ICodecAPI interface (strmif.h)

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[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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 ICodecAPI interface sets and retrieves settings on an encoder or decoder filter.

Note

APIs declared in strmif.h are not supported for Universal Windows Platform (UWP) apps. To use ICodecAPI in a UWP app, use the version declared in icodecapi.h.

Inheritance

The ICodecAPI interface inherits from the IUnknown interface. ICodecAPI also has these types of members:

Methods

The ICodecAPI interface has these methods.

 
ICodecAPI::GetAllSettings

The GetAllSettings method gets the codec's current properties and writes them to a stream. (ICodecAPI.GetAllSettings)
ICodecAPI::GetDefaultValue

The GetDefaultValue method gets the default value of a codec property. (ICodecAPI.GetDefaultValue)
ICodecAPI::GetParameterRange

The GetParameterRange method gets the range of values for a codec property. (ICodecAPI.GetParameterRange)
ICodecAPI::GetParameterValues

The GetParameterValues method gets the list of possible values for a codec property. (ICodecAPI.GetParameterValues)
ICodecAPI::GetValue

The GetValue method gets the current value of a codec property.
ICodecAPI::IsModifiable

The IsModifiable method queries whether a codec property can be changed, given the codec's current configuration. (ICodecAPI.IsModifiable)
ICodecAPI::IsSupported

The IsSupported method queries whether a codec supports a given property. (ICodecAPI.IsSupported)
ICodecAPI::RegisterForEvent

The RegisterForEvent method registers the application to receive events from the codec. (ICodecAPI.RegisterForEvent)
ICodecAPI::SetAllDefaults

The SetAllDefaults method resets all codec properties to their default values. (ICodecAPI.SetAllDefaults)
ICodecAPI::SetAllDefaultsWithNotify

The SetAllDefaultsWithNotify method resets all codec properties to their default values, and returns a list of the properties that changed. (ICodecAPI.SetAllDefaultsWithNotify)
ICodecAPI::SetAllSettings

The SetAllSettings method reads codec properties from a stream and sets them on the codec. (ICodecAPI.SetAllSettings)
ICodecAPI::SetAllSettingsWithNotify

The SetAllSettingsWithNotify method reads codec properties from a stream, sets them on the codec, and returns a list of the properties that changed. (ICodecAPI.SetAllSettingsWithNotify)
ICodecAPI::SetValue

The SetValue method sets the value of a codec property. (ICodecAPI.SetValue)
ICodecAPI::SetValueWithNotify

The SetValueWithNotify method sets a property on a codec and returns a list of other properties that changed as a result. (ICodecAPI.SetValueWithNotify)
ICodecAPI::UnregisterForEvent

The UnregisterForEvent method unregisters the application for a specified encoder event. (ICodecAPI.UnregisterForEvent)

Remarks

This interface defines a generic mechanism for setting properties on a codec (encoder or decoder). A codec property is a key/value pair, where the key is a GUID and the value is a VARIANT. The interpretation of the VARIANT data depends on the property GUID. For a list of codec property GUIDs, see Codec API Properties.

Codec Profiles

Codecs can optionally store profile and capability information in the system registry. This information enables applications to query the device during device enumeration. Default profiles are stored in the following registry key:
HKEY_LOCAL_MACHINE
   Software
      Classes
         CLSID
            Category
               Profiles
Each profile is a registry key whose default string is a text description of the profile. Each value has a GUID name, followed by a string value containing the numeric GUID value. For example:
C++ 
  HLKM\Software\Classes\CLSID\<category>\Profiles\DVD
    default "HQ DVD"
    REG_SZ {...} = "0"
    REG_SZ {...} = "1234"
where {...} is a property GUID that the application can map into its user interface. Microsoft is currently considering the definition of a set of standard profiles.

Default codec capabilities are stored under HLKM\Software\Classes\CLSID&lt;category>\Instance&lt;Filter CLSID>\Capabilities. Each value has a GUID name, followed by a string value containing the numeric GUID value. For example:

C++ 
HLKM\Software\Classes\CLSID\<category>\Instance\<My DVD encoder>\Capabilities
     default "My DVD encoder"
     REG_SZ_MULTI {...}
where {...} is a property GUID that the application can map into its user interface.

Requirements

Requirement Value
Minimum supported client Windows XP with SP2 [desktop apps | UWP apps]
Minimum supported server Windows Server 2003 R2 [desktop apps | UWP apps]
Target Platform Windows
Header strmif.h (include Dshow.h)

See also

Decoder Settings for Windows Media Center Edition

Encoder API