JP2009100361A - Information processor, and method of controlling data transfer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information processor that achieves preferred transfer of moving image data to a decoder. <P>SOLUTION: After sending an instruction for setting a unit of data transfer to a decoder 22 to the minimum value to a buffering control portion 201, a decoding performance monitoring portion 202 sequentially sends an instruction for incrementing a unit of data transfer one step to a buffering control portion 201 until so-called frame missing occurs, while monitoring an output frame rate of the moving image data decoded via the decoder 22. Further, when the frame missing occurs, the decoding performance monitoring portion 202 finally sends an instruction for setting the unit of data transfer for decreasing a unit of data transfer one step to the buffering control portion 201 once. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a data transfer control technique suitable for application to, for example, a personal computer having a function of reproducing video content stored in a recording medium such as an HD DVD (High Definition Digital Versatile Disk).

  In recent years, various types of personal computers such as a notebook type and a desktop type are widely used. In this type of personal computer, for example, software for reproducing video content stored in a storage medium such as an HD DVD is generally installed.

The video content is stored in a storage medium as compressed and encoded moving image data. Further, it is necessary to supply the moving image data read from the storage medium without excess or deficiency to a decoder that performs decoding processing on the compressed and encoded moving image data. For this reason, various proposals have been made regarding a mechanism for appropriately setting a buffer size when buffering moving image data (see, for example, Patent Document 1).
JP 2006-66995 A

  By the way, in a computer in which the decoder is also implemented by software, for example by installing a high-performance processor, the supply of buffered moving image data to the decoder is completed in the system memory, but load distribution Due to various circumstances such as the above, in a computer having a decoder mounted in hardware, data transfer through a data transfer path occurs when buffered moving image data is supplied to the decoder.

  In this case, if the transfer unit of the moving image data from the system memory (buffer) to the decoder is small, for example, more operational opportunities such as a DMA (Direct Memory Access) controller that controls the data transfer are generated. If the transfer unit is large, an input waiting state, that is, an underflow state may occur on the decoder side. As described above, depending on the configuration of the computer, not only the setting of the buffer size but also a mechanism for appropriately setting the transfer unit of moving image data is strongly required.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an information processing apparatus and a data transfer control method that realizes optimization of transfer processing of moving image data to a decoder. .

  To achieve the above object, an information processing apparatus according to the present invention comprises an input means for inputting compressed and encoded moving image data, and buffering for storing the moving image data input by the input means in a system memory. Means, a hardware decoder for decoding the moving image data, and data transfer for transferring the moving image data stored in the system memory by the buffering means to the hardware decoder via a data transfer path And adjusting means for adjusting a transfer unit of moving image data by the data transfer unit based on an output state of moving image data after being decoded by the hardware decoder.

  According to the present invention, it is possible to optimize the moving image data transfer processing to the decoder.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of the information processing apparatus according to the present embodiment with the display unit opened. This information processing apparatus is realized as, for example, a notebook-type personal computer 1 that can be driven by a battery.

  The computer 1 includes a computer main body 2 and a display unit 3. The display unit 3 incorporates a display device composed of an LCD (Liquid Crystal Display) 15.

  The display unit 3 is attached to the computer main body 2 so as to freely rotate between an open position where the upper surface of the computer main body 2 is exposed and a closed position covering the upper surface of the computer main body 2. The computer main body 2 has a thin box-shaped casing. On the upper surface thereof, a keyboard 24, a power button 4 for powering on / off the computer 1, an input operation panel 5, a touch pad 25, a speaker. 21 etc. are arranged.

  FIG. 2 is a diagram showing a system configuration of the computer 1.

  2, the computer 1 includes a CPU 11, a north bridge 12, a main memory 13, a display controller 14, a video memory (VRAM) 14A, a south bridge 16, a BIOS-ROM 17, a hard disk drive (HDD) 18, an HD ( High Definition) DVD drive (HD DVD) 19, sound controller 20, decoder 22, embedded controller / keyboard controller IC (EC / KBC) 23, power supply circuit 26, battery 27, network controller 28, TV tuner 29, etc. .

  The CPU 11 is a processor that controls the operation of the computer 1, and executes an operating system (OS) 100 loaded from the HDD 18 to the main memory 13 and various application programs including utilities that operate under the control of the OS 100. To do. The various application programs include a video playback application 200.

  The video playback application 200 is software for viewing HD standard video content stored on the HD DVD 19. The video playback application 200 reads the compression-coded moving image data from the HD DVD 19 and buffers it on the main memory 13 (in which it is loaded) while decoding the compression-coded moving image data. The DMA controller 121 is appropriately requested to transfer the buffered compressed and encoded moving image data to the decoder 22 to be executed.

  The DMA controller 121 is built in the north bridge 12 and has a function of transferring data in a designated area on the main memory 13 to a designated peripheral device without involvement of the CPU 11 (after operation). The video playback application 200 can operate the DMA controller 121 by outputting a predetermined interrupt signal.

  That is, each time the compressed and encoded moving image data buffered on the main memory 13 is supplied to the decoder 22, an interrupt for operating the DMA controller 121 is generated, and the transfer unit for one time is increased. Therefore, it is preferable in terms of efficiency to reduce the number of times as much as possible. On the other hand, if the buffering amount on the main memory 13 is increased and the transfer unit for one transfer is increased unnecessarily, the decoder 22 may be in an input waiting state to cause a so-called frame drop. Therefore, the computer 1 has a mechanism for appropriately setting the transfer unit of data transfer from the main memory 13 to the decoder 22, and this point will be described in detail below.

  Note that the video playback application 200 can view a digital TV broadcast program received by the TV tuner 29 in addition to the HD standard video content stored in the HD DVD 19. The moving image data decoded by the decoder 22 is transferred to the display controller 14 via the video reproduction application 200 and displayed on the LCD 15.

  The CPU 11 also executes the BIOS stored in the BIOS-ROM 17. The BIOS is a program for hardware control.

  The north bridge 12 incorporating the above-described DMA controller 121 is a bridge device that connects the local bus of the CPU 11 and the south bridge 16. The north bridge 12 has a function of executing communication with the display controller 14 via a bus, and also includes a memory controller that controls access to the main memory 13. The display controller 14 controls the LCD 15 used as a display device of the computer 1.

  The south bridge 16 is a controller that controls various devices on the PCI bus and the LPC bus. The south bridge 16 is directly connected to the BIOS-ROM 17, the HDD 18, the HD DVD 19, the sound controller 20, the decoder 22, and the like, and also has a function of controlling them. The decoder 22 is connected to the south bridge 16 via a PCI Express standard serial bus, and inputs / outputs the above-described moving image data via the serial bus.

  The HDD 18 is a storage device that stores various software and data. The HD DVD 19 is a drive unit for driving a storage medium such as an HD DVD in which video content is stored. The sound controller 20 is a sound source controller that controls the speaker 21.

  The EC / KBC 23 is a one-chip microcomputer in which an embedded controller for power management and a keyboard controller for controlling the keyboard 24 and the touch pad 25 are integrated. The EC / KBC 23 cooperates with the power supply circuit 26 to control supply of power from the battery 27 or the external AC power supply to each unit.

  The network controller 28 is a communication device that executes communication with an external network such as the Internet. The TV tuner 29 is a receiving device for receiving digital TV broadcast program data from the outside.

  FIG. 3 is a diagram showing functional blocks of the video playback application 200. As described above, the video playback application 200 that is one of the various application programs is loaded from the HDD 18 to the main memory 13 and operates under the control of the OS 100. As shown in FIG. 3, the video reproduction application 201 includes a buffering control unit 201 and a decoding performance monitoring unit 202.

  The buffering control unit 201 performs control so that the compressed moving image data read from the HD DVD 19 is supplied to the decoder 22 by an appropriate amount. The storage amount of the compressed moving image data is a predetermined amount. Each time the fixed amount is reached, the DMA controller 121 is requested to transfer the predetermined amount of compressed moving image data to the decoder 22 (by generating an interrupt signal).

  The decoding performance monitoring unit 202 instructs the buffering control unit 201 to transfer the predetermined amount, that is, the transfer unit of the compressed moving image data. The moving image data decoded by the decoder 22 is displayed on the LCD 15 by being transferred to the display controller 14, but when the video content stored in the storage medium is composed of, for example, 24 frames / second, The decoding performance monitoring unit 202 monitors whether the output frame rate of the moving image data after decoding from the decoder 22 satisfies the 24 frames / second (reference value). If it is detected that the output frame rate does not satisfy the reference value, the decoding performance monitoring unit 202 instructs the buffering control unit 201 to reduce the transfer unit of the compressed moving image data to the decoder 22 by one step. Instruct.

  More specifically, it is assumed that the buffering control unit 201 can accept the designation of the transfer unit in the range of 16 Kbytes to 64 Kbytes and in units of 2 Kbytes. In this case, the decoding performance monitoring unit 202 first instructs the buffering control unit 201 to use the minimum value of 16 Kbytes as a transfer unit.

  Using the minimum value of 16 Kbytes as a transfer unit means that the operation frequency of the DMA controller 121 is maximized. That is, the load on the CPU 11 that receives an interrupt is the largest. Therefore, the decoding performance monitoring unit 202 buffers the buffer so that the transfer unit increases stepwise in order to reduce the operation frequency as long as the output frame rate of the moving image data decoded by the decoder 22 satisfies the reference value. An instruction is given to the ring control unit 201. As a result, the load on the CPU 11 relating to the reproduction of video content is minimized within a range in which so-called frame dropping does not occur.

  By the dynamic control of the data transfer unit by the decoding performance monitoring unit 202, for example, even if the video playback application 200 is operated on various computers having different hardware specifications, no artificial tuning work is required for each computer. Can be.

  Note that when the compressed moving image data read from the HD DVD 19 is accumulated, the buffering control unit 201 refers to, for example, a predetermined field in the header part to determine whether information indicating a data delimiter is included. Monitor. When the information indicating the data delimiter is detected, the buffering control unit 201 does not reach the amount instructed by the decoding performance monitoring unit 202 even if the accumulated amount of the compressed moving image data reaches the amount specified by the decoding performance monitoring unit 202. The DMA controller 121 is requested to transfer the accumulated amount. Further, the buffering control unit 201 requests the DMA controller 121 to transfer the accumulated amount even when the input of the compressed moving image data is interrupted beyond a certain period.

  FIG. 4 is a flowchart showing a data transfer control procedure executed by the video playback application 200 operating on the computer 1.

  First, the decoding performance monitoring unit 202 of the video playback application 200 first sets the data transfer unit of the compressed moving image data to the decoder 22 to the buffering control unit 201 as the initial value (the buffering control unit 201 can accept the most data). An instruction for setting a smaller value is given (step A1).

  After giving this instruction, the decoding performance monitoring unit 202 monitors the output frame rate of the moving image data after decoding from the decoder 22 (step A2), and checks whether or not so-called frame dropping has occurred (step A3). ). If no frame dropping has occurred (NO in step A3), the decoding performance monitoring unit 202 gives an instruction for increasing the data transfer unit by one step to the buffering control unit 201 (step A4).

  The processing from step A2 to step A4 is repeated until a frame drop occurs (YES in step A3). When a frame drop occurs, the decoding performance monitoring unit 202 now reduces the data transfer unit by one level. Is given to the buffering control unit 201 (step A5). The data transfer unit set in step A5 is the optimum value in the hardware specifications of the computer 1, and the decoding performance monitoring unit 202 thereafter monitors the output frame rate of the moving image data after decoding from the decoder 22. If the frame dropout occurs (YES in step A7), an instruction for reducing the data transfer unit by one step is given to the buffering control unit 201 (step A8), and the environment of the computer 1 Respond dynamically to changes.

  Thus, according to the computer 1, automatic adjustment of the moving image data transfer unit by the DMA controller 121 from the main memory 13 to the decoder 22 is realized.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine a component suitably in different embodiment.

The perspective view which shows the external appearance of the information processing apparatus which concerns on one Embodiment of this invention The figure which shows the system configuration | structure of the information processing apparatus of the embodiment FIG. 3 is a diagram showing functional blocks of a video playback application that operates on the information processing apparatus of the embodiment. A flowchart showing a data transfer control procedure executed by a video playback application operating on the information processing apparatus of the embodiment

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Information processing apparatus (computer), 2 ... Computer main body, 3 ... Display unit, 11 ... CPU, 12 ... North bridge, 13 ... Main memory, 14 ... Display controller, 14A ... VRAM, 15 ... LCD, 16 ... South bridge 17 ... BIOS-ROM, 18 ... HDD, 19 ... HD DVD, 20 ... sound controller, 21 ... speaker, 22 ... decoder, 23 ... embedded controller / keyboard controller IC (EC / KBC), 24 ... keyboard, 25 ... touch Pads 26... Power supply circuit 27 27 Battery 28 Network controller 29 TV tuner 100 Operating system (OS) 200 Video playback application 201 Buffering control unit 202 Decoding performance monitoring unit

Claims (5)

Input means for inputting compressed and encoded video data;
Buffering means for storing the moving image data input by the input means on a system memory;
A hardware decoder that performs decoding processing on the moving image data;
Data transfer means for transferring the moving image data stored in the system memory by the buffering means to the hardware decoder via a data transfer path;
An adjustment unit that adjusts a transfer unit of moving image data by the data transfer unit based on an output state of moving image data after being decoded by the hardware decoder;
An information processing apparatus comprising:   The adjusting means reduces the moving image data transfer unit by the data transferring means when the output frame rate of the moving image data decoded by the hardware decoder does not reach a predetermined value. The information processing apparatus according to claim 1.   When predetermined information is included in the moving image data, waiting for the amount of moving image data stored in the system memory by the buffering means to reach the transfer unit determined by the adjusting means. 2. The information according to claim 1, further comprising control means for causing the data transfer means to transfer the moving image data stored in the system memory at that time to the hardware decoder. Processing equipment.   When the input of the moving image data by the input unit stops after a predetermined period, the amount of moving image data stored in the system memory by the buffering unit reaches the transfer unit determined by the adjusting unit. And further comprising control means for causing the data transfer means to transfer the moving image data stored in the system memory at that time to the hardware decoder without waiting. 1. An information processing apparatus according to 1. A computer having a system memory, a hardware decoder that performs decoding processing on compression-encoded moving image data, and a DMA controller that transfers data on the system memory to various peripheral devices including the hardware decoder The data transfer control method of
The computer
Accumulating input video data on the system memory,
Transferring the moving image data stored in the system memory to the hardware decoder by the DMA controller;
Adjusting a transfer unit of moving image data from the system memory to the hardware decoder by the DMA controller based on an output state of moving image data after being decoded by the hardware decoder;
A data transfer control method.

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