5

我正在尝试使用以下代码将主监视器屏幕和辅助监视器屏幕记录到两个单独的文件中。

const uint32_t MAX_DISPLAY = 2;
CGDirectDisplayID displays[MAX_DISPLAY] = {0};
CGGetActiveDisplayList(MAX_DISPLAY, displays, &m_nDisplays);

NSString* dest_file[2] = {0};
NSURL* dest_path[2] = {0};

AVCaptureConnection *CaptureConnection[2] = {0};

NSDictionary *videoCleanApertureSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                            @2048, AVVideoCleanApertureWidthKey,
                                            @1152, AVVideoCleanApertureHeightKey,
                                            @0, AVVideoCleanApertureHorizontalOffsetKey,
                                            @0, AVVideoCleanApertureVerticalOffsetKey,
                                            nil];

NSDictionary *videoAspectRatioSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                          @3,AVVideoPixelAspectRatioHorizontalSpacingKey,
                                          @3,AVVideoPixelAspectRatioVerticalSpacingKey,
                                          nil];

 NSNumber* bitsPerSecond = [NSNumber numberWithDouble:1024*1000];

NSDictionary *codecSettings =  [NSDictionary dictionaryWithObjectsAndKeys:
                               bitsPerSecond, AVVideoAverageBitRateKey,
                               videoCleanApertureSettings, AVVideoCleanApertureKey,
                               videoAspectRatioSettings, AVVideoPixelAspectRatioKey,
                               nil];

NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                               AVVideoCodecH264, AVVideoCodecKey,
                               codecSettings,AVVideoCompressionPropertiesKey,
                               AVVideoScalingModeResize,AVVideoScalingModeKey,
                               @2048, AVVideoWidthKey,
                               @1152, AVVideoHeightKey,
                               nil];

for( int nIdx = 0; nIdx < m_nDisplays; ++nIdx )
{
    m_session[nIdx] = [[AVCaptureSession alloc] init];
    dest_file[nIdx] = [NSString stringWithFormat:@"%@_%d.MOV",destination_path,nIdx];
    dest_path[nIdx] = [NSURL fileURLWithPath: dest_file[nIdx] ];


    // Create a ScreenInput with the display and add it to the session
    m_movie_file_input[nIdx] = [[[AVCaptureScreenInput alloc] initWithDisplayID:displays[nIdx]] autorelease];    
    [m_movie_file_input[nIdx] removesDuplicateFrames ];

    if ([m_session[nIdx] canAddInput:m_movie_file_input[nIdx]])
    {
        [m_session[nIdx] addInput:m_movie_file_input[nIdx]];
    }

    // Create a MovieFileOutput and add it to the session
    m_movie_file_output[nIdx] = [[[AVCaptureMovieFileOutput alloc] init] autorelease];
    if ([m_session[nIdx] canAddOutput:m_movie_file_output[nIdx]])
    {
        [m_session[nIdx] addOutput:m_movie_file_output[nIdx]];
    }

    CaptureConnection[nIdx] = [m_movie_file_output[nIdx] connectionWithMediaType:AVMediaTypeVideo];

    [m_movie_file_output[nIdx] setOutputSettings : videoSettings forConnection : CaptureConnection[nIdx]];

    // Start running the session
    [m_session[nIdx] startRunning];

    [m_movie_file_output[nIdx] startRecordingToOutputFileURL:dest_path[nIdx]    recordingDelegate:self];

}

我将两个屏幕都保存到两个单独的文件中。但是，在为辅助监视器（即第二次循环）调用 startRecordingToOutputFileURL API 时，我收到如下所示的错误：

VTCompressionSessionCreate 在 /SourceCache/CoreMedia_frameworks/CoreMedia-1562.19/Sources/VideoToolbox/VTCompressionSession.c 第 897 行发出 err=-8973 (err) (VTVideoEncoderStartSession failed)

此外，辅助监视器的压缩参数（比特率）设置不正确，它采用了一些不同的值，而不是我在程序中指定的值。

有人可以帮我吗？也请让我知道这是这样做的正确方法。

提前致谢

乔治

4

0 回答 0