Data processing: speech signal processing – linguistics – language – Audio signal bandwidth compression or expansion
Reexamination Certificate
1998-08-20
2001-03-20
Dorvil, Richemond (Department: 2741)
Data processing: speech signal processing, linguistics, language
Audio signal bandwidth compression or expansion
C345S520000
Reexamination Certificate
active
06205429
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a device for manipulating information, and relates more particularly to a device for manipulating information in an audio decoder.
2. Description of the Background Art
Implementing an efficient and effective method for manipulating digital information is a significant consideration of system designers and manufacturers. However, the techniques available to manipulate the digital information often requires expensive modification of existing hardware or the development of new hardware.
Digital information is now in widespread use in consumer products such as compact disc (CD) players, digital video disc (DVD) players, digital video broadcast (DVB), and other systems. This widespread use of digitized audio and video information in the consumer market has led to a demand for more information to be incorporated in a single, convenient form. For example, entire movies may need to be included on a single CD. This demand led, in part, to the development of digital video discs (DVDs).
A single DVD may hold up to twenty-five times more information than a conventional CD. Thus, a single DVD is capable of holding both the video and audio portions of an entire two-hour movie. In addition, a DVD has the capacity to hold variety of other information such as widescreen picture information, six-channel surround sound, multilingual audio tracks, subtitles, and multiple camera angles. These features are not available on a CD because of capacity limitations.
DVD was developed with a standardized file format for the audio portion of the individual data. The standardized file format bundles data into packets of information. Each packet contains a header portion and the audio data portion. The header portion typically contains parameters that the audio system uses to process and playback the audio data. For example, the parameters may contain information about the audio data format, the playback speed, whether the audio data has been downsampled, or the type of data compression used.
A typical DVD system transfers the audio and video data in a continuous stream in which each packet is transferred in sequence. The DVD system transfers each packet beginning at a specific time interval. Until now there has been no convenient method to analyze the parameters within each packet before audio playback. This, in turn, has meant that developers have been unable to modify existing playback systems or to develop new, low-cost systems that advantageously use the information contained in the parameters. In addition, developers have been unable to incorporate user-entered host parameters into the audio data to manipulate the audio playback systems directly from the data. The foregoing problems thus present significant obstacles for effectively implementing an efficient method to manipulate digital information.
SUMMARY OF THE INVENTION
This invention relates generally to a device for manipulating information, and relates more particularly to a device for manipulating information in an audio decoder. Initially, in one embodiment of the present invention, the information is received as a data bit stream that a demultiplexer (DEMUX) separates into video data and audio packets. The video data is manipulated and displayed on a video monitor. The DEMUX further splits the audio packets into packets of audio data and packet parameters. The packets of audio data are stored in dynamic random-access memory (DRAM) and the packet parameters are initially transferred to a control manager. In addition, the control manager receives host parameters from a control processor. The host parameters are generated in response to system user commands to control the processing and playback of the corresponding packet of audio data. After receiving the packet parameters and host parameters, the control manager sends an interrupt command to an audio decoder notifying the audio decoder that the control manager has parameters to load. Each set of packet parameters directly correspond to a specific packet of audio data from a particular audio packet.
Next, an information handler determines whether the control manager is sending the interrupt command to transmit packet parameters or host parameters. If the control manager is sending packet parameters, then the information handler writes the packet parameters into an information buffer at that current position (the position in the information buffer pointed to by an information buffer write pointer). The information handler then moves the information buffer write pointer to the next available position in the information buffer. In the preferred embodiment, the information handler also copies the host parameters from the previous position in the information buffer (the position that immediately precedes the current position pointed to by the information buffer write pointer) into the current position in the information buffer.
However, if the control manager is relaying host parameters to the information handler, then the information handler writes the host parameters into the current information buffer position (the position in the information buffer pointed to by the information buffer write pointer). The information handler does not move the information buffer write pointer after writing the host parameters into the information buffer.
In a background process for decoding the packets of audio data, the information handler initially uses the packet parameters from the current information buffer location (the location in the information buffer pointed to by a read background pointer) to decode the corresponding packet of audio data stored in DRAM and stores the decoded packet of audio data in audio buffers. Then, the information handler moves the read background pointer to the next parameter buffer in the information buffer. In the preferred embodiment, the information handler may use the packet parameters to perform various functions such as downsampling the packet of audio data, identifying the format of the packet of audio data, or unpacking the packet of audio data.
While the information handler is receiving and writing the parameters to the information buffer and decoding the packet of audio data, the information handler is also outputting decoded packets of audio data to a digital-to-analog converter (DAC). In a foreground process for outputting decoded packets of audio data, the information handler outputs the decoded packets of audio data in the audio buffers to the DAC. Initially, the information handler transfers the current decoded packet of audio data to the DAC. Then, the information handler updates all the packet parameters for the foreground process at the current parameter buffer location (the location in the information buffer pointed to by a read foreground pointer) and moves the read foreground pointer to the next parameter buffer location. The transferred packet of audio data contains that data previously decoded by the information handler during the background process.
The information handler begins transferring the decoded packets of audio data to the DAC at specific times. In the preferred embodiment, the DAC sends an interrupt signal to the information handler to request the immediate transfer of a decoded packet of audio data. The decoded packets of audio data are transferred at a steady rate, which is controlled by the internal clock of the audio decoder. In the preferred embodiment, the internal clock is set to begin transfer of data every 4800 Hz. Alternatively, the internal clock may be set to begin transfer data every 9600 Hz. Thus, in the preferred embodiment, the DAC will interrupt the information handler to request a decoded packet of audio data at a regular frequency of 4800 Hz.
The DAC request for decoded packets of audio data must occur without any delay so that the system user does not hear any interruption in the playback of the audio data by the audio system. Therefore, the packets of audio data must be decoded prior to the conversion by the DAC. The DAC interrupts the
Dorvil Richemond
Koerner Gregory J.
Nolan Daniel A.
Simon & Koerner LLP
Sony Corporation
LandOfFree
System and method to manipulate information in an audio decoder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method to manipulate information in an audio decoder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method to manipulate information in an audio decoder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2454732