QMedia Video media commands

QM_SetVideoMediaCompression

QM_SetVideoMediaCompression(movieRef; trackID; codecType; codecQuality; codecDepth):error
movieRef Longint Movie reference
trackID Longint Track ID
codecType String4 Codec type
codecQuality Longint Compression quality
codecDepth Longint Color depth
error Longint Error result

Changes the compression options that are used when adding samples to a video track.

Parameter movieRef is the reference to the movie instance. The movie reference must have been previously obtained with a call to QM_NewMovieFromFile.

Parameter trackID is the ID of the track.

Parameter codecType is the four character identifier of the compressor (codec) component. For a list of available compressor components, use the QM_GetCodecList command.

Parameter codecQuality is the compression quality. QMedia defines the following constants for specifying the compression quality:

qm_MinQuality 0 Minimum compression quality.
qm_LowQuality 256 Low compression quality.
qm_NormalQuality 512 Normal compression quality.
qm_HighQuality 768 High compression quality.
qm_MaxQuality 1023 Maximum compression quality.
qm_LosslessQuality 1024 Lossless compression quality.

Parameter codecDepth specifies the color depth at which video samples are compressed. A value of 0 means that the compressor component must choose the best depth for the video samples.

QMedia sets the default compression options to the following values:

Codec:"jpeg"
Quality:qm_NormalQuality (512)
Depth:0 (use best depth)

Example

  `Set the compression settings for video track $trackID
 
C_STRING(4;$codec)
C_LONGINT($quality;$depth)
 
$codec:="jpeg" `JPEG codec
$quality:=qm_HighQuality `High quality
$depth:=0 `Best depth
 
$err:=QM_SetVideoMediaCompression ($movie;$trackID;$codec;$quality;0)
 
 

Related commands

QM_GetVideoMediaCompression Returns the compression options of new video samples.
QM_DoCodecSettingsDialog Displays the compression settings dialog.
QM_GetCodecs Returns the list of all QuickTime codecs

QMedia © Escape OE
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