KR20140148304A

KR20140148304A - Transport stream switching method, apparatus and system

Info

Publication number: KR20140148304A
Application number: KR20140067662A
Authority: KR
Inventors: 조숙희; 김종호; 추현곤; 최진수; 김진웅
Original assignee: 한국전자통신연구원
Priority date: 2013-06-19
Filing date: 2014-06-03
Publication date: 2014-12-31

Abstract

The present invention discloses a transport stream switching method. The method includes the steps of receiving a plurality of different input streams, receiving a switch command for a first input stream currently output from the plurality of input streams, Searching for an Out-point of the first input stream and an In-point of the second output stream newly outputting a virtual P picture stream and a Null-packet between the exit point and the entry point; And performing a transfer from the first input stream to the second input stream based on the exit point and the entry point.

Description

TRANSPORT STREAM SWITCHING METHOD, APPARATUS AND SYSTEM,

The present invention relates to a transport stream switching method, apparatus and system, and more particularly, to a transport stream switching method, apparatus and system, in which two or more MPEG-2 transport streams (TS) output from different encoders are selected The present invention relates to an MPEG-2 TS switching apparatus and method for switching and outputting one MPEG-2 TS.

1 is a diagram showing an exemplary view of an in-point and an out-point for switching an MPEG-2 TS.

Referring to FIG. 1, the conventional MPEG-2 TS switching method is a TS switching method in a manner provided by ISO / IEC 1381-1 MPEG-2 Systems. The "transition point" is divided into "In-Point" and "Out-Point", where the entry point is the point at which the new stream can be converted and the exit point is converted back to the existing stream . In the conventional TS conversion method, as shown in FIG. 1, in order to continuously switch the video without a continuous transition, the system waits until a picture satisfying the constraint condition is obtained, and then starts switching the point of time as the switching point. The picture satisfying the constraint means that the last picture should be an I or P picture based on a presentation time stamp (PTS) in the case of an exit point, and the start of a video stream of a new stream (B stream in FIG. 1) It should be a picture. In addition, a B-picture (B-picture in dotted line in the B stream) behind the in-point I-picture to be replaced is to be encoded so as not to refer to an image before the point of time of replacement. Otherwise, since the information of the image referenced by the B picture in the dotted line can not be obtained, there arises a problem that the decoder can not properly restore these B pictures.

2 is a diagram illustrating an embodiment in which a plurality of MPEG-2 TSs are connected.

2, in the case of the MPEG-2 TS conversion scheme provided by ISO / IEC 1381-1 MPEG-2 Systems, an MPEG-2 TS is already prepared for each program as shown in FIG. 2, Of TS in order. Therefore, as shown in FIG. 2, the beginning of the advertisement 1 TS to be transferred after the program 1 TS is already encoded as an IDR (Instantaneous Decoding Refresh) picture. Therefore, since the entry point will be an IDR picture, there is no problem since there is no B-picture in dotted line in the B stream in Fig.

However, when a plurality of MPEG-2 TSs are continuously input from different encoders, there is a problem in that delay time is excessively long after waiting for an IDR picture to be transferred in a stream to be transferred.

In addition, in order to eliminate the problem that decoding of a B picture next to an I picture can not be performed in a stream to be switched, it is possible to use a closed GOP structure. However, when encoding a video of a broadcast program in a broadcast, encoding is generally performed in an Open GOP structure in consideration of the encoding efficiency. However, encoding in a closed GOP structure only at a point where stream replacement is expected is almost impossible because the setting of the encoder must be changed.

In addition, it is required to transfer two TSs as soon as possible without buffering a plurality of inputted MPEG-2 TSs. To this end, a switchable time point is defined as a P or I picture on the basis of a DTS (Decoding Time Stamp) It is only necessary to input an I picture of the B stream.

FIG. 3 is a diagram showing an example of an entry point at which delay greatly occurs in the MPEG-2 TS conversion.

Referring to FIG. 3, it is difficult to break the A stream because the P picture of the A stream is input to the I picture that appears first in the B stream after finding the exit point. As a result, when the P or I picture of the A stream ends, It can be switched at the moment when an I-picture of the stream is input, so that there is a problem that the switching delay time becomes considerably long.

FIG. 4A shows an example of a mixed broadcast of a conventional HDTV and a 3DTV service, and FIG. 4B shows an example of a mixed broadcast of a conventional HDTV and a multi-channel service.

Referring to FIGS. 4A and 4B, when an HDTV program, a 3D program, and a multi-channel service program are mixed and served in a single channel, a problem may occur during MPEG-2 TS switching.

Accordingly, there is a need to connect two MPEG-2 TSs in a form that can be restored without splitting or breaking the audio or video at the time of connecting two different MPEG-2 TSs.

An object of the present invention is to provide a method for connecting two MPEG-2 TSs (Transport Streams) output from different encoders to each other. And to provide a method and an apparatus for connecting different MPEG-2 TSs in a form that can be restored without a loss of audio or image distortion at the time of connection.

According to an aspect of the present invention, there is provided a transport stream switching method comprising: receiving a plurality of different input streams; receiving a switching command for a first input stream currently output from the plurality of input streams; Searching for an Out-point of the first input stream and an In-point of a newly output second input stream based on the command, picture stream from the first input stream to the second input stream and performing a transfer from the first input stream to the second input stream based on the exit point and the entry point.

The exit point is searched to the start point of the first I or P picture after the transfer command and the entry point can be searched as the start point of the first I picture after the exit point.

Wherein the virtual P-picture stream is inserted as a substitute for the picture stream of the first input stream from the exit point to the entry point, and a null packet is inserted in accordance with the length of the picture stream from the exit point to the entry point. ).

The virtual P-picture stream may be a stream in which motion information of all macroblocks and residual signal are made to be 0 according to an encoding scheme through analysis of a video ES (Element Stream) included in the first or second input stream .

If there is a P or B picture of a second input stream after the entry point that refers to a picture preceding the entry point, replacing the P or B picture with the virtual P picture stream, can do.

Wherein a PTS (Presentation Time Stamp), a DTS (Decoding Time Stamp) and a PCR (Program Clock Reference) time stamp of the second input stream after the entry point are consecutive PTSs based on time information of the first input stream, DTS, and PCR timestamps.

Wherein when the second input stream is a 3D left video stream, the right video stream corresponding to the 3D left video is switched when the switching is based on an input point of the second input stream, The PTS of the right video stream is corrected based on the stored PTS and the PCR of the right video stream is corrected based on the PCR of the first input stream .

After the first transfer from the first input stream to the second input stream and again after the second transfer from the second input stream to the first input stream, Counting a first frame count value as a frame number of a first input stream and a second frame count value as a frame number of a second input stream until a transfer command is input; And performing the second transfer according to the result of the comparison.

Wherein when the second frame count value is greater than the first frame count value, when the second frame count value is greater than the first frame count value, A null packet can be inserted between the output point of the second input stream and the input point of the first input stream.

The picture stream up to the entry point of the first input stream after the inserted null packet is replaced with the virtual P picture stream and the packet length can be adjusted using the null packet.

Wherein when the first frame count value is greater than the second frame count value, when the second frame count value is smaller than the second frame count value, The first P picture stream and the second P picture stream are inserted between the output point of the 2 input stream and the input point of the first input stream, And further insert the virtual P picture stream until the two values become equal.

The switching of the audio signal from the first input stream to the second input stream is performed by storing the PTS of the picture to which the video is to be switched and setting the time corresponding to the PTS of the audio to be input later, &Lt; / RTI >

A different ring buffer may be configured for the first input stream and the second input stream to calculate and store time information in units of frames included in the time information in an audio PES (Packetized Elementary Stream).

According to an aspect of the present invention, there is provided a transport stream switching apparatus including an input stream receiver for receiving a plurality of different input streams, a switch command for receiving a switch command for a first input stream, A search unit for searching an Out-point of the first input stream and an In-point of a newly output second input stream based on the transfer command, An insertion unit for inserting a virtual P picture stream into the first input stream, and a switch performing unit for performing switching from the first input stream to the second input stream based on the exit point and the entry point.

Wherein the inserting unit inserts the virtual P-picture stream in place of the picture stream of the first input stream from the exit point to the entry point, and inserts the null packet into the length of the picture stream from the exit point to the entry point You can fill it right.

After the first transfer from the first input stream to the second input stream and again after the second transfer from the second input stream to the first input stream, Further comprising: a frame counter for counting a first frame count value, which is the number of frames of the first input stream, and a second frame count value, which is the number of frames of the second input stream, And the second frame count value, and perform the second transfer according to the comparison result.

According to an aspect of the present invention, there is provided a transport stream switching system including a plurality of encoders for generating and transmitting a plurality of encoded input streams, and a plurality of encoders for receiving the plurality of input streams, Wherein the transport stream switcher receives a switch command for a first input stream which is currently output among the plurality of input streams, and outputs the switch command to the output port of the first input stream based on the switch command, (P-picture) between an output point of the searched first input stream and an input point of a second input stream, ) Stream is inserted into the second input stream from the first input stream based on the exit point and the entry point. In which it can perform a transfer.

According to the transport stream switching method, apparatus and system of the present invention, in linking two MPEG-2 TS (Transport Streams) output from different encoders in an Open GOP structure, two different MPEG -2 It is possible to restore without interrupting audio or image distortion at the time of connecting TS. It is possible to change the time as soon as possible after receiving the switching command from the user without buffering the two input TSs. It has effect. Therefore, this technology is indispensable for broadcasting services that mix HDTV with 3DTV or multi-channel services in one channel.

According to the transport stream switching method, apparatus and system of the present invention, the processing time until input and output to the MPEG-2 TS switching unit is minimized, the delay of the broadcasting program is shortened. Therefore, It can be processed immediately without storing it.

Figure 1 illustrates an exemplary view of an In-Point and an Out-Point for MPEG-2 TS switching,
2 is a diagram illustrating an embodiment in which a plurality of MPEG-2 TSs are connected,
3 is a diagram showing an example of an entry point at which delay greatly occurs in MPEG-2 TS conversion,
4A shows an example of a mixed broadcast of a conventional HDTV and a 3DTV service,
4B shows an example of a hybrid broadcast of a conventional HDTV and a multi-channel service,
5 is a diagram illustrating an input / output format of an MPEG-2 TS switcher according to an embodiment of the present invention for supporting a broadcast service in which 3DTV and HDTV are mixed in one channel;
FIG. 6 is a flowchart schematically showing a transport stream switching method according to an embodiment of the present invention;
7 is a conceptual diagram for explaining a configuration of a video stream upon switching from a first input stream to a second input stream according to a transport stream switching method according to an embodiment of the present invention;
8 is a conceptual diagram illustrating an exemplary view of a PTS change for a video ES in a switched second input stream, according to an embodiment of the present invention;
FIG. 9 is a flowchart illustrating a transmission method according to another exemplary embodiment of the present invention, which is performed according to a frame count value of a first and a second input stream,
10 is a diagram illustrating a transmission stream switching method according to another embodiment of the present invention. In the switching from the second input stream to the first input stream, when the second frame count at the exit point is larger than the first frame count A conceptual view showing an exemplary view,
11 is a diagram illustrating a transmission stream switching method according to another embodiment of the present invention. In the switching from the second input stream to the first input stream, when the second frame count at the exit point is larger than the first frame count A conceptual diagram showing an exemplary appearance of PTS value generation,
12 is a diagram illustrating a transmission stream switching method according to another embodiment of the present invention. In the switching from the second input stream to the first input stream, when the first frame count at the exit point is larger than the second frame count A conceptual view showing an example of
13 is a diagram illustrating a transmission stream switching method according to another embodiment of the present invention. In the switching from the second input stream to the first input stream, when the first frame count at the exit point is larger than the second frame count Lt; RTI ID = 0.0 > PTS < / RTI >
FIG. 14 is a conceptual diagram for explaining an example of calculating time information for an audio frame and storing it in a ring buffer in the transport stream switching method according to an embodiment of the present invention; FIG.
15 is a conceptual diagram for explaining an example of switching of an audio stream in a transport stream switching method according to an embodiment of the present invention;
16 is a block diagram illustrating a transport stream switching apparatus according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. And / or < / RTI > includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

Broadcast service environment in which 3DTV and HDTV are mixed

Currently, a terrestrial DTV is broadcasting a single broadcast program on one channel. However, if a service-compatible 3DTV service or a multi-mode service (MMS) for providing a plurality of programs in one channel is introduced, one HDTV program There may be a mixed broadcast in which a plurality of programs are served, such as a 3DTV program or an MMS program.

The service-compatible 3DTV scheme is a 3DTV scheme compatible with existing HDTV broadcasting services by encoding and transmitting streams of left and right images. A user who owns an existing HDTV receives only signals encoded by the MPEG-2 encoder from the 3DTV signals, The broadcast can be watched. Similarly, in a multi-channel service, a user who owns an existing HDTV can view one program from a plurality of programs.

On the other hand, if a user has a TV or a terminal capable of 3DTV or MMS viewing, the user can select and watch 3DTV and a plurality of programs. At this time, broadcasters should switch from one HDTV program to a 3DTV program or an MMS program, or vice versa, and switch to a HDTV program in a 3DTV program or an MMS program to transmit an MPEG-2 TS. At this time, even if the transmitted MPEG-2 TS is output from different encoders, the existing HDTV users are required to continuously view only one HDTV broadcast, so that no audio interruption or image distortion should occur.

5 is a diagram illustrating an input / output format of an MPEG-2 TS converter according to an embodiment of the present invention for supporting a broadcasting service in which 3DTV and HDTV are mixed in one channel.

5, one HDTV program is encoded by the MPEG-2 encoder 510 with respect to the HDTV signal 502 and the 3DTV program is encoded with the HDTV (left video) signal 502 and the right video signal 504, Is encoded in the 3DTV encoder 520. [ For safety reasons, it is common for broadcasters to operate two encoders 510 and 520 continuously for 24 hours, whether the program is an HDTV or a 3DTV program. Accordingly, the HDTV encoder 510, the 3DTV encoder 520, and the MPEG-2 TS converter 530 continue normal operation regardless of the program. In the case of an HDTV program, the 3DTV encoder 520 will encode only the left image 502 and the right image 504 will output null data. The MPEG-2 TS switcher 530 for supporting mixed broadcasts basically outputs the TS inputted from the MPEG-2 encoder 510, and when the 3DTV program is started, the TS is switched to the TS input from the 3DTV encoder 520 Output. At this time, the TS output from the 3DTV encoder 520 includes an HDTV program. The viewer who owns the HDTV receives and decodes only the HDTV signal from the MPEG-2 TS output from the 3DTV encoder 520 while changing to the 3DTV program. It is important that the video / audio of the HDTV is not broken. On the other hand, a viewer who owns 3DTV likewise continuously receives and decodes only the HDTV signal and receives information such as 3DTV program, and decides whether to watch HDTV or 3DTV according to the viewer's preference. Therefore, the video and audio of the HDTV (left image) 502 should not be broken, but the right image 504 is decoded when the user selects the 3DTV viewing mode. Therefore, do. For this reason, when switching from the HDTV program TS to the 3DTV program TS, the MPEG-2 TS switcher 530 searches and processes the exit point and the entrance point based on the HDTV program TS and the left image 502 TS in the 3DTV program TS . When the entry point of the left image 502 is determined and the transfer processing is performed, the right image 504 TS performs the transfer processing of the right image 504 TS based on the entry point of the left image 502 TS. Although the transport stream (TS) only refers to the MPEG-2 TS in this specification, it is also possible to use a stream such as another transport stream, for example, an MMT (MPEG Media Transport) stream. In addition, the service signal to be switched is not necessarily limited to HDTV and 3DTV, and may be used in any case of switching of any service method having different coding schemes. Even if the coding method is the same, The switching method of the present invention can be used when necessary.

How to switch transport streams

6 is a flowchart schematically showing a transport stream switching method according to an embodiment of the present invention.

Referring to FIG. 6, a transport stream switching apparatus (not shown) first receives a plurality of different input streams (S610). The different input streams may be streams having different encoding schemes as streams requiring conversion. The different input streams may be streams received from different encoders. When a plurality of input streams are received, the device monitors whether there is a transfer command (S620). The transfer command can be entered automatically or manually. For example, a user who wishes to switch can input a transfer command using a user interface (not shown), or can automatically input a transfer command through user setting. It is also possible to input the change command periodically by setting the time for automatic input. Upon receiving the transfer command, the apparatus searches for an exit point and an entry point (S630). As described above, the exit point and the entrance point are the first input stream and the second input stream (the first input stream is the stream currently being outputted and the output is ended through the transfer, and the second input stream is newly (I.e., a stream to be outputted). That is, it is possible to find the exit point based on the first input stream, and to find the entry point based on the second input stream from the exit point location. However, according to one embodiment of the present invention, unlike the conventional method, only the absolute relationship between the exit point and the entrance point of the first and second input streams involved in the switching is determined based on the absolute relationship between the first input stream and the second input stream itself . That is, through this, the exit point and the entrance point can be pushed backward according to the relative relationship, thereby preventing the transfer time from being delayed.

After searching for the exit point and the entry point, a virtual P picture stream and a null packet are inserted between the exit point and the entry point (S640). The virtual P picture stream according to an exemplary embodiment of the present invention may include video encoding such as MPEG-2, Advanced Video Coding (AVC), and High Efficiency Video Coding (HEVC) through analysis of a video ES included in an input transport stream The virtual P-picture ES can be generated in advance and stored in the memory in a stream in which the motion information of all the macroblocks is 0 and the train signal is made 0 according to the method. In some cases, the temporal relationship between the entry point search process and the virtual P-picture and null packet insertion process may be preceded by any one of them. That is, after a search for an exit point, a virtual P picture and a null packet are inserted until an entry point appears, a virtual P picture and a null packet insertion may be terminated by searching a picture stream satisfying an entry point condition, It is also possible to scan an entry point and insert a virtual P picture and a null packet between the retrieved entry point and the exit point. Null packets fill the length of the P or B picture stream from the output point of the first input stream to the input point of the second input stream to match the length.

After the virtual P picture stream and Null packet insertion, the device performs a switch from the ingress point to the second input stream (S650).

7 is a conceptual diagram for explaining a configuration of a video stream upon switching from a first input stream to a second input stream according to a transport stream switching method according to an embodiment of the present invention.

Referring to FIG. 7, the first input stream 710 and the second input stream 720 can be input when the power of the transport stream switching apparatus (for example, MPEG-2 TS switching apparatus) is turned on. In this case, the first input stream may be an HDTV TS and the second input stream may be a 3DTV TS (refer to FIG. 5). In this case, the HDTV TS is automatically output to the first input stream 710. At this time, a 3DTV program may be started and a user may give a switch command 702 to switch to the second input stream 720 (3DTV TS). As described above, the transfer command 702 can be input automatically or manually. When the transfer command 702 is input, an exit point 712 is searched based on the video in the first input stream 710, and the left video image 720 in the second input stream 720 (3DTV TS) P picture stream 732 until an entry point 714 appears on the basis of the P picture stream 732. [ Then, the length of the video stream of the first input stream 710 is filled with null packets as much as the length of the P or B picture stream from the exit point 712 to the entry point 714.

Referring to output stream 730, the P or B picture portion of the first input stream 710 is replaced with a virtual P picture stream 732 in stream section 732 corresponding to the first input stream 710, do. The virtual P-picture ES 732 is a stream made such that the motion information of all the macroblocks is 0 and the residual signal is 0 so that the amount of data is much smaller than the actual video picture ES so that the first PEC after the exit point 712 It is easy to fill the start position of the I picture with the null packet at the entry point 714.

According to an embodiment of the present invention, by replacing two B pictures 716 with a dotted line after an entry point 714 with an imaginary P picture ES 736, even if two separate TSs are connected, It prevents you. Since the two B pictures 716 in the dotted line refer to the image before the entry point 714 of the second input stream, since the reference image exists before the transfer, there is no image to be referenced, Therefore, it is possible to replace the virtual P-picture ES 736 with the virtual P-picture ES 736 to prevent the picture from being broken. At this time, when two videos are coded in different coding schemes, the virtual P-picture ES 732 and the entry point 732 from the exit point 712 to the entry point 714 (from the point of view of the output stream 730) 714), the virtual P-picture ES 736 may be another type of ES.

According to an embodiment of the present invention, the video in the first input stream 710 (HDTV TS) uses an MPEG-2 encoder and the left video in the second input stream 720 (3DTV TS) uses an MPEG- The virtual P-picture ES 732 from the exit point 712 to the entry point 714 and the virtual P-picture ES 736 after the entry point 714 are the same virtual P-picture ES.

8 is a conceptual diagram showing an exemplary view of a PTS change for a video ES in a switched second input stream in a transport stream switching method according to an embodiment of the present invention.

Referring to FIG. 8, in the ES outputted as shown in FIG. 7, a PTS (Presentation Time Stamp), a DTS (Decoding Time Stamp), and a DTS are applied to the left video ES in the second input stream 820 The time stamp of the PCR (Program Clock Reference) must be modified. The time stamp is modified to be a time stamp of PTS, DTS, and PCR that are consecutive based on the time information of the HDTV MPEG-2 TS, which is the first input stream 810. At this time, DTS and PCR can be processed according to the PTS.

In another embodiment of the present invention, the right video ES transition in the 3DTV TS in the 3DTV TS transition in the HDTV TS is based on the left video ES. In other words, if PTS of the video in which the switching is started is found by searching the entrance point based on the left video ES in the 3DTV TS, and the right video ES of the input 3DTV MPEG-2 TS is displayed, the PTS and DTS are corrected based on the stored PTS And modify the PCR based on the PCR of the first input stream 810.

Re-transfer command processing procedure

9 is a flowchart illustrating a transmission method according to a frame count value of first and second input streams in a transport stream switching method according to another embodiment of the present invention.

9, the transport stream switching device (not shown) performs a first switch from the first input stream to the second input stream (S910), counts the number of frames for the first and second input streams (S920). This is not necessarily performed after the first transfer, but is performed by resetting the transfer time point as a starting point in a state where a frame counter (not shown) counts the number of frames for the first and second input frames . &Lt; / RTI > Then, a second transfer command, which is a re-transfer from the second input stream to the first input stream, is input (S930). For example, it may include a case of switching from the HDTV TS to the 3DTS, outputting the 3DTV TS, and receiving the switching command for switching from the 3DTV TS to the HDTV TS again. At this time, the apparatus compares the count value of the second input frame with the count value of the first input frame from the first transmission to the input of the transfer command (S940). At this time, the process for the second transfer can be performed differently according to the comparison result.

As a result of comparison, if the count value of the second input frame is larger than the count value of the first input frame, a null packet is inserted by the packet length corresponding to the difference value between the second input frame and the first input frame (S950 ). Then, the picture stream from the inserted null packet to the entry point of the first input stream can be replaced with the virtual P picture stream (S960). After replacing with a virtual P picture, a null packet is inserted to match the length of the packet (S970), as in the above-described embodiment. Then, a second transfer is performed at the entry point of the first input stream (S980).

If the count value of the first input frame is greater than the count value of the second input frame as a result of the comparison (S940), a virtual P picture stream is inserted for the number of packets corresponding to the difference value (S955). Then, even at the moment of inserting the stream of the virtual P picture, frame counting for the first and second input streams is continued from the first transmission, and the virtual P picture stream is further inserted until the two frame count values become equal (S965). If the two frame count values become equal, the process is terminated and a second transfer is performed at the entry point of the first input stream (S980).

10 is a diagram illustrating a transmission stream switching method according to another embodiment of the present invention. In the switching from the second input stream to the first input stream, when the second frame count at the exit point is larger than the first frame count Fig.

10, a second input stream 1020 (3DTV TS) is transferred from a first input stream 1010 (HDTV TS) to a second input stream 1020 (3DTV TS) Input from the first input stream 1010 to the second input stream 1020 so that there is no problem with the video and audio signals when the first input stream 1010 is switched back to the first input stream 1010 (HDTV TS) The number of video frames in the stream 1010 and the number of video frames output in the second input stream 1020 (e.g., the number of left video frames) are continuously counted. The number of frames of the first input stream 1010 (HDTV TS) is Frame_Count_1, and the number of frames output from the second input stream 1020 (3DTV TS) is Frame_Count_2. Upon receiving the transfer command 1002 from the second input stream 1020 to the first input stream 1010, it searches for an exit point 1012 and an entry point 1014 as described above. The TS switching processing method is divided into two depending on which of the Frame_Count_1 and Frame_Count_2 values at the exit point 1012 is larger.

First, when the Frame_Count_2 at the exit point 1012 is larger than the Frame_Count_1, the null packet 1032 is filled by the packet length corresponding to the frame number obtained by subtracting the frame_Count_2 from the Frame_Count_1. The embodiment of FIG. 10 shows an example of the case where Frame_Count_2 Frame_Count_1 = 2 frames at the outgoing point 1012. FIG. A null packet 1032 is filled with a packet length corresponding to a P-picture and a B-picture indicated by a dotted line in a video ES in the first input stream 1010 (HDTV TS). The four picture ESs 1034 from the dotted B picture to the entry point are replaced with the virtual P picture ES as a part corresponding to the first input stream, and as described above, using the null packet, the packet length .

11 is a diagram illustrating a transmission stream switching method according to another embodiment of the present invention. In the switching from the second input stream to the first input stream, when the second frame count at the exit point is larger than the first frame count Fig. 8 is a conceptual diagram showing an exemplary appearance of PTS value generation. Fig.

Referring to FIG. 11, similarly, it is necessary to change the time stamp values such as PTS, DTS, and PCR. In the case of switching from the second input stream 1120 (3DTV TS) to the first input stream 1110 (HDTV TS), only the time stamp value for the virtual P-picture ES is generated and set as shown in FIG. 11 . The entry point 1114 in the first input stream 1110 (HDTV TS) that is switched back in is connected to the I picture without changing the time stamp (connected with time stamp "65" in FIG. 11).

12 is a diagram illustrating a transmission stream switching method according to another embodiment of the present invention. In the switching from the second input stream to the first input stream, when the first frame count at the exit point is larger than the second frame count As shown in FIG.

12, a case where Frame_Count_2 at the exit point 1212 of the second input stream 1220 is input smaller than Frame_Count_1 will be described. In this case, a virtual P picture stream 1232 is interleaved by the number of frames obtained by subtracting Frame_Count_2 from Frame_Count_1. The input of the first input stream 1210 (HDTV TS) continues even at the moment when the virtual P picture stream 1232 is interleaved and output, so that the number of video frames in the first input stream 1210 (HDTV TS) Continues to count, and Frame_Count_2 is continuously increased by inserting the virtual P picture stream 1232 until the two values are equal. In the embodiment of FIG. 12, an embodiment of the case where Frame_Count_1 - Frame_Count_2 = 6 frames at the out point 1212 is shown, and in the embodiment of FIG. 12, two virtual P picture streams 1234 And a packet position where an arbitrary frame of the first input stream 1210 (HDTV TS) is started when a total of eight virtual P picture streams are inserted is adjusted. For the three pictures preceding the entry point 1214, the packet length is adjusted through the virtual P picture and the null packet as in the previous embodiment.

13 is a diagram illustrating a transmission stream switching method according to another embodiment of the present invention. In the switching from the second input stream to the first input stream, when the first frame count at the exit point is larger than the second frame count Lt; RTI ID = 0.0 > PTS < / RTI >

Referring to FIG. 13, similarly, time stamp values such as PTS, DTS, and PCR need to be changed. In the case of switching from the second input stream 1320 (3DTV TS) to the first input stream 1310 (HDTV TS), only the time stamp value for the inserted virtual P-picture ES 1332 is newly generated . The entry point 1314 in the first input stream 1310 (HDTV TS) that is switched back in is connected to the I picture without changing the time stamp (connected to the time stamp '65' in FIG. 13).

Processing of audio frames

Generally, since a sync signal is searched based on an audio signal, an audio signal is transmitted later than a video signal. Therefore, the audio stores the PTS of the picture in which the video is transferred, and the time corresponding to the PTS at which the PTS of the audio to be input later is transferred corresponds to the switching time.

FIG. 14 is a conceptual diagram for explaining an example of calculating time information for an audio frame in a transport stream switching method according to an embodiment of the present invention and storing the time information in a ring buffer. FIG.

Referring to FIG. 14, in the case of a video stream, since ES for one frame is composed of one PES, the PES unit may be switched. However, in the case of an audio stream, ES for a plurality of frames in one PES The PES unit may cause a problem that the AC-3 decoder can not properly decode the audio signal, and may seriously affect the entire stream. This is because most decoders are processed based on audio signals. Therefore, the audio must be switched in ES units in the PES. However, since time information exists in units of PES, in the present invention, different ring buffers 1430 and 1432 are configured for two input streams 1410 and 1420 as shown in FIG. 14, It is possible to calculate and store the time information of the frame unit included therein. That is, each AC 3 frame in the audio PES 1410 of the first input stream is stored with the time information of the PTS in the ring buffer # 1 1430, and each AC 3 frame in the audio PES 1420 of the second input stream The AC3 frame, which is the ES, can be separately stored in the ring buffer # 2 1432 together with the time information of the PTS. Accordingly, even when the audio PES of the input stream is switched in the middle, it is possible to find an ES corresponding to the switching time and to support the switching in the corresponding AC3 frame.

15 is a conceptual diagram for explaining an example of audio stream switching in the transport stream switching method according to an embodiment of the present invention.

15, in the transfer from the first input stream audio PES 1510 to the second input stream audio PES, the ring buffer # 2 (FIG. 15) storing the ES unit time information and the ES data of the second input stream audio PES 1532) to calculate the switching time based on the PTS of the corresponding PES. Then, control is performed so that switching from the AC3 frame 1542 of the second input stream corresponding to the calculated switching time point to the second input stream can be performed.

Other uses

In the transport stream switching method according to an embodiment of the present invention, not only interchange between HDTV TS and 3DTV TS but also interchange between two different HDTV TSs and interchange between TSs for multi-channel service in HDTV TS It is possible.

In addition, the MPEG-2 TS switcher of the present invention includes a program specific information (PSI) information generation function suitable for a service according to which switching between MPEG-2 TSs is to be performed.

Transport stream switching device

16 is a block diagram illustrating a transport stream switching apparatus according to an embodiment of the present invention. 16, a transport stream switching apparatus 1600 according to an embodiment of the present invention includes a receiving unit 1610, a switching command input unit 1620, a control unit 1630, a storage unit 1640, a frame counter 1650, and an output 1660.

Referring to FIG. 16, a receiving unit 1610 receives a plurality of different input streams. The received input stream may be a stream received from a different encoder. The coding scheme may be the same or different. The receiving unit 1610 receives an input stream using wired or wireless communication.

The transfer command input unit 1620 inputs a transfer command manually or automatically. In the case of manual input, a transfer command can be inputted from a user who wants to transfer command through a user interface (not shown), and in case of automatic input, a transfer command can be inputted according to a set input condition. The input condition may be set based on time, and a transfer command may be inputted periodically every specific time period. Alternatively, a transfer command from channel 1 to channel 2 may be automatically performed at a specific time by setting a reservation time, In addition, a channel condition, a network condition, and the like can be set, and a switch command can be automatically input according to the state of the network (available bandwidth, packet loss rate, and the like).

The control unit 1630 controls the transfer of input streams among the input streams in response to the input of the transfer command. The control unit 1630 includes a searching unit 1631, an inserting unit 1632, a switching performing unit 1633, a video analyzing unit 1634, a time stamp correcting unit 1635, a count value comparing unit 1636, 1637 < / RTI >

The search unit 1631 searches the entry point of the second input stream that is newly output by the exit point of the first input stream and the switch that is terminated by the current output switch. The exit point may be searched for the start point of the first I or P picture after the switch command and the entry point may be searched for the starting point of the first I picture after the exit point.

The inserter 1632 inserts a virtual P picture stream and a null packet between the exit point and the entry point. The insertion unit 1632 can receive the virtual P picture stream from the virtual P picture storage unit 1642 and insert it between the exit point and the entry point. The insertion unit 1632 may insert a virtual P-picture stream by replacing a picture that refers to an image before the entry point of the P or B picture after the entry point. At this time, the P or B picture receives and inserts a virtual P picture based on the encoding method of the second input stream from the virtual P picture storage unit 1642.

The switching execution unit 1633 performs switching between the input streams at the input point.

The video analyzer 1634 analyzes the video ES of the input stream input through the receiver 1610, generates a virtual P-picture stream, and stores the virtual P-picture stream in the virtual P-picture storage 1642. When the encoding methods of the first and second input streams are different, different virtual P picture streams can be generated and stored.

The time stamp correcting unit 1635 receives the PTS, DTS and PCR information of each input stream from a time stamp (not shown), and corrects the PTS, DTS and PCR information appropriately for switching between input streams. For example, the time stamp corrector 1635 may modify the PTS, DTS, and PCR information of the second input stream to be time stamps of PTS, DTS, and PCR that are consecutive based on the time information of the first input stream.

When the count value comparison unit 1636 performs a second transfer (re-transfer) from the second input stream to the first input stream after the first transfer from the first input stream to the second input stream, The counter 1650 receives the frame count values of the first input stream and the second input stream based on the first switching time point and compares the sizes of the two values. The inserting method of the virtual P picture stream and the null packet in the inserting unit 1632 may be changed according to the comparison result of the count value comparing unit 1636. [ For example, when the frame count value of the second input stream is larger than the frame count value of the first input stream, a null packet is inserted by the packet length corresponding to the frame number of the difference value, Can be replaced with a virtual P picture stream, and the packet length can be adjusted using a null packet. On the contrary, when the frame count value of the first input stream is larger than the frame count value of the second input stream, the virtual P picture stream is inserted consecutively for the number of packets corresponding to the difference value, So that the virtual P picture stream can be further inserted until the two values become equal.

The audio time control unit 1637 controls the audio PES of the different input streams received in different ring buffers (e.g., ring buffer # 1, ring pager # 2) in the audio buffer 1646 configured in the storage unit 1640, The time information is stored separately. The audio time control unit 1637 stores the PTS of the picture to which the video is to be switched, and compares the PTS of the audio to be input later with the PTS of the audio to be inputted later. Then, the switching is performed in the ES (e.g., AC3 frame) of the second input stream corresponding to the determined switching time.

The storage unit 1640 includes a virtual P-picture storage unit 1642 for storing at least one virtual P-picture stream generated by the video analysis unit 1634, a video buffer 1644 for temporarily storing the video stream, 1646).

The frame counter 1650 counts the number of frames of the input frame to be received.

The output unit 1660 outputs the resultant stream in which the switching is performed. The output unit 1660 may display an image of the switched input stream after decoding through a decoding unit (not shown). Alternatively, the video data may be transmitted to another output device as occasion demands.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions as defined by the following claims It will be understood that various modifications and changes may be made thereto without departing from the spirit and scope of the invention.

Claims

Receiving a plurality of different input streams;
Receiving a switching command for a first input stream currently output among the plurality of input streams;
Searching for an Out-point of the first input stream and an In-point of a newly output second input stream based on the transfer command;
Inserting a virtual P picture stream between the exit point and the entry point; And
And performing a transfer from the first input stream to the second input stream based on the exit point and the entry point.

The method according to claim 1,
The exit point is searched to the start point of the first I or P picture of the first input stream after the switch command and the entry point is searched to the start point of the first I picture of the second input stream after the exit point Characterized in that the transport stream is switched by the switching means.

The method according to claim 1,
Wherein the virtual P-picture stream is inserted as a substitute for the picture stream of the first input stream from the exit point to the entry point, and a null packet is inserted in accordance with the length of the picture stream from the exit point to the entry point. ) Of the transport stream.

The method according to claim 1,
The virtual P-picture stream is a stream in which motion information of all macroblocks and a residual signal are made to be 0 according to a coding scheme through analysis of a video ES (Element Stream) included in the first or second input stream To the transport stream.

The method according to claim 1,
If there is a P or B picture of a second input stream after the entry point that refers to a picture preceding the entry point, replacing the P or B picture with the virtual P picture stream, Wherein the transport stream is a transport stream.

The method according to claim 1,
Wherein a PTS (Presentation Time Stamp), a DTS (Decoding Time Stamp) and a PCR (Program Clock Reference) time stamp of the second input stream after the entry point are consecutive PTSs based on time information of the first input stream, DTS, and PCR. &Lt; RTI ID = 0.0 > 11. < / RTI >

The method according to claim 6,
And if the second input stream is a 3D left video stream, the right video stream corresponding to the 3D left video is switched,
The PTS of the picture corresponding to the entry point of the second input stream is stored and the PTS of the right picture stream and the DTS of the right picture stream are stored on the basis of the stored PTS when the switch is made on the basis of the entry point of the second input stream. And corrects the PCR of the right video stream based on the PCR of the first input stream.

The method according to claim 1,
When a second transfer from the second input stream back to the first input stream is performed after the first transfer from the first input stream to the second input stream,
Counting a first frame count value, which is the number of frames of the first input stream from the first transmission to the input of a switching command for the second transmission, and a second frame count value, which is the number of frames of the second input stream; And
Comparing the first frame count value with the second frame count value and performing the second transfer according to the comparison result.

9. The method of claim 8,
If the second frame count value is greater than the first frame count value,
When the second switch is performed, a packet length corresponding to the number of frames obtained by subtracting the second frame count value from the first frame count value is provided between the output point of the second input stream and the input point of the first input stream And a null packet is inserted.

10. The method of claim 9,
Wherein the picture stream from the inserted null packet to the entry point of the first input stream is replaced with the virtual P picture stream and the packet length is adjusted using the null packet.

9. The method of claim 8,
If the first frame count value is greater than the second frame count value,
When the second frame count value is subtracted from the second frame count value, the number of packets corresponding to the number of frames obtained by subtracting the first frame count value from the output point of the second input stream and the input point of the first input stream, Insert a virtual P-picture stream,
Further comprising counting the first frame count and the second frame count continuously while inserting and outputting the virtual P picture stream, and further inserting the virtual P picture stream until the two values become equal to each other How to convert streams.

The method according to claim 1,
The switching of the audio signal from the first input stream to the second input stream is performed by storing the PTS of the picture to which the video is to be switched and setting the time corresponding to the PTS of the audio to be input later, To the transport stream.

13. The method of claim 12,
A ring buffer is configured for the first input stream and the second input stream, and the time information of each frame included in the packetized elementary stream (PES) is calculated and stored. To the transport stream.

An input stream receiving unit receiving a plurality of different input streams;
A transfer command input unit for receiving a transfer command for the first input stream currently output from the plurality of input streams;
A search unit for searching an Out-point of the first input stream and an In-point of a newly output second input stream based on the transfer command;
An insertion unit for inserting a virtual P picture stream between the exit point and the entry point; And
And a transfer performing unit for performing transfer from the first input stream to the second input stream based on the exit point and the entry point.

15. The apparatus of claim 14, wherein the insert
Inserting the virtual P-picture stream in place of the picture stream of the first input stream from the exit point to the entry point,
And the null packet is filled in accordance with the length of the picture stream from the exit point to the entry point.

15. The method of claim 14,
The virtual P-picture stream is a stream in which motion information of all macroblocks and a residual signal are made to be 0 according to a coding scheme through analysis of a video ES (Element Stream) included in the first or second input stream To the transport stream.

15. The method of claim 14,
After the first transfer from the first input stream to the second input stream and again after the second transfer from the second input stream to the first input stream, Further comprising: a frame counter for counting a first frame count value, which is the number of frames of the first input stream up to input of a shift command, and a second frame count value, which is the number of frames of the second input stream,
Wherein the first frame count value is compared with the second frame count value, and the second transfer is performed according to the comparison result.

18. The method of claim 17,
If the second frame count value is greater than the first frame count value,
When the second switch is performed, a packet length corresponding to the number of frames obtained by subtracting the second frame count value from the first frame count value is provided between the output point of the second input stream and the input point of the first input stream And a null packet is inserted.

18. The method of claim 17,
If the first frame count value is greater than the second frame count value,
When the second frame count value is subtracted from the second frame count value, the number of packets corresponding to the number of frames obtained by subtracting the first frame count value from the output point of the second input stream and the input point of the first input stream, Insert a virtual P-picture stream,
Further comprising counting the first frame count and the second frame count continuously while inserting and outputting the virtual P picture stream, and further inserting the virtual P picture stream until the two values become equal to each other Stream switching device.

A plurality of encoders for generating and transmitting a plurality of encoded input streams; And
And a transport stream converter for receiving the plurality of input streams from the plurality of encoders and performing switching to a specific input stream,
The method includes receiving a switching command for a first input stream currently output from the plurality of input streams, receiving an out-point of the first input stream and an input port of a newly output second input stream, A picture P picture stream is inserted between an output point of the searched first input stream and an input point of a second input stream, And performs switching from the first input stream to the second input stream.