Microsoft DirectX 8.0 |
Sets and retrieves properties on groups in Microsoft® DirectShow® Editing Services (DES).
A group contains one or more tracks, and possibly one or more compositions, which in turn contain source clips of a uniform type, such as video or audio. Groups are the topmost compositions in a timeline, and also support the AMTimelineComp object. A timeline can contain multiple groups.
Each group has the following attributes:
Methods
ClearRecompressFormatDirty Not supported for Visual Basic. GetGroupName Retrieves the application-defined name of the group. GetMediaType Not supported for Visual Basic. GetOutputBuffering Retrieves the number of frames rendered in advance during preview. GetOutputFPS Retrieves the output frame rate of this group. GetPreviewMode Retrieves the preview mode for the group. GetPriority Retrieves the group's priority. GetSmartRecompressFormat Not supported for Visual Basic. GetTimeline Retrieves the timeline to which this group belongs. IsRecompressFormatDirty Not supported for Visual Basic. IsSmartRecompressFormatSet Not supported for Visual Basic. SetGroupName Sets the application-defined name of the group. SetMediaType Not supported for Visual Basic. SetMediaTypeForVB Specifies the media type for the group. SetOutputBuffering Specifies the number of frames rendered in advance during preview. SetOutputFPS Sets the uncompressed output frame rate for this group. SetPreviewMode Sets the preview mode for the group. SetRecompFormatFromSource Sets the video recompression format using the compression format from a source file. SetSmartRecompressFormat Not supported for Visual Basic. SetTimeline Not supported for Visual Basic.
Not supported for Visual Basic.
Syntax
object.ClearRecompressFormatDirty()
Retrieves the application-defined name of the group.
Syntax
object.GetGroupName() As String
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
Return Value
Returns the application-defined name of the group.
Error Codes
If the method fails, an error is raised.
Not supported for Visual Basic.
Syntax
object.GetMediaType( pmt As _AMMediaType )
Retrieves the number of frames rendered in advance during preview.
Syntax
object.GetOutputBuffering( pnBuffer As Long )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- pnBuffer
- Variable that receives the number of buffered frames.
Error Codes
If the method fails, an error is raised.
Retrieves the output frame rate of this group.
Syntax
object.GetOutputFPS( pFPS As Double )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- pFPS
- Variable that receives the output frame rate, in frames per second.
Error Codes
If the method fails, an error is raised.
Retrieves the preview mode for the group.
Syntax
object.GetPreviewMode( pfPreview As Long )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- pfPreview
- Variable that receives a value indicating the preview mode. If zero, the group is in authoring mode. If non-zero, the group is in preview mode.
Error Codes
If the method fails, an error is raised.
Remarks
In preview mode, frames are dropped during slow effects or transitions to keep the video synchronized with the audio. The video might look choppy as a result. In authoring mode, every frame is rendered. Authoring mode is appropriate for writing files; for on-screen preview, the video might become out of sync with the audio.
Retrieves the group's priority.
Syntax
object.GetPriority( pPriority As Long )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- pPriority
- Variable that receives the group's priority.
Error Codes
If the method fails, an error is raised.
Not supported for Visual Basic.
Syntax
object.GetSmartRecompressFormat( ppFormat As Long )
Retrieves the timeline to which this group belongs.
Syntax
object.GetTimeline( ppTimeline As AMTimeline )
Parts
- object
- Object expression that evaluates to an AMTimeline object.
- ppTimeline
- AMTimeline object that receives the timeline. If the group is not part of a timeline, the object is set to Nothing.
Error Codes
If the method fails, an error is raised.
Not supported for Visual Basic.
Syntax
object.IsRecompressFormatDirty( pVal As Long )
Not supported for Visual Basic.
Syntax
object.IsSmartRecompressFormatSet( pVal As Long )
Sets the application-defined name of the group.
Syntax
object.SetGroupName( pGroupName As String )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- pGroupName
- Name of the group.
Error Codes
If the method fails, an error is raised.
Not supported for Visual Basic. Use the SetMediaTypeForVB method instead.
Syntax
object.SetMediaType( pmt As _AMMediaType )
Specifies the media type for the group.
Syntax
object.SetMediaTypeForVB( Val As Long )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- Val
- Value that specifies the media type:
Zero Video Non-zero Audio
Error Codes
If the method fails, an error is raised.
Remarks
This method supports the following formats.
- Video: 320 × 240 16-bit RGB, 555 format (MEDIASUBTYPE_RGB555).
- Audio: 44.1-kHz stereo PCM, 16 bits per sample (MEDIASUBTYPE_PCM).
Specifies the number of frames rendered in advance during preview.
Syntax
object.SetOutputBuffering( nBuffer As Long )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- nBuffer
- Number of frames to buffer during preview. Must be two or greater.
Error Codes
If the method fails, an error is raised, and Err.Number can be set to one of the following values:
E_INVALIDARG Invalid argument.
Remarks
A larger buffer requires more memory but can result in smoother previewing, especially during effects or transitions that require more time to render. The default buffer is 30 frames.
Sets the uncompressed output frame rate for this group.
Syntax
object.SetOutputFPS( FPS As Double )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- FPS
- Output frame rate for this group, in frames per second. The value cannot equal zero, and cannot have more than seven digits after the decimal place.
Error Codes
If the method fails, an error is raised, and Err.Number can be set to one of the following values:
E_INVALIDARG Invalid argument.
Remarks
Rendered output from this group runs at the specified frame rate, and all edits on the source material are rounded to the nearest frame boundary, as defined by the frame rate.
Sets the preview mode for the group.
Syntax
object.SetPreviewMode( fPreview As Long )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- fPreview
- Value that specifies the preview mode. If zero, the group is in authoring mode. If non-zero, the group is in preview mode.
Error Codes
If the method fails, an error is raised.
Remarks
In preview mode, frames are dropped during slow effects or transitions to keep the video synchronized with the audio. The video might look choppy as a result. In authoring mode, every frame is rendered. Authoring mode is appropriate for writing files; for on-screen preview, the video might be out of sync with the audio.
Sets the video recompression format using the compression format from a source file.
Syntax
object.SetRecompFormatFromSource( pSource As AMTimelineSrc )
Parts
- object
- Object expression that evaluates to an AMTimelineGroup object.
- pSource
- IAMTimelineSrc object.
Error Codes
If the method fails, an error is raised, and Err.Number can be set to one of the following values:
E_NO_TIMELINE The group is not within a timeline. E_OUTOFMEMORY Insufficient memory. VFW_E_INVALIDMEDIATYPE Source file has no video stream.
Remarks
This method finds the source file associated with pSource, retrieves the media type of the first video stream in the file, and sets the group compression format using that type.
Not supported for Visual Basic.
Syntax
object.SetSmartRecompressFormat( pFormat As Long )
Not supported for Visual Basic.
Syntax
object.SetTimeline( pTimeline As AMTimeline )