Question

我刚刚创建了一个使用QTKit合并两个视频的简单应用

以下是问题：

我刚刚发现如果我尝试合并两个宽度不同的视频。高度输出是一个视频，其高度和宽度与大视频相同，但包含带有黑色和宽边框的小视频。

问题：

如何将两个视频合并在一起并获得格式正确（宽度/高度）的输出视频？

更好地了解我需要的示例：

我有两个视频：

视频1 = 1920 x 1280 VIdeo 2 = 1280 x 960

我想要的是：1920 x 1280的视频（需要升级和裁剪小视频）

代码：

-(void)voidMethodToCombine {


NSError *err = nil;
QTMovie *myCombinedMovie = [[QTMovie alloc] initToWritableData:[NSMutableData data] error:&err];
if (err)
{
    NSRunAlertPanel(@"Errore nella creazione del video",[err localizedDescription], nil, @"Chiudi", nil, nil);
    return;
    return;
}


// Create the File Open Dialog class.
NSSavePanel *savePanel = [NSSavePanel savePanel]; //Dove salvo il video ?


if ([savePanel runModal])//Se premo ok
{   
    [indicatore setUsesThreadedAnimation:YES];
    [indicatore startAnimation:self];
    NSURL *saveURL = savePanel.URL;
    NSString *savePath = [saveURL path];
//Prelevo i 2 percorsi e gli inserisco negli array

NSString *video1 = [URLVideo1 stringValue];
NSString *video2 = [URLVideo2 stringValue];

NSURL *theURLvideo1 = [NSURL fileURLWithPath:video1];

NSURL *theURLvideo2 = [NSURL fileURLWithPath:video2];

if((theURLvideo1) && (theURLvideo2)) {



NSArray *myMovieURLs = [NSArray arrayWithObjects:theURLvideo1,theURLvideo2, nil];

for (NSURL *url in myMovieURLs)
{
    QTMovie *theMovie = [QTMovie movieWithURL:url error:&err];
    if (err){
        NSRunAlertPanel(@"Errore durante il caricamento di uno dei film",[err localizedDescription], nil, @"Chiudi", nil, nil);
        return;
    }
    QTTimeRange timeRange = QTMakeTimeRange(QTZeroTime, [theMovie duration]);
    QTTime insertionTime = [myCombinedMovie duration]; 
    [myCombinedMovie insertSegmentOfMovie:theMovie timeRange:timeRange atTime:insertionTime];
}

NSDictionary *writeAttributes = [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], QTMovieFlatten, nil]; 
//Pannello di path salvataggio

bool success = [myCombinedMovie writeToFile:savePath withAttributes:writeAttributes error:&err];




[indicatore stopAnimation:self];
NSBeep();
NSString *dove = [[NSString alloc] initWithFormat:@"Video esportato in:\n%@",savePath];
NSRunAlertPanel(@"Esportazione avvenuta con successo!", dove, @"Ok", nil, nil);

if (!success)
{
    NSRunAlertPanel(@"Errore durante il salvataggio del video.",[err localizedDescription], nil, @"Chiudi", nil, nil);
    return;
    return;
}
}
//Se non esiste alcun percorso
else {

    NSRunAlertPanel(@"Impossibile selezionare i file.", @"Controlla di aver specificato un percorso.", @"Chiudi", nil, nil);
}

Answer 1

要做到这一点，最简单的方法是使用AVFoundation框架而不是QTKit，因为编辑/操作视频要容易得多（imo），虽然看起来有点慢，而且代码可能不那么紧凑。

我建议首先阅读https://developer.apple.com/library/mac/documentation/AudioVideo/Conceptual/AVFoundationPG/AVFoundationPG.pdf

上的AVFoundation编程指南

但这是一个让你入门的基本例子。在开始之前，请确保已链接到AVFoundation和CoreMedia框架。

在您的标题中除了您可能添加AVAssetExportSession *exporter和NSTimer *timer的任何其他方法或ivars，以及方法- (void) monitorProgress;。

然后，您的实现文件将包含以下方法（假设您使用名为doIt的IBAction触发该方法）。不要忘记#import <AVFoundation/ AVFoundation.h>和#import <CoreMedia/CoreMedia.h>：

- (IBAction)doIt:(id)sender {
// Initial array of movie URLs
NSArray *myMovieURLs = [NSArray arrayWithObjects:[NSURL fileURLWithPath:@"/path/to/first.mov"], [NSURL fileURLWithPath:@"/path/to/second.mov"], nil];

// Create the composition & A/V tracks
AVMutableComposition *comp = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionVideoTrack = [comp addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVMutableCompositionTrack *compositionAudioTrack = [comp addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

// A reference for insertion start time
CMTime startTime = kCMTimeZero;

for (int i=0; i< [myMovieURLs count]; i++){
    // Get asset 
    NSURL *movieURL = [myMovieURLs objectAtIndex:i];
    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:movieURL options:nil];

    // Get video and audio tracks (assuming video exists - test for audio as an empty track will crash the program!) and insert in composition tracks
    AVAssetTrack *videoTrack = [[asset tracksWithMediaType:AVMediaTypeVideo] objectAtIndex:0];
    bool success = [compositionVideoTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [asset duration]) ofTrack:videoTrack atTime:startTime error:nil];

    if ([[asset tracksWithMediaType:AVMediaTypeAudio]count]){
        AVAssetTrack *audioTrack = [[asset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
        success = [compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, [asset duration]) ofTrack:audioTrack atTime:startTime error:nil];
    }

    // increment the start time to the end of this first video
    startTime = CMTimeAdd(startTime, [asset duration]);
}

//Set the output URL
NSURL *outputURL = [NSURL fileURLWithPath:@"/path/to/output.mov"];

/* Create the exporter.  
 Note the preset type is up to you to choose.  If you wanted, you could check the asset's size (with [asset naturalSize]) or other values above and use that to base your preset on. 
 Use exportPresetsCompatibleWithAsset: to get a list of presets that are compatible with a specific asset.
 */
NSLog(@"Compat presets you could use: %@", [AVAssetExportSession exportPresetsCompatibleWithAsset:comp]);
exporter = [[AVAssetExportSession alloc] initWithAsset:comp presetName:AVAssetExportPreset640x480];

[exporter setOutputURL:outputURL];
[exporter setOutputFileType:AVFileTypeQuickTimeMovie];
[exporter exportAsynchronouslyWithCompletionHandler:^(void){
    switch ([exporter status]) {
        case AVAssetExportSessionStatusFailed:
            NSLog(@"Export failed: %@", [[exporter error] localizedDescription]);
            break;
        case AVAssetExportSessionStatusCancelled:
            NSLog(@"Export canceled");
            break;
        default:
            break;
    }
}];

// This is just a simple timer that will call a method to log the progress
timer=[NSTimer scheduledTimerWithTimeInterval:5
                                       target:self
                                     selector:@selector(monitorProgress)
                                     userInfo:nil
                                      repeats:YES];
}



-(void)monitorProgress{ 
if ([exporter progress] == 1.0){
    [timer invalidate];
}

NSLog(@"Progress: %f",[exporter progress]* 100);

}

QTKit - 合并两个不同宽度和高度的视频？

1 个答案: