KR100540982B1 - Portable WMA decoder - Google Patents

Abstract

The present invention relates to a hardwired portable WMA decoding apparatus, comprising: WMA data storage means; First header information analyzing means; Second header information analyzing means; Huffman decryption means; Main processing means; Sound output means; Control means; And a clock generating means, the apparatus for decoding WMA data, having a predetermined storage capacity, storing the WMA data received from the WMA data storage means, and storing the stored data under control of the control means. And an input data storing means for outputting to the first header information analyzing means, the second header information analyzing means and the Huffman decoding means, wherein the control means determines whether new WMA data can be stored in the input data storing means. When the new data can be stored and when it is not possible, the WMA data storage means outputs a data request signal and a data request stop signal to control the reception of the WMA data.

According to the present invention, the data can be prevented from being excessively inputted to operate sufficiently even using a small memory, and the power can be reduced by selectively supplying a clock only where necessary. .

WMA, Decryption, Hardwired

Description

Portable WMA decoder {Portable WMA decoder}

1 is a diagram showing the format of a WMA (Windows Media audio) file

2 is a block diagram showing the configuration of the apparatus of the present invention.

3 illustrates a timing table of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for decoding data having a WMA (Windows Media Audio) format from Microsoft, and more particularly, to a portable WMA decoding device manufactured using a hardwired method.

The WMA format file developed by Microsoft maintains the same sound quality as the existing Moving Picture Expert Group (MPEG), but the file size is only half of that of MPEG.

In general, files in WMA format (hereinafter referred to as "WMA files") are also decoded by software through a program called Windows Media Player, produced by Microsoft Corporation, and output as sound.

However, in order to smoothly decode WMA files and output sound using software such as Windows Media Player, a device equipped with the above software has at least a CPU and a large storage capacity having the same functions as a home computer. Since it is necessary, the decoding method using the above software has a disadvantage in that it is somewhat inadequate due to the large volume of the device to be driven in the portable device.

When a decoding apparatus is implemented using a DSP (Digital Signal Processor) that implements a program in hardware through a method of porting a program written in a programming language such as the C programming language, the decoding method is performed using software. On the other hand, decoding can be performed by using a portable device having a smaller volume. However, in the case of DSP, the circuit structure is changed according to the purpose of use, not the structure of the circuit. As it has a general-purpose structure to be used, there are many unnecessary circuits, and when implementing a decoding apparatus using a DSP, it is necessary to secure more memory capacity than an appropriate memory capacity, and there is no method of reducing power consumption. .

In order to solve the above problems, an object of the present invention is to provide a hardwired portable WMA decoding apparatus that is specialized for decoding a WMA file and can be implemented with only a small memory capacity and a small power consumption.

The present invention to achieve the above object is WMA data storage means for storing WMA (Windows Media Audio) data; First header information analysis means for parsing first header information for decoding WMA data received from the WMA data storage means; Second header information analyzing means for parsing second header information for decoding a packet constituting the WMA data received from the WMA data storing means; Huffman decoding means for decoding Huffman coded data among packets constituting the WMA data received from the WMA data storage means; Main processing means for receiving the decoded data from the Huffman decoding means, converting a signal in the frequency domain into a signal in the spatial domain, and reproducing it as a Pulse Code Modulation (PCM) signal; Sound output means for outputting the PCM signal received from the main processing means as a sound signal; Control the reception of the WMA data from the WMA data storage means, and output a control signal instructing the operation of each of the first header information analyzing means, the second header information analyzing means, the Huffman decoding means, and the main processing means. Control means for; And clock generation means for providing a clock synchronized to said control means, said first header information analysis means, said second header information analysis means, said Huffman decoding means, said main processing means and said sound output means. An apparatus for decoding data, said apparatus having a predetermined storage capacity, storing said WMA data received from said WMA data storage means, and storing said stored data under said control of said control means. A second header information analyzing means and an input data storing means for outputting to the Huffman decoding means, wherein the control means judges whether the new WMA data can be stored in the input data storing means and saves the new data. If it is not possible, data request signal and data request are being sent to the WMA data storage means, respectively. And outputting the signal and provides a hard-wired (hardwired) system for a portable WMA decoding apparatus, characterized in that for controlling the reception of the WMA data.

The portable WMA decoding apparatus further comprises a PCM signal storage means for storing the PCM signal input from the main processing means to the sound output means and supplying the stored data to the sound output means for processing in the sound output means. And the sound output means outputs a processing stop signal to the main processing means when the PCM signal storage means can no longer store the PCM signal, and when the main processing means receives the processing stop signal, It is preferable to stop the processing of the decoded data from the Huffman decoding means.

Preferably, the clock generating means provides the clock when an operation of the constituent means is performed for each of the constituent means, in accordance with the control signal of the control means.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 illustrates a general form of a WMA (Windows Media Audio) format to be decoded in the present invention.

The WMA format has an ASF (Advanced Stream Format) header 101, which holds information for decoding WMA data, each packet having a packet information header 111, a payload information header 112, The super frame header 113, the main header 114, and the Huffman data 115 are configured.

The function of each header is not an important feature of the present invention, and also known technology, so that anyone skilled in the art to which the present invention belongs may know the detailed description thereof.

2 is a block diagram showing the configuration of the system of the present invention.

The system of the present invention includes a control means 201, an input data storage means 202, a first header information analysis means 203, a second header information analysis means 204, a Huffman decryption means 205, a main processing means ( 206, main processing storage means 207, sound output means 208, PCM signal storage means 209, and clock generating means 210.

WMA data to be decoded in the present invention is stored in the WMA data storage means (not shown). The WMA data storage means may serve as a buffer for temporarily storing a part of data input from the outside in a streaming manner, but the WMA data storage function may be stored in advance and transferred to the control means 201. desirable.

The control means 201 controls the reception of the WMA data stored in the WMA data storage means according to whether or not the storage space is found in the input data storage means 202, the first header information analysis means 203, The two header information analyzing means 204, the Huffman decoding means 205, and the main processing means 206 output control signals for instructing the operation of the constituent means, respectively.

The input data storage means 202 temporarily stores the data input to the control means 201, and stores the data stored under the control of the control means 201 in the first header information analyzing means 103 and the second header information analyzing means. 204, Huffman decryption means 205, and main processing means 206.

The first header information analyzing means 203 decodes and analyzes an Advanced Stream Format (ASF) header that holds information necessary for decoding WMA data.

The second header information analyzing means 204 includes a packet information header 111, a payload information header 112, and a super frame header 113 which hold information necessary to decode each layer of each packet. ), The main header 114 is decoded and analyzed.

The Huffman decoding means 205 performs run-length decoding of the Huffman data 115 in the WMA data using the Huffman codebook.

The main processing means 206 receives the data Spec_coef outputted from the Huffman decoding means 205 and converts the signal in the frequency domain into the signal in the spatial domain through an inverse modified discrete cosine transformation. The PCM signal is output through the Pulse Code Modulation Reconstruction process. The output PCM signal is preferably divided into a signal for the left channel (L_CH PCM) and a signal for the right channel (R_CH PCM).

The main processing storage means 207 serves as an internal memory of the main processing means 206 and is used as a memory for the operation of the main processing means 206.

The sound output unit 208 receives the PCM signal processed and processed in parallel, stores it in the PCM signal storage unit 209, and converts the stored signal into a continuous analog signal according to a sampling frequency period in a serial manner.

The PCM signal storing means 209 stores the PCM signal output from the main processing means 206 and provides it to the sound output means 208.

The clock generating means 210 generates a clock for driving the system and supplies it to each component. At this time, the operation of each component is detected according to the control signal output from the control means so that the clock is supplied to the component only at the time when each component is operated.

The following describes the operation of the system of the present invention in more detail.

When the decoding of the file in the WMA format starts, the control means 201 makes the DEMAND signal requesting WMA data high and transmits it to the WMA data storage means (not shown). When the DEMAND signal is HIGH, the WMA data is transmitted from the WMA data storage means to the control means 201.

The WMA data transmitted to the control means 201 is stored in the input data storage means 202 (STRM DATA). The control means 201 controls so that the data (STRM DATA) stored in the input data storage means 202 is supplied to each component.

When the storage capacity of the input data storage means 202 is full and no further data can be stored, the control means 201 sets the DEMAND signal low and further data until new data can be stored again. Will not be received.

Thus, in the present invention, since the WMA data is received depending on whether the storage capacity of the input data storage means 202 is found, even if the capacity of the input data storage means 202 is small, the WMA data is not affected. The advantage is that it can be decrypted.

Data stored in the input data storage means 202 (STRM DATA) is controlled by the control means 201, the first header information analysis means 203, the second header information analysis means 204, Huffman decoding means ( 205). The control means 201 transmits a control signal instructing the operation of the necessary configuration means while supplying the data stored in the input data storage means 202.

At the beginning of the WMA data, as shown in FIG. 1, an ASF header, which stores information necessary for decoding a WMA file, is located. The ASF header is decoded and analyzed by the first header information analyzing means 203.

The first header information analyzing means 203 stores the data stored in the input data storing means 202 when the fASF signal, which is a control signal output from the control means 201 to the first header information analyzing means 203, is high. (STRM DATA) is received from the control means 201 to decode the ASF header. The decoded information is transmitted to the second header information analyzing means 204, the Huffman decoding means 205, the control means 201, and the like and used to decode the WMA data.

When the ASF header is analyzed, the control means 201 analyzes the header included in each packet using the second header information analyzing means 204. The second header information analyzing means 204 has a fPACINFO signal that indicates decoding of the packet information header 111 output from the control means 201 to the second header information analyzing means 204, or is high. (Payload) The fPAYINFO signal indicating decoding of the information header 112 is HIGH, the fSUPER signal indicating decoding of the super frame header 113 is HIGH, or the decoding of the main header 114 is not performed. When the indicating fMHEAD signal is HIGH, the data STRM DATA stored in the input data storage means 202 is received from the control unit 201 and the corresponding header is decoded. The decoded information is transmitted to the Huffman decoding means 205, the control means 201, and the like and used to decode the WMA data.

When the header of each layer of the packet is analyzed by the second header information analyzing means 204, the Huffman decoding means 205 decodes the Huffman data 115 by using the header header.

The Huffman decoding means 205 is stored in the input data storage means 202 when the fHUFFMAN signal instructing decoding of the Huffman data 115 output from the control means 201 to the Huffman decoding means 205 is high. The data SSTR DATA is received from the control means 201 and outputs a signal SPEC_COEF on which run-length decoding is performed using the Huffman codebook.

The signal SPEC_COEF processed by the Huffman decoding means 205 is converted into a Pulse Code Modulation (PCM) signal by the main processing means 206 and output. The main processing means 206 receives the signal SPEC_COEF output from the Huffman decoding means 205 when the fMAIN signal output from the control means 201 to the main processing means 206 is high, and performs an inverse discrete cosine transform (Inverse). Modified Discrete Cosine Transformation is performed to convert the signal in the frequency domain to the signal in the spatial domain, and then output the PCM signal through PCM reproduction (Pulse Code Modulation Reconstruction). At this time, the main processing means 206 uses the main processing storage means 207 as an internal memory for calculation.

The PCM signal output from the main processing means 206 is preferably divided into a signal for the left channel (L_CH PCM) and a signal for the right channel (R_CH PCM).

The PCM signal output from the main processing means 206 is output by the sound output means 208 as a continuous sound signal in synchronization with the sampling frequency period.

At this time, all the data processing up to the main processing means 206 is processed in a parallel manner, but the sound output means 208 is processed in a serial manner and output, so that up to the main processing means 206 The data processing speed and the data processing speed in the sound output means 208 are different from each other.

For this reason, the sound output means 208 stores the signal input from the main processing means 206 in the PCM signal storage means 209, carries only the data necessary for processing, and performs the output.

At this time, the sound output means 208 checks whether the storage capacity of the PCM signal storage means 209 is exhausted, and when no new data can be stored anymore, the fpcm_full signal output to the main processing means 206 is high ( HIGH) to stop the operation in the main processing means 206.

That is, in the case of the present invention, whether or not to stop the operation of the main processing means 206 is determined according to whether or not the data can be stored in the PCM signal storage means 209, even if the storage capacity of the PCM signal storage means 209 is small. There is an advantage that does not affect the operation of the entire system.

In addition, the sound output means 208 checks the amount of data stored in the PCM signal storage means 209, and at the time and control means 201 where all the data stored in the PCM signal storage means 209 are output. When it is determined that processing for the next frame is necessary using the time until the input WMA data is input to the sound output means 208 through each process, the control means 201 is notified to the control means 201 via the fpcm_offset signal. In step 201, a control signal for processing the next frame is output.

That is, it takes a predetermined time until the WMA data is input to the control means 201 and starts to be output from the main processing means 206 through each process, and the PCM signal stored in the PCM signal storage means 209 Since it will be output through the sound output means 208 at a constant speed so that the amount of PCM signal stored in the PCM signal storage means 209 can be known how long it takes to output all the stored signals, The sound output means 208 outputs through the main processing means 206 after the WMA data is input to the control means 201 in order for the amount of data stored in the PCM signal storage means 209 to output all of the data. The fpcm_offset signal is transmitted to the control means 201 at a point in time remaining until it takes the same amount of time as the time required until it is reached, or at a point in time at least a time before considering the error of the system. And to start the process for the next frame.

By doing so, the Huffman decryption means 205, the main processing means 206, and the main processing means 206 have the longest idle time within the limit of not disturbing the function of the system, thereby minimizing power consumption. do.

The clock generating means 210 generates a clock so that each constituent means, namely, the control means 201, the first header information analyzing means 203, the second header information analyzing means 204, the Huffman decoding means 205, the main The processing means 206 and the sound output means 208 are provided.

At this time, the clock generating means 210 receives the control signal output from the control means 201 (not shown), selects the component means to be supplied with the clock according to each control signal and supplies the clock.

For example, when a control signal for instructing an operation in the second header information analyzing means 204 such as an fPACINFO signal, an fPAYINFO signal, an fSUPER signal, an fMHEAD signal is set to HIGH and output, the second header information analysis is performed. Selectively activates the clock supplied to each component by enabling only the clock clk_parse supplied to the means 204, and disabling the clock clk_main supplied to the main processing means 206 and the like. Let's do it.

A specific embodiment is shown in FIG. 3. In the present embodiment associated with FIG. 2, the clock supplied to the control means 201, the first header information analysis means 203, and the sound output means 208 is supplied with a clock clk_sys that is always active. Although the same type of clock clk_parse is supplied to the two header information analyzing means 204 and the Huffman decoding means 205 and a separate clock clk_main is supplied to the main processing means 206, the second header Free modifications are also possible within the scope of the technical idea of the present invention, such that the information analysis means 204 and the Huffman decoding means 205 are set so that separate clocks are supplied.

As shown in FIG. 3, while the fASF signal is set high and the operation of the first header information analyzing means 203 is in progress, all of the clocks clk_parse and clk_main other than the clock clk_sys are inactivated, and the fPACINFO signal and fPAYINFO are disabled. Only the clock clk_main is deactivated while the signal, the fSUPER signal, the fMHEAD signal, or the fHUFFMAN signal is set high and the operation of the second header information analyzing means 204 and the Huffman decoding means 205 is in progress.

In addition, when the fMAIN signal is set high and the operation is performed only in the main processing means 206, the clock clk_main is activated but the clock clk_parse is inactivated, so that the second header information analyzing means 204 and the Huffman decoding means ( It is possible to prevent the operation of the 205 to save the power consumed therein.

After the processing is finished in the main processing means 206, the apparatus of the present invention is idle for a while until a signal (fpcm_offset) is transmitted to the control means 201 for the sound output means 208 to start decoding the next frame. In this case, the clock (clk_parse) and the clock (clk_main) are both disabled so as to reduce power consumption.

By selectively activating the clock supplied as described above, a component that is not currently used has an advantage of reducing power consumption required for operation because the supplied clock is inactive.

As described above, according to the present invention, the input data storage means 202 controls the input of the WMA data from the WMA data storage means (not shown) according to whether the new data can be stored, and the PCM signal storage means ( By controlling the operation of the main processing means 206 according to whether or not new data can be input to 209, to prevent unnecessary data from being excessively input, a memory having a small capacity can be used and an operation means requiring operation. Since only a clock can be supplied to reduce power consumption, a portable WMA decoding device having low power and small capacity can be manufactured.

Claims (3)

WMA data storage means for storing WMA (Windows Media Audio) data; First header information analysis means for parsing first header information for decoding WMA data received from the WMA data storage means; Second header information analyzing means for parsing second header information for decoding a packet constituting the WMA data received from the WMA data storing means; Huffman decoding means for decoding Huffman coded data among packets constituting the WMA data received from the WMA data storage means; Main processing means for receiving the decoded data from the Huffman decoding means, converting a signal in the frequency domain into a signal in the spatial domain, and reproducing it as a Pulse Code Modulation (PCM) signal; Sound output means for outputting the PCM signal received from the main processing means as a sound signal; Control the reception of the WMA data from the WMA data storage means, and output a control signal instructing the operation of each of the first header information analyzing means, the second header information analyzing means, the Huffman decoding means, and the main processing means. Control means for; And clock generation means for providing a clock synchronized to said control means, said first header information analysis means, said second header information analysis means, said Huffman decoding means, said main processing means and said sound output means. In the apparatus for decoding data, The WMA data received from the WMA data storage means, having a predetermined storage capacity, and storing the WMA data under the control of the control means; Further comprising input data storage means for outputting to the Huffman decoding means, The control means determines whether new WMA data can be stored in the input data storage means, and outputs a data request signal and a data request stop signal to the WMA data storage means, respectively, when the new data can be stored or not. Hardwired portable WMA decoding apparatus, characterized in that for controlling the reception of the WMA data. The portable WMA decoding apparatus of claim 1, wherein PCM signal storage means for storing the PCM signal input from the main processing means to the sound output means and for supplying the stored data to the sound output means for processing in the sound output means; The sound output means outputs a processing stop signal to the main processing means when the PCM signal storage means can no longer store the PCM signal, and the main processing means receives the processing stop signal and the Huffman decoding means. A hardwired portable WMA decoding apparatus, characterized in that the processing of the data decoded from the data is stopped. 2. The hardwired as claimed in claim 1, wherein the clock generating means provides the clock when an operation of the constituent means is performed for each of the constituent means, in accordance with the control signal of the control means. Portable WMA decoding device.

Images