The present disclosure relates to data processing devices and methods for processing digital television broadcast signals, and the like.
In processing digital television broadcast signals, processes are basically performed according to the following flow. That is, from signals received by an antenna, a necessary signal is selected by a tuner, and a transport stream (TS) is generated. Then, filtering the TS based on IDs of packets, decrypting (descrambling) the TS with respect to broadcast encryption, section filtering, storing, and an AV process are performed (see, for example, Japanese Patent Publication No. H07-327051, Japanese Patent Publication No. H07-297855, and Japanese Patent Publication No. H09-275381).
However, in the descrambling process of decrypting the TS with respect to the broadcast encryption, a large number of operations has to be performed, and thus a circuit for performing the descrambling process has to be operated at a high speed, which increases power consumption of the circuit. Moreover, when data before the descrambling is temporarily stored in a shared memory, a large portion of the transmission bandwidth of the shared memory is occupied for the descrambling process, which reduces the speed of other processes using the shared memory.
It is an objective of the present disclosure to reduce power consumption of a data processing device.
An example data processing device of the present disclosure includes: an error corrector configured to perform demodulation and error correction on a received signal to output error-corrected data, the received signal transmitting packets which include packet identifiers and are encrypted by broadcast encryption; and a transport stream generator configured to generate a transport stream based on the error-corrected data. The error corrector selects the packets including a set packet identifier, and outputs the selected packets as the error-corrected data.
With this configuration, a packet including a set packet identifier is selected, so that it is possible to reduce the number of packets on which processes are performed. Thus, power consumption of the data processing device can be reduced.
An example data processing method of the present disclosure includes: performing demodulation and error correction on a received signal to output error-corrected data, the received signal transmitting packets which include packet identifiers and are encrypted by broadcast encryption; and generating a transport stream based on the error-corrected data. In the performing, the packets including a set packet identifier are selected, and the selected packets are output as the error-corrected data.
According to the disclosure, power consumption of the data processing device can be reduced. Moreover, it is possible to reduce the number of packets on which processes are performed, so that the speed of processes other than processes performed by the data processing device can be improved when a shared memory is used.
Embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, components indicated by reference numbers having the same last two digits correspond to each other, and are identical or equivalent components.
Functional blocks to be described herein can be typically implemented by hardware. For example, the functional blocks can be formed on a semiconductor substrate as part of an integrated circuit (IC). The IC as used herein includes a large-scale integrated circuit (LSI), an application-specific integrated circuit (ASIC), a gate array, a field programmable gate array (FPGA), and the like. Alternatively, some or all of the functional blocks may be implemented by software. For example, such a functional block can be implemented by a program executable on a processor. In other words, the functional blocks to be described herein may be implemented by hardware, by software, or by any combination of hardware and software.
The front end section 110 includes an A/D converter 112, a synchronization detector 114, a fast Fourier transformer 116, a waveform equalizer 118, an error corrector 122, and a transport stream (TS) generator 124. The back end section 130 includes a transport decoder 132, and an audiovisual (AV) generator 134 serving as a video generator. The front end section 110 may be formed on a single semiconductor substrate, and the back end section 130 may be formed on another single semiconductor substrate.
As an example, reception of a signal of an orthogonal frequency division multiplexing (OFDM) scheme by the receiver of
An antenna 102 receives signals transmitted from broadcast stations, or the like, and feeds the received signals to the tuner 104. The tuner 104 selects a signal having a desired frequency among the fed received signals, and outputs the selected signal to the A/D converter 112. The A/D converter 112 performs A/D conversion on the input signal, and outputs the converted signal to the synchronization detector 114.
The synchronization detector 114 detects establishment of synchronization and the synchronization state of the received signal. For example, when a pilot signal, which is a known signal, is received at predetermined timing, this indicates that establishment of synchronization has been detected. The synchronization detector 114 outputs the synchronized signal to the fast Fourier transformer 116. The fast Fourier transformer 116 performs fast Fourier transform on the input signal, and outputs the transformed signal to the waveform equalizer 118.
In S102 of
In S118, the filter section 158 performs a PID filtering process on the result of the Viterbi decoding. More specifically, the following process is performed. PIDs of packets which should be passed through the filter section 158 are set in the PID setting section 163. The PID setting section 163 outputs the set PIDs to the PID filter 162. The Reed-Solomon decoder 161 performs a Reed-Solomon decoding process on part of the result of the Viterbi decoding, the part including PIDs. The Reed-Solomon decoder 161 outputs the result of the Reed-Solomon decoding process to the PID filter 162. As illustrated in
The buffer 166 stores the packets output from the PID filter 162, and outputs the stored packets to the Reed-Solomon decoder 168. In S120, the Reed-Solomon decoder 168 performs a Reed-Solomon decoding process also on parts of the packets output from the buffer 166, the parts having not been processed in the Reed-Solomon decoder 161. The Reed-Solomon decoder 168 outputs the process result to the TS generator 124.
As described above, the error corrector 122 performs demodulation and error correction on the received signal, and outputs the error-corrected data to the TS generator 124. Here, the error corrector 122 selects the packets including the set packet identifiers, and outputs the selected packets as the error-corrected data.
In S132, the TS generator 124 generates a TS from the process result of the Reed-Solomon decoder 168. That is, the TS generator 124 outputs the packets processed in the Reed-Solomon decoder 168 to the transport decoder 132 at regular intervals at a predetermined rate.
In S140, the transport decoder 132 selects packets from the generated TS, and outputs the selected packets to a memory, in which the packets are stored. Then, in S142, the transport decoder 132 reads the packets from the memory, and decrypts with respect to the broadcast encryption, that is, descrambles the read packets.
In S144, the transport decoder 132 determines whether or not the descrambled packets include AV data. When the descrambled packets include AV data, the process proceeds to S152, whereas when the descrambled packets do not include AV data, the process proceeds to S146. In S146, the transport decoder 132 performs section filtering on the packets which do not include AV data, that is, selects packets required to playback a program. In S148, the transport decoder 132 performs a section process on the packets selected in S146 to utilize section data included in the packets.
In S152, the transport decoder 132 selects the packets including AV data, and outputs the selected packets to the AV generator 134. The AV generator 134 decodes video and audio from the packets which are selected by the transport decoder 132, and which include AV data, and outputs the obtained video and audio signals to the display 142. The display 142 displays video images and outputs audio based on the video signal and the audio signal obtained in S152.
In the descrambling process of decrypting the packets with respect to broadcast encryption, a large number of operations has to be performed. Thus, the transport decoder 132 which performs descrambling has to be operated at a high speed. For this reason, the back end section 130 including the transport decoder 132 is operated, for example, at a clock frequency more than ten times as high as the clock frequency of the front end section 110.
In the data processing device of
A variation of the error corrector 122 of
The Reed-Solomon decoder 368 performs a Reed-Solomon decoding process on a result of Viterbi decoding, and outputs the result to the PID filter 162. Here, the Reed-Solomon decoder 368 performs the Reed-Solomon decoding process on the entirety of packets. The PID filter 162 selects only packets including PIDs output from the PID setting section 163 from the result of the Reed-Solomon decoding process, and outputs the selected packets to the TS generator 124. With the error corrector 322 of
The filter section 458 performs the following PID filtering process on a result of Viterbi decoding. In the PID setting section 163, PIDs of packets which should be passed through the filter section 458 are set. The PID setting section 163 outputs the set PIDs to the Reed-Solomon encoder 464.
The Reed-Solomon encoder 464 performs a Reed-Solomon encoding process on leading three bytes of
With the error corrector 422 of
Variations of the data processing device of
In S217 of
In S218, the filter section 158 performs a PID filtering process on the result of the Viterbi decoding as described below. PIDs of packets which should be passed through the filter section 158 and data for the section filtering to select necessary packets are set in the PID setting section 163. The PID setting section 163 outputs the set PIDs and the set data for the section filtering to the PID filter 162.
Based on the set data for the section filtering and the obtained data for the section filtering, the PID filter 162 determines whether or not the packets are necessary. The PID filter 162 selects packets which are determined to be necessary, and include the packet identifiers set in the PID setting section 163 from the result of the Reed-Solomon decoding process, and outputs the selected packets to the buffer 166. Other processes in
When the data in the adaptation field is thus utilized to select necessary packets before the descrambling process (S142), it is possible to further reduce the number of packets which are subjected to a descrambling process. Thus, power consumption of the data processing device can be reduced. Moreover, when a shared memory is used, it is possible to improve the speed of processes other than those performed by the data processing device.
For the error corrector 422 of
Based on the data for the section filtering set in the PID setting section 163, the Reed-Solomon encoder 464 generates data of adaptation fields of packets which should be determined to be necessary. The Reed-Solomon encoder 464 performs a Reed-Solomon encoding process on part from the leading portion to the adaptation field of
The PID filter 462 selects packets including the encoded result output from the Reed-Solomon encoder 464 from a result of Viterbi decoding, and outputs the selected packets to the buffer 166. A similar variation is valid for the error corrector 522 of
Likewise, the transport decoder 132 may perform section filtering by using the data of the adaptation fields prior to a descrambling process. That is, the data for the section filtering to select necessary packets is set in the transport decoder 132. The transport decoder 132 obtains data for the section filtering included in the adaptation fields of the packets, and stores the obtained data.
Based on the set data for the section filtering and the obtained data for the section filtering, the transport decoder 132 determines whether or not the packets are necessary. When the packets are determined to be necessary, the transport decoder 132 selects the packets from TS, and outputs the selected packets to a memory, in which the packets are stored (S140). Then, the transport decoder 132 reads the packets from the memory to perform the descrambling process.
As described above, the transport decoder 132 can also utilize data of the adaptation fields to select necessary packets prior to the descrambling process, and it is possible to further reduce the number of packets which are subjected to the descrambling process.
The TS generator 624 separates a TS into AV data AVD including data representing video images and data representing audio, section data SED, and particular data PCD such as program clock reference (PCR) which is necessary to generate video images, and outputs the separated data pieces to the transport decoder 632. The transport decoder 632 outputs the AV data AVD without processing to the AV generator 134, and performs necessary processes on the section data SED and the particular data PCD.
With the data processing device of
As described above, the present invention is useful to data processing devices, etc.
Many features and advantages of the present invention are obvious from the above description, and hence it is intended to cover all of such features and advantages of the present invention by the appended claims. As many changes and modifications can be easily made by those skilled in the art, the present invention should not be limited to the constructions and operations identical to those illustrated and described herein. Accordingly, it is to be understood that all appropriate modifications and equivalents fall within the scope of the present invention.
Number | Date | Country | Kind |
---|---|---|---|
2009-194478 | Aug 2009 | JP | national |
This is a continuation of PCT International Application PCT/JP2010/005083 filed on Aug. 17, 2010, which claims priority to Japanese Patent Application No. 2009-194478 filed on Aug. 25, 2009. The disclosures of these applications including the specifications, the drawings, and the claims are hereby incorporated by reference in their entirety.
Number | Date | Country | |
---|---|---|---|
Parent | PCT/JP2010/005083 | Aug 2010 | US |
Child | 13401073 | US |