders 11a and 11b, the TS output to the outside is changed from the active system to the standby system (encoders 11a to 11b) by the switching control signal from the control means 13. Or switching from the standby system to the active system.

  The control means 13 is a processor that is the execution subject of the computer program, and according to the control program, the pre-analysis control function 13a for controlling the pre-analysis means 15a and 15b, the encoder control function 13b for controlling the encoders 11a and 11b, and TS switching Each of the TS switching control functions 13c for controlling the means 12 functions. The operation of each of these means will be described later.

  3 and 4 are timing charts for explaining the operation of TS switching performed in the video stream switching system 10 shown in FIG. FIG. 3 shows the case where the image quality information is “not in a state that can cause image quality degradation”, and FIG. 4 shows the case where the image quality information is “in a state that can cause image quality degradation”. FIG. 5 is a flowchart for explaining the operation of TS switching shown in FIGS. 3 to 4 performed in the video stream switching system 10 shown in FIG.

  The example shown in FIGS. 3 and 4 shows an operation of switching TS from “active system to standby system” (from encoder 11a to 11b). Further, the time required for processing by the pre-analyzing means 15a and 15b, that is, the delay time for the delay means 14a and 14b to delay the video signal is 1 GOP (Group Of Picture). The length of this processing can be arbitrarily set according to actual processing performance.

  When a system switching command is input from the outside to the control means 13 (step S101), the prior analysis control function 13a issues a switching control signal to the prior analysis means 15a and 15b (step S102). The pre-analyzing means 15a and 15b that have received this control signal determine whether or not the input video signal is in a state that can cause image quality degradation between the timings immediately before switching, and the determination result. Is output to the pre-analysis control function 13a as image quality information (step S103).

  In parallel with these steps S102 to 103, the delay means 14a and 14b delay the video signal by the time required for the processing (step S104). Then, the encoder control function 13b determines whether or not the image quality information “which can cause image quality degradation” has been output from the pre-analyzing means 15a and 15b (step S105).

  If it is not “a state that can cause image quality degradation” in step S105, the encoder control function 13b issues a switching control signal to the encoders 11a and 11b, that is, at a switching point that matches the timing delayed by the delay means 14a and 14b. The operation is performed with the code amount suppressed. Then, the TS switching control function 13c performs TS switching by the TS switching means 12 at the switching point (step S106).

  If it is “a state that can cause image quality degradation” in step S105, the TS switching control function 13c emits image quality control signals from the encoders 11a and 11b in the GOP at the timing delayed by the delay means 14a and 14b. That is, in order to maintain the image quality, more specifically, the encoders 11a and 11b are operated without suppressing the code amount for the image signal in the “state that can cause image quality degradation” (step S107). Then, using the timing after 1 GOP as a switching point, the TS is switched by the same operation in step S106 described above (step S108).

  In the example shown in FIG. 3, image quality information “not in a state that can cause image quality degradation” is output to the prior analysis control function 13a. In this case, the delay means 14a and 14b delay the video signal by 1 GOP, and the TS switching control function 13c sets the timing after the delayed 1 GOP as a switching point to switch the TS. Meanwhile, in the encoders 11a and 11b, the code amount is appropriately adjusted so that the switching can be performed between the end of the GOP and the beginning of the next GOP. Therefore, the switching can be smoothly performed at the set switching point. .

  In the example shown in FIG. 4, when a video whose scene changes greatly, such as a scene change, is detected at the timing immediately before the switching of the input video signal, the image quality information “is in a state that can cause image quality degradation”. Is output to the pre-analysis control function 13a. In this case, the delay means 14a and 14b delay the video signal by 1 GOP as usual, but the TS switching control function 13c sets the timing after 1 GOP further than the delayed 1 GOP as a switching point to switch the TS. I do.

  Then, the encoder control function 13b instructs the encoders 11a and 11b to perform encoding (image quality control signal) under a condition that does not deteriorate the image quality. Then, if there is a determination result that the GOP immediately after the GOP in the “state that can cause image quality degradation” is not in a state that can cause image quality degradation from the prior analysis means 15a and 15b via the prior analysis control function 13a, the GOP The encoder 11a appropriately adjusts the amount of code so that the switching can be performed at the end (encoder control function 13b, switching control signal), and the TS switching unit 12 switches the TS at that timing (TS switching control function 13c). .

(Overall operation of the first embodiment)
Next, the overall operation of the above embodiment will be described.
The video stream switching method according to the present embodiment includes a plurality of encoders that perform encoding processing on a video signal input from the outside and output a transport stream, and a transport stream output from each encoder. When a system switching command is input from the outside in a video stream switching system provided with TS switching means for selecting and switching to either one of them and outputting to the outside (step S101 in FIG. 5) The pre-analysis control function issues a control signal to the pre-analysis means provided in each encoder (step S102 in FIG. 5), and the pre-analysis means that receives the control signal switches the transport stream by the TS switching means. When the frame is executed, a frame that may cause image quality degradation is p Of Picture) is determined (step S103 in FIG. 5), and the image quality is maintained during the GOP when the pre-analysis means determines that a frame in a state that can cause image quality degradation is included. Then, the encoder control function instructs the encoder to adjust the code amount so that the transport stream can be switched at the end of the GOP immediately after the GOP (step S107 in FIG. 5), and the end of the GOP with the code amount adjusted. Thus, the TS switching control function issues a control signal for switching the transport stream to the TS switching means (step S108 in FIG. 5).

  In addition, when the pre-analyzing unit determines that a frame that may cause image quality degradation is not included, the encoder control function controls the encoder so that the transport amount can be switched at the end of the GOP. The TS switching control function issues a control signal for switching the transport stream to the TS switching means at the end of the GOP that is instructed and the code amount is adjusted (step S106 in FIG. 5).

  Then, the delay means provided in each encoder delays the video signal by the time required for processing by the pre-analysis means and inputs it to the TS switching means (FIG. 5, step S104).

Here, each of the above operation steps may be programmed so as to be executable by a computer, and these may be executed by the control means 13 which is a processor that directly executes each of the steps. The program may be recorded on a non-temporary recording medium, such as a DVD, a CD, or a flash memory. In this case, the program is read from the recording medium by a computer and executed.
By this operation, this embodiment has the following effects.

  In the present embodiment, TS switching is performed by the GOP immediately after avoiding the TS switching by the GOP in a “state in which image quality can be deteriorated”. Therefore, even if the encoder operates to “suppress image quality” to create a blank portion, the above-described problem does not occur. Therefore, TS can be switched without any problem between the GOPs that have become the blank portion, and image quality deterioration that is noticeable to human eyes does not occur at the time of switching.

  Each element technology for realizing this configuration, that is, the pre-analysis means, the delay means, and the TS switching means can be easily realized by existing techniques. However, there is the novelty and inventive step of the present invention in that the above-mentioned effects can be obtained by combining them into the above-described configuration.

(Second Embodiment)
The video stream switching system 210 according to the second embodiment of the present invention is an encoder device in which the encoders 11a to 11b and the pre-analysis means 15a to 15b are integrated for each system.

With the above configuration, it is possible to obtain the same effect as that of the first embodiment.
Hereinafter, this will be described in more detail.

  FIG. 6 is an explanatory diagram showing the configuration of the video stream switching system 210 according to the second embodiment of the present invention. The video stream switching system 210 includes two systems of encoding devices 220a and 220b. The encoding device 220a is the active system, and the encoding device 220b is the standby system. The same TS switching means 12 and control means 13 as in the first embodiment are provided.

  The encoding device 220a includes the same encoder 11a, delay means 14a, and pre-analysis means 15a as in the first embodiment. The encoding device 220b also incorporates the same encoder 11b, delay means 14b, and pre-analysis means 15b as in the first embodiment.

  That is, the video stream switching system 210 has a configuration in which a delay unit and a pre-analysis unit are built in the encoding apparatus, and the substantial operation content and the effect obtained thereby are the video stream according to the first embodiment. It is the same as the switching system 10. Therefore, elements having the same operation are given the same name and reference number, and the description is omitted.

(Extended embodiment)
As described above, each of the embodiments described so far can be extended in various ways without changing the gist thereof.
Each of the above-described embodiments has been described only with respect to MPEG-2. It is also applicable to H.264 / MPEG-4 AVC.

  FIG. 7 is an explanatory diagram showing the configuration of the video stream switching system 310 according to the extension of the embodiment of the present invention. The video stream switching system 310 has the same configuration as the video stream switching system 210 according to the second embodiment, but the encoding devices 220a and 220b are replaced with other encoding devices 320a and 320b. The encoding devices 320a and 320b are input with different video signals and the same synchronization signal. The video signals may be different from each other, or may be the same video with different resolutions. Of course, similar to the one described in the second embodiment, each of the encoding devices 320a and 320b incorporates an encoder, a delay unit, and a pre-analysis unit.

  In each of the above-described embodiments, the same video signal is input to each of the active and standby encoders. However, if the synchronization signal is the same, the image quality is not deteriorated even for different video signals. It is possible to switch TS. Of course, the video stream switching system 10 according to the first embodiment may switch TSs for different video signals in the same manner.

  The present invention has been described with reference to the specific embodiments shown in the drawings. However, the present invention is not limited to the embodiments shown in the drawings, and any known hitherto provided that the effects of the present invention are achieved. Even if it is a structure, it is employable.

  Regarding the embodiment described above, the main points of the new technical contents are summarized as follows. In addition, although part or all of the said embodiment is summarized as follows as a novel technique, this invention is not necessarily limited to this.

(Supplementary note 1) Selects one of a plurality of encoders that encode a video signal input from the outside and output a transport stream, and a transport stream output from each encoder. And TS switching means for switching to external output,
Pre-analyzing means for determining whether or not each of the encoders includes a frame in a GOP (Group Of Picture) of the video signal in a state that can cause image quality degradation when the TS switching means switches the transport stream. And
When a system switching command is input from the outside and the pre-analysis unit determines that the GOP of the video signal at the time when the system switching command is performed includes a frame in a state that can cause the image quality degradation, A video stream switching system comprising control means for causing the TS switching means to switch the transport stream at a GOP immediately after a GOP.

(Supplementary note 2) The supplementary note 1 is characterized in that each encoder is provided with delay means for delaying the video signal by a time required for processing by the preliminary analysis means and inputting the delayed video signal to the TS switching means. Video stream switching system.

(Supplementary note 3) The control means
When the system switching command is input from the outside, the prior analysis means determines whether the GOP of the video signal at the time when the system switching command is performed includes a frame in a state that can cause the image quality degradation. A pre-analysis control function for controlling the
An encoder control function for instructing the encoder to maintain the image quality during the GOP when the pre-analysis unit determines that the frame in a state that may cause the image quality degradation is included;
The video stream switching system according to claim 2, further comprising: a TS switching control function that causes the TS switching unit to switch the transport stream at a GOP immediately after the GOP.

(Supplementary Note 4) When the pre-analysis unit determines that the encoder control function of the control unit does not include a frame in a state that can cause the image quality degradation, the transport stream is switched at the end of the GOP. The encoder is instructed to adjust the code amount so that the image quality can be reduced, and when the pre-analyzing unit determines that a frame in a state that can cause the image quality deterioration is included, the end of the GOP immediately after the GOP 4. The video stream switching system according to appendix 3, wherein the encoder is instructed to adjust a code amount so that a transport stream can be switched.

(Supplementary note 5) The video stream switching system according to supplementary note 1, wherein the encoder and the pre-analysis unit are an encoding device integrated for each of the systems.

(Supplementary note 6) The video stream switching system according to supplementary note 2, wherein the encoder, the pre-analysis unit, and the delay unit are an encoding device integrated for each system.

(Supplementary Note 7) Select one of a plurality of encoders that perform encoding processing on an externally input video signal and output a transport stream, and a transport stream output from each encoder And a video stream switching system including TS switching means for switching to an external output,
When a system switching command is input from the outside, the pre-analysis control function issues a control signal to the pre-analysis means provided in each encoder,
Whether the GOP (Group Of Picture) of the video signal includes a frame in a state in which the pre-analyzing unit that has received the control signal can cause image quality degradation when the TS switching unit switches the transport stream. Judging
When the pre-analysis unit determines that a frame that can cause the image quality degradation is included, the image quality is maintained during the GOP, and the transport stream is switched at the end of the GOP immediately after the GOP. The encoder control function instructs the encoder to adjust the code amount so that it can be performed,
A video stream switching method, wherein a TS switching control function issues a control signal for switching the transport stream to the TS switching means at the end of the GOP with the code amount adjusted.

(Supplementary Note 8) When the pre-analysis unit determines that the frame in a state that can cause the image quality deterioration is not included, an operation of adjusting the code amount so that the transport stream can be switched at the end of the GOP. The encoder control function instructs the encoder;
8. The video stream switching method according to appendix 7, wherein the TS switching control function issues a control signal for switching the transport stream to the TS switching means at the end of the GOP with the code amount adjusted.

(Supplementary note 9) The supplementary note 7 is characterized in that the delay means provided in each encoder delays the video signal by a time required for processing by the preliminary analysis means and inputs it to the TS switching means. The video stream switching method described.

(Supplementary Note 10) Select one of a plurality of encoders that perform encoding processing on an externally input video signal and output a transport stream, and a transport stream output from each encoder And a video stream switching system including TS switching means for switching to an external output,
In the processor provided in the video stream switching system,
When a system switching command is input from the outside, when the TS switching unit switches the transport stream with respect to the pre-analyzing unit provided in each encoder, a frame in a state that may cause image quality degradation is displayed in the video. A procedure for issuing a control signal for determining whether or not the signal is included in a GOP (Group Of Picture) of the signal;
When the pre-analysis unit determines that a frame that can cause the image quality degradation is included, the image quality is maintained during the GOP, and the transport stream is switched at the end of the GOP immediately after the GOP. A procedure for instructing the operation to adjust the code amount so that it can be performed,
And a video stream switching program that causes the TS switching means to execute a procedure for issuing a control signal for switching the transport stream at the end of the GOP with the code amount adjusted.

(Additional remark 11) When the said prior analysis means judges that the frame of the state which can cause the said image quality degradation is not included, the operation | movement which adjusts code amount so that the said transport stream can be switched at the end of the said GOP. A procedure for instructing the encoder;
11. The video stream switching program according to appendix 10, wherein the TS switching unit is further caused to issue a control signal for switching the transport stream at the end of the GOP with the code amount adjusted.

  The present invention relates to MPEG-2 and H.264. It can be widely used in broadcasting facilities and video distribution facilities that handle video stream signals according to standards such as H.264 / MPEG-4 AVC.

1, 10, 210, 310 Video stream switching system 2a, 2b, 11a, 11b Encoder 3, 12 TS switching means 4a, 4b, 15a, 15b Preanalysis means 5, 13 Control means 13a Preanalysis control function 13b Encoder control function 13c TS switching control function 14a, 14b Delay means 220a, 220b, 320a, 320b Encoding device

Claims (10)

Select and switch between a plurality of encoders that encode a video signal input from outside and output a transport stream, and a transport stream output from each encoder, TS switching means for output to the outside,
Pre-analyzing means for determining whether or not each of the encoders includes a frame in a GOP (Group Of Picture) of the video signal in a state that can cause image quality degradation when the TS switching means switches the transport stream. And
When a system switching command is input from the outside and the pre-analysis unit determines that the GOP of the video signal at the time when the system switching command is performed includes a frame in a state that can cause the image quality degradation, A video stream switching system comprising control means for causing the TS switching means to switch the transport stream at a GOP immediately after a GOP.   2. The video stream according to claim 1, wherein each of the encoders is provided with a delay unit that delays the video signal by a time required for processing by the prior analysis unit and inputs the delayed video signal to the TS switching unit. Switching system. The control means is
When the system switching command is input from the outside, the prior analysis means determines whether the GOP of the video signal at the time when the system switching command is performed includes a frame in a state that can cause the image quality degradation. A pre-analysis control function for controlling the
An encoder control function for instructing the encoder to maintain the image quality during the GOP when the pre-analysis unit determines that the frame in a state that may cause the image quality degradation is included;
The video stream switching system according to claim 2, further comprising a TS switching control function that causes the TS switching means to switch the transport stream at a GOP immediately after the GOP. When the pre-analysis unit determines that the encoder control function of the control unit does not include a frame in a state that can cause the image quality degradation, a code is set so that the transport stream can be switched at the end of the GOP. by reducing the amount direct the operation to suppress the image quality to the encoder, wherein when said to include the frame of the conditions that can cause image degradation pre-analysis means determines the last GOP immediately following the GOP video stream switching system according to claim 3, characterized in that, for instructing the operation to suppress the image quality by reducing the amount of code to perform the switching of the transport stream to the encoder.   2. The video stream switching system according to claim 1, wherein the encoder and the prior analysis means are an encoding device integrated for each of the systems. Select and switch between a plurality of encoders that encode a video signal input from outside and output a transport stream, and a transport stream output from each encoder, In a video stream switching system provided with TS switching means for output to the outside,
When a system switching command is input from the outside, the pre-analysis control function issues a control signal to the pre-analysis means provided in each encoder,
Whether the GOP (Group Of Picture) of the video signal includes a frame in a state in which the pre-analyzing unit that has received the control signal can cause image quality degradation when the TS switching unit switches the transport stream. Judging
When the pre-analysis unit determines that a frame that can cause the image quality degradation is included, the image quality is maintained during the GOP, and the transport stream is switched at the end of the GOP immediately after the GOP. the operation to suppress the image quality by reducing the amount of code to perform encoder control function instructs the encoder,
A video stream switching method, wherein a TS switching control function issues a control signal for switching the transport stream to the TS switching means at the end of a GOP in which the code amount is reduced and the image quality is suppressed . If the frame of the conditions that can cause the image quality deterioration is the determination pre-analysis means is not included, the operation to suppress the last by reducing the amount of code to perform the switching of the transport stream quality of the GOP The encoder control function instructs the encoder,
The TS switching control function issues a control signal for switching the transport stream to the TS switching means at the end of the GOP in which the code amount is reduced and the image quality is suppressed . Video stream switching method.   7. The video according to claim 6, wherein delay means provided in each of the encoders delays the video signal by a time required for processing by the prior analysis means and inputs the delayed video signal to the TS switching means. Stream switching method. Select and switch between a plurality of encoders that encode a video signal input from outside and output a transport stream, and a transport stream output from each encoder, In a video stream switching system provided with TS switching means for output to the outside,
In the processor provided in the video stream switching system,
When a system switching command is input from the outside, when the TS switching unit switches the transport stream with respect to the pre-analyzing unit provided in each encoder, a frame in a state that may cause image quality degradation is displayed in the video. A procedure for issuing a control signal for determining whether or not the signal is included in a GOP (Group Of Picture) of the signal;
When the pre-analysis unit determines that a frame that can cause the image quality degradation is included, the image quality is maintained during the GOP, and the transport stream is switched at the end of the GOP immediately after the GOP. procedure for instructing the operation to suppress the smaller to the picture quality code amount to perform,
And a video stream switching program that causes the TS switching means to execute a procedure for issuing a control signal for switching the transport stream at the end of a GOP in which the image amount is suppressed by reducing the code amount. If the frame of the conditions that can cause the image quality deterioration is the determination pre-analysis means is not included, the operation to suppress the last by reducing the amount of code to perform the switching of the transport stream quality of the GOP A procedure for instructing the encoder,
10. The method according to claim 9, further comprising: causing the TS switching unit to further execute a control signal for switching the transport stream at the end of a GOP in which the image amount is suppressed by reducing the code amount. Video stream switching program.

Images