Creating Settings Presets to Configure the Exporter

Alternate Approach

Alternately, you can manually configure the exporter using the various QTAtom routines.

To use this technique, first get the default settings from the exporter, use the functions which operate on QuickTime atoms to locate the atoms associated with the desired settings, then update the atoms for the new settings. Next, configure the exporter with the new settings. Finally, call ConvertMovieToFile or ConvertMovieToDataRef to perform the conversion, passing the fully configured export component as the last parameter to this function.

Here's the detailed steps:

• Find and open the desired export component.

• Call MovieExportGetSettingsAsAtomContainer to retrieve the default settings from the export component

• Use the QTAtom routines to locate the particular atoms

• Change the atom settings as desired

• Call MovieExportSetSettingsFromAtomContainer to set the exporter settings

• Call ConvertMovieToFile or ConvertMovieToDataRef to perform the conversion, passing the fully configured export component as the last parameter to this function.

This technique is demonstrated in Technical Q&A QA1147, 'Programmatic configuration of a Movie Export Component'.

As noted above, only part of the settings atoms used to configure the exporters are documented. Therefore, it may not be possible to fully configure the exporter using this technique.

However, the definitions for the settings atoms used with the Standard Image Compression Dialog component and functions such as SCSetInfo can be found in the QuickTimeComponents.h header file.

Atoms for the visual settings can be found in the kQTSettingsVideo ('vide') container atom. Atoms for the audio settings can be found in the kQTSettingsSound ('soun') container atom.

For example, the spatial compression parameters used with the Standard Image Compression Dialog component are stored in the 'vide' container atom in an atom with ID scSpatialSettingsType ('sptl') and data in an SCSpatialSettings structure:

struct SCSpatialSettings {

  CodecType           codecType;

  CodecComponent      codec;

  short               depth;

  CodecQ              spatialQuality;

};

Similarly, temporal compression parameters are stored in an atom with ID scTemporalSettingsType ('tprl') and data in an SCTemporalSettings structure:

struct SCTemporalSettings {

  CodecQ              temporalQuality;

  Fixed               frameRate;

  long                keyFrameRate;

};

Compression data rate settings are stored in an atom with ID scDataRateSettingsType ('drat') and data in an SCDataRateSettings structure:

struct SCDataRateSettings {

  long                dataRate;

  long                frameDuration;

  CodecQ              minSpatialQuality;

  CodecQ              minTemporalQuality;

};

References

• Technical Q&A QTMTB62, 'Batch Exporting movie sound tracks with ConvertMovieToFile'

• Technical Q&A QA1147, 'Programmatic configuration of a Movie Export Component'

• QTDataExchange sample code

• BackgroundExporter sample code

• Finding Movie Export Components