NSFileHandleReadCompletionNotification未过帐

Question

我有一个关于NSFileHandleReadCompletionNotification不发帖的问题。我正在通过管道将一个NSTask的结果传递给另一个。无论出于什么原因，我的getData方法都不会被调用。有什么想法吗？这两个任务都工作正常，因为我正在将预期的文件写入我的硬盘。只是没有通知。

- (void) encodeVideo:(NSString*)path
{
    NSString* ffmpegPath = [[NSBundle mainBundle] pathForResource:@"ffmpeg" ofType:@""];
    NSString* presetFile = [[NSBundle mainBundle] pathForResource:@"128" ofType:@"ffpreset"];

    NSTask* encodeTask = [[NSTask alloc] init];

    NSMutableArray* arguments = [[NSMutableArray alloc] init];
    [arguments addObject:@"-y"];
    [arguments addObject:@"-i"];
    [arguments addObject:path];
    [arguments addObject:@"-f"];
    [arguments addObject:@"mpegts"];
    [arguments addObject:@"-ac"];
    [arguments addObject:@"2"];
    [arguments addObject:@"-fpre"];
    [arguments addObject:presetFile];
    [arguments addObject:@"-s"];
    [arguments addObject:@"320x240"];
    [arguments addObject:@"-aspect"];
    [arguments addObject:@"320:240"];
    [arguments addObject:@"-async"];
    [arguments addObject:@"2"];
    [arguments addObject:@"-"];

    [encodeTask setLaunchPath: ffmpegPath];
    [encodeTask setArguments: arguments];
    [encodeTask setStandardOutput:[NSPipe pipe]];

    NSMutableArray* segmentArguments = [[NSMutableArray alloc] init];
    [segmentArguments addObject:@"-t"];
    [segmentArguments addObject:@"10"];
    [segmentArguments addObject:@"-f"];
    [segmentArguments addObject:@"/Users/Morgan/Desktop/LiveStreamServer/video"];
    [segmentArguments addObject:@"-S"];
    [segmentArguments addObject:@"1"];

    NSString* segmenterPath = [[NSBundle mainBundle] pathForResource:@"mediastreamsegmenter" ofType:@""];
    NSLog(@"%@", segmenterPath);
    NSTask* segmentTask = [[NSTask alloc] init];

    [segmentTask setLaunchPath: segmenterPath];
    [segmentTask setArguments: segmentArguments];

    [segmentTask setStandardInput:[encodeTask standardOutput]];
    [segmentTask setStandardOutput:[NSPipe pipe]];
    [segmentTask setStandardError:[NSPipe pipe]];

    NSFileHandle *file = [[segmentTask standardOutput] fileHandleForReading];
    [file readInBackgroundAndNotify];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(getData:) name:NSFileHandleReadCompletionNotification object:file];

    [segmentTask launch];
    [encodeTask launch];

    [arguments release];
    [segmentArguments release];
}

- (void) getData: (NSNotification *)aNotification
{
    NSData *data = [[aNotification userInfo] objectForKey:@"NSFileHandleNotificationDataItem"];
    NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

    NSLog(@"%@", string);
    [[aNotification object] readInBackgroundAndNotify];
}

Answer 1

还需要在后台读取stdError。将其输出到管道中，但没有读取它，因此缓冲区被填满。