diff options
Diffstat (limited to 'asio/asio.h')
| -rw-r--r-- | asio/asio.h | 115 |
1 files changed, 107 insertions, 8 deletions
diff --git a/asio/asio.h b/asio/asio.h index 3003130..8ec811f 100644 --- a/asio/asio.h +++ b/asio/asio.h @@ -3,9 +3,12 @@ /*
Steinberg Audio Stream I/O API
- (c) 1997 - 1999, Steinberg Soft- und Hardware GmbH
+ (c) 1997 - 2005, Steinberg Media Technologies GmbH
+
+ ASIO Interface Specification v 2.1
+
+ 2005 - Added support for DSD sample data (in cooperation with Sony)
- ASIO Interface Specification v 2.0
basic concept is an i/o synchronous double-buffer scheme:
@@ -131,7 +134,7 @@ enum { // these are used for 32 bit data buffer, with different alignment of the data inside
// 32 bit PCI bus systems can be more easily used with these
- ASIOSTInt32MSB16 = 8, // 32 bit data with 18 bit alignment
+ ASIOSTInt32MSB16 = 8, // 32 bit data with 16 bit alignment
ASIOSTInt32MSB18 = 9, // 32 bit data with 18 bit alignment
ASIOSTInt32MSB20 = 10, // 32 bit data with 20 bit alignment
ASIOSTInt32MSB24 = 11, // 32 bit data with 24 bit alignment
@@ -147,9 +150,56 @@ enum { ASIOSTInt32LSB16 = 24, // 32 bit data with 18 bit alignment
ASIOSTInt32LSB18 = 25, // 32 bit data with 18 bit alignment
ASIOSTInt32LSB20 = 26, // 32 bit data with 20 bit alignment
- ASIOSTInt32LSB24 = 27 // 32 bit data with 24 bit alignment
+ ASIOSTInt32LSB24 = 27, // 32 bit data with 24 bit alignment
+
+ // ASIO DSD format.
+ ASIOSTDSDInt8LSB1 = 32, // DSD 1 bit data, 8 samples per byte. First sample in Least significant bit.
+ ASIOSTDSDInt8MSB1 = 33, // DSD 1 bit data, 8 samples per byte. First sample in Most significant bit.
+ ASIOSTDSDInt8NER8 = 40, // DSD 8 bit data, 1 sample per byte. No Endianness required.
+
+ ASIOSTLastEntry
};
+/*-----------------------------------------------------------------------------
+// DSD operation and buffer layout
+// Definition by Steinberg/Sony Oxford.
+//
+// We have tried to treat DSD as PCM and so keep a consistant structure across
+// the ASIO interface.
+//
+// DSD's sample rate is normally referenced as a multiple of 44.1Khz, so
+// the standard sample rate is refered to as 64Fs (or 2.8224Mhz). We looked
+// at making a special case for DSD and adding a field to the ASIOFuture that
+// would allow the user to select the Over Sampleing Rate (OSR) as a seperate
+// entity but decided in the end just to treat it as a simple value of
+// 2.8224Mhz and use the standard interface to set it.
+//
+// The second problem was the "word" size, in PCM the word size is always a
+// greater than or equal to 8 bits (a byte). This makes life easy as we can
+// then pack the samples into the "natural" size for the machine.
+// In DSD the "word" size is 1 bit. This is not a major problem and can easily
+// be dealt with if we ensure that we always deal with a multiple of 8 samples.
+//
+// DSD brings with it another twist to the Endianness religion. How are the
+// samples packed into the byte. It would be nice to just say the most significant
+// bit is always the first sample, however there would then be a performance hit
+// on little endian machines. Looking at how some of the processing goes...
+// Little endian machines like the first sample to be in the Least Significant Bit,
+// this is because when you write it to memory the data is in the correct format
+// to be shifted in and out of the words.
+// Big endian machine prefer the first sample to be in the Most Significant Bit,
+// again for the same reasion.
+//
+// And just when things were looking really muddy there is a proposed extension to
+// DSD that uses 8 bit word sizes. It does not care what endianness you use.
+//
+// Switching the driver between DSD and PCM mode
+// ASIOFuture allows for extending the ASIO API quite transparently.
+// See kAsioSetIoFormat, kAsioGetIoFormat, kAsioCanDoIoFormat
+//
+//-----------------------------------------------------------------------------*/
+
+
//- - - - - - - - - - - - - - - - - - - - - - - - -
// Error codes
//- - - - - - - - - - - - - - - - - - - - - - - - -
@@ -403,9 +453,14 @@ enum kAsioSupportsTimeInfo, // if host returns true here, it will expect the
// callback bufferSwitchTimeInfo to be called instead
// of bufferSwitch
- kAsioSupportsTimeCode, // supports time code reading/writing
-
- kAsioSupportsInputMonitor, // supports input monitoring
+ kAsioSupportsTimeCode, //
+ kAsioMMCCommand, // unused - value: number of commands, message points to mmc commands
+ kAsioSupportsInputMonitor, // kAsioSupportsXXX return 1 if host supports this
+ kAsioSupportsInputGain, // unused and undefined
+ kAsioSupportsInputMeter, // unused and undefined
+ kAsioSupportsOutputGain, // unused and undefined
+ kAsioSupportsOutputMeter, // unused and undefined
+ kAsioOverload, // driver detected an overload
kAsioNumMessageSelectors
};
@@ -860,7 +915,14 @@ enum kAsioCanInputGain,
kAsioCanInputMeter,
kAsioCanOutputGain,
- kAsioCanOutputMeter
+ kAsioCanOutputMeter,
+
+ // DSD support
+ // The following extensions are required to allow switching
+ // and control of the DSD subsystem.
+ kAsioSetIoFormat = 0x23111961, /* ASIOIoFormat * in params. */
+ kAsioGetIoFormat = 0x23111983, /* ASIOIoFormat * in params. */
+ kAsioCanDoIoFormat = 0x23112004, /* ASIOIoFormat * in params. */
};
typedef struct ASIOInputMonitor
@@ -905,6 +967,43 @@ enum kTransMonitor // trackSwitches
};
+/*
+// DSD support
+// Some notes on how to use ASIOIoFormatType.
+//
+// The caller will fill the format with the request types.
+// If the board can do the request then it will leave the
+// values unchanged. If the board does not support the
+// request then it will change that entry to Invalid (-1)
+//
+// So to request DSD then
+//
+// ASIOIoFormat NeedThis={kASIODSDFormat};
+//
+// if(ASE_SUCCESS != ASIOFuture(kAsioSetIoFormat,&NeedThis) ){
+// // If the board did not accept one of the parameters then the
+// // whole call will fail and the failing parameter will
+// // have had its value changes to -1.
+// }
+//
+// Note: Switching between the formats need to be done before the "prepared"
+// state (see ASIO 2 documentation) is entered.
+*/
+typedef long int ASIOIoFormatType;
+enum ASIOIoFormatType_e
+{
+ kASIOFormatInvalid = -1,
+ kASIOPCMFormat = 0,
+ kASIODSDFormat = 1,
+};
+
+typedef struct ASIOIoFormat_s
+{
+ ASIOIoFormatType FormatType;
+ char future[512-sizeof(ASIOIoFormatType)];
+} ASIOIoFormat;
+
+
ASIOError ASIOOutputReady(void);
/* Purpose:
this tells the driver that the host has completed processing
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