Subformat GUIDs for Compressed Audio Formats
For Windows 7, new subformat GUIDs have been added to the Ksmedia.h header file to provide support for compressed audio formats. Subformat GUIDs indicate the specific subformat of a data format. These formats are defined by the Consumer Electronics Association (CEA) standard for uncompressed audio.
As a result of the CEA-861-D standard, you must ensure that audio formats that are not supported by a CEA device are not transmitted to such a device. High definition multimedia interface (HDMI) and DisplayPort are examples of CEA devices.
For user-mode access, the GUIDs are specified in the SubFormat member of WAVEFORMATEXTENSIBLE and in the FormatExt member of WAVEFORMATEXTENSIBLE_IEC61937. For kernel-mode access for audio drivers, the GUIDs are specified in the DataRange member of the KSDATARANGE_AUDIO structure.
The GUIDs for the available compressed audio formats are listed in the following table.
Note Not all the available formats are supported by the Windows 7 HD audio class driver. The formats supported by Windows 7 are indicated in the tables with an asterisk (*).
| CEA 861 type | SubFormat GUID | Description |
|---|---|---|
0x00 |
Refer to the stream. |
|
0x01 |
00000000-0000-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_WAVEFORMATEX |
IEC 60958 PCM |
0x02 |
00000092-0000-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_DOLBY_DIGITAL |
AC-3 |
0x03 |
00000003-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_MPEG1 |
MPEG-1 (Layer1 & 2) |
0x04 |
00000005-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_MPEG3 |
MPEG-3 (Layer 3) |
0x05 |
00000004-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_MPEG2 |
MPEG-2 (Multichannel) |
0x06 |
00000006-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_AAC |
Advanced audio coding* (MPEG-2/4 AAC in ADTS) |
0x07 |
00000008-0000-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_DTS |
Digital Theater Sound (DTS) |
0x0a |
0000000a-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_DOLBY_DIGITAL_PLUS |
Dolby Digital Plus |
0x0f |
Unused. |
Reserved |
The GUIDs for audio formats that are transmitted in high bit-rate audio sample packets are listed in the following table.
| CEA 861 type | SubFormat GUID | Description |
|---|---|---|
0x0b |
0000000b-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_DTS_HD |
DTS-HD (24-bit, 95KHz) |
0x0c |
0000000c-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_DOLBY_MLP |
MAT(MLP)- Meridian Lossless Packing (Dolby Digital True HD - 24-bit 196KHz/up to 18M bps, 8 channels) |
0x0e |
00000164-0000-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_WMA_PRO |
Windows Media Audio (WMA) Pro |
The GUIDs for compressed audio formats that can be implemented by third-party solutions are listed in the following table.
| CEA 861 type | SubFormat GUID | Description |
|---|---|---|
0x08 |
00000008-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_ATRAC |
Adaptive Transform Acoustic Coding (ATRAC) |
0x09 |
00000009-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_ONE_BIT_AUDIO |
One-bit audio |
0x0d |
0000000d-0cea-0010-8000-00aa00389b71 KSDATAFORMAT_SUBTYPE_IEC61937_DST |
Direct Stream Transport (DST) |
The following code example shows how an audio miniport driver defines and initializes a KSDATARANGE_AUDIO structure for use with an HDMI sink that has a fully functional Dolby Digital Plus decoder. A sink of this type supports transfer rates of 44.1 and 48 KHz.
For a sampling rate of 48 KHz, an audio miniport driver uses the following code to define and initialize a KSDATARANGE_AUDIO structure. This code shows the data ranges that the audio miniport driver exposes:
//Define and initialize KSDATARANGE_AUDIO structure
// for use with a sample rate of 48 KHz.
KSDATARANGE_AUDIO drDDPlus48;
drDDPlus48.DataRange.FormatSize = sizeof(KSDATARANGE_AUDIO);
drDDPlus48.DataRange.Flags = 0; // Ignored.
drDDPlus48.DataRange.SampleSize = 0; // Ignored.
drDDPlus48.DataRange.Reserved = 0;
drDDPlus48.DataRange.MajorFormat = KSDATAFORMAT_TYPE_AUDIO;
drDDPlus48.DataRange.SubFormat = KSDATAFORMAT_SUBTYPE_IEC61937_DOLBY_DIGITAL_PLUS;
drDDPlus48.DataRange.Specifier = KSDATAFORMAT_SPECIFIER_WAVEFORMATEX;
drDDPlus48.MaximumChannels = 2
drDDPlus48.MinimumBitsPerSample = 16; // All encoded data is transmitted at
drDDPlus48.MaximumBitsPerSample = 16; // 16 bits over IEC 60958.
drDDPlus48.MinimumSampleFrequency = 192000; // 48 KHz * 4.
drDDPlus48.MaximumSampleFrequency = 192000;
For a sampling rate of 44.1 KHz, an audio miniport driver uses the following code to define and initialize a KSDATARANGE_AUDIO structure:
//Define and initialize KSDATARANGE_AUDIO structure
// for use with a sample rate of 41.1 KHz.
KSDATARANGE_AUDIO drDDPlus44;
drDDPlus44.DataRange.FormatSize = sizeof(KSDATARANGE_AUDIO);
drDDPlus44.DataRange.Flags = 0 // Ignored.
drDDPlus44.DataRange.SampleSize = 0 // Ignored.
drDDPlus44.DataRange.Reserved = 0;
drDDPlus44.DataRange.MajorFormat = KSDATAFORMAT_TYPE_AUDIO;
drDDPlus44.DataRange.SubFormat = KSDATAFORMAT_SUBTYPE_IEC61937_DOLBY_DIGITAL_PLUS;
drDDPlus44.DataRange.Specifier = KSDATAFORMAT_SPECIFIER_WAVEFORMATEX;
drDDPlus44.MaximumChannels = 2
drDDPlus44.MinimumBitsPerSample = 16; // All encoded data is transmitted at
drDDPlus44.MaximumBitsPerSample = 16; // 16 bits over IEC 60958.
drDDPlus44.MinimumSampleFrequency = 176400; // 44.1 KHz * 4
drDDPlus44.MaximumSampleFrequency = 176400;