JPH10126768A - Digital broadcasting receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the reproduction of video which cannot be complemented by a human. SOLUTION: When an error detecting part 30 does not secure a prescribed level of transmission quality, a controlling part 40 confirms the decoding state of a present situation, requests the reformat of an MPEG decoding part if it is not a reproduction waiting state, updates control information to a reproduction waiting state, makes a telop generating part 60 generate a reproductive instruction event in other processes that carry out information reproduction and immediately makes the part 60 generate a reproductive instruction event if it is not in the reproduction waiting state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for receiving a digital broadcast utilizing a digital video compression technique, and more particularly to a method for dealing with a decoding error caused by a transmission error.

[0002]

2. Description of the Related Art For example, MPEG (Moving Picture Image Coding Experts)
In digital broadcasting using a stream encoded according to an information compression standard such as Group), if the transmission quality deteriorates so that error correction cannot be performed, video data cannot be accurately decoded on the broadcast receiving apparatus side. Image disturbance occurs. For this reason, unlike analog broadcasting, a video at a level that cannot be complemented by humans will be reproduced. In the case of analog broadcasting, the effect is such that image quality is degraded due to image noise.In the case of digital broadcasting, for example, even a few-bit error is an important control data. In such a case, there is a possibility that the image may be reproduced in a state where it cannot be complemented by humans, that is, the image itself cannot be recognized by human vision.

Accordingly, the present invention has been made in view of such a problem, and when a stream having a quality level that cannot be decoded in an appropriate state is received, decoding of the received stream is stopped and human complementation is performed. An object of the present invention is to suppress the reproduction of a video that cannot be performed.

[0004]

According to the first aspect of the present invention, there is provided a digital broadcast receiving at least a stream including video data through a selected transmission channel. A receiving apparatus, comprising: demodulating means for demodulating a received stream as digitized stream data; video reproducing means for reproducing video data encoded from the stream data demodulated by the demodulating means; Video output means for outputting video data reproduced by the means, error detection of the stream data demodulated by the demodulation means, transmission quality detection means for detecting transmission quality, and detection by the transmission quality detection means. If the transmission quality is lower than a predetermined level, the video reproduced by the video reproducing means Characterized in that it comprises an output stop means for stopping the output of the over data.

In this digital broadcast receiving apparatus, a received stream is demodulated as digitized stream data, encoded video data is reproduced from the demodulated stream data, and output as video data. At this time, the transmission quality is detected by detecting an error in the demodulated stream data. If the detected transmission quality is lower than a predetermined level, the output stop means stops outputting the reproduced video data. As a result, when a stream with a quality level that cannot be decoded in an appropriate state is received, decoding of the received stream is stopped, and a playback video in a state that can not be complemented by human eyes is output Can be prevented.

According to a second aspect of the present invention, there is further provided a screen information generating means capable of generating predetermined screen information, and when the transmission quality detected by the transmission quality detecting means is lower than a predetermined level, The output of the video data reproduced by the video reproducing means may be stopped, and instead, the screen information generated by the screen information generating means may be output by the screen information output means.

In this case, not only the output of the video data reproduced by the video reproducing means is stopped, but also the screen information generated by the screen information generating means is output instead. If the display content indicating that the output of the reproduced video data is stopped because the transmission quality is lower than the predetermined level is output as the predetermined screen information, it is convenient to inform the user. Such a notification is effective because simply stopping the output of the reproduced video data may cause the user to misunderstand that the failure has occurred. The display content to be notified may be composed of, for example, only characters, or may be configured to be displayed by being combined with a predetermined background video. Of course, if a voice output unit is provided, it is preferable to use voice notification.

With this configuration, when a stream having a quality level that cannot be decoded in an appropriate state is received, the fact is notified until the quality level of the received stream reaches a level at which decoding can be performed. Can be more convenient. As the stream, streams based on various encoding standards can be adopted. For example, as a representative stream, a digital information compression standard M
The PEG2 standard is conceivable. MPEG2 is premised on being applied to various applications including broadcasting and communication, and should be applied in the field of digital broadcasting such as interactive television and multi-channel digital satellite broadcasting realized by two-way CATV. There are many. In the case of a system employing MPEG2, even if reception of data including a transmission error can be detected by the MPEG2 system separation unit in accordance with the standard, error control cannot be performed in the entire system, so that decoding cannot be performed in an appropriate state. Quality level may be reduced. Therefore, when the transmission quality is lower than the predetermined level, by stopping the output of the reproduced video data, it is possible to prevent the output of the reproduced video in a state that cannot be complemented by human eyes.

[0009] Naturally, the present invention is not limited to MPEG2, and any other coding standard applicable to digital broadcasting can be similarly employed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a digital broadcast receiving apparatus 1 according to one embodiment of the present invention. The digital broadcast receiving apparatus 1 according to the present embodiment includes:
This is a device for receiving a digital broadcast from an external broadcasting center (not shown). Here, it is assumed that the digital broadcast is received as a code multiplexed stream compressed according to the MPEG2 standard. MPEG2 is premised on being applied to various applications including broadcasting and communication.
It is often applied in the field of digital broadcasting such as interactive television and multi-channel digital satellite broadcasting realized by bidirectional CATV and the like.

The digital broadcast receiving apparatus 1 includes a tuner unit 10 for selecting a transmission channel to be received, and a demodulation unit as “demodulation means” for demodulating a stream received on the transmission channel selected by the tuner unit 10. 20 and
An error detection unit 30 as "transmission quality detection means" for detecting an error in the data demodulated and digitized by the demodulation unit 20, and a control unit 40 for controlling the entire system and corresponding to "output stop means". An MPEG system separation unit 50 for performing separation control of the MPEG2 system on the data demodulated and digitized by the demodulation unit 20, and a telop generation unit 60 as "screen information generation means" for generating a predetermined telop And an MPEG video decoding unit 70 as a "video reproducing unit" for decoding MPEG standard video data, an MPEG audio decoding unit 80 for decoding MPEG standard audio data, and an MPEG video decoding unit 70. The decoded video data is reproduced and output, and the telop data from the A video synthesizing output unit 90 as a "video output unit" and a "screen information output unit" for synthesizing and outputting data, and an audio output unit 100 for reproducing and outputting audio data decoded by the MPEG audio decoding unit 80 And an MMI (man-machine interface) input unit 11 for inputting an instruction request from a user
0.

The control unit 40 inputs a request from an operator via the MMI input unit 110, controls the tuner unit 10, and selects and sets a transmission channel to receive. The digital broadcast stream received through the tuner unit 10 is input to the MPEG system separation unit 50 as data demodulated and digitized by the demodulation unit 20. That M
The PEG system separation section 50 separates contents (video data, audio data, etc.) in accordance with the MPEG2 system standard, and outputs decoded data to the MPEG2 video decoding section 70 and the MPEG audio decoding section 80 according to the contents. Each of the decoding units 70 and 80 decodes the input decoded data, and performs analog conversion through a video synthesis output unit 90 for video and an audio output unit 100 for audio, and outputs the converted data.

On the other hand, the data demodulated by the demodulation unit 20 is also input to the error detection unit 30 in parallel to generate transmission error information. The transmission error information generated here is notified to the control unit 40 in real time, and the control unit 40 detects the level of the transmission quality. As a result of the level detection by the control unit 40, when it is determined that the level cannot be decoded, the control unit 4
The value 0 controls the telop generation unit 60 to output information such as telops at the same time as executing the decoding stop control.

Next, the operation of the digital broadcast receiving apparatus 1 having the above configuration will be described with reference to the flowchart of FIG. First, when the digital broadcast receiving apparatus 1 is activated or when the designation of the transmission channel is changed,
Initialization processing of hardware and software used in the transmission error control processing is performed (S10). S10
After the initialization process is completed, the process enters a transmission error control process (S20 to S130) which is repeatedly executed.

In this transmission error control processing, first, information (BER: Bit) of a transmission error detected in real time.
The transmission quality information statistically analyzed from the error rate is generated, and the transmission quality is analyzed (S20). next,
Based on the analysis result of the transmission quality, it is determined whether the transmission quality is at a level that can be decoded by comparing it with a predetermined threshold, and it is determined whether or not the predetermined quality level can be ensured (S30).

When a predetermined quality level can be ensured (S4
0: YES), and confirm the decryption state so far (S:
50), if not in the reproducing state (S60: NO), the control information is updated to the reproducing state (S70). After that, another MPEG decoding process that continues the normal MPEG decoding process is performed.
A reproduction instruction event is generated in the decryption process (S8).
0). If it is during reproduction (S60: YES), S7
The process shifts to S80 without executing the process of 0.

On the other hand, if a negative determination is made in S40, that is, if the predetermined quality level cannot be ensured, the process proceeds to S90. In S90, the current decryption state is confirmed, and if it is not in the reproduction waiting state (S100: NO), the next MPE
For the G decoding process, a request for re-initialization of the MPEG decoding unit is made (S100), and the control information is updated to a playback waiting state (S120). After that, a reproduction instruction event is generated in another process for reproducing information such as registered telops (S130). The contents of the telop may indicate that the output of the reproduced video data is stopped because the transmission quality is lower than a predetermined level. If it is in the reproduction waiting state (S100: YES), S1
The process proceeds to S130 without executing the processes of S10 and S120.

After executing the respective reproduction control processes in S80 or S130, the process returns to S20 to repeat the next process. As described above, the digital broadcast receiving apparatus 1 demodulates the received stream as digitized stream data, and detects the level of the transmission quality of the demodulated data. Then, when it is determined that the level cannot be decoded, the stop control of the decoding is executed and, at the same time, information such as a predetermined telop is output. Thus, when a stream is received at a quality level that cannot be decoded in an appropriate state, it is possible to prevent output of a reproduced video in a state that cannot be complemented by human eyes.

Further, instead of stopping the output of the video data, if the display content indicating that the output of the reproduced video data is stopped because the transmission quality is lower than a predetermined level is output,
It is convenient to inform the user. Such a notification is effective because simply stopping the output of the reproduced video data may cause the user to misunderstand that the failure has occurred. The display content to be notified may be composed of, for example, only characters, or may be configured to be displayed by being combined with a predetermined background video. Of course, notification by voice via the audio output unit 100 may be used together.

As described above, the present invention is not limited to such an embodiment, and can be implemented in various forms without departing from the gist of the present invention. For example, in the above-described embodiment, the description has been given assuming that the stream is received as a code multiplexed stream compressed according to the MPEG2 standard. However, the present invention is not limited to this. Can be adopted as well.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a digital broadcast receiving device according to an embodiment.

FIG. 2 is a flowchart illustrating a process executed by the digital broadcast receiving device of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Digital broadcast receiving apparatus 10 ... Tuner part 20 ... Demodulation part 30 ... Error detection part 40 ... Control part 50 ... MPEG system separation part 60 ... Telop generation part 70 ... MPEG video decoding part 80 ... MPEG audio decoding part 90 ... Video synthesis Output unit 100: Audio output unit 110: MMI input unit

Claims (4)

[Claims] 1. A digital broadcast receiving apparatus for receiving a stream containing at least video data through a selected transmission channel, comprising: a demodulation means for demodulating the received stream as digitized stream data; Video reproducing means for reproducing video data encoded from the stream data demodulated by the means; video output means for outputting video data reproduced by the video reproducing means; Error detection, transmission quality detection means for detecting the transmission quality, if the transmission quality detected by the transmission quality detection means is lower than a predetermined level, the output of the video data reproduced by the video reproduction means Digital broadcast receiving apparatus comprising output stopping means for stopping . 2. A screen information generating means capable of generating predetermined screen information, and outputting the screen information generated by the screen information generating means instead of the video data stopped by the output stopping means. 2. The digital broadcast receiving apparatus according to claim 1, further comprising screen information output means. 3. The screen information generating means can generate, as the predetermined screen information, a display content indicating that output of video data reproduced by the video reproducing means is stopped because transmission quality is lower than a predetermined level. 3. The digital broadcast receiving apparatus according to claim 1, wherein 4. The digital broadcast receiving apparatus according to claim 1, wherein said stream is an MPEG2 stream code-multiplexed according to the MPEG2 standard.