JP5506250B2 - Stream decoding apparatus and stream decoding method - Google Patents

Description

  The present invention relates to a stream decoding apparatus, a stream decoding method, a program, and a storage medium, and more particularly to a technique suitable for use in time division to decode a plurality of streams in parallel.

  In recent years, as broadcasting and communication infrastructure has matured, end users can easily obtain a huge number of video / audio streams from various routes. In addition, as represented by thin displays and projectors, as the display device becomes larger, a new request for simultaneously viewing a plurality of streams on one display device has arisen.

  Under such circumstances, in recent years, technologies for enabling a plurality of streams to be handled by a single system have been developed for home televisions and recorders. The heart of this system is a stream decoding module (hereinafter referred to as a decoder) that decodes a compressed stream. For example, in a dedicated processor called DSP, a plurality of streams can be processed in parallel by time-sharing with a single processor.

  In addition, the development of information compression technology has diversified video / audio stream formats. In order to cope with such diversification, the decoder uses a single module for MPEG2, H.264. H.264, JPEG, and other formats are now available.

  Here, for example, a frame rate representing a display interval between the respective screens is set in the moving image stream, and it is necessary to perform a certain amount of decoding processing within a certain time in order to maintain display quality. On the other hand, since the decoding processing resources provided by the decoder are limited, in order to maintain the display quality of the stream, it is necessary to request the decoding processing from the decoder within the range of the decoding processing resources provided by the decoder. In particular, when a decoding process is requested to a decoder that can simultaneously decode a plurality of streams, the sum of the requested decoding processes needs to be within the range of the decoding process resource.

  For example, Patent Document 1 or Patent Document 2 discloses a technique for requesting a decoder to perform decoding processing within a range of decoding processing resources provided by the decoder when a plurality of streams are decoded by a single decoder. Yes. In the MPEG decoder described in Patent Document 1, an allocation amount is determined in advance according to stream sequence header information such as a frame rate, thereby suppressing the occurrence of a decoding error. In the moving picture decoding apparatus described in Patent Document 2, the total amount of necessary decoding processing resources is estimated from the sequence header information, and compared with the decoding processing resources provided by the decoder. As a result of the comparison, if a shortage of decoding processing resources is predicted, a stream with low priority is down-converted.

JP 2001-309371 A JP 2002-112195 A

  However, in the conventional method, guarantee of display quality and effective use of decoding processing resources are not realized at the same time. Hereinafter, a plurality of examples in which effective use of the decoding processing resource is not sufficiently realized when priority is given to the guarantee of display quality will be given.

  The MPEG2 broadcast stream has an HD (High Definition) mode and an SD (Standard Definition) mode, and these modes change depending on the broadcast time zone even in the same stream. Therefore, in order to guarantee the display quality, it is necessary to always secure a decoding processing resource capable of performing decoding processing with a certain margin in the HD mode. As a result, when the content of the actual broadcast stream is in the SD mode, the processing capacity of the reserved decoder can be afforded and the decoding processing resources cannot be fully utilized.

  As a more specific example, an MPEG2 video stream is composed of an I picture, a P picture, and a B picture, and the normal P picture and B picture decoding process is heavier than the I picture decoding process. Therefore, if the decoding processing resources of the decoder are secured in accordance with the decoding process of the P picture and the B picture, the processing capacity of the decoder can be afforded when processing the I picture, and the decoding processing resources cannot be fully utilized.

  Further, even in a stream in which the frame rate and the processing mode do not change, the necessary decoding processing resources of the decoder greatly change according to the change in the content of the contained content. In order to guarantee the display quality, it is necessary to secure the decoding processing resources of the decoder in accordance with the maximum load. Therefore, when a scene with a low load is decoded, the reserved processing capacity of the decoder can be afforded, and the decoding processing resources cannot be fully utilized.

FIG. 11 is a diagram illustrating an outline of a method for assigning decoding processing resources to a plurality of streams when priority is given to display quality guarantee.
In FIG. 11, reference numerals 1101 to 1104 denote streams for which a decoding start request is requested from the decoder. In the example illustrated in FIG. 11, it is assumed that a request to start decoding is made in the order of broadcast reception A stream 1101, broadcast reception B stream 1102, broadcast reception C stream 1103, and still image decode stream 1104.

  Reference numerals 1105 to 1107 represent reference times when the decoder allocates decoding processing resources to each stream, and are set to 1/30 s, for example, in consideration of the frame rate of the broadcast reception A stream 1101.

  Here, in order to guarantee the display quality, it is required that the decoding processing resources are not insufficient at all reference times. In the example illustrated in FIG. 11, in consideration of the maximum load of each stream, the broadcast reception A stream 1101 and the broadcast reception B stream 1102 are the only streams that can accept the decoding start request. On the other hand, at the reference time t2 and the reference time t3, the decoding process of the broadcast reception A stream 1101 and the broadcast reception B stream 1102 is less than the decoding process at the reference time t1. As a result, free times 1108 and 1109 of decoding processing resources are generated.

  As described above, if it is determined whether or not the decoding start request can be accepted based on the maximum load of each stream in order to guarantee the display quality, the necessary decoding processing resources cannot be utilized to the maximum extent. Also, even when a free time occurs in the decoding processing resource, the decoding processing cannot be assigned to another stream.

  In contrast to the above-described pattern, priority may be given to effective use of decoding processing resources, and display quality may not be sufficiently guaranteed. Such a pattern corresponds to, for example, a method of assigning a priority to each stream and allocating a decoding processing resource based on the priority after once receiving all the streams.

FIG. 12 is a diagram for explaining an outline of a method for assigning decoding processing resources to a plurality of streams when effective use of decoding processing resources is realized using priority.
In FIG. 12, reference numerals 1201 to 1204 denote streams for which a decoding start request is requested from the decoder. In the example illustrated in FIG. 12, the decoding processing priority order is broadcast reception A stream 1201, broadcast reception B stream 1202, broadcast reception C stream 1203, and still image decoding stream 1204.

  Reference numerals 1205 to 1207 represent reference times when the decoder allocates decoding processing resources to each stream, and are set to 1/30 s, for example, in consideration of the frame rate of the broadcast reception A stream 1201.

  Here, at the reference time t2 and the reference time t3, since the decoding process of the broadcast reception A stream 1201 and the broadcast reception B stream 1202 is light, there is a decoding process resource in the broadcast reception C stream 1203 having the next highest decoding process priority. Assigned and decrypted. However, sufficient decoding processing resources for completely decoding the broadcast reception C stream 1203 are not secured, resulting in insufficient times 1208 and 1209. Here, when the broadcast reception C stream 1203 is a stream whose decoding quality is to be guaranteed, the decoding process in which the shortage time occurs does not satisfy the request.

  In this way, when decoding processing resources are allocated using priority in order to effectively use the decoding processing resources, there is a possibility that only a part of the stream for which the decoding quality should be guaranteed is decoded and the display quality is guaranteed. Can not.

  In view of the above-described problems, the present invention guarantees the display quality of a stream that requires quality guarantee and efficiently uses decoding processing resources when performing decoding processing of a plurality of streams in a time-sharing manner in parallel. The purpose is to be able to.

The stream decoding apparatus according to the present invention is a stream decoding apparatus that decodes a plurality of input streams in parallel, a receiving unit that receives a decoding start request for each of the plurality of streams in units of streams, and a decoding that is performed by the receiving unit. A switching unit that switches a stream to be decoded from among the streams for which a start request has been received; and a decoding unit that decodes the stream switched by the switching unit, wherein the receiving unit requires a guarantee of decoding quality. For the first stream, the decoding start request is accepted when the decoding quality is guaranteed and decoding by the decoding means is possible based on the processing margin of the decoding means, and the guarantee of the decoding quality is not required For the second stream, the decoding start request regardless of the processing margin by the decoding means Accepted, said switching means, said first stream as a stream of the decoding target, and wherein the priority switching than the second stream.

  According to the present invention, when decoding processing of a plurality of streams is performed in a time-sharing manner in parallel, the display quality of the guarantee type stream can be ensured and decoding processing resources can be used effectively.

It is a block diagram which shows the structural example of the stream decoding apparatus of 1st Embodiment. It is a figure which shows an example of the detailed information of the stream input into a reception part. It is a flowchart which shows an example of the decoding process procedure in 1st Embodiment. It is a flowchart which shows an example of the process sequence which receives a decoding start request. It is a flowchart which shows an example of the process sequence which receives a decoding completion request. It is a flowchart which shows an example of the process sequence which selects a stream. It is a figure which shows the example list of estimation of the maximum required amount of a decoding process resource. It is a figure which shows an example of the acceptance determination result. It is a block diagram which shows the structural example of the stream decoding apparatus of 2nd Embodiment. It is a flowchart which shows an example of the decoding process procedure of 2nd Embodiment. It is a figure explaining the outline of the allocation method of a decoding process resource. It is a figure explaining the outline of the allocation method of a decoding process resource. It is a figure which shows an example of the process result when the decoding process shown in FIG. 6 is applied. It is a figure which shows an example of the display screen of an image | video at the time of performing a decoding process. It is a figure which shows an example of the definition file of a service classification and a decoding quality classification.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The technical scope of the present invention is not limited to this embodiment.
FIG. 1 is a block diagram illustrating a configuration example of a stream decoding device 100 according to the present embodiment.
In FIG. 1, a reception unit 101 receives a plurality of streams, decoding quality information of each stream, and a decoding request for each stream, and selectively receives a request to start decoding. Here, the decoding quality information refers to a first stream that requires a guarantee of decoding quality (hereinafter referred to as a guarantee stream) and a second stream that does not require a guarantee of decoding quality (hereinafter referred to as a best effort stream). It is information indicating the type. The decoding quality information is given from a module that issues a decoding request to the stream decoding apparatus 100, for example.

  Among the streams that require decoding processing, there are guarantee type streams that should guarantee decoding quality and best effort type streams that do not require guarantee of decoding quality. As an example of the best effort type stream, in the decoding process of a still image, since there is no frame rate, there is no time restriction on the decoding process. Further, since the pre-decoding process for specifying the stream format does not involve display, there is no time restriction on the decoding process. Furthermore, for example, content acquired via the Internet includes a stream that is allowed to be displayed at best effort regardless of a predetermined frame rate. These best-effort streams can be partially decoded even under circumstances where sufficient decoding processing resources cannot be secured.

  The switching unit 102 sequentially allocates the decoding processing resources to the plurality of streams for which the reception unit 101 has received the decoding start request, and switches the streams to be decoded according to the allocation. The decoding unit 103 performs a decoding process on the stream to be decoded by the switching unit 102. The control unit 104 controls the entire stream decoding device 100.

  The decryption request accepted by the accepting unit 101 is given as a decryption start request or a decryption end request triggered by an operation by a user, such as a TV switch ON / OFF or a channel change. Various input devices such as a remote controller, a keyboard, a mouse, a digitizer, a touch panel, and a joystick are assumed as input means for inputting operations by these users. In this embodiment, any input means may be used.

  Further, as output means for outputting an output stream that is a decoding result of the decoding unit 103, for example, various output devices such as a monitor as a video output means and a speaker and headphones as an audio output means are assumed. In the present embodiment, any output means may be used as with the input means.

FIG. 2 is a diagram illustrating an example of detailed information of a stream input to the reception unit 101 in the present embodiment.
In FIG. 2, reference numerals 201 to 204 denote input streams input to the receiving unit 101, and are arranged in the order in which the decoding start requests are received in FIG.

  Reference numeral 205 denotes a stream ID. For example, a unique stream ID is assigned to each stream by the receiving unit 101. In the example shown in FIG. 2, stream IDs “0001” to “0004” are assigned in the order in which the decryption start requests are received. Reference numeral 206 denotes a decoding quality type, and a guarantee type or a best effort type is assigned to each stream.

  Reference numeral 207 denotes a service type, which is given the type of service to which each stream belongs. Reference numeral 208 denotes a stream type. For example, a compression format of each stream is given. Reference numeral 209 denotes the frame rate of the target stream, and reference numerals 210 and 211 denote the horizontal size and vertical size of the target stream, respectively.

  Here, the information of the service type 207 is acquired from a module that requests the stream decoding apparatus 100 to perform a decoding process. Further, the information of the stream type 208 is acquired from the processing result of Demux that divides the signal multiplexed in the previous stage of the stream decoding apparatus 100 into a plurality of streams. Further, the information of the frame rate 209, the horizontal size 210, and the vertical size 211 are respectively acquired from the sequence header information of the attribute information of the input stream input to the receiving unit 101.

  FIG. 3 is a flowchart showing an example of the decoding processing procedure in the present embodiment. Hereinafter, the processing of the present embodiment will be described with reference to a specific example of FIG. 2 along a flowchart.

  In FIG. 3, the processing is started when the power of the stream decoding apparatus 100 is turned on. In step S301, the control unit 104 initializes the system. This initialization process includes various controls when the stream decoding apparatus 100 is turned on. For example, the initialization process includes setting of register values necessary for the decoding process of the decoding unit 103 and checking the state of memory resources and hardware resources of the entire stream decoding apparatus 100.

  Next, in step S <b> 302, the reception unit 101 acquires information on the maximum available decoding processing resource amount X held by the decoding unit 103. In the present embodiment, the following description will be made assuming that the maximum available decoding processing resource amount X per unit time is 400 Mcycle / sec.

  Next, in step S303, the reception unit 101 sets 0 as the initial value of the decoding processing resource amount xc that has already been allocated. In step S304, the receiving unit 101 determines whether a new processing request has been received. If the result of this determination is that a new processing request has been accepted, processing proceeds to step S305. On the other hand, if the result of determination in step S304 is that a new processing request has not been received, processing proceeds to step S309. In the present embodiment, as shown in FIG. 2, the following description will be made assuming that the decoding start request for the stream 201 is first received and then the decoding start requests for the stream 202 to the stream 204 are sequentially received.

  Next, in step S305, the type of the new processing request determined to be accepted in step S304 is determined. As a result of the determination, if the new processing request is a decryption start request, the process proceeds to step S306, and if the new processing request is a decryption end request, the process proceeds to step S307. If the new processing request is another request, the process proceeds to step S308. In the specific example shown in FIG. 2, since the decoding start request is accepted for the stream 201 to the stream 204, the process proceeds to step S306 sequentially.

  Next, in step S306, the accepting unit 101 selectively accepts the decryption start request based on the decryption start request determined in step S305. Detailed contents of this processing will be described in detail in the description of the flowchart of FIG.

  On the other hand, in step S307, the accepting unit 101 accepts the decryption end request based on the decryption end request determined in step S305. The detailed contents of this processing will be described in detail in the description of the flowchart of FIG. Further, in step S308, various processes are performed based on the other requests determined in step S305. Examples of the processing performed in step S308 include setting of decoding parameters.

  Next, in step S <b> 309, the switching unit 102 selects a stream on which decoding processing is to be performed from the streams that have been received by the receiving unit 101 so far. The detailed contents of this processing will be described in detail in the description of the flowchart of FIG. In step S310, the decoding unit 103 performs a decoding process on the stream selected in step S309.

  Next, in step S311, it is determined whether or not to end the decoding process. If the result of this determination is that the decoding process is not terminated, processing returns to step S304. On the other hand, if the result of determination in step S311 is that the decoding process is to end, processing proceeds to step S312. In step S312, the control unit 104 performs a system end process and ends the process. This termination processing includes various controls prior to turning off the power of the stream decoding apparatus 100. For example, termination processing of memory resources and hardware resources is sequentially performed.

FIG. 4 is a flowchart illustrating an example of a processing procedure for selectively receiving a decryption start request by the receiving unit 101 in step S306 of FIG.
In FIG. 4, first, in step S401, it is determined whether or not the stream targeted by the decoding start request is a guarantee type stream. If the result of this determination is a guarantee type stream, the process proceeds to step S402. On the other hand, if the result of determination in step S401 is a best effort stream, the process proceeds to step S405. In the specific example illustrated in FIG. 2, when any decoding start request of the stream 203 is received from the stream 201, the process proceeds to step S <b> 402 because the target stream is a guarantee type stream. On the other hand, if a request to start decoding the stream 204 is received, the process proceeds to step S405.

  Next, in step S402, information on the maximum amount of decoding processing resource xa required by the target guarantee type stream is acquired based on the attribute information of the stream. At this time, the maximum decoding processing resource amount xa uses, for example, an estimation list of the maximum required amount of decoding processing resources as shown in FIG. Here, the maximum required amount 701 of the decoding processing resource shown in FIG. 7 is calculated in advance in consideration of the decoding processing capability of the decoding unit 103, and is held in the receiving unit 101 at the time of system initialization.

  Also, depending on the service type, the frame rate and size may change over time despite the same stream. The estimation list of the maximum required amount of the decoding processing resource shown in FIG. 7 also corresponds to a stream with a variable frame rate and size, and holds a value considering this variable as the maximum required amount of the decoding processing resource. In the case of the stream 201 to the stream 203 illustrated in FIG. 2, the maximum decoding processing resource amount is calculated as 200 Mcycle / sec with reference to the row 702 and the row 703.

  Next, in step S403, the maximum decoding processing resource amount xa calculated in step S402 and the currently assigned decoding processing resource amount xc are added, and the addition result is compared with the maximum available decoding processing resource amount X. To do. As a result of the comparison, if the maximum available decoding processing resource amount X is larger, the process proceeds to step S404. On the other hand, if the result of determination in step S403 is greater, the process proceeds to step S406.

  In the case of the specific example shown in FIG. 2, since it is determined that the maximum available decoding processing resource amount X is larger until the processing of the stream 201 and the stream 202, the process proceeds to step S404. However, when the stream 203 is processed, the addition result is 600 Mcycle / sec with respect to the maximum available decoding processing resource amount X = 400 Mcycle / sec. Since the addition result is larger, the process proceeds to step S406.

  Next, in step S404, the sum of the currently allocated decoding processing resource amount xc and the maximum decoding processing resource amount xa calculated in step S402 is set as the currently allocated decoding processing resource amount xc.

  In step S405, a request to start decoding the target stream is received, pre-processing necessary for the decoding process is performed, and the process ends. For this preprocessing, for example, processing for temporarily accumulating the target stream in the stream decoding device 100, processing for securing memory for accumulating the output stream, and necessary for the decoding unit 103 to perform decoding processing Such as register settings. On the other hand, in step S406, the decoding start request for the target guarantee type stream is rejected.

  Through the above processing steps, the receiving unit 101 of the stream decoding device 100 according to the present embodiment changes the decoding start request receiving process between the guarantee type stream and the best effort type stream. As a result, a decoding start request can be accepted for a guarantee type stream only when a decoding processing resource can be sufficiently allocated, and a decoding start request can be accepted for a best effort type stream regardless of the allocation state of the decoding processing resource. In the case of the specific example shown in FIG. 2, the acceptance / non-permission determination result 801 as shown in FIG. 8 is obtained by repeating the processing steps shown in FIG. 4 by the processing shown in FIG.

FIG. 5 is a flowchart showing an example of a processing procedure for accepting a decryption end request by the accepting unit 101 in step S307 of FIG.
In FIG. 5, first, in step S501, it is determined whether or not the stream targeted by the decoding end request is a guarantee type stream. As a result of the determination, if the stream is a guarantee type stream, the process proceeds to step S502. On the other hand, if the result of determination in step S501 is a best effort stream, the process proceeds to step S503.

  Next, in step S502, information on the maximum decoding processing resource amount xa of the target guarantee type stream is acquired based on the stream attribute information, and the decoding processing resource amount xa is obtained from the currently allocated decoding processing resource amount xc. Is subtracted. Then, the subtraction result is set as the currently assigned decoding processing resource amount xc.

  Next, in step S503, post-processing in the decoding process is performed, and the process ends. This post-processing includes, for example, releasing the memory reserved for the target stream and setting a register necessary for the decoding unit 103 to stop the decoding process.

FIG. 6 is a flowchart illustrating an example of a processing procedure for selecting a stream to be decoded by the switching unit 102 in step S309 in FIG.
In FIG. 6, first, in step S601, a new one is selected from the guarantee type streams that have already received the decoding start request in step S306 in FIG. 3, and this is set as a decoding target stream. In the case of the specific example shown in FIG. 2, the subsequent processing will be described assuming that the stream 201 has been selected.

  Next, in step S602, it is determined whether or not the current decoding target stream can be decoded. If the result of this determination is that decoding is possible, processing proceeds to step S608. On the other hand, if the result of determination in step S602 is that decoding is not currently possible, processing proceeds to step S603. Here, for determining whether or not decoding is currently possible, for example, information such as whether or not a stream equal to or greater than a threshold is stored in a memory for storing streams in the switching unit 102 is used. In the case of the specific example shown in FIG. 2, the following description will be made assuming that the stream 201 is determined to be decodable.

  Next, in step S603, it is determined whether or not it has been determined whether or not decoding can be performed for all guarantee type streams for which a decoding start request has been received. As a result of this determination, if there is a guarantee type stream for which it is not determined whether or not decoding is possible, the process returns to step S601. On the other hand, as a result of the determination in step S603, if it is determined whether or not all guarantee type streams can be decoded, the process proceeds to step S604.

  Next, in step S604, a new one is selected from the best-effort streams that have already received a decoding start request, and this is set as a decoding target stream. In step S605, it is determined whether or not the current decoding target stream can be decoded.

  If the result of this determination is that decoding is possible, processing proceeds to step S608. On the other hand, if the result of determination in step S605 is that decoding is currently impossible, processing proceeds to step S606. As in step S603, for example, information such as whether or not a stream equal to or greater than the threshold is accumulated in the memory that accumulates the stream in the switching unit 102 is used to determine whether or not decoding is currently possible.

  Next, in step S606, it is determined whether or not it has been determined whether or not decoding is possible for all the best effort streams that have received the decoding start request. As a result of the determination, if there is a best effort type stream for which it is not determined whether or not decoding is possible, the process returns to step S604. On the other hand, as a result of the determination in step S606, if it is determined whether all the best effort streams can be decoded, the process proceeds to step S607. In step S607, since there is no stream that can be decoded, there is no stream for which the decoding process is performed.

  On the other hand, in step S608, the decoding target stream is selected as a stream to be subjected to decoding processing. In the specific example illustrated in FIG. 2, the stream 201 is selected as a stream for performing the decoding process.

  Through the above processing steps, the switching unit 102 of the stream decoding device 100 preferentially selects a guarantee type stream as a decoding target stream. The best effort stream is selected as a decoding target stream only when the guarantee stream cannot be decoded.

FIG. 13 is a diagram illustrating an example of a processing result when the decoding process illustrated in FIG. 6 is applied to the specific example illustrated in FIG.
In FIG. 13, reference numerals 1301 to 1304 denote streams for which a decoding request has been made to the stream decoding apparatus 100. In the example illustrated in FIG. 13, the broadcast reception A stream 1301, the broadcast reception B stream 1302, the broadcast reception C stream 1303, and the still image decoding stream 1304 correspond to the stream 201 to the stream 204 illustrated in FIG.

  Reference numerals 1305 to 1307 denote reference times when the decoding unit 103 allocates decoding processing resources to each stream, and are set to 1/30 s, for example, in consideration of the frame rate of the broadcast reception A stream 1301.

  Here, at the reference time t2 and the reference time t3, the decoding processing of the broadcast reception A stream 1301 and the broadcast reception B stream 1302 is lighter than that at the reference time t1. Therefore, a decoding processing resource is allocated to the still image decoding stream 1304 which has received a decoding start request as a best effort type stream, and decoding processing is performed. As a result, for example, as shown in FIG. 14, the decoding result 1402 of the broadcast reception A stream 1301, the decoding result 1403 of the broadcast reception B stream 1302, and the decoding result 1404 of the still image decoding stream 1304 are output on the screen 1401. It becomes possible.

  Here, the still image decoding stream 1304 is a best-effort stream that does not require a decoding quality guarantee, although sufficient decoding processing resources are not allocated. For this reason, the decoding result 1404 of the still image decoding stream 1304 can be an effective display for the user.

  The example shown in FIG. 14 is a specific example in the video stream decoding process, but it goes without saying that the same effect can be obtained for other processes such as an audio stream decoding process. Furthermore, it goes without saying that the scope of the present embodiment includes the case where the present invention is applied to a plurality of processes in the same apparatus.

  As described above, according to the stream decoding apparatus 100 in the present embodiment, a decoding request is received for a best-effort stream even when there is no room for decoding processing resources. Then, the guarantee type stream is preferentially decoded, and the best effort type stream is decoded when there is no room for decoding processing resources. As a result, when decoding processing of a plurality of streams is performed in a time-sharing manner in parallel, the display quality of the guarantee type stream can be ensured and decoding processing resources can be used effectively.

  In this embodiment, the guarantee type stream is preferentially decoded, and the best effort type stream is decoded when there is no room for decoding processing resources. At this time, there are a plurality of best effort type streams to be decoded. There is also a case. Therefore, the reception unit 101 assigns a decoding process priority indicating the priority of the decoding process to the best effort type stream. Then, when there are a plurality of best-effort streams to be decoded, the switching unit 102 may select a decoding to be decoded based on this decoding processing priority. Note that the decoding process priority may be set to any priority order, such as giving priority in the order in which the decoding start request is received.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to a flowchart of FIG. 10 focusing on differences from the first embodiment. The technical scope of the present invention is not limited to this embodiment.
FIG. 9 is a block diagram illustrating a configuration example of the stream decoding apparatus 900 according to the present embodiment.
In FIG. 9, a quality determination unit 904 determines the type of a guarantee type stream or a best effort type stream for each stream based on attribute information of an input stream, and receives a reception unit 901 as decoding quality information. Notify

  The receiving unit 901 receives a plurality of streams, decoding quality information of each stream, and a decoding request for each stream, and selectively receives a request to start decoding. The switching unit 902 sequentially allocates decoding processing resources to a plurality of streams for which the reception unit 901 has received a decoding start request, and switches the streams to be decoded according to the allocation. The decoding unit 903 performs a decoding process on the stream to be decoded by the switching unit 902. The control unit 905 controls the entire stream decoding apparatus 900.

  The decryption request accepted by the accepting unit 901 is given as a decryption start request or a decryption end request triggered by, for example, a user operation input such as TV switch ON / OFF or channel change. Various input devices such as a remote controller, a keyboard, a mouse, a digitizer, a touch panel, and a joystick are assumed as input means for inputting operations by these users. In this embodiment, any input means may be used.

  Further, as output means for outputting a stream as a decoding result of the decoding unit 903, for example, various output devices such as a monitor as a video output means and a speaker and headphones as an audio output means are assumed. In the present embodiment, any output means may be used as with the input means.

FIG. 10 is a flowchart illustrating an example of a decoding processing procedure in the present embodiment. Hereinafter, the processing of the present embodiment will be described along a flowchart.
In FIG. 10, the processing is started when the power of the stream decoding apparatus 900 is turned on. In step S1001, the control unit 905 initializes the system. This initialization processing includes various controls when the stream decoding apparatus 900 is turned on. For example, the initialization process includes setting of register values necessary for the decoding process of the decoding unit 903, confirmation of the state of memory resources and hardware resources of the entire stream decoding apparatus, and the like.

  Next, in step S <b> 1002, the reception unit 901 acquires information on the decoding processing resource amount X held by the decoding unit 903. In step S1003, the reception unit 901 sets 0 as the initial value of the currently allocated decoding processing resource amount xc.

  Next, in step S1004, the reception unit 901 determines whether a new processing request has been received. If it is determined that a new processing request has been received, the process advances to step S1005. On the other hand, if the result of determination in step S1004 is that a new processing request has not been received, processing proceeds to step S1010.

  Next, in step S1005, the quality determination unit 904 determines the decoding quality type based on the attribute information of the stream targeted by the new processing request determined to be received in step S1004. The determination of the decoding quality type uses, for example, a definition file in which the service type of the stream is associated with the decoding quality type.

FIG. 15 is a diagram illustrating an example of a definition file in which a service type of a stream and a decoding quality type are associated with each other.
In the specific example illustrated in FIG. 15, for example, in a row 1501, a broadcast reception service that is a moving image stream is associated with a guarantee type stream. On the other hand, in row 1502, a still image decoding service that is a still image stream is associated with a best effort stream.

  Also, as shown in FIG. 15, network content for which the network bandwidth is guaranteed is associated with a guarantee stream, and network content for which the network bandwidth is not guaranteed is associated with a best effort stream.

  On the other hand, in addition to displaying the stream on the display, decoding may be necessary to perform predecoding processing or the like for specifying the stream format instead of displaying on the display. When the attribute information includes information indicating whether or not display is displayed, a display display is associated with a guarantee stream, and a display display is not associated with a best effort stream.

  Next, in step S1006, the type of a new processing request determined to be accepted in step S1004 is determined. As a result of the determination, if the new processing request is a decryption start request, the process proceeds to step S1007. If the new processing request is a decryption end request, the process proceeds to step S1009. If the new processing request is another request, the process advances to step S1009.

  Next, in step S1007, the accepting unit 901 selectively accepts a decryption start request based on the decryption start request determined in step S1006. The contents of this process are the same as those in the flowchart of FIG. 4 described in the first embodiment, and a description thereof will be omitted.

  On the other hand, in step S1008, the accepting unit 901 accepts the decryption end request based on the decryption end request determined in step S1006. The contents of this process are the same as those in the flowchart of FIG. 5 described in the first embodiment, and a description thereof will be omitted.

  Further, in step S1009, various processes are performed based on the other requests determined in step S1006. Examples of the processing performed in step S1009 include setting of decoding parameters.

  Next, in step S1010, the switching unit 902 selects a stream on which decoding processing is to be performed from among the streams that have been received by the receiving unit 901 so far. The contents of this process are the same as those in the flowchart of FIG. 6 described in the first embodiment, and a description thereof will be omitted. In step S1011, the decoding unit 903 performs a decoding process on the stream selected in step S1010.

  Next, in step S1012, it is determined whether or not to end the decoding process. If the result of this determination is that the decoding process is not terminated, processing returns to step S1004. On the other hand, if the result of determination in step S1012 is to end decoding processing, processing proceeds to step S1013. In step S1013, the control unit 905 performs a system termination process and terminates the process. This termination process includes various controls prior to the power-off of the stream decoding apparatus 900. For example, the termination process of memory resources and hardware resources is sequentially performed.

  As described above, according to the stream decoding apparatus 900 of the present embodiment, the decoding quality type is determined from the service type of the stream, and the decoding request is received even when there is no room for decoding resources for the best effort type stream. Then, the guarantee type stream is preferentially decoded, and the best effort type stream is decoded when there is no room for decoding processing resources. As a result, when decoding processing of a plurality of streams is performed in a time-sharing manner in parallel, the display quality of the guarantee type stream can be ensured and decoding processing resources can be used effectively.

  Similarly to the first embodiment, when there are a plurality of best-effort streams to be decoded, a decoding process priority is assigned and a decoding to be decoded is selected based on the decoding process priority. You may do it. Furthermore, the processing procedures shown in the first embodiment and the second embodiment may be realized in the same apparatus, and may be operated by switching the operation mode, for example.

(Other embodiments according to the present invention)
The object of the present invention is also achieved in the following cases. First, a storage medium storing software program codes for realizing the functions of the first and second embodiments described above is supplied to a system or apparatus. Needless to say, this can also be achieved by the computer (or CPU or MPU) of the system or apparatus reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the computer-readable storage medium storing the program code constitutes the present invention.

100 stream decoding device, 101 receiving unit, 102 switching unit, 103 decoding unit, 104 control unit

Claims (11)

A stream decoding device that decodes a plurality of input streams in parallel,
Accepting means for accepting a decoding start request in units of streams for the plurality of streams;
Switching means for switching the stream to be decoded from among the streams whose decoding start request has been received by the receiving means;
Decoding means for decoding the stream switched by the switching means,
The accepting unit starts the decoding of the first stream that requires a guarantee of the decoding quality when the decoding unit can guarantee the decoding quality based on the processing margin of the decoding unit and can be decoded by the decoding unit. For the second stream that accepts the request and does not require the guarantee of the decoding quality, the decoding start request is accepted regardless of the processing margin by the decoding means,
It said switching means, as the first stream of the decoding target stream, stream decoding apparatus according to claim preferentially switched than the second stream. A stream decoding device that decodes a plurality of input streams in parallel,
Quality determining means for determining whether or not decoding quality is guaranteed based on the attribute information of the stream;
Accepting means for accepting a decoding start request in units of streams for the plurality of streams;
Switching means for switching the stream to be decoded from among the streams whose decoding start request has been received by the receiving means;
Decoding means for decoding the stream switched by the switching means,
The accepting means guarantees the decoding quality based on the processing margin of the decoding means for the first stream determined to require the decoding quality guarantee by the quality determining means and decodes by the decoding means If the second stream is determined not to require decoding quality guarantee by the quality determination means , the decoding start request is received regardless of the processing margin of the decoding means. Accept
It said switching means, as the first stream of the decoding target stream, stream decoding apparatus according to claim preferentially switched than the second stream.   The said quality determination means determines the said stream as a said 1st stream about the stream which displays, The said 2nd stream is determined about the stream which is not displayed. Stream decoding device.   4. The stream decoding apparatus according to claim 2, wherein the quality determination unit determines the moving image stream as the first stream, and determines the still image stream as the second stream. .   The quality determination means determines the stream for which the network bandwidth is guaranteed as the first stream, and determines the stream for which the network bandwidth is not guaranteed as the second stream. The stream decoding apparatus according to any one of claims 2 to 4. The accepting unit gives a decoding processing priority to the second stream,
The switching means switches the decoding target stream according to the decoding processing priority for the second stream after switching the first stream preferentially as a decoding target stream. The stream decoding apparatus according to any one of claims 1 to 5. A stream decoding method in a stream decoding device for decoding a plurality of input streams in parallel,
Accepting a decoding start request in units of streams for the plurality of streams;
A switching step of switching the decoding target stream from the streams for which the decoding start request has been received in the receiving step;
A decoding step of decoding the stream switched in the switching step,
In the receiving step, for the first stream that requires a guarantee of decoding quality, the decoding is performed when the decoding quality is guaranteed and decoding in the decoding step is possible based on the processing margin of the decoding step. For the second stream that accepts the start request and does not require the guarantee of the decoding quality , the decoding start request is accepted regardless of the processing margin of the decoding step,
Wherein in the switching step, the first stream as a stream of the decoding target, stream decoding method comprising preferentially switched than the second stream. A stream decoding method in a stream decoding device for decoding a plurality of input streams in parallel,
A quality determining step for determining whether or not decoding quality is guaranteed based on the attribute information of the stream;
Accepting a decoding start request in units of streams for the plurality of streams;
A switching step of switching the decoding target stream from the streams for which the decoding start request has been received in the receiving step;
A decoding step of decoding the stream switched in the switching step,
In the reception step, for the first stream determined to require decoding quality guarantee in the quality determination step, the decoding quality is guaranteed based on the processing margin of the decoding step and the decoding step The decoding start request is accepted when decoding is possible, and the decoding start is performed for the second stream determined not to require the decoding quality guarantee in the quality determination step regardless of the processing margin of the decoding step. Accept the request
Wherein in the switching step, the first stream as a stream of the decoding target, stream decoding method comprising preferentially switched than the second stream. A program for causing a computer to execute parallel decoding of a plurality of input streams,
Accepting a decoding start request in units of streams for the plurality of streams;
A switching step of switching the decoding target stream from the streams for which the decoding start request has been received in the receiving step;
And causing the computer to execute a decoding step of decoding the stream switched in the switching step,
In the receiving step, for the first stream that requires a guarantee of decoding quality, the decoding is performed when the decoding quality is guaranteed and decoding in the decoding step is possible based on the processing margin of the decoding step. For the second stream that accepts the start request and does not require the guarantee of the decoding quality , the decoding start request is accepted regardless of the processing margin of the decoding step,
Wherein in the switching step, the first stream as a stream of the decoding target, the program to the second characteristic preferentially a switching Turkey than stream. A program for causing a computer to execute parallel decoding of a plurality of input streams,
A quality determining step for determining whether or not decoding quality is guaranteed based on the attribute information of the stream;
Accepting a decoding start request in units of streams for the plurality of streams;
A switching step of switching the decoding target stream from the streams for which the decoding start request has been received in the receiving step;
And causing the computer to execute a decoding step of decoding the stream switched in the switching step,
In the reception step, for the first stream determined to require decoding quality guarantee in the quality determination step, the decoding quality is guaranteed based on the processing margin of the decoding step and the decoding step The decoding start request is accepted when decoding is possible, and the decoding start is performed for the second stream determined not to require the decoding quality guarantee in the quality determination step regardless of the processing margin of the decoding step. Accept the request
Wherein in the switching step, the first stream as a stream of the decoding target, the program to the second characteristic preferentially a switching Turkey than stream.   A computer-readable storage medium storing the program according to claim 9 or 10.

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