ACM Wrapper Filter (Compact 2013)

3/26/2014

The ACM Wrapper filter enables codecs that use the Audio Compression Manager (ACM) to join a DirectShow filter graph.

Decompression is only to PCM audio.

When wrapping a compressor, this filter appears in the audio compressor category and can support additional interfaces.

There should never be any need to add it manually to a graph; it is pulled in automatically by the Filter Graph Manager. It is used only for playback or sample rate conversion.

The ACM Wrapper filter supports the following ACM stream drivers and codecs:

  • WMA
  • G.711
  • MP3
  • MS ADPCM
  • IMA ADPCM

The following table shows the filter properties.

Filter property

Description

Filter Interfaces

IBaseFilter

Input Pin Media Types

MEDIATYPE_Audio, MEDIASUBTYPE_NULL

Input Pin Interfaces

IMemInputPin, IPin, IQualityControl

Output Pin Media Types

MEDIATYPE_Audio, MEDIASUBTYPE_PCM. Any combination of the following is possible:

  • Samples per second (kHz): 44.1, 22.05, 11.025, or 8.0.
  • Channels: stereo or mono.
  • Bits per sample: 8 or 16.

Output Pin Interfaces

IMediaPosition, IMediaSeeking, IPin, IQualityControl

Filter CLSID

CLSID_ACMWrapper

Executable

Quartz.dll

Merit

MERIT_NORMAL

Filter Category

CLSID_AudioCompressorCategory

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