How to merge video and audio files?

问题

My question is: How to merge video and audio files that has almost the same duration?

I searched and got some answers to this question. However when I try the code they gave, it just does not produce a "non-zero byte" movie.

Could you take a look at it and see where it went wrong?

-(void)putTogether
{
NSLog(@"Starting to put together all the files!");

AVMutableComposition *mixComposition = [AVMutableComposition composition];

NSString *audioPath = @"/Users/admin/Documents/Sound.caf";
NSURL *audioUrl = [NSURL fileURLWithPath:audioPath];
//AVURLAsset *audioasset = [AVURLAsset URLAssetWithURL:audioUrl options:nil];
AVURLAsset *audioasset = [[AVURLAsset alloc]initWithURL:audioUrl options:nil];

NSString *videoPath = @"/Users/admin/Documents/video.mp4";
NSURL *videoUrl = [NSURL fileURLWithPath:videoPath];
//AVURLAsset *videoasset = [AVURLAsset URLAssetWithURL:videoUrl options:nil];
AVURLAsset *videoasset = [[AVURLAsset alloc]initWithURL:videoUrl options:nil];

NSString *moviepath = @"/Users/admin/Documents/fmovie.mov";
NSURL *movieUrl = [NSURL fileURLWithPath:moviepath];

if([[NSFileManager defaultManager] fileExistsAtPath:moviepath])
{
    [[NSFileManager defaultManager] removeItemAtPath:moviepath error:nil];
}

AVMutableCompositionTrack *compositionTrackB = [mixComposition addMutableTrackWithMediaType:AVMediaTypeVideo preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *clipVideoTrackB = [[videoasset tracksWithMediaType:AVMediaTypeVideo] lastObject];
[compositionTrackB insertTimeRange:CMTimeRangeMake(      kCMTimeZero, videoasset.duration)  ofTrack:clipVideoTrackB atTime:kCMTimeZero error:nil];

AVMutableCompositionTrack *compositionTrackA = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *clipAudioTrackA = [[audioasset tracksWithMediaType:AVMediaTypeAudio] lastObject];
[compositionTrackA insertTimeRange:CMTimeRangeMake(kCMTimeZero, audioasset.duration)  ofTrack:clipAudioTrackA atTime:kCMTimeZero error:nil];

AVAssetExportSession *exporter =[[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetHighestQuality];
//AVAssetExportSession *exporter =[AVAssetExportSession exportSessionWithAsset:mixComposition presetName:AVAssetExportPresetLowQuality];
NSParameterAssert(exporter!=nil);
exporter.outputFileType=AVFileTypeQuickTimeMovie;
exporter.outputURL=movieUrl;
CMTime start=CMTimeMake(0, 600);
CMTime duration=CMTimeMake(600, 600);
CMTimeRange range=CMTimeRangeMake(start, duration);
exporter.timeRange=range;
[exporter exportAsynchronouslyWithCompletionHandler:nil];
}

回答1:

(Answered by the OP by an edit in the question. Converted to a community wiki answer. See Question with no answers, but issue solved in the comments (or extended in chat) )

The OP wrote:

I solved my problem.

For the ones who have same problem as I did, here is the simple solution:

a.Delete the following code:

CMTime start=CMTimeMake(0, 600);
CMTime duration=CMTimeMake(600, 600);
CMTimeRange range=CMTimeRangeMake(start, duration);
exporter.timeRange=range;

b.(optional)Rewrite completion handler:

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

c.Then wait long enough for the program to complete writing.

来源：https://stackoverflow.com/questions/9329316/how-to-merge-video-and-audio-files

标签

ios5

avassetwriter

avassetexportsession

avcomposition