Apparatus and method for playback of waveform sample data

• US 20020007426A1
• Filed: 09/06/2001
• Published: 01/17/2002
• Est. Priority Date: 01/09/1998
• Status: Active Grant

• Current Assignee: Takashi Suzuki, Tokiharu Ando
• Original Assignee: Takashi Suzuki, Tokiharu Ando
• Inventors: Ando, Tokiharu, Suzuki, Takashi
• Granted Patent: US 6,553,436 B2
• Time in Patent Office: Days
• US Class Current: 710/25
• CPC Class Codes: G06F 3/16 Sound input; Sound output speech processing G10L
• CPC Class Codes: G10H 1/0058 Transmission between separate instruments or between individual components of a musical system G10H1/0083 takes precedence
• CPC Class Codes: G10H 2210/391 Automatic tempo adjustment, correction or control
• CPC Class Codes: G10H 2240/071 Wave, i.e. Waveform Audio File Format, coding, e.g. uncompressed PCM audio according to the RIFF bitstream format method
• CPC Class Codes: G10H 2240/311 MIDI transmission G10H2240/056 takes precedence

Abstract

An audio record/playback system is configured using a RAM containing PC buffers and a sound input/output board which is equipped with another RAM containing P buffers and R buffers as well as a digital audio circuit. At a playback mode, waveform sample data consisting of waveform samples are subjected to burst transfer using a PCI bus from the PC buffer to the P buffer in a first half duration of each sampling period with respect to one channel. In a second half duration, one of the waveform samples is transferred from the P buffer to the digital audio circuit, wherein it is subjected to digital audio processing. Thus, the waveform sample data are played back in response to prescribed timings synchronized with sampling periods. At a record mode, waveform sample data corresponding to sounds to be picked up are supplied to the digital audio circuit, from which they are transferred to the R buffer. Then, the waveform sample data are transferred to the PC buffer. At a sequence playback mode, a set of WAVE data are loaded from an external storage unit to the RAM with respect to multiple channels in response to a sequence playback instruction. Then, the WAVE data are transferred to the sound input/output board, by which they are played back. Incidentally, when playback is completed with respect to one channel, next WAVE data regarding another channel are automatically loaded to the RAM.

Claims

1. A waveform playback apparatus comprising:

a CPU that controls the apparatus as a whole;

a memory that stores a plurality of waveform data which are played back by a plurality of channels;

a buffer memory that stores waveform data of plural samples with respect to each of the plurality of channels;

a digital audio circuit that inputs the waveform data of the plurality of channels in a sampling period;

a bus having a burst transfer function;

a first transfer circuit that transfers the waveform data stored in the memory via the bus with respect to each of the channels; and

a second transfer circuit that reads the waveform data from the buffer memory by each of the plural samples in each sampling period with respect to each of the channels independently, so that the second transfer circuit transfers the read waveform data to the digital audio circuit,

wherein the buffer memory stores a part of the waveform data stored in the memory with respect to each of the channels, and

wherein when the second transfer circuit starts data transfer for a single specific channel, the first transfer circuit performs burst transfer, using units of plural samples, on a top portion of the waveform data to the buffer memory, so that after the second transfer circuit starts the data transfer for the single specific channel, the first transfer circuit performs burst transfer, using units of plural samples, on following waveform data following the waveform data which have been already transferred to the buffer memory if a prescribed vacant area is created in the buffer memory due to the data transfer performed by the second transfer circuit.

2. A waveform playback apparatus according to claim 1, wherein the first transfer circuit gives a higher priority to a channel corresponding to a large vacant area of the buffer memory, so that the first transfer circuit performs the burst transfer regarding the following waveform data with respect to the channel.

3. A waveform playback apparatus according to claim 1, wherein the first transfer circuit performs the burst transfer so that the waveform data are sequentially transferred to the buffer memory, in which the prescribed vacant area is created, by units of plural samples in order.

4. A waveform output circuit connected with a bus having a burst transfer function, comprising:

a buffer memory that stores waveform data of plural samples with respect to each of a plurality of channels;

a first transfer circuit that accesses a memory storing waveform data of the plurality of channels to perform burst transfer, using units of plural samples, on the waveform data of at least one channel every sampling period;

a digital audio circuit that inputs the waveform data of the plurality of channels every sampling period; and

a second transfer circuit that reads each of the plural samples of the waveform data stored in the buffer memory every sampling period, so that the second transfer circuit transfers the read waveform data to the digital audio circuit,

wherein when the second transfer circuit starts data transfer for a single specific channel, the first transfer circuit performs burst transfer, using units of plural samples, on a top portion of the waveform data to the buffer memory, so that after the second transfer circuit starts the data transfer for the single specific channel, the first transfer circuit performs burst transfer, using units of plural samples, on following waveform data following the waveform data which have been already transferred to the buffer memory if a prescribed vacant area is created in the buffer memory due to the data transfer performed by the second transfer circuit.

5. A waveform playback method using a bus having a burst transfer function, comprising the steps of:

storing waveform data of a plurality of channels in a memory;

performing first data transfer to transfer the waveform data stored in the memory to a storage area, which is provided for each of the channels, via the bus; and

performing second data transfer in such a way that the waveform data stored in the buffer memory are read by each sample every sampling period with respect to each of the channels independently and are transferred to the digital audio circuit,

wherein the buffer memory i s capable of storing a part of the waveform data stored in the memory with respect to each channel, and

wherein when the second data transfer is initiated with respect to a single specific channel, the first data transfer is performed in such a way that a top portion of the waveform data are subjected to burst transfer, using units of plural samples, to the buffer memory, so that after the second data transfer is started with respect to the single specific channel, the first data transfer is performed in such a way that following waveform data following the waveform data which have been already transferred to the buffer memory, are subjected to burst transfer, using units of plural samples, from the memory to the buffer memory if a prescribed vacant area is created in the buffer memory due to the second data transfer.

6. A waveform playback method for playing back waveform data in response to an instruction given from a CPU, said waveform playback method comprising the steps of:

sequentially transferring waveform data stored in a memory by each of prescribed portions from a top portion of the waveform data, so that the waveform data are sequentially transferred to a buffer memory via a bus in accordance with the instruction given from the CPU; and

generating a timing signal when a count value of a counter counting a number of timing pulses coincides with timing data set by the CPU; and

sequentially playing back the waveform data stored in the buffer memory from the top portion in response to the timing signal.

7. A waveform playback apparatus comprising:

a CPU for controlling the apparatus as a whole;

a first bus connected to the CPU;

a memory, connected to the first bus, which stores a plurality of waveform data;

a second bus provided independently of the first bus;

a buffer memory having storage areas for a plurality of channels respectively, the buffer memory being connected to the second bus and being capable of storing a part of the waveform data;

supply means for sequentially supplying the waveform data to be played back for each channel from the memory to the storage area of the buffer memory corresponding to each channel, wherein supply of the waveform data is performed from a top portion;

a register to which the CPU sets timing data for each channel;

a counter for counting a number of timing pulses;

timing generation means for generating a timing signal based on a count value of the counter and the timing data set to the register; and

read playback means for reading the waveform data from the storage area of the buffer memory in response to the timing signal so as to play back the waveform data with respect to each channel.

8. A waveform output circuit for accessing a memory, which is connected with a bus and which stores a plurality of waveform data, to read and play back the waveform data, said waveform output circuit comprising:

a buffer memory having a plurality of storage areas, each of which is capable of storing a part of the waveform data with respect to each of the plurality of channels;

supply means for accessing the memory to sequentially read the waveform data to be played back in each channel from a top portion to the storage area of the buffer memory corresponding to each channel;

a register for storing timing data;

a counter for counting a number of timing pulses;

timing generation means for generating a timing signal based on a count value of the counter and the timing data set to the register; and

read playback means for reading the waveform data from the storage area of the buffer memory in response to the timing signal so as to play back the waveform data with respect to each channel.

9. A sequence playback apparatus for dealing with waveform data by using “

n”

(where “

n”

is an integer) channels, comprising;

a memory for storing a plurality of waveform data;

a sequence memory for storing a plurality of event data in order, wherein the plurality of event data represent playback timings of the plurality of waveform data respectively;

a buffer memory having “

n”

storage areas which correspond to the “

n”

channels respectively;

channel assignment means for sequentially assigning the event data stored in the sequence memory to open channels which are sequentially released in operations within the “

n”

channels, wherein assignment of the event data is started with respect to the event data whose timing comes first;

supply means for supplying the storage area of the buffer memory with the waveform data designated by the event data within the plurality of waveform data, wherein the waveform data are sequentially supplied to the buffer memory from a top portion by each of prescribed portions;

a counter for counting a number of timing pulses;

detection means for detecting a playback timing of the event data assigned to each channel on the basis of a count value of the counter;

read playback means for accessing the storage area of the buffer memory in response to the detected playback channel to sequentially read and play back the waveform data with respect to each channel whose playback timing is detected; and

channel release means for detecting a channel that the read playback means completes reading operation so as to release the channel.

10. A waveform record/playback system comprising:

a first memory having a plurality of storage areas, each of which stores waveform sample data consisting of plural waveform samples with respect to each of channels;

a bus having a burst transfer function; and

sound board means connected with the bus,

wherein the sound board means comprises

a second memory having a plurality of buffer areas corresponding to the channels respectively,

first transfer means for performing burst transfer so that the waveform sample data are subjected to burst transfer from the first memory to the second memory with respect to each of the channels every sampling period,

digital audio processing means for performing digital audio processing, and

second transfer means for transferring each of waveform samples from the second memory to the digital processing means every sampling period with respect to each of the channels.

11. A waveform record/playback system according to claim 10 further comprising:

timing generation means for generating playback timings; and

sound playback means for playing back the waveform sample data by producing sounds corresponding to output of the digital audio processing means in response to the playback timings.

12. A waveform record/playback system according to claim 10 further comprising sound input means for inputting waveform sample data representing sounds to be picked up, so that the input waveform sample data are subjected to the digital audio processing to produce processed waveform sample data, wherein the processed waveform sample data are temporarily stored in the second memory and are then transferred to the first memory via the bus.

13. A waveform record/playback system according to claim 10, wherein both of the first memory and the second memory are configured by random access memories.

14. A waveform record/playback system according to claim 10 further comprising external storage means for storing programs and/or waveform sample data.

15. A waveform record/playback system according to claim 14, wherein the external storage means is configured using a hard disk and/or a CDROM.

16. A waveform record/playback system according to claim 10, wherein the bus is configured by a PCI bus.

17. A waveform record/playback system according to claim 10, wherein the second memory contains a first number of play buffers and a second number of record buffers, wherein the play buffer is used exclusively for playback so that the waveform sample data are subjected to burst transfer from the first memory to the play buffer of the second memory with respect to each of the channels, while the record buffer is used exclusively for record so that output of the digital audio means is temporarily stored in the record buffer and is then transferred to the first memory with respect to each of the channels.

18. A waveform record/playback system according to claim 10, wherein the second transfer means accesses the second memory in a first half duration of the sampling period while the first transfer means accesses the second memory in a second half duration of the sampling period.

19. A waveform record/playback system according to claim 10, wherein the digital audio means is configured by a mixer and/or a digital signal processor.

20. A waveform playback method comprising the steps of:

accessing a memory to read waveform sample data consisting of a plurality of waveform samples with respect to each of channels;

performing burst transfer on the waveform sample data to a buffer memory every sampling period with respect to each of the channels;

designating playback timings;

transferring each of the plurality of waveform samples to a digital audio circuit every sampling period in response to the playback timings; and

producing sounds based on output of the digital audio circuit.

21. A waveform record method comprising the steps of:

inputting audio signals representing sounds to be picked up;

performing digital audio processing on the audio signals to produce waveform sample data consisting of a plurality of waveform samples;

transferring each of the waveform samples to a buffer memory every sampling period;

performing burst transfer on the waveform sample data from the buffer memory to a memory every sampling period; and

recording the waveform sample data on the memory.

22. A data transfer method for sequence playback in which WAVE data are sequentially played back in accordance with sequence data, said data transfer method comprising the steps of:

transferring a first set of WAVE data from an external storage to a memory in advance; and

additionally loading next WAVE data, following the WAVE data which have been already transferred to the memory, to the memory every time playback is completed with respect to one WAVE data stored in the memory.

23. A data transfer method employed in an audio record/playback system, comprising the steps of:

performing a transfer preparation process, in a first half duration of each sampling period, so as to determine a channel, for which data transfer is performed, within a plurality of channels;

performing a first transfer process corresponding to a burst transfer using a high-speed bus on waveform sample data, consisting of a plurality of waveform samples, between a first memory and a second memory, in a second half duration of each sampling period, with respect to the channel which is determined by the transfer preparation process; and

performing a second transfer process in the first half duration of each sampling period in such a way that one waveform sample is transferred between the second memory and a digital audio circuit.

24. A data transfer method according to claim 23, wherein in the first transfer process, the burst transfer is performed using the high-speed bus whose bus use right is secured prior to the burst transfer and which is then released after completion of the burst transfer.

25. A data transfer method according to claim 23 further comprising the steps of:

counting a number of timing pulses synchronized with the sampling periods to produce a count value;

generating a timing signal based on the count value and timing data which are set in advance; and

initiating playback of the waveform sample data stored in the second memory in response to the timing signal with respect to each of the plurality of channels.

26. A sequence playback method comprising the steps of:

loading waveform sample data to a first memory with respect to a plurality of channels in response to a sequence playback instruction;

performing a burst transfer with respect to one of the plurality of channels so that waveform sample data consisting of a plurality of waveform samples are sequentially transferred using a high-speed bus from a first memory to a second memory;

detecting a playback start timing which is set in advance;

starting a data transfer at the playback start timing so that the waveform sample data are transferred from the second memory to a digital audio circuit;

effecting digital audio processing on the waveform sample data in the digital audio circuit in accordance with sequence data related to the sequence playback instruction; and

playing back the waveform sample data subjected to the digital audio processing until a playback end timing which is set in advance.

27. A sequence playback method according to claim 26 further comprising the steps of:

detecting occurrence of a channel interrupt which is caused to occur when the burst transfer is completed with respect to one of the plurality of channels;

detecting a channel which differs from the plurality of channels and whose waveform sample data should be loaded to the first memory; and

further loading the waveform sample data of the channel to the first memory.

28. A machine-readable media storing programs and data that cause an audio record/playback system incorporating a computer to perform a data transfer method comprising the steps of:

performing a transfer preparation process, in a first half duration of each sampling period, so as to determine a channel, for which data transfer is performed, within a plurality of channels;

performing a first transfer process corresponding to a burst transfer using a high-speed bus on waveform sample data, consisting of a plurality of waveform samples, between a first memory and a second memory, in a second half duration of each sampling period, with respect to the channel which is determined by the transfer preparation process; and

performing a second transfer process in the first half duration of each sampling period in such a way that one waveform sample is transferred between the second memory and a digital audio circuit.

29. A machine-readable media storing waveform sample data and programs that cause an audio playback system incorporating a computer to perform a sequence playback method comprising the steps of:

loading the waveform sample data to a first memory with respect to a plurality of channels in response to a sequence playback instruction;

performing a burst transfer with respect to one of the plurality of channels so that waveform sample data consisting of a plurality of waveform samples are sequentially transferred using a high-speed bus from a first memory to a second memory;

detecting a playback start timing which is set in advance;

starting a data transfer at the playback start timing so that the waveform sample data are transferred from the second memory to a digital audio circuit;

effecting digital audio processing on the waveform sample data in the digital audio circuit in accordance with sequence data related to the sequence playback instruction; and

playing back the waveform sample data subjected to the digital audio processing until a playback end timing which is set in advance.