AVAssetExportSession-仅mov音频文件无法导出？

Question

我有一个音频播放器，应该可以播放多种音频格式。 该应用程序正在使用BASS音频库，并且需要一些导出。 以下是格式。 除了.mov（仅音频）格式的文件外，其他所有文件都工作正常。

关于解决此问题的正确方法有什么想法？

---

exportSession = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetPassthrough];
if (nil == exportSession)
    @throw [NSException exceptionWithName:TSUnknownError reason:@"Couldn't create AVAssetExportSession" userInfo:nil];

if ([[assetURL pathExtension] compare:@"mp3"] == NSOrderedSame) {
    [self doMp3ImportToFile:destURL completionBlock:completionBlock];
    return;
}

exportSession.outputURL = destURL;

// set the output file type appropriately based on asset URL extension
if ([[assetURL pathExtension] compare:@"m4a"] == NSOrderedSame) {
    exportSession.outputFileType = AVFileTypeAppleM4A;
} else if ([[assetURL pathExtension] compare:@"wav"] == NSOrderedSame) {
    exportSession.outputFileType = AVFileTypeWAVE;
} else if ([[assetURL pathExtension] compare:@"aif"] == NSOrderedSame) {
    exportSession.outputFileType = AVFileTypeAIFF;
} else if ([[assetURL pathExtension] compare:@"mp4"] == NSOrderedSame) {
    exportSession.outputFileType = AVFileTypeMPEG4;
} else if ([[assetURL pathExtension] compare:@"mov"] == NSOrderedSame) {
    exportSession.outputFileType = AVFileTypeQuickTimeMovie;
} else {
    @throw [NSException exceptionWithName:NSInvalidArgumentException reason:@"unrecognized file extension" userInfo:nil];
}

Answer 1

对于仅音频轨道.mov文件，输出应为

AVAssetExportSession *exportSession=[AVAssetExportSession exportSessionWithAsset:asset presetName:AVAssetExportPresetAppleM4A];

exportSession.outputURL=pathURL;
exportSession.outputFileType=AVFileTypeAppleM4A;