IMpegAudioDecoder interface (mpegtype.h)
[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The IMpegAudioDecoder interface is exposed on the MPEG-1 Audio Decoder filter and it enables applications to control decoding parameters. Most of these methods are useful only when an application is running on an older system and needs to sacrifice quality to increase performance. The default values provide the optimal decoding quality.
The two methods that are still useful in some scenarios are get_DualMode and put_DualMode. These methods enable applications to access either the right or left channel in VCD-based karaoke discs.
Inheritance
The IMpegAudioDecoder interface inherits from the IUnknown interface. IMpegAudioDecoder also has these types of members:
Methods
The IMpegAudioDecoder interface has these methods.
| IMpegAudioDecoder::get_AudioFormat Returns the audio format of the connected input pin. |
| IMpegAudioDecoder::get_DecoderAccuracy Returns the decoder accuracy as a three-level quality setting. |
| IMpegAudioDecoder::get_DecoderWordSize Returns the word size used to decode, either eight or 16 bit. |
| IMpegAudioDecoder::get_DualMode Returns which channel is currently being decoded. |
| IMpegAudioDecoder::get_FrequencyDivider Returns the frequency divider as a quality setting equal to CD Audio, FM Radio, or AM Radio. |
| IMpegAudioDecoder::get_IntegerDecode Returns whether the decoder is currently using integer-based decoding as opposed to floating point decoding. |
| IMpegAudioDecoder::get_Stereo Returns whether the decoder is decoding the encoded stream into stereo or mono PCM. |
| IMpegAudioDecoder::put_DecoderAccuracy Specifies the decoder accuracy as a three-level quality setting. |
| IMpegAudioDecoder::put_DecoderWordSize Specifies the word size used by the decoder. |
| IMpegAudioDecoder::put_DualMode Specifies the channel to be decoded. |
| IMpegAudioDecoder::put_FrequencyDivider Specifies the frequency divider as a three-level setting corresponding to the quality of CD Audio, FM Radio, or AM Radio. |
| IMpegAudioDecoder::put_IntegerDecode Specifies whether the decoder will use integer-based decoding. |
| IMpegAudioDecoder::put_Stereo Specifies whether the decoder will decode the encoded stream into stereo or mono PCM. |
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 2000 Professional [desktop apps only] |
| Minimum supported server | Windows 2000 Server [desktop apps only] |
| Target Platform | Windows |
| Header | mpegtype.h |