显示MPEG-4导出组件对话框

Question

下面是我的一个基于文档的QTKit应用程序的代码，它通过显示三个设备选项的popUp导出到固定的苹果设备格式。NSNumberWithLong:mpg4‘选项也工作得很好，但它缺乏自定义输出设置。我想集成熟悉的QT 4导出组件对话框，以便用户可以自定义MPEG-4输出选项。

有人能解释一下如何做到这一点吗？

谢谢。

-paul。

- (void)exportPanelDidEnd:(NSSavePanel *)sheet returnCode:(int)returnCode contextInfo:(void *)contextInfo
{
int which = [mExportTypePopUpButton indexOfSelectedItem];
int                 selectedItem;
NSMutableDictionary *settings = nil;
static NSArray      *exportTypes = nil;

// init
if (exportTypes == nil)
{
    exportTypes = [[NSArray arrayWithObjects:

                    //[NSNumber numberWithLong:'mpg4'],   ///MPEG-4

                    [NSNumber numberWithLong:'M4VH'],   ///Apple Tv
                    [NSNumber numberWithLong:'M4VP'],   ///iPhone
                    [NSNumber numberWithLong:'M4V '],   ///iPod

                    nil] retain];
}





if (returnCode == NSOKButton)
{
    // init
    selectedItem = [mExportTypePopUpButton indexOfSelectedItem];
    settings = [NSMutableDictionary dictionaryWithCapacity:2];
    [settings setObject:[NSNumber numberWithBool:YES] forKey:QTMovieExport];



    if ((selectedItem >= 0) && (selectedItem < [exportTypes count]))
        [settings setObject:[exportTypes objectAtIndex:selectedItem] forKey:QTMovieExportType];

    if (which==0)

        [mReceiver setStringValue:@"Apple Tv"];


    if (which==1)

        [mReceiver setStringValue:@"iPhone"];


    if (which==2)

        [mReceiver setStringValue:@"iPod"];





    /
    if (![mMovie writeToFile:[sheet filename] withAttributes:settings])
        NSRunAlertPanel(@"Cancel", @"Export terminated.", nil, nil, nil);



}

}

Answer 1

下面是我们将要使用的标准Quicktime组件导出设置对话框：

​

​

该对话框仅在Quicktime框架中可用(不要与QTKit混淆)，因此存在以下限制：

仅限

1. 32位内部版本的
2. 没有任何iOS集成。

您需要做的第一件事是将您的应用程序链接到Quiktime框架，确保您在32位Intel体系结构中构建它，并启用了build Active architecture Only设置。

目标是打开对话框，设置必要的导出设置，并使用它们导出影片。

我将以相反的顺序提供代码片段，从实际的对话调用开始，回到所需结构的使用。我们必须使用大量的代码，所以需要一些耐心。

该对话框需要Quicktime组件。在我们的示例中，我们将使用MPEG4组件。我们提供组件，先前存储的设置，并打开对话框：

#import <QuickTime/QuickTimeComponents.h>

- (void)editExportSetting:(JSMovieExportSetting*)setting
{
    MovieExportComponent exporter = OpenComponent(_MPEG4Component.component);
    Boolean canceled;
    [self updateMovieExportComponent:exporter withExportSetting:setting];
    ComponentResult err = MovieExportDoUserDialog(exporter, NULL, NULL, 0, 0, &canceled);
    if (!canceled)
    {
        if (err == 0)
        {
            [self updateExportSetting:setting withMovieExportComponent:exporter];
        }
    }
    CloseComponent(exporter);   
}

当用户完成编辑并单击“确定”按钮时，我们将存储设置以供以后使用。OpenComponent函数需要Component数据类型。我已经为它构建了一个方便的类包装器，请参见下面的清单。

现在我们需要获取MPEG4组件：

- (JSQTComponent*)MPEG4Component
{
    /*
     MPEG-4
     */
    ComponentDescription description;
    description.componentType = 1936746868;
    description.componentSubType = 1836082996;
    description.componentManufacturer = 1634758764;
    description.componentFlags = 269058096;
    description.componentFlagsMask = 66207;

    return [self componentWithDescription:description];
}

- (JSQTComponent*)componentWithDescription:(ComponentDescription)description
{
    JSQTComponent* result = nil;
    for (JSQTComponent* component in [self components])
    {
        if ([component isEqualToComponentDescription:description])
        {
            result = component;
            break;
        }
    }
    return result;
}

- (NSArray*)components
{
    if (_components == nil)
    {
        _components = [NSMutableArray new];
        QTAtomContainer resources = NULL;
        OSErr err = GetComponentPublicResourceList(kQTPresetsListResourceType, 1, 0, &_componentDescription, nil, nil, &resources);

        if (err != noErr)
        {
            NSLog(@"JSQTComponentDataModel error: %d", err);
        }
        else if (resources != NULL)
        {
            QTAtom currChild = 0;
            QTAtom nextChild = 0;
            OSErr err;
            unsigned atomsCount = QTCountChildrenOfType(resources, kParentAtomIsContainer, 0);
            for (UInt16 i=0; i < atomsCount; i++)
            {
                QTAtom compAtomId = 0;
                if (QTFindChildByIndex(resources, kParentAtomIsContainer, kQTMetaDataCommonKeyComposer, i+1, &compAtomId))
                {
                    Component component = (Component)compAtomId;
                    err = QTNextChildAnyType(resources, kParentAtomIsContainer, currChild, &nextChild);
                    if (err == noErr && nextChild)
                    {
                        [_components addObject:[[[JSQTComponent alloc] initWithComponent:component] autorelease]];
                    } 
                    else
                    {
                        NSLog(@"Error %d getting item %d\n", err, i);
                    }
                    currChild = nextChild;
                }
            }
            QTDisposeAtomContainer(resources);
        }
    }
    return _components;
}

基本上，我们在列表中查找具有所需描述的组件。该列表是为了获取特定类型的组件而构建的，因为Quicktime有大量不同的一次。

我们只对为电影出口创建的那些感兴趣。

ComponentDescription _componentDescription;

_componentDescription.componentType = MovieExportType;
_componentDescription.componentSubType = kAnyComponentSubType;
_componentDescription.componentManufacturer = kAnyComponentManufacturer;
_componentDescription.componentFlags = canMovieExportFiles;
_componentDescription.componentFlagsMask = canMovieExportFiles;

列表被缓存以备将来使用，不要忘了在dealloc中释放它。

到目前为止，我们进展得还不错。我们得到了我们的MPEG4组件对象，从中得到了Component结构。现在，我们需要将上次存储的设置应用于组件。

- (void)updateMovieExportComponent:(MovieExportComponent)component withExportSetting:(JSMovieExportSetting*)movieExportSetting
{
    NSData* presetSettings = movieExportSetting.exportSettings;
    Handle settings = NewHandleClear([presetSettings length]);
    if (settings)
    {
        memcpy(*settings, [presetSettings bytes], GetHandleSize(settings));
        // Set movie export settings from the settings QTAtomContainer
        MovieExportSetSettingsFromAtomContainer(component, (QTAtomContainer)settings);
        DisposeHandle(settings);
    }
}

如果您在没有任何设置的情况下第一次使用该组件，该对话框将显示一次默认值。

在用户完成编辑并按下OK后，我们需要存储设置：

- (void)updateExportSetting:(JSMovieExportSetting*)movieExportSetting withMovieExportComponent:(MovieExportComponent)component
{
    QTAtomContainer settings;
    ComponentResult err = MovieExportGetSettingsAsAtomContainer(component, &settings);
    if (err == 0)
    {
        NSData* exportSettings = [NSData dataWithBytes:*settings length:GetHandleSize(settings)];
        movieExportSetting.exportSettings = exportSettings;
    }
}

JSMovieExportSetting是一个包装器，请参见下面的清单。您可以轻松地将其序列化到一个文件中以存储设置。

最后一步是使用我们刚刚获得的电影转换设置。好消息是，我们不再需要使用Quicktime，我们可以使用QTKit方法。

QTMovie* movie = [QTMovie movieWithFile:sourceFilePath error:outError];

NSDictionary* settings = [movieExportSetting movieAttributes];

[movie writeToFile:outputFilePath withAttributes:settings error:outError]

如果需要，设置电影委托并实现movie: shouldContinueOperation: withPhase: atPercent: withAttributes:来查看进度。

您可以在下面找到所使用的类的列表。我希望这能帮到你。

JSQTComponent

@interface JSQTComponent : NSObject
{
    Component _component;
    ComponentDescription _componentDescription;
    NSString* _name;
    NSString* _info;
    NSString* _icon;
}

- (id)initWithComponent:(Component)component;

@property (nonatomic, readonly) Component component;
@property (nonatomic, readonly) ComponentDescription componentDescription;
@property (nonatomic, retain) NSString* name;
@property (nonatomic, retain) NSString* info;
@property (nonatomic, retain) NSString* icon;

- (BOOL)isEqualToComponentDescription:(ComponentDescription)anotherComponentDescription;

@end

@实现JSQTComponent

@合成组件= _component；@合成图标= _componentDescription；@合成名称= _name；@合成信息= _info；@合成图标= _icon；

• (id)initWithComponent:(Component)component { self =超级初始化；if (self != nil) { _component =组件；self getDescription；}返回self；}
• (void)getDescription { _name release；_info release；_icon release；super dealloc；}
• (void)getDescription{ OSErr err；Handle aName = NewHandleClear(255)；Handle anInfo = NewHandleClear(255)；Handle anIcon = NewHandleClear(255)；Handle iconSuite = NULL；err = GetComponentInfo(_component，&_componentDescription，aName，anInfo，anIcon)；if (err == 0) { self.name = NSString stringWithPStringHandle:aName；self.info = NSString stringWithPStringHandle:anInfo；self.icon = NSString stringWithPStringHandle:anIcon； //err = GetComponentIconSuite(aComponent，&iconSuite)；} DisposeHandle(aName)；DisposeHandle(anInfo)；DisposeHandle(anIcon)；DisposeHandle(iconSuite)； }
• (BOOL)isEqualToComponentDescription:(ComponentDescription)anotherComponentDescription { return (_componentDescription.componentType == anotherComponentDescription.componentType) && (_componentDescription.componentSubType == anotherComponentDescription.componentSubType) && (_componentDescription.componentManufacturer == anotherComponentDescription.componentManufacturer); }

@end

JSMovieExportSetting

@interface JSMovieExportSetting : NSObject <NSCoding>
{
    NSString* _name;
    NSNumber* _componentSubType;
    NSNumber* _componentManufacturer;
    NSData* _exportSettings;

    NSDictionary* _movieAttributes;
}

- (id)initWithName:(NSString*)name attributes:(NSDictionary*)attributes;

@property (nonatomic, retain) NSString* name;
@property (nonatomic, retain) NSNumber* componentSubType;
@property (nonatomic, retain) NSNumber* componentManufacturer;
@property (nonatomic, retain) NSData* exportSettings;
@property (nonatomic, readonly) NSDictionary* movieAttributes;

@end


@implementation JSMovieExportSetting

...

- (NSDictionary*)movieAttributes
{
    if (_movieAttributes == nil)
        _movieAttributes = [[NSDictionary dictionaryWithObjectsAndKeys:
                            [NSNumber numberWithBool:YES], QTMovieExport,
                            _componentSubType, QTMovieExportType,
                            _componentManufacturer, QTMovieExportManufacturer,
                            _exportSettings, QTMovieExportSettings, nil] retain];
    return _movieAttributes;
}

- (void)setExportSettings:(NSData*)exportSettings
{
    if (_exportSettings != exportSettings)
    {
        [_exportSettings release];
        _exportSettings = [exportSettings retain];

        [_movieAttributes release];
        _movieAttributes = nil;
    }
}

...

@end