JP2008172335A - Digital broadcast receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a user to easily view a program by using a frame excellent in videos and/or a sound of a hierarchy and a synthetic frame for complementing decode errors among the hierarchies to one another. <P>SOLUTION: The receiver comprises: a stream separating means for separating video and/or sound data and control information including a time of day information from a data stream; an encoding system extracting means for extracting from control information encoding the system control information of the video or sound data; a data error detecting means for extracting a data error position of a video or sound data in each hierarchy; an identical data position extracting means for extracting an identical data position for making corresponding video and a sound among the hierarchies synchronous with each other on the basis of the time of the day information; and a mutually complementary synthesizing means for complementing video or a sound frame data at the data error position by frames of mutual hierarchies on the basis of the identical data position and generating data where video or a sound continues. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a digital broadcasting that simulcasts the same program using a plurality of hierarchies in the same time zone, and always reproduces using a good frame of video or audio regardless of the reception state or reception state. The present invention relates to a broadcast receiving apparatus.

On December 1, 2003, digital terrestrial broadcasting in Japan started. In this digital broadcasting system, as shown in FIG. 3, a frequency bandwidth of 5.6 MHz is allocated to one broadcasting station, for example, for one channel. This bandwidth is divided into 13 equal parts (about 429 kHz, which is a unit called “segment”). The broadcasting station is determined to be able to broadcast 1 to 3 programs by combining the number of the 13 segments into a hierarchy. In the terrestrial digital television broadcasting system, OFDM (Orthogonal Frequency Division Multiplexing) is adopted as a modulation method, and a segment unit is a signal modulated by OFDM. In addition, the data in segment units can be freely changed. Among the above 13 pieces, for example, a hierarchy consisting of 12 segments is formed to broadcast one high-definition video program and a program for mobile terminals, and 4 pieces. Several service forms are possible, such as broadcasting three different standard definition programs and programs for mobile terminals using a hierarchy of segments.
As another service form of terrestrial digital broadcasting, simultaneous broadcasting is performed in which the same program is broadcast in the same time zone using a plurality of layers having different numbers of segments. This simulcast is for providing the same program service for fixed reception at home, etc., for mobile reception such as automobiles, or for mobile phone reception.

  By the way, especially in the case of a digital broadcast receiving device mounted on a moving body such as an automobile, a broadcast wave from a relay station of each broadcasting station is often received due to movement. The electric field strength of the broadcast wave deteriorates depending on the reception position, such as the influence of the location or the like, or the distance change from the radio tower or the relay station. In addition, when there is a near-field operation due to movement with respect to a radio tower or relay station, due to the Doppler effect, the frequency of the direct wave in the broadcast carrier wave differs from the frequency of the reflected wave from the building, etc., and fading (frequency interference) cause. For this reason, the digital broadcast receiving apparatus cannot properly select a carrier wave due to a change in the electric field strength of the received signal or a change in a plurality of frequencies, leading to a reduction in image quality and sound quality. In the case of a mobile object, the electric field intensity of the broadcast wave changes due to bad weather or high speed running. Therefore, in a mobile digital broadcast receiving apparatus, video and audio may be interrupted or video and audio may be disturbed. Thus, when a video or audio failure occurs, the user feels uncomfortable and is forced to switch to another channel. In addition, when simultaneous broadcasting using a plurality of hierarchies is being performed, there is a trouble that a change to other hierarchies that can improve the reception state must be performed manually.

  In response to the problems described above, in a digital broadcast receiving apparatus that can receive each layer of simulcast using multiple layers of digital broadcast, video and audio are output in a reception state that seems to be interrupted. Even in such a case, a technique has been proposed in which output can be manually or automatically switched to an optimum hierarchy of reception states (see, for example, Patent Document 1). In this technique, in the configuration for automatic switching, a database that holds the broadcasting system for each layer of each broadcasting station is provided, and the detection of the electric field strength of the received digital broadcast signal and / or the reproduction state of the layer is performed, The hierarchy that improves the reception state is determined according to the detected electric field strength and / or the reproduction state, the broadcast system of the determined hierarchy is extracted with reference to the database, and the output is switched to the output of the hierarchy based on the broadcast system I am doing so. For this reason, setting screen providing means for setting the detected electric field strength reference and the reproduction state reference is provided.

JP 2003-274302 A

The conventional digital broadcast receiving apparatus switches the hierarchy of the reception state by the above method, but has the following problems.
In a digital broadcast receiving apparatus mounted on a mobile body such as an automobile, there is a problem that the hierarchy is frequently switched when the electric field strength fluctuates violently such as multipath fading. In addition, since switching is performed for each layer depending on the electric field strength and the reproduction state, there is a problem that even if only the video is interrupted and the audio is sufficiently heard, the video and the audio are switched together in the case of television broadcasting. Furthermore, image playback and audio playback are combined before and after depending on the switching timing between hierarchies, and there is a problem that when the hierarchies to be played back frequently are switched, it is not possible to recognize that they are moving back and forth. . Furthermore, since there is a problem in the reproduction state, only the hierarchy is switched. Therefore, even if there is an error in the video or audio data of each hierarchy after the switching, there is a problem that the error reproduction cannot be avoided.

  The present invention has been made to solve the above-mentioned problems, and uses a frame of video and / or audio having a good level for simultaneous broadcasting and a composite frame for mutually complementing decoding errors between layers. Accordingly, an object of the present invention is to obtain a digital broadcast receiving apparatus that makes it easy to view a reception state and a program.

  The digital broadcast receiving apparatus according to the present invention uses at least two layers in which segments constituting a transmission frequency band are combined, and video data and / or audio data of the same program of television broadcasting or audio broadcasting is stored in each layer. A digital broadcast receiving apparatus that receives a simulcast that multiplexes and performs hierarchical transmission, demodulates and decodes to generate video and / or audio frame data of each layer, and modulates and transmits each layer from a received signal Transmission method control information extracting means for extracting transmission method control information in which a rate is set; stream separating means for separating control information including video data and / or audio data and time information from the demodulated data stream; and the stream separation From control information separated by means, video data and / or An encoding method extracting means for extracting voice data encoding method control information; a data error detecting means for extracting a data error position of video data or audio data of each layer separated by the stream separating means; and a stream separating means. Based on the separated time information, the same data position extracting means for extracting the same data position for synchronizing the corresponding video and / or audio between layers, and the same data position extracted by the same data position extracting means A complementary complementary combining means for generating video and / or audio continuous data by complementing video and / or audio frame data at the data error position detected by the data error detection means with frames of each other's hierarchy. It is equipped with.

  According to the present invention, as frame data of video or audio output for reproduction from the frame buffer, frame data having a layer with few errors and a good resolution is used, or an error portion is detected as an error between two layers. Since composite frame data complemented with frames of a few layers is used, video and audio playback errors can be reduced without using radio wave reception status monitoring means and hierarchy switching means, and there is less discomfort Enable playback of video and audio.

Embodiment 1 FIG.
1 is a block diagram showing a functional configuration of a digital broadcast receiving apparatus according to Embodiment 1 of the present invention. This digital broadcast receiving apparatus uses at least two hierarchies combining segments constituting a transmission frequency band, receives a simulcast that performs hierarchical transmission by multiplexing video and audio data of the same program on each hierarchies, Video and / or audio frame data is demodulated and decoded to synthesize video and / or audio frame data by complementing the error-prone portion of one layer frame with the error-reducing portion of the other layer. It is something to regenerate. Although the configuration of FIG. 1 shows an example of television broadcasting, the present invention can also be applied to digital audio broadcasting.
In the figure, a tuner 10 is means for receiving a radio wave of digital broadcasting and generating a reception signal including layer 1 and layer 2 performing simulcast. The transmission scheme control information extracting means 11 is a means for extracting transmission scheme control information in which the number of layers, the modulation scheme and transmission rate of each layer are set, from a TMCC (Transmission and Multiplexing Configuration Control) signal multiplexed on the received signal. . The layer 1 demodulation means 12 demodulates the layer 1 of the broadcast wave based on the layer 1 modulation method included in the transmission method control information, and generates a layer 1 data stream, that is, MPEG2-TS (Moving Picture Expert Group 2-Transport Stream: Hereinafter, simply referred to as TS.) A means for obtaining a component and performing error correction processing on a TS in layer 1. Similar to the hierarchy 1 demodulation means 12, the hierarchy 2 demodulation means 13 is a means for demodulating the broadcast wave hierarchy 2 to obtain a hierarchy 2 TS and performing error correction processing on the hierarchy 2 TS. The stream separation unit 14 performs filtering processing using the PID (Packet ID) numbers included in the demodulated layer 1 and layer 2 TS headers, thereby causing video and audio TS packets (video data and audio data) of each layer to be filtered. , Section information, time information (PCR; Program Clock Reference) and the like. Further, the stream separating means 14 in the present invention includes the same data position extracting means for extracting the same data position for synchronizing the corresponding video and audio between the hierarchy 1 and the hierarchy 2 based on the separated time information. .

  The encoding method extraction unit 15 extracts the encoding method control information from the stream identifier included in the header of the TS received from the stream separation unit 14 and from the stream identifier included in the section information from the section configuration unit 16 described later. Means. The section configuration means 16 is means for assembling section information such as PAT (Program Association Table), PMT (Program Map Table), etc. from the TS packets related to the distributed section information. The video frame size detection means 17 detects the frame size of the video included in the hierarchy 1 and the hierarchy 2 from the sequence header information acquired by the section construction means 16, the later-described hierarchy 1 video decoding means 20 and the later-described hierarchy 2 video decoding means 21. Means. The audio sampling frequency detection means 241 is included in the hierarchy 1 and the hierarchy 2 from the audio decoding control information composed of the audio ES header information acquired by the section configuration means 16, the postscript hierarchy 1 audio decoding means 24 and the postscript hierarchy 2 audio decoding means 25. This is means for detecting the sampling frequency of the sound to be recorded.

The video data error detecting means 18 is a means for extracting the data error position of the video data of each layer separated by the stream separating means 14. The layer 1 video decoding means 20, the hierarchy 2 video decoding means 21, and the hierarchy 1 video decoding error The frame detection means 22 and the layer 2 video decoding error frame detection means 23 are configured.
The layer 1 video decoding unit 20 generates a PES (Packetized Elementary Stream) and ES (Elementary Stream) from the TS packet of the layer 1 video, and then performs ES according to the encoding method control information acquired by the encoding method extraction unit 15. Is generated to generate video frame data of layer 1, and the comparison between the control data of layer 1 video acquired from the section construction means 16 and the header information included in the TS of layer 1 video, It is means for detecting errors and obtaining the results as video decoding error information including data error position information. The layer 2 video decoding unit 21 performs the same processing as the layer 1 video decoding unit 20 on the TS packet of layer 2 video, and obtains video decoding error information including the layer 2 video frame data and data error position information. Means. The layer 1 video decoding error frame detection unit 22 is a unit that buffers the decoded frame 1 video frame data and detects a frame having an error part based on the video decoding error information. The layer 2 video decoding error frame detection unit 23 is a unit that performs the same processing as the layer 1 video decoding error frame detection unit 22 on the decoded layer 2 video frame data.

The audio data error detecting means 19 is a means for extracting the data error position of the audio data of each layer separated by the stream separating means 14, and is a hierarchy 1 audio decoding means 24, a hierarchy 2 audio decoding means 25, a hierarchy 1 audio decoding error. The frame detection unit 26 and the layer 2 audio decoding error frame detection unit 27 are configured.
The layer 1 audio decoding unit 24 generates PES and ES from the TS packet of layer 1 audio, and then decodes the ES according to the encoding method control information acquired by the encoding method extraction unit 15 to generate audio frame data In addition, the comparison between the control data of the layer 1 audio acquired from the section configuration means 16 and the header information included in the audio TS data, and the detection of a decoding error occurring at the time of decoding, the data error position information is included. This is means for obtaining audio decoding error information. The layer 2 audio decoding unit 25 performs the same processing as the layer 1 audio decoding unit 24 on the TS packet of the layer 2 audio, and performs an audio decoding error including layer 2 audio frame data and data error position information. It is a means to obtain information. The layer 1 audio decoding error frame detecting means 26 is a means for buffering the decoded frame 1 audio frame data and detecting a frame having an error portion based on the audio decoding error information. The layer 2 audio decoding error frame detection unit 27 is a unit that performs the same processing as the layer 1 audio decoding error frame detection unit 26 on the decoded layer 2 audio frame data.

  Based on the output video size given as a condition and the frame size of the layer 1 and layer 2 video detected by the video frame size detection unit 17, the video output size determination unit 28 It is a means for determining a scaling value (enlargement ratio or reduction ratio) for each size. The layer 1 video size scaling unit 29 is based on the frame scaling value of the layer 1 video determined by the video output size determination unit 28 and is the output of the decoded layer 1 which is the output of the layer 1 video decoding error frame detection unit 22. It is a means for scaling the frame size of video frame data. The layer 2 video size scaling unit 30 is a unit that scales the frame size of the decoded video frame data of layer 2 by the same processing as the layer 1 video size scaling unit 29.

  The audio sampling frequency determining unit 242 converts the conversion value of the sampling frequency of the audio included in each layer based on the output audio sampling frequency given as a condition and the audio sampling frequency of each layer detected by the audio sampling frequency detecting unit 241. This is a means for determining (enlargement ratio or reduction ratio). The layer 1 audio sampling frequency conversion unit 261 is a decoded layer that is an output of the layer 1 audio decoding error frame detection unit 22 based on the sampling frequency conversion value of the layer 1 audio determined by the audio sampling frequency determination unit 242. This is means for converting the sampling frequency of one audio frame data. The layer 2 audio sampling frequency converting means 271 is a means for converting the sampling frequency of the decoded layer 2 audio frame data by the same processing as the layer 1 audio sampling frequency converting means 261.

The video mutual complement synthesizing means 31 complements the video frame data at the data error position detected by the video data error detecting means 18 with the frames of the respective layers based on the same data position extracted by the same data position extracting means. This means for generating continuous video data comprises a video writing order determining means 32, a video frame buffer 33 and a video writing means 321.
The video frame buffer 33 is means for temporarily storing video frame data for reproduction. The video writing order determination unit 32 determines the layer of the modulation scheme having a strong error resistance out of the layer 1 and the layer 2 based on the transmission scheme control information acquired from the transmission scheme control information extraction unit 11 by a method described later. A high-resolution video is determined from the frame size value of each hierarchical video acquired from the hierarchical 1 video size scaling unit 29 and the hierarchical 2 video size scaling unit 30, and is stored in the video frame buffer 33 based on these determination results. It is a means for determining the writing hierarchy and the writing order. Whether the video writing means 321 writes video frame data of a hierarchy having high error tolerance and high video resolution to the video frame buffer 33 according to the writing order determined by the video writing order determining means 32 by a method described later. Or means for overwriting the video frame data of the other layer so as to complement the error part of the video frame data of one layer.

The speech mutual complement synthesizing unit 34 complements the audio frame data at the data error position detected by the audio data error detecting unit 19 with the frames of the mutual hierarchies based on the same data position extracted by the same data position extracting unit. This means generates voice continuous data, and is composed of a voice writing order determination means 35, a voice frame buffer 36 and a voice writing means 351.
The audio frame buffer 36 is means for temporarily storing audio frame data for reproduction. The voice writing order determination unit 35 performs a hierarchy determination of a scheme having a high error tolerance based on the transmission scheme control information acquired from the transmission scheme control information extraction unit 11 and a layer 1 voice sampling frequency conversion unit 261 by a method described later. In addition, the audio resolution is determined based on the audio sampling frequency value of each layer after decoding obtained from the layer 2 audio sampling frequency conversion means 271, and based on these determination results, the layer to be written to the audio frame buffer 36 It is means for determining the writing order. The audio writing means 351 writes the video frame data of a layer having high error tolerance into the audio frame buffer 36 according to the writing order determined by the audio writing order determination unit 35, as described later, or one of the hierarchies. This is means for overwriting the audio frame data of the other layer so as to complement the error portion of the audio frame data.

Next, the operation will be described. Here, it is assumed that the frames corresponding to the video and audio in both layers are synchronized.
First, the tuner 10 receives a radio wave of digital broadcasting and generates a reception signal including a hierarchy 1 and a hierarchy 2 that perform a simulcast. The transmission method control information extracting unit 11 extracts the number of layers multiplexed in the received signal and the modulation method information of each layer, and outputs the extracted information to the layer 1 demodulating unit 12 and the layer 2 demodulating unit 13 as transmission method control information. The received signal is given to the hierarchy 1 demodulation means 12 and the hierarchy 2 demodulation means 13. The layer 1 demodulating means 12 demodulates based on the modulation method of the layer 1 included in the transmission method control information extracted by the transmission method control information extracting unit 11 and generates a layer 1 TS. An error correction process is performed for this. In this processing, the error bit of the TS header is set for the data that has not been error corrected together with the output data after error correction, and is output to the stream separation means 14 at the subsequent stage. On the other hand, for layer 2, the layer 2 demodulator 13 performs the same processing as layer 1 and outputs the error-corrected layer 2 TS to the stream separator 14. The stream separation means 14 performs filtering on each TS of the layer 1 and layer 2 by the PID (Packet ID) number included in the demodulated layer 1 and layer 2 TS headers, Separated into voice TS packets and TS packets such as section information. In this case, a TS packet having a PID of layer 1 video is sent to the layer 1 video decoding unit 20, a TS packet having a PID of layer 2 video is sent to the layer 2 video decoding unit 21, and a TS packet having a PID of layer 1 audio is layered. The TS packet having the PID of the layer 2 speech is sent to the 1 speech decoding unit 24, the TS packet having the PID constituting the section is sent to the section construction unit 16 and the encoding included in the TS header The system control information is distributed and output to the encoding system extraction means 15. In addition, the same data that synchronizes the corresponding video and audio between layer 1 and layer 2 based on the time information separated by the stream separation unit 14 by the same data position extraction unit included in the stream separation unit 14 Extract position. Based on this same data position information, the following data processing is performed in synchronization.

  The section construction means 16 that has received a TS packet having a PID that constitutes a section constructs section information such as PAT, PMT, etc. from the data, and among these information, layer 1 video, layer 2 video, layer 1 audio, and layer Control information and content information related to two audio signals are respectively associated with encoding method extraction means 15, video frame size detection means 17, layer 1 video decoding unit 20, layer 2 video decoding unit 21, audio sampling frequency detection unit 241, layer The data is output to the 1 audio decoding means 24 and the hierarchy 2 audio decoding means 25. The encoding method extraction means 15 extracts the encoding method information from the section information assembled by the section configuration means 16 and from the stream identifier included in the TS header received from the stream separation means 14. The coding method control information is configured by combining the information, and via the section configuration unit 16, the layer 1 video decoding unit 20, the layer 2 video decoding unit 21, the layer 1 audio decoding unit 24, and the layer 2 audio decoding unit 25. To each.

  The layer 1 video decoding means 20 generates a video PES from the TS packet of the layer 1 video given from the stream separation means 14, and from this PES, a decoding time DTS (Decoding Time Stamp) and a display time PTS (Presentation Time Stamp). Get header information. Next, a video ES is generated from the video PES, and video decoding control information including sequence header information is extracted. Further, the generated video ES is decoded in accordance with the encoding method control information acquired by the encoding method extraction unit 15 to obtain the video frame data of the first layer. At this time, the comparison between the control data of the layer 1 video acquired from the section construction unit 16 and the header information included in the TS of the layer 1 video, the sequence generated at the time of decoding, the picture, the slice, and the macroblock Error detection is performed, and those results are obtained as video decoding error information including data error position information. The layer 2 video decoding unit 21 also performs the same processing as the layer 1 video decoding unit 20 to generate layer 2 video frame data and video decoding error information. Similarly, the layer 1 audio decoding unit 24 and the layer 2 audio decoding unit 25 also generate audio frame data and audio decoding error information corresponding to each layer.

  In the case of the layer 1 video decoding unit 20 and the layer 2 video decoding unit 21, the video frame size information is extracted from the video decoding control information including the sequence header information extracted during decoding and is sent to the video frame size detection unit 17. . The video decoding error information is sent to the layer 1 video decoding error frame detection unit 22 and the layer 2 video decoding error frame detection unit 23 together with the decoded video frame data including the decoding error. The layer 1 video decoding error frame detection means 22 buffers the decoded frame 1 video frame data and, based on the layer 1 video decoding error information, identifies a frame having an error portion from the layer 1 video frame data. It is detected and output to the layer 1 video size scaling means 29 together with the video decoding error information and the decoded video frame data. The layer 2 video decoding error frame detection unit 23 performs the same operation as the layer 1 video decoding error frame detection unit 22 on the layer 2 video frame data.

On the other hand, the video frame size detection means 17 obtains information related to the video frame size from the section information assembled by the section construction means 16, and the sequence obtained from the hierarchy 1 video decoding means 20 and the hierarchy 2 video decoding means 21. Together with the video frame size information included in the header information, the video frame size of each layer is detected and sent to the video output size determining means 28. In the video output size determining means 28, based on the output video size given as a condition and the frame size of the video of the hierarchy 1 and hierarchy 2 detected by the video frame size detection means 17, the video frames of the hierarchy 1 and hierarchy 2 are concerned. A scaling value for each size is calculated. In this case, as an output video size given as a condition, a predetermined video output size, a video output size that can be displayed acquired from a connected display, an output video size obtained from an output device, or the like is used. Further, the scaling value for the frame size of the video of the hierarchy 1 and the video of the hierarchy 2 is calculated using a predetermined calculation formula that takes the least common multiple for the output video size and the frame size of the video of each hierarchy, for example. Is done. The scaling values for the frame sizes of the layer 1 and layer 2 images determined by the image output size determining unit 28 are given to the corresponding layer 1 image size scaling unit 29 and the layer 2 image size scaling unit 30.
The layer 1 video size scaling unit 29 outputs the decoded layer 1 video frame data from the layer 1 video decoding error frame detection unit 22 based on the scaling value acquired from the video output size determination unit 28 to the layer 1 video output. Scaled to the size and temporarily stored together with the video decoding error information of layer 1. The layer 2 video size scaling unit 30 also performs the same processing as the layer 1 video size scaling unit 29, scales the decoded video frame data of layer 2 to the video output size of layer 2, and Temporarily stored with video decoding error information.

Next, the writing order determination operation by the video writing order determination unit 32 and the writing operation by the video writing unit 321 will be described with reference to the flow shown in FIG.
First, the video writing order determining unit 32 extracts the modulation scheme for each layer from the transmission scheme control information acquired from the transmission scheme control information extracting unit 11 (step ST1). Next, it is determined which modulation scheme of the layer has high error tolerance (step ST2). When layer 1 is a modulation scheme with higher error tolerance than layer 2, the video resolution of the decoded video frame size of each layer obtained from layer 1 video size scaling unit 29 and layer 2 video size scaling unit 30 is as follows: It is determined which layer is better (step ST3). On the other hand, in step ST 2, even when the layer 2 is a modulation scheme having higher error tolerance than the layer 1, each layer acquired from the layer 1 video size scaling unit 29 and the layer 2 video size scaling unit 30 is similarly obtained. It is determined which layer is better for the video resolution of the decoded video frame size (step ST4).

  In the above step ST3, when the video resolution is higher in the hierarchy 1 than in the hierarchy 2, the video writing order determining means 32 determines that the frame buffer writing order is only the hierarchy 1 (step ST5). The video writing means 321 acquires the video frame data of the hierarchy 1 including the error portion of the scaled frame size from the hierarchy 1 video size scaling means 29 according to this determination order, and writes only the data as it is (step ST6). On the other hand, in step ST3, when the video resolution of layer 2 is better than that of layer 1, the video writing order determination unit 32 determines the frame buffer writing order as the order of layer 1 and layer 2 (step ST7). In the video writing unit 321, first, after acquiring the frame 1 video frame data including the error portion of the scaled frame size from the layer 1 video size scaling unit 29 in accordance with this determination order, it is written as it is (step ST 8). Subsequently, the scaled frame size layer 2 video frame data obtained from the layer 2 video size scaling means 30 is written in the same position where it was first written with the error location masked (step ST9). Therefore, in the case of these steps ST8 and ST9, as the finally written video frame data, the masked portion of the layer 2 video frame data is replaced with the previously written layer 1 video frame data portion. Thus, the frame is composed of data of different layers.

Further, in step ST4, when the video resolution of layer 1 is better than that of layer 2, the video writing order determining unit 32 determines the frame buffer writing order as the order of layer 2 and layer 1 (step ST10). In accordance with this determination order, the video writing unit 321 acquires the video frame data of the layer 2 including the error portion of the scaled frame size from the layer 2 video size scaling unit 30 and directly writes it into the video frame buffer (step ST11). Then, the scaled frame size video frame data obtained from the level 1 video size scaling means 29 is written in the same position where the error was first masked (step ST12). Therefore, in the case of these steps ST11 and ST12, the finally written video frame data is the one that has been replaced with the portion of the video frame data of the layer 2 that was previously written in place of the mask of the video frame data of the layer 1 Thus, the frame is composed of data of different layers.
On the other hand, in step ST4, when the video resolution of layer 2 is better than that of layer 1, the video writing order determination unit 32 determines that the frame buffer writing order is only layer 2 (step ST13). In accordance with this determination order, the video writing unit 321 acquires the video frame data of the layer 2 including the error portion of the scaled frame size from the layer 2 video size scaling unit 30, and writes only the data as it is (step ST14).

When the writing order determined by the video writing order determination means 32 is arranged, if it is determined that the layer of the modulation scheme having high error resistance and the layer having a high video resolution are the same, only the video frame data of the same layer is used. When it is determined that the error-resistant modulation method layer and the video resolution layer are different from each other, the video frame data of the error-resistant modulation method layer is written first, followed by the video. The video frame data of the higher resolution layer is to be written.
Further, when the writing operation of the video writing means 321 is arranged, when it is determined that the layer of the modulation scheme having high error resistance and the layer of high video resolution are the same, only the video frame data of the same layer is written as it is. When it is determined that the hierarchy of the modulation scheme having high error tolerance and the hierarchy of high video resolution are different, the video frame data of the hierarchy of the modulation scheme having high error tolerance to be written first is written in the video frame buffer 33 as it is. Then, the video frame data of the higher layer of the video resolution to be written next is written in the same position of the video frame buffer 33 written first by masking the position where the decoding error occurs.

  On the other hand, in the operation of audio, the layer 1 audio decoding unit 24 generates an audio PES from the TS packet of layer 1 audio given from the stream separation unit 14, and the decoding time DTS, display time PTS, etc. from this PES Get the header information. Next, an audio ES is generated from the audio PES, and an audio sampling frequency is extracted from the audio ES header information. Further, the generated speech ES is decoded in accordance with the encoding method control information acquired by the encoding method extraction unit 15 to obtain the audio frame data of the first layer. At this time, the control data of the layer 1 sound acquired from the section construction unit 16 and the header information included in the TS of the layer 1 sound are compared, and a decoding error that occurs at the time of decoding is detected. As a result, the data Obtained as audio decoding error information including error position information. The layer 2 audio decoding unit 25 performs the same processing as the layer 1 audio decoding unit 24, and obtains audio decoding error information including layer 2 audio frame data and data error position information.

  In the case of the hierarchy 1 audio decoding means 24 and the hierarchy 2 audio decoding means 25, the audio sampling frequency included in the hierarchy 1 and the hierarchy 2 is extracted from the audio decoding control information consisting of the audio ES header information being decoded. This is sent to the detecting means 241. Also, the audio decoding error information is sent to the layer 1 audio decoding error frame detecting unit 26 and the layer 2 audio decoding error frame detecting unit 27 together with the decoded audio frame data including the decoding error. The layer 1 audio decoding error frame detecting means 26 buffers the decoded frame 1 audio frame data, and based on the layer 1 audio decoding error information, extracts a frame having an error portion from the layer 1 audio frame data. Detected and output to the layer 1 audio sampling frequency converting means 261 together with audio decoding error information and decoded audio frame data. The layer 2 audio decoding error frame detection unit 27 performs the same operation as the layer 1 audio decoding error frame detection unit 26 on the layer 2 audio frame data.

On the other hand, the audio sampling frequency detection unit 241 acquires information related to the audio sampling frequency from the section information assembled by the section configuration unit 16, and the audio obtained from the layer 1 audio decoding unit 24 and the layer 2 audio decoding unit 25. The audio sampling frequency of each layer is detected from the audio decoding control information made up of ES header information and sent to the audio sampling frequency determining means 242. The audio sampling frequency determining unit 242 converts the converted value for the sampling frequency of the audio included in each layer based on the output audio sampling frequency given as a condition and the audio sampling frequency of each layer detected by the audio sampling frequency detecting unit 241. (Enlargement ratio or reduction ratio) is determined respectively. In this case, as an output audio sampling frequency given as a condition, a predetermined audio output sampling frequency or an audio output sampling frequency designated by other means is used. In addition, the conversion value for the sampling frequencies of the audio of layer 1 and layer 2 is calculated in advance so as to take, for example, the least common multiple of the audio output sampling frequency and the sampling frequency of audio of layer 1 and layer 2 Calculated using the formula. The conversion values of the sampling frequencies of the hierarchy 1 and hierarchy 2 determined by the audio sampling frequency determination means 242 are given to the corresponding hierarchy 1 audio sampling frequency conversion means 261 and hierarchy 2 audio sampling frequency conversion means 271.
The layer 1 audio sampling frequency conversion unit 261 converts the decoded layer 1 audio frame data from the layer 1 audio decoding error frame detection unit 26 based on the converted value acquired from the audio output sampling frequency determination unit 242 to the layer 1 The audio output size is converted and temporarily stored together with the audio decoding error information of layer 1. The layer 2 audio sampling frequency conversion unit 271 also performs the same processing as the layer 1 audio sampling frequency conversion unit 261 to convert the decoded layer 2 audio frame data to the layer 2 audio output sampling frequency, Temporarily held together with layer 2 audio decoding error information.

Next, as in the case of video, the writing order determination operation by the voice writing order determination unit 35 and the writing operation by the voice writing unit 351 will be described with reference to the flow shown in FIG.
The voice writing order determining means 35 first extracts the modulation scheme for each layer from the transmission scheme control information acquired from the transmission scheme control information extracting section 11 (step ST1). Next, it is determined which modulation scheme of the layer has high error tolerance (step ST2). When the layer 1 is a modulation scheme having higher error tolerance than the layer 2, the decoded audio frame sampling frequency of each layer obtained from the layer 1 audio decoding error frame detecting unit 26 and the layer 2 audio decoding error frame detecting unit 27 For which audio resolution, which layer is better is determined (step ST3). On the other hand, in step ST2, if layer 2 has stronger error tolerance, similarly, the decoded audio frame of each layer obtained from layer 1 audio decoding error frame detection unit 26 and layer 2 audio decoding error frame detection unit 27 It is determined which layer is better for the audio resolution of the sampling frequency (step ST4).

  In step ST3, when the audio resolution of layer 1 is better than that of layer 2, the audio writing order determination unit 35 determines that the frame buffer writing order is only layer 1 (step ST5). In accordance with this determination order, the audio writing unit 351 acquires the audio frame data of the layer 1 including the sampling frequency error portion converted from the layer 1 audio sampling frequency conversion unit 261, and only the data is directly used as the audio frame buffer 36. (Step ST6). On the other hand, in step ST3, when the audio resolution of layer 2 is better than that of layer 1, the audio writing order determination unit 35 determines the frame buffer writing order as the order of layer 1 and layer 2 (step ST7). In accordance with this determination order, the voice writing unit 351 first acquires the layer 1 speech frame data including the sampling frequency error portion converted from the layer 1 speech sampling frequency conversion unit 261 and writes it as it is (step ST8). Then, the audio frame data of the sampling frequency converted in the layer 2 acquired from the layer 2 audio sampling frequency conversion means 271 is written in the same position where the error was first written, masking the error part (step ST9). Therefore, in the case of these steps ST8 and ST9, as the audio frame data finally written, the masked portion of the layer 2 audio frame data is replaced with the previously written layer 1 audio frame data part. Thus, the frame is composed of data of different layers.

In step ST4, when the audio resolution of layer 1 is better than that of layer 2, the audio writing order determining means 35 determines the frame buffer writing order as the order of layer 2 and layer 1 (step ST10). In accordance with this determination order, the voice writing unit 351 first acquires and writes the layer 2 speech frame data including the sampling frequency error portion converted from the layer 2 speech sampling frequency conversion unit 271 as it is (step ST11). Subsequently, the audio frame data of the sampling frequency converted from the layer 1 acquired from the layer 1 audio sampling frequency conversion means 261 is written in the same position where the error was first written by masking the error part (step ST12). Therefore, in the case of these steps ST11 and ST12, the audio frame data data finally written is replaced with the portion of the audio frame data of the layer 2 previously written in the masked portion of the audio frame data of the layer 1 It becomes a frame composed of data of different layers.
On the other hand, in step ST4, when the audio resolution of layer 2 is better than that of layer 1, the audio writing order determination unit 35 determines that the frame buffer writing order is only layer 2 (step ST13). In accordance with this determination order, the voice writing unit 351 acquires layer 2 audio frame data including the sampling frequency error portion converted from the layer 2 audio sampling frequency conversion unit 271 and writes only the data as it is (step ST14). ).

When the writing order determined by the voice writing order determination means 35 is arranged, if it is determined that the hierarchy of the modulation scheme having high error resistance and the hierarchy having a high voice resolution are the same, only the voice frame data of the same hierarchy is used. If it is determined that the layer of the modulation scheme with higher error tolerance and the layer with higher audio resolution are different, the audio frame data of the layer with the modulation scheme with higher error tolerance is written first, and then the audio The audio frame data of the higher resolution layer is to be written.
Further, when the writing operation of the voice writing means 351 is arranged, when it is determined that the layer of the modulation scheme having high error resistance and the layer of high voice resolution are the same, only the voice frame data of the same layer is written as it is. If it is determined that the layer of the modulation scheme having high error resistance and the layer having high audio resolution are different, the audio frame data of the layer of the modulation scheme having high error resistance to be written first is written in the audio frame buffer 36 as it is. Then, the audio frame data of the higher layer of the audio resolution to be written next is written at the same position of the audio frame buffer 36 that was written first, masking the location where the decoding error occurs.

As described above, according to the first embodiment, the transmission scheme control information in which the modulation scheme of each layer is set is extracted from the received signal, and the frame having the error portion is based on the video decoding error information obtained at the time of decoding. Based on the detected and extracted transmission method control information, the layer of the modulation method having strong error resistance is determined from the two layers, and the layer having the high video resolution of the decoded video frame size is determined. In this case, if it is determined that the error-resistant modulation method layer and the video resolution layer are the same, only the video frame data of the same layer is written, and the error-resistant modulation method layer and the video resolution If it is determined that the higher layer is different, first write the video frame data of the higher error-resistant modulation scheme, then The hierarchy and the order of writing are determined so that the video frame data of the higher image resolution layer is written, and when writing to the video frame buffer, it is determined that the layer of the modulation scheme having high error resistance and the layer of the higher video resolution are the same. If it is determined that only the video frame data of the same layer is written as it is, and it is determined that the layer of the modulation scheme having high error tolerance and the layer of high video resolution are different, the error tolerance to be written first is The video frame data of the higher modulation layer is written as it is, and the video frame data of the higher video resolution layer to be written next is masked at the location where the decoding error occurred and written at the same position where it was written first. ing. The same processing is performed for voice. Therefore, as video and audio frame data output for reproduction from the frame buffer, frame data having a layer with few errors and a good resolution is used, or a frame having a layer with few errors is used for an error portion between two layers. Since the combined frame data complemented with each other is used, video and audio playback errors can be reduced without using radio wave reception status monitoring means and hierarchy switching means. Enable.
In addition, since the decoded video frame data of each layer is scaled to have the same size, the present invention can be applied even when the video frame size differs depending on the layer, and the write operation to the video frame buffer is performed. Can be made easier.
In addition, since the sampling frequency of the decoded audio frame data of each layer is converted to the same frequency, the present invention can be applied even when the audio sampling frequency differs depending on the layer, The write operation can be facilitated.
In addition, since the video and audio data for each layer are obtained by decoding the encoding method control information of each layer, the present invention can be applied even if the encoding methods are different.

It is a block diagram which shows the function structure of the digital broadcast receiver by Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the frame buffer writing order determination means of the image | video and audio | voice which concerns on Embodiment 1 of this invention. It is explanatory drawing showing the structure of the frequency bandwidth, segment, and hierarchy of terrestrial digital broadcasting.

Explanation of symbols

  10 tuner, 11 transmission method control information extracting means, 12 layer 1 demodulating means, 13 layer 2 demodulating means, 14 stream separating means (including identical data position extracting means), 15 encoding method extracting means, 16 section constituting means, 17 Video layer size detecting means, 20 layer 1 video decoding means, 21 layer 2 video decoding means, 22 layer 1 video decoding error frame detecting means, 23 layer 2 video decoding error frame detecting means, 24 layer 1 audio decoding means, 25 layer 2 Audio decoding means, 26 layer 1 audio decoding error frame detecting means, 27 layer 2 audio decoding error frame detecting means, 28 video output size determining means, 29 layer 1 video size scaling means, 30 layer 2 video size scaling means, 32 video writing Order decision Determining means, 33 video frame buffer, 35 audio writing order determining means, 36 audio frame buffer, 241 audio sampling frequency detecting means, 242 audio sampling frequency determining means, 261 layer 1 audio sampling frequency converting means, 271 layer 2 audio sampling frequency conversion Means, 321 video writing means, 351 audio writing means.

Claims (10)

Use simulcast that uses at least two hierarchies that combine segments that make up the transmission frequency band and multiplexes video data and / or audio data of the same program of television broadcast or audio broadcast to each hierarchy and performs hierarchical transmission A digital broadcast receiver that receives, demodulates, and decodes to generate video and / or audio frame data of each layer,
Transmission method control information extracting means for extracting transmission method control information in which the modulation method and transmission rate of each layer are set from the received signal;
Stream separating means for separating control information including video data and / or audio data and time information from the demodulated data stream;
Encoding method extraction means for extracting video data and / or audio data encoding method control information from the control information separated by the stream separation means;
Data error detection means for extracting data error positions of video data or audio data of each layer separated by the stream separation means;
Based on the time information separated by the stream separation means, the same data position extracting means for extracting the same data position for synchronizing the corresponding video and / or audio between layers,
Based on the same data position extracted by the same data position extraction means, the video and / or audio frame data at the data error position detected by the data error detection means is complemented with the frames of the respective layers, and the video And / or a complementary complement synthesizing unit for generating continuous data of voice. Data error detection means
Video decoding means for generating video frame data by decoding the video data separated by the stream separation means based on the coding method control information extracted by the coding method extraction means, and a data error in the video data of each layer Video data error detection means for extracting the position,
The mutually complementary synthesizing means mutually complements the video frame data at the data error position of the video of each hierarchy detected by the video data error detecting means with the frames of the mutual hierarchies based on the same data position. 2. The digital broadcast receiving apparatus according to claim 1, wherein the video complementary complement synthesizing means is generated as continuous data. The video data error detection means has video decode error frame detection means for each layer for detecting a frame having an error location based on video decode error information obtained by the video decode means during decoding of the video data of each layer,
Video frame size detecting means for detecting the decoded video frame size from the video decoding control information extracted during the decoding of the video decoding means;
Video output size determining means for determining a scaling value for the frame size of the video of each layer, based on the output video size given as a condition and the video frame size of each layer acquired by the video frame size detecting unit;
Video size for each layer that scales the frame size of the decoded video frame data output from the video decoding error frame detection unit based on the frame scaling value of the video of each layer determined by the video output size determination unit 3. The digital broadcast receiving apparatus according to claim 2, further comprising a scaling unit. Video mutual complement synthesis means
A video frame buffer for temporarily storing video frame data scaled by the video size scaling means;
Based on the transmission method control information acquired from the transmission method control information extraction means, the level of error tolerance between layers for the modulation method of each layer is determined, and the video frame size of each layer detected by the video frame size detection means is determined. Video writing order determining means for obtaining, determining the size of the video frame size between layers, and determining whether or not to write video data of each layer to the video frame buffer and the order of writing;
4. The digital broadcast receiving apparatus according to claim 3, further comprising video writing means for writing to the video frame buffer in accordance with the writing order determined by the video writing order determining means. The video decoding means, the video decoding error frame detecting means, the video size scaling means or the video writing means is the first to write to the video frame buffer when outputting the video frame data of each layer according to the writing order determined by the video writing order determining means. The video frame data of the hierarchy is output as it is, and the video frame data of the hierarchy to be written after the second is masked and output only where the decoding error has occurred,
5. The digital broadcast receiving apparatus according to claim 4, wherein the video writing means outputs video frame data between layers to the same data position to the video frame buffer. The data error detection means includes: audio decoding means for decoding the audio data separated from the stream separation means based on the encoding method control information extracted by the encoding method extraction means, and generating audio frame data; Voice data error detection means for extracting the data error position of the voice data of
The mutual complement synthesizing unit mutually complements the audio frame data of the audio data error position of each layer detected by the audio data error detection unit with the frames of the respective layers based on the same data position, and 2. A digital broadcast receiving apparatus according to claim 1, wherein said digital broadcast receiving and synthesizing means generates continuous data. The audio data error detection means has audio decode error frame detection means for each layer for detecting a frame having an error location based on audio decode error information obtained during decoding of the audio data of each layer by the audio decode means,
Audio sampling frequency detection means for extracting the audio sampling frequency after decoding from the audio decoding control information extracted during decoding by the audio decoding means;
Audio sampling frequency determining means for determining a conversion value for the sampling frequency of the audio included in each layer, based on the output audio sampling frequency given as a condition and the sampling frequency obtained from each layer by the audio sampling frequency detecting unit; ,
7. The digital broadcast receiving apparatus according to claim 6, further comprising audio sampling frequency conversion means for each layer that samples audio frame data of each layer based on the sampling frequency determined by the audio sampling frequency determining means. . Speech mutual complement synthesis means
An audio frame buffer for temporarily storing audio frame data converted by the audio sampling frequency conversion means for each layer;
Based on the transmission method control information acquired from the transmission method control information extraction means, determine the layer of the modulation method having a strong error resistance out of the two layers, determine the layer having a high sampling frequency of the decoded audio frame, Based on these determination results, voice writing order determining means for determining the hierarchy and writing order of the voice frame data to be written to the voice frame buffer;
According to the determination order of the audio writing order determining means, audio frame data of a layer having a high error tolerance and a high audio sampling frequency is written to the audio frame buffer, or if not, an audio frame of one layer 8. The digital broadcast receiving apparatus according to claim 7, further comprising audio writing means for overwriting the audio frame data of the other layer so as to complement an error portion of the data. The voice writing order determination means is determined by the voice sampling frequency detection means and the determination of the strength of error tolerance between the hierarchies for the modulation scheme of each layer, based on the transmission scheme control information acquired from the transmission scheme control information extraction means, and the voice sampling frequency detection means Obtain the audio sampling frequency of each layer, determine whether the audio sampling frequency is high or low between layers, determine whether or not to write audio data of each layer to the audio frame buffer and the order of writing,
9. The digital broadcast receiving apparatus according to claim 8, wherein the voice writing means writes to the voice frame buffer according to the writing order determined by the voice writing order determination means. The audio decoding means, the audio decoding error frame detecting means, the audio sampling frequency converting means or the audio writing means writes the audio deframe data of each layer in the audio frame buffer when outputting the audio deframe data according to the writing order determined by the audio writing order determining means. The audio frame data of the first layer is output as it is, and the audio frame data of the layer to be written after the second is masked and output only at the location where the decoding error occurs,
10. The digital broadcast receiving apparatus according to claim 9, wherein the audio writing means outputs audio frame data between hierarchies to the audio frame buffer at the same position.

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