Dolby Digital Sound

By the time DVDs came out in 1997, Dolby Digital had become the default surround sound format. To this day, Dolby Digital 5.1 is considered by many to be the surround sound standard, still. Everyone wants High-quality audio for their laptops/PCs. But not all devices come with high-quality audio like Dolby/Dolby Digital Plus Sound. Here, I am sharing a tutorial for people who want Dolby for their Laptops/PCs. There 4 versions of Dolby Audio Listed Below. Dolby Digital, also known as Dolby AC-3, is the name for audio compression technologies developed by Dolby Laboratories.Originally named Dolby Stereo Digital until 1995, except for Dolby TrueHD, the audio compression is lossy, based on the modified discrete cosine transform (MDCT) algorithm. Dolby Atmos is a popular surround sound format, a competitor to DTS:X, and it's found in everything from the biggest commercial cinemas to the smallest of home theaters. Dolby Digital is an all-digital surround sound format that handles audio compression, so it’s available only for digital content. DVDs and HDTV use Dolby Digital (DVDs may also contain some other system, such as DTS — Digital Theater Systems). Dolby Digital 5.1 represents the current minimum level of performance that you should require from your.

-->

The Dolby audio decoder is a Media Foundation transform (MFT) that encodes mono or stereo audio to Dolby Digital, also called Dolby AC-3. The encoder does not support multi-channel input, such as the 5.1 channel configuration.

Important

For versions of Windows prior to Windows 8, the Microsoft implementation of the Dolby Digital technology is restricted under terms of the Dolby Digital licensing program to use by Microsoft applications.

For more information about Dolby Digital audio, refer to Advanced Television Systems Committee (ATSC) document Digital Audio Compression Standard (AC-3, E-AC-3) Revision B.

Class Identifier

The class identifier (CLSID) of the Dolby audio decoder is CLSID_CMSDolbyDigitalEncMFT, defined in the header file wmcodecdsp.h.

Output Types

The output type must be set first, before the input type. The following table lists the required and optional attributes for the output media type.

Attribute	Description	Remarks
MF_MT_MAJOR_TYPE	Major type.	Required. Must be MFMediaType_Audio.
MF_MT_SUBTYPE	Audio subtype.	Required. Must be MFAudioFormat_Dolby_AC3.
MF_MT_AUDIO_SAMPLES_PER_SECOND	Samples per second.	Required. The following values are supported: 32000 44100 48000
MF_MT_AUDIO_NUM_CHANNELS	Number of channels.	Required. Must be either 1 (mono) or 2 (stereo).
MF_MT_AUDIO_CHANNEL_MASK	Specifies the assignment of audio channels to speaker positions.	Optional. If set, the value must be 0x3 for stereo (front left and right channels) or 0x4 for mono (front center channel).
MF_MT_AUDIO_AVG_BYTES_PER_SECOND	Bit rate of the encoded AC-3 stream, in bytes per second.	Optional. See Remarks for valid values. If this attribute is not set, the encoder uses a default bit rate, as described in Remarks.

If the optional attributes are not set, the encoder adds them to the media type after the type is set.

Input Types

The following table lists the required and optional attributes for the input media type.

Attribute	Description	Remarks
MF_MT_MAJOR_TYPE	Major type.	Required. Must be MFMediaType_Audio.
MF_MT_SUBTYPE	Audio subtype.	Required. Must be MFAudioFormat_PCM or MFAudioFormat_Float.
MF_MT_AUDIO_BITS_PER_SAMPLE	Number of bits per audio sample.	Required. The value must be 16 if the subtype is MFAudioFormat_PCM, or 32 if the subtype is MFAudioFormat_Float.
MF_MT_AUDIO_SAMPLES_PER_SECOND	Samples per second.	Required. Must match the output type.
MF_MT_AUDIO_NUM_CHANNELS	Number of channels.	Required. Must match the output type.
MF_MT_AUDIO_BLOCK_ALIGNMENT	Block alignment, in bytes.	Required. Calculate the value as follows: MFAudioFormat_PCM: Number of channels × 2. MFAudioFormat_Float: Number of channels × 4.
MF_MT_AUDIO_AVG_BYTES_PER_SECOND	Bit rate of the encoded AC3 stream, in bytes per second.	Required. Must equal block alignment × samples per second.
MF_MT_AUDIO_CHANNEL_MASK	Specifies the assignment of audio channels to speaker positions.	Optional. If set, the value must match the output type.
MF_MT_AUDIO_VALID_BITS_PER_SAMPLE	Number of valid bits of audio data in each audio sample.	Optional. If set, the value must be identical to MF_MT_AUDIO_BITS_PER_SAMPLE.

The encoder does not support sample-rate conversion or stereo/mono conversion.

Remarks

Each Dolby AC-3 audio frame contains 1536 audio samples per channel. However, each input buffer to the encoder may contain any number of PCM samples. The size of each input buffer must be a multiple of the block alignment. The encoder caches input samples until it has enough for 1536 audio samples per channel; at which point the encoder outputs one AC-3 frame.

Each output buffer contains one raw AC-3 frame. The duration is equivalent to the duration of 1536 PCM samples at the current sampling rate (32 msec) at 48 kHz sample rate, 34.83 msec at 44.1 kHz, and 48 msec at 32 kHz). The size of each output buffer depends on the bit rate and the sample rate.

To specify the encoding bit rate, set the MF_MT_AUDIO_AVG_BYTES_PER_SECOND attribute in the output type. The following table shows the relation between encoding bit rate and MF_MT_AUDIO_AVG_BYTES_PER_SECOND.

Bit rate (kbps)	MF_MT_AUDIO_AVG_BYTES_PER_SECOND	Remarks
64	8000	Mono only.
80	10000	Mono only.
96	12000	Mono only.
112	14000	Mono only.
128	16000	Mono or stereo.
160	20000	Mono or stereo.
192	24000	Mono or stereo. This is the default setting for mono.
224	28000	Mono or stereo.
256	32000	Mono or stereo. This is the default setting for stereo.
320	40000	Stereo only.
384	48000	Stereo only.
448	56000	Stereo only.

Cff my darling libertysugars legacy stables near me. The default encoding bit rate is set at 256 kbps for stereo and 192 kbps for mono. The default settings are reflected in the media types returned by the encoder's IMFTransform::GetOutputAvailableType method.

Example Media Types