JP2002152780A - Transport stream generator - Google Patents

Abstract

(57) [Summary] [PROBLEMS] An object of the present invention is to output an endless video with a small capacity memory by minimizing the amount of video information. SOLUTION: The structure of a transport stream provided with program sequence information and a mechanism for display and decoding in a sequence layer is incorporated in one frame, and the structure of the transport stream is stored in a RAM.
From the head address specified by the first counter,
The address of the memory is output endlessly until the end address, the data corresponding to the address is output from the RAM, and the rewriting is performed by the rewriting device so that the continuity of the data is maintained only when the data of the second counter is output. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a transport stream generator which can be used for production, adjustment, and design of digital broadcasting equipment and can output endless images with a small-capacity memory.

[0002]

2. Description of the Related Art FIG. 6 schematically shows a conventional transport stream generator. Programmable Address Counter (Programmable Address)
Counter) 10, a semiconductor memory or hard disk 12 including a RAM in which a transport stream (TS) is written, and a PTS, DTS, PCR, Continuit
It is composed of a y counter changing device 14. The programmable-address-counter 10 outputs the address of the memory endlessly from the designated start address to the end address. Data corresponding to the address is output from the RAM 12. The transcribing unit 14 transposes the data so as to maintain the continuity of the data only when the data of the second counter (PTS, DTS, PCR, ContinuityCounter) is output. If this change is not performed, the transport stream data will reverse in time when the end address returns to the start address.

FIG. 7 is a block diagram showing in detail the portion of the transcoder shown in FIG. The transport stream data corresponding to the address to be counted up is stored in the RAM 12.
Are output sequentially. The data output from the RAM 12 is input to a buffer memory (FIFO) 15. This is PTS,
This is because a buffer memory is required because the data matching conditions of the DTS, PCR, and Continuity Counter are not in units of one word. In FIG. 7, the second counter (PTS, DT
S, PCR, Continuity Counter 13 are shown in detail, and a match determination circuit 16, a selector 17, and an adder 1 are shown.
8. As shown in FIG. 7, the operation of the second counter 13 is such that, for example, when three words of data match, the match determination circuit 16 sends a signal to the selector 17 notifying that a change occurs, and the selector 17 The adder 18 selects and outputs the result of adding the circulation time to the original data. At the normal time when no coincidence occurs, the output of the buffer memory 15 is output as it is.

Normally, a transport stream written to a semiconductor memory such as the RAM 12 or a hard disk has video and audio multiplexed. Among them, an image having a large capacity has a configuration as shown in FIG. The picture layer constitutes one frame. Usually, 30 pictures are displayed per second. That is, the transport stream data has a large capacity with 30 pictures per second.

[0005] Pictures are composed of three types: an I picture having data independently, a P picture for performing prediction and compression from a backward frame, and a B picture for performing forward and backward prediction and compressing. The GOP layer is composed of a combination of these three types of pictures. The sequence layer further includes a plurality of GOP layers. The sequence layer has a standard that can end at the sequence end or start again from the sequence header without the sequence end.

[0006] When the video having the above configuration is multiplexed with audio, it is decomposed into small chunks of packets and multiplexed. At this time, PTS,
A time stamp called DTS is added. Also,
A PCR, which is a substitute for a clock serving as a reference for displaying and decoding this, is appropriately added. Usually, PCR is appropriately arranged within the range of the standard. Also, in the case of video, PTS and DTS need not necessarily be provided for each picture (frame).

[0007] When testing a broadcast equipment system, a transport stream in which video and audio of appropriate lengths are multiplexed is usually repeatedly output to a RAM or other semiconductor memory or hard disk.

[0008]

However, the amount of video information is large even though it is compressed.
In the case of a semiconductor memory including the above, it becomes very expensive. A hard disk is an inexpensive means, but has a high risk of crash and a large number of unstable factors when repeated output is considered.

The present invention has been made in view of the above circumstances, and minimizes the amount of video information and minimizes the danger of crashes by repeatedly using a hard disk when testing broadcast equipment systems. It is another object of the present invention to sufficiently cope with a small-capacity semiconductor memory.

[0010]

According to one aspect of the present invention, there is provided a first counter for outputting a memory address endlessly from a designated start address to an end address. A semiconductor memory for storing the configuration of a transport stream incorporated in at least one frame and outputting data corresponding to the address, and a semiconductor memory for maintaining data continuity only when data of the second counter is output. And a transcoder for performing the above-mentioned processing, characterized in that the sequence layer of the transport stream is provided with program arrangement information and a mechanism for display and decoding.

According to such a configuration, the structure of a transport stream in which program sequence information and a mechanism for display and decoding are added to the sequence layer is incorporated into one frame, and the structure of the transport stream is Is stored in a semiconductor memory, an address of the memory is output endlessly from a start address designated by the first counter to an end address, data corresponding to the address is output from the memory, and data of the second counter is output. Only when it is done, a breaker is used to maintain the continuity of data.

[0012] Then, it becomes possible to greatly reduce the amount of information of a video image as compared with the related art. Therefore, the video can be output with a small-capacity memory by using the conventional hardware almost as it is and with the minimum configuration of the transport stream.

Further, the invention according to claim 2 is characterized in that the sequence layer of the transport stream is composed of at least one I picture. With such a configuration, the sequence layer is simplified. In particular, since the sequence layer can be composed of one I picture, an image can be output with a small-capacity memory.

The invention according to claim 3 is characterized in that the sequence layer of the transport stream comprises at least a plurality of frames of a combination of I picture, B picture and P picture. With such a configuration, the image quality can be increased, and the capacity can be output with a small-capacity memory because the capacity is almost the same as that of a single I-picture.

[0015]

FIG. 1 shows the structure of a transport stream stored in a semiconductor memory. Since the hardware such as the RAM 12, which is a basic part of the present invention, is configured in the same manner as the conventional hardware shown in FIG.

However, the transport stream is different from the conventional structure, and the GOP layer is composed of one picture. In the MPEG standard, the GOP layer may not be provided. In other words, the sequence layer includes one picture. One frame is configured by adding program sequence information called PAT and PMT, which are the minimum required for a transport stream, and PCR to one sequence layer.
The PCR is also inserted in the middle of one frame in the figure.
One or more may be used.

The minimum structure constituting the transport stream is incorporated in one frame and stored in a semiconductor memory such as the RAM 12, and the first counter is a programmable-address-counter.
The address of the memory is output endlessly from the start address specified by the mable address counter (10) to the end address. The data for that address is R
Output from AM12. The rewriting device performs rewriting so as to maintain the continuity of data only when the data of the second counter (PTS, DTS, PCR, Continuity Counter) 13 is output. This makes it possible to output an endless image with a small-capacity memory.

The above is a basic example, and the output is a still image. In the case of digital broadcasting, unlike analog broadcasting, if incorrect data (transport stream) is input to a decoder (tuner), the screen may freeze. In the case of a still image, it may not be possible to determine whether the image is frozen or displayed correctly. Therefore, prepare a plurality of frames as shown in FIG.
Moving images can be displayed as shown in FIG. 3 by repeatedly outputting one frame a certain number of times and then repeatedly outputting the next frame.

The reason why one frame is repeated a certain number of times is that, when it is repeated every time, the movement cannot be followed by human eyes. As a result, it is possible to supply a test signal that can determine whether the screen is frozen or displayed correctly.

FIG. 4 shows a simplified example of hardware for actually controlling the repetition of a frame. By not connecting the high-order data of the counter 1 to the address bus of the RAM, the same data is repeatedly output in three bits in the above example, that is, eight times, and then the clock is input to the counter 2 to select the next data. . In the above example, 2 bits, that is, four types of data are repeatedly selected. Actually, the number of repetitions and the number of selected data can be set programmable.

FIG. 5 shows another embodiment of the present invention. R
The structure of the transport stream stored in the semiconductor memory such as the AM is not a structure of one I picture, but a plurality of frames by a combination of B and P pictures. As a result, the B and P pictures are prediction pictures, and in the case of a still picture, they are exactly the same as the preceding and succeeding pictures, so that the compression rate is very high. G composed of one I picture, two P pictures, and three B pictures
The capacity of the OP is little different from that of a single I picture. However, image quality for the same capacity is high. In addition, this example can be easily applied to a pseudo moving image composed of a plurality of frames by setting a picture to a GOP layer.

[0022]

According to the present invention, it is possible to greatly reduce the amount of video information as compared with the conventional one. Can be output in the memory of Therefore, a semiconductor memory such as a RAM can be dealt with with a small capacity without using a hard disk which may cause a crash.

[Brief description of the drawings]

FIG. 1 shows a structure of a transport stream stored in a semiconductor memory according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing repeated output of a plurality of frames.

FIG. 3 is an explanatory diagram showing a moving image display by repeatedly outputting a plurality of frames.

FIG. 4 is a simplified block diagram of hardware for controlling repetition of a plurality of frames.

FIG. 5 shows a structure of a transport stream stored in a semiconductor memory according to another embodiment of the present invention.

FIG. 6 is a block diagram schematically showing a conventional transport stream generator.

FIG. 7 is a block diagram showing in detail a portion of the transcoder shown in FIG. 6;

FIG. 8 shows a configuration of a transport stream in which video and audio including large-capacity video are multiplexed.

[Explanation of symbols]

 10 First counter 12 RAM 13 Second counter

Claims (3)

[Claims] A first memory which outputs a memory address endlessly from a designated start address to an end address.
Counter, a semiconductor memory for storing the configuration of the transport stream incorporated in at least one frame, and outputting data corresponding to the address, and maintaining the continuity of data only when the data of the second counter is output. In a transport stream generator comprising: a transposition unit that transposes to a program sequence information in a sequence layer of the transport stream;
A transport stream generator provided with a mechanism for displaying and decoding. 2. The transport stream generator according to claim 1, wherein the sequence layer of the transport stream comprises at least one I picture. 3. The transport stream generator according to claim 1, wherein the sequence layer of the transport stream comprises at least a plurality of frames of a combination of I picture, B picture and P picture.