ios - 无法将 caf 格式转换为 m4a 格式

我使用以下代码将 caf 格式转换为 m4a 格式并保存到 Iphone 的另一个目录，它在 Xcode 4.6.3 的 IOS6 中工作，但是当我更新到 Xcode 5 时，它不再工作了。如果在 Xcode 5 中使用 IOS6 模拟器，它会再次工作。

-(void)saveFile {
    NSString *docDirPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    outputFile = [NSURL fileURLWithPath:[docDirPath stringByAppendingPathComponent: [NSString stringWithFormat: @"%i.m4a", currentCueIndex + 1000]]];
}

所以我想知道这是 IOS 7 的错误还是 Apple 改变了什么？

谢谢

更新

AVURLAsset *audioAsset = [[AVURLAsset alloc]initWithURL:recordedTmpFile options:nil];
AVMutableComposition *mixComposition = [AVMutableComposition composition];
AVMutableCompositionTrack *compositionTrackA = [mixComposition     addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

AVAssetTrack *clipAudioTrack = [[audioAsset tracksWithMediaType:AVMediaTypeAudio] lastObject];

[compositionTrackA insertTimeRange:CMTimeRangeMake(kCMTimeZero, audioAsset.duration)  ofTrack:clipAudioTrack atTime:kCMTimeZero error:nil];

AVAssetExportSession *exporter =[[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetAppleM4A];

[self saveFile];


NSParameterAssert(exporter!=nil);
exporter.outputFileType=AVFileTypeAppleM4A;
exporter.outputURL=outputFile;
// Subtract a fraction of a second so the first word isn't chopped off
clipStartTime = clipStartTime - kSilenceBeforeFirstAudio;

CMTime start=CMTimeMake(clipStartTime * 100, 100);
CMTime duration=CMTimeMake(clipDuration * 100, 100);
CMTimeRange range=CMTimeRangeMake(start, duration);
exporter.timeRange=range;
[exporter exportAsynchronouslyWithCompletionHandler:nil];

---

Best Answer-推荐答案

好的，我发现了问题。 应该替换这一行

[exporter exportAsynchronouslyWithCompletionHandler:nil];

到

   [exporter exportAsynchronouslyWithCompletionHandler:^{
        int exportStatus = exporter.status;
        switch (exportStatus) {

            case AVAssetExportSessionStatusFailed: {

                NSError *exportError = exporter.error;
                NSLog (@"AVAssetExportSessionStatusFailed: %@", exportError);
                break;
            }
            case AVAssetExportSessionStatusCompleted: {
                NSLog (@"AVAssetExportSessionStatusCompleted--");
                break;
            }
            case AVAssetExportSessionStatusUnknown: {
                NSLog (@"AVAssetExportSessionStatusUnknown");
                break;
            }
            case AVAssetExportSessionStatusExporting: {
                NSLog (@"AVAssetExportSessionStatusExporting");
                break;
            }
            case AVAssetExportSessionStatusCancelled: {
                NSLog (@"AVAssetExportSessionStatusCancelled");
                break;
            }
            case AVAssetExportSessionStatusWaiting: {
                NSLog (@"AVAssetExportSessionStatusWaiting");
                break;
            }
            default: { NSLog (@"didn't get export status"); break;}
        }

    }];

关于ios - 无法将 caf 格式转换为 m4a 格式，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19116339/