我有很多的麻烦搞清楚如何使用苹果的硬件加速的视频框架，以解压缩的H.264视频流。几个星期后，我想通了，并希望分享丰富的例子，因为我无法找到一个。

我的目标是给介绍一个全面的，指导性视频工具箱的例子WWDC '14会话513 。我的代码不会编译或运行，因为它需要有基本的H.264码流集成（如视频从文件中读取或从网上流媒体等），需要根据具体的情况来进行调整。

我要指出，我除了我，而谷歌搜索的主题学会了与视频EN /解码的经验非常少。我不知道所有的视频格式，结构参数等详细信息，以便我只包括什么，我认为你需要知道的。

我使用的XCode 6.2，并已部署到正在运行的iOS 8.1和8.2的iOS设备。

Answer 1:

概念：

的NALU：的NALU是简单地改变具有NALU起始码报头长度的数据块0x00 00 00 01 YY ，其中的前5位YY告诉你什么类型的NALU这是因此什么类型的数据在报头。（因为你只需要前5位，我用YY & 0x1F是拿到相关位）。我列出什么所有这些类型的方法NSString * const naluTypesStrings[]但你并不需要知道他们全部是。

参数：您的解码器需要的参数，所以它知道H.264视频数据的存储方式。您需要设置的2 序列参数集（SPS）和图片参数集（PPS），他们都有自己的NALU类型号。你不需要知道什么是参数的含义，解码器知道如何处理他们做。

H.264流格式：在大多数H.264流，将收到一组初始的PPS和SPS参数随后的I帧（又名IDR帧或平齐帧）NALU。然后将接收多个P帧的NALU（也许几十左右），然后另一组参数（其可以是相同的初始参数）和第i帧，更多的P帧等。i帧比大得多P帧。从概念上讲，你能想到的我帧视频的整个形象和P帧只是已给予该I帧，直到收到下一个I帧的变化。

程序：

通过您的H.264码流单个NALU的。 我不能为这一步显示的代码，因为它在很大程度上取决于你所使用的视频源。我做了这个图形显示我与（“数据”中的图形是“帧”在我下面的代码）的工作，但你的情况，可能会有所不同。我的方法receivedRawVideoFrame:被称为我每次接收一帧（时间uint8_t *frame ），它是2种类型中的一个。在该图中，那些帧2种类型是2个大紫色框。
创建一个从您的SPS一CMVideoFormatDescriptionRef和PPS的NALU与CMVideoFormatDescriptionCreateFromH264ParameterSets（）。 不这样做，首先你不能显示任何帧。 SPS和PPS可能看起来像数字的混乱，但VTD知道如何处理他们做。所有你需要知道的是， CMVideoFormatDescriptionRef是视频数据的描述中，相同的宽度/高度，格式类型（ kCMPixelFormat_32BGRA ， kCMVideoCodecType_H264等），宽高比，色彩空间等你的解码器将不放参数，直到一个新的组到达（有时参数经常怨恨，即使他们没有改变）。
重新包装的IDR和非IDR帧的NALU根据“AVCC”的格式。 这意味着除去NALU起始码，并用一个4字节的报头，指出NALU的长度替换它们。你并不需要为SPS和PPS的NALU做到这一点。（请注意，4个字节的NALU长度标题是big-endian的，所以如果你有一个UInt32值，它必须是字节交换复制到之前CMBlockBuffer使用CFSwapInt32 。我这样做，我的代码htonl函数调用。）
打包IDR和非IDR NALU帧到CMBlockBuffer。 不要与SPS PPS参数NALU都做到这一点。所有你需要知道CMBlockBuffers是，他们来包装任意数据块的核心媒体的方法。（在视频流水线的任何压缩的视频数据被包裹在此。）
打包CMBlockBuffer到CMSampleBuffer。 所有你需要知道CMSampleBuffers是他们包裹起来我们CMBlockBuffers与其它信息（这里将是CMVideoFormatDescription和CMTime ，如果CMTime使用）。
创建VTDecompressionSessionRef和饲料样品的缓冲液为VTDecompressionSessionDecodeFrame（）。 另外，您也可以使用AVSampleBufferDisplayLayer及其enqueueSampleBuffer:方法，你将不再需要使用VTDecompSession。这是简单的设置，但是，如果出了问题喜欢VTD会不会引发错误。
在VTDecompSession回调，使用所得CVImageBufferRef显示视频帧。 如果您需要将转换CVImageBuffer到一个UIImage ，看到我的StackOverflow回答这里。

其他说明：

H.264流可以有很大的差异。从我了解到，NALU起始码头有时3个字节 （ 0x00 00 01 ），有时4（ 0x00 00 00 01 ）。我的代码工作为4个字节; 你将需要改变周围的一些东西，如果你有3个工作。
如果您想了解更多有关的NALU，我发现这个答案是非常有帮助的。以我为例，我发现我并不需要忽略“模仿防止”字节所描述的，所以我个人跳过的一步，但你可能需要知道。
如果您VTDecompressionSession输出错误号（如-12909）查找错误代码在你的XCode项目。查找您的Project Navigator中VideoToolbox框架，打开它，找到头VTErrors.h。如果你不能找到它，我还在下面列出的另一种回答了所有的错误代码。

代码示例：

因此，让我们通过声明一些全局变量和包括VT框架（VT =视频工具箱）开始。

#import <VideoToolbox/VideoToolbox.h>

@property (nonatomic, assign) CMVideoFormatDescriptionRef formatDesc;
@property (nonatomic, assign) VTDecompressionSessionRef decompressionSession;
@property (nonatomic, retain) AVSampleBufferDisplayLayer *videoLayer;
@property (nonatomic, assign) int spsSize;
@property (nonatomic, assign) int ppsSize;

下面阵列仅用于使得可以打印出正在接收什么类型的NALU帧。如果你知道所有这些类型的意思是，对你有好处，你知道更多关于H.264比我:)我的代码只处理类型1，5，7和8。

NSString * const naluTypesStrings[] =
{
    @"0: Unspecified (non-VCL)",
    @"1: Coded slice of a non-IDR picture (VCL)",    // P frame
    @"2: Coded slice data partition A (VCL)",
    @"3: Coded slice data partition B (VCL)",
    @"4: Coded slice data partition C (VCL)",
    @"5: Coded slice of an IDR picture (VCL)",      // I frame
    @"6: Supplemental enhancement information (SEI) (non-VCL)",
    @"7: Sequence parameter set (non-VCL)",         // SPS parameter
    @"8: Picture parameter set (non-VCL)",          // PPS parameter
    @"9: Access unit delimiter (non-VCL)",
    @"10: End of sequence (non-VCL)",
    @"11: End of stream (non-VCL)",
    @"12: Filler data (non-VCL)",
    @"13: Sequence parameter set extension (non-VCL)",
    @"14: Prefix NAL unit (non-VCL)",
    @"15: Subset sequence parameter set (non-VCL)",
    @"16: Reserved (non-VCL)",
    @"17: Reserved (non-VCL)",
    @"18: Reserved (non-VCL)",
    @"19: Coded slice of an auxiliary coded picture without partitioning (non-VCL)",
    @"20: Coded slice extension (non-VCL)",
    @"21: Coded slice extension for depth view components (non-VCL)",
    @"22: Reserved (non-VCL)",
    @"23: Reserved (non-VCL)",
    @"24: STAP-A Single-time aggregation packet (non-VCL)",
    @"25: STAP-B Single-time aggregation packet (non-VCL)",
    @"26: MTAP16 Multi-time aggregation packet (non-VCL)",
    @"27: MTAP24 Multi-time aggregation packet (non-VCL)",
    @"28: FU-A Fragmentation unit (non-VCL)",
    @"29: FU-B Fragmentation unit (non-VCL)",
    @"30: Unspecified (non-VCL)",
    @"31: Unspecified (non-VCL)",
};

现在，这是所有魔术发生。

-(void) receivedRawVideoFrame:(uint8_t *)frame withSize:(uint32_t)frameSize isIFrame:(int)isIFrame
{
    OSStatus status;

    uint8_t *data = NULL;
    uint8_t *pps = NULL;
    uint8_t *sps = NULL;

    // I know what my H.264 data source's NALUs look like so I know start code index is always 0.
    // if you don't know where it starts, you can use a for loop similar to how i find the 2nd and 3rd start codes
    int startCodeIndex = 0;
    int secondStartCodeIndex = 0;
    int thirdStartCodeIndex = 0;

    long blockLength = 0;

    CMSampleBufferRef sampleBuffer = NULL;
    CMBlockBufferRef blockBuffer = NULL;

    int nalu_type = (frame[startCodeIndex + 4] & 0x1F);
    NSLog(@"~~~~~~~ Received NALU Type \"%@\" ~~~~~~~~", naluTypesStrings[nalu_type]);

    // if we havent already set up our format description with our SPS PPS parameters, we
    // can't process any frames except type 7 that has our parameters
    if (nalu_type != 7 && _formatDesc == NULL)
    {
        NSLog(@"Video error: Frame is not an I Frame and format description is null");
        return;
    }

    // NALU type 7 is the SPS parameter NALU
    if (nalu_type == 7)
    {
        // find where the second PPS start code begins, (the 0x00 00 00 01 code)
        // from which we also get the length of the first SPS code
        for (int i = startCodeIndex + 4; i < startCodeIndex + 40; i++)
        {
            if (frame[i] == 0x00 && frame[i+1] == 0x00 && frame[i+2] == 0x00 && frame[i+3] == 0x01)
            {
                secondStartCodeIndex = i;
                _spsSize = secondStartCodeIndex;   // includes the header in the size
                break;
            }
        }

        // find what the second NALU type is
        nalu_type = (frame[secondStartCodeIndex + 4] & 0x1F);
        NSLog(@"~~~~~~~ Received NALU Type \"%@\" ~~~~~~~~", naluTypesStrings[nalu_type]);
    }

    // type 8 is the PPS parameter NALU
    if(nalu_type == 8)
    {
        // find where the NALU after this one starts so we know how long the PPS parameter is
        for (int i = _spsSize + 4; i < _spsSize + 30; i++)
        {
            if (frame[i] == 0x00 && frame[i+1] == 0x00 && frame[i+2] == 0x00 && frame[i+3] == 0x01)
            {
                thirdStartCodeIndex = i;
                _ppsSize = thirdStartCodeIndex - _spsSize;
                break;
            }
        }

        // allocate enough data to fit the SPS and PPS parameters into our data objects.
        // VTD doesn't want you to include the start code header (4 bytes long) so we add the - 4 here
        sps = malloc(_spsSize - 4);
        pps = malloc(_ppsSize - 4);

        // copy in the actual sps and pps values, again ignoring the 4 byte header
        memcpy (sps, &frame[4], _spsSize-4);
        memcpy (pps, &frame[_spsSize+4], _ppsSize-4);

        // now we set our H264 parameters
        uint8_t*  parameterSetPointers[2] = {sps, pps};
        size_t parameterSetSizes[2] = {_spsSize-4, _ppsSize-4};

        // suggestion from @Kris Dude's answer below
        if (_formatDesc) 
        {
            CFRelease(_formatDesc);
            _formatDesc = NULL;
        }

        status = CMVideoFormatDescriptionCreateFromH264ParameterSets(kCFAllocatorDefault, 2, 
                                                (const uint8_t *const*)parameterSetPointers, 
                                                parameterSetSizes, 4, 
                                                &_formatDesc);

        NSLog(@"\t\t Creation of CMVideoFormatDescription: %@", (status == noErr) ? @"successful!" : @"failed...");
        if(status != noErr) NSLog(@"\t\t Format Description ERROR type: %d", (int)status);

        // See if decomp session can convert from previous format description 
        // to the new one, if not we need to remake the decomp session.
        // This snippet was not necessary for my applications but it could be for yours
        /*BOOL needNewDecompSession = (VTDecompressionSessionCanAcceptFormatDescription(_decompressionSession, _formatDesc) == NO);
         if(needNewDecompSession)
         {
             [self createDecompSession];
         }*/

        // now lets handle the IDR frame that (should) come after the parameter sets
        // I say "should" because that's how I expect my H264 stream to work, YMMV
        nalu_type = (frame[thirdStartCodeIndex + 4] & 0x1F);
        NSLog(@"~~~~~~~ Received NALU Type \"%@\" ~~~~~~~~", naluTypesStrings[nalu_type]);
    }

    // create our VTDecompressionSession.  This isnt neccessary if you choose to use AVSampleBufferDisplayLayer
    if((status == noErr) && (_decompressionSession == NULL))
    {
        [self createDecompSession];
    }

    // type 5 is an IDR frame NALU.  The SPS and PPS NALUs should always be followed by an IDR (or IFrame) NALU, as far as I know
    if(nalu_type == 5)
    {
        // find the offset, or where the SPS and PPS NALUs end and the IDR frame NALU begins
        int offset = _spsSize + _ppsSize;
        blockLength = frameSize - offset;
        data = malloc(blockLength);
        data = memcpy(data, &frame[offset], blockLength);

        // replace the start code header on this NALU with its size.
        // AVCC format requires that you do this.  
        // htonl converts the unsigned int from host to network byte order
        uint32_t dataLength32 = htonl (blockLength - 4);
        memcpy (data, &dataLength32, sizeof (uint32_t));

        // create a block buffer from the IDR NALU
        status = CMBlockBufferCreateWithMemoryBlock(NULL, data,  // memoryBlock to hold buffered data
                                                    blockLength,  // block length of the mem block in bytes.
                                                    kCFAllocatorNull, NULL,
                                                    0, // offsetToData
                                                    blockLength,   // dataLength of relevant bytes, starting at offsetToData
                                                    0, &blockBuffer);

        NSLog(@"\t\t BlockBufferCreation: \t %@", (status == kCMBlockBufferNoErr) ? @"successful!" : @"failed...");
    }

    // NALU type 1 is non-IDR (or PFrame) picture
    if (nalu_type == 1)
    {
        // non-IDR frames do not have an offset due to SPS and PSS, so the approach
        // is similar to the IDR frames just without the offset
        blockLength = frameSize;
        data = malloc(blockLength);
        data = memcpy(data, &frame[0], blockLength);

        // again, replace the start header with the size of the NALU
        uint32_t dataLength32 = htonl (blockLength - 4);
        memcpy (data, &dataLength32, sizeof (uint32_t));

        status = CMBlockBufferCreateWithMemoryBlock(NULL, data,  // memoryBlock to hold data. If NULL, block will be alloc when needed
                                                    blockLength,  // overall length of the mem block in bytes
                                                    kCFAllocatorNull, NULL,
                                                    0,     // offsetToData
                                                    blockLength,  // dataLength of relevant data bytes, starting at offsetToData
                                                    0, &blockBuffer);

        NSLog(@"\t\t BlockBufferCreation: \t %@", (status == kCMBlockBufferNoErr) ? @"successful!" : @"failed...");
    }

    // now create our sample buffer from the block buffer,
    if(status == noErr)
    {
        // here I'm not bothering with any timing specifics since in my case we displayed all frames immediately
        const size_t sampleSize = blockLength;
        status = CMSampleBufferCreate(kCFAllocatorDefault,
                                      blockBuffer, true, NULL, NULL,
                                      _formatDesc, 1, 0, NULL, 1,
                                      &sampleSize, &sampleBuffer);

        NSLog(@"\t\t SampleBufferCreate: \t %@", (status == noErr) ? @"successful!" : @"failed...");
    }

    if(status == noErr)
    {
        // set some values of the sample buffer's attachments
        CFArrayRef attachments = CMSampleBufferGetSampleAttachmentsArray(sampleBuffer, YES);
        CFMutableDictionaryRef dict = (CFMutableDictionaryRef)CFArrayGetValueAtIndex(attachments, 0);
        CFDictionarySetValue(dict, kCMSampleAttachmentKey_DisplayImmediately, kCFBooleanTrue);

        // either send the samplebuffer to a VTDecompressionSession or to an AVSampleBufferDisplayLayer
        [self render:sampleBuffer];
    }

    // free memory to avoid a memory leak, do the same for sps, pps and blockbuffer
    if (NULL != data)
    {
        free (data);
        data = NULL;
    }
}

下面的方法创建您的VTD会议。重新创建它，每当你收到新的参数。（您不必每次收到的参数，可以肯定的时间来重新创建它。）

如果你想设置为目的地属性CVPixelBuffer ，阅读了关于corevideo的PixelBufferAttributes值，并把他们NSDictionary *destinationImageBufferAttributes 。

-(void) createDecompSession
{
    // make sure to destroy the old VTD session
    _decompressionSession = NULL;
    VTDecompressionOutputCallbackRecord callBackRecord;
    callBackRecord.decompressionOutputCallback = decompressionSessionDecodeFrameCallback;

    // this is necessary if you need to make calls to Objective C "self" from within in the callback method.
    callBackRecord.decompressionOutputRefCon = (__bridge void *)self;

    // you can set some desired attributes for the destination pixel buffer.  I didn't use this but you may
    // if you need to set some attributes, be sure to uncomment the dictionary in VTDecompressionSessionCreate
    NSDictionary *destinationImageBufferAttributes = [NSDictionary dictionaryWithObjectsAndKeys:
                                                      [NSNumber numberWithBool:YES],
                                                      (id)kCVPixelBufferOpenGLESCompatibilityKey,
                                                      nil];

    OSStatus status =  VTDecompressionSessionCreate(NULL, _formatDesc, NULL,
                                                    NULL, // (__bridge CFDictionaryRef)(destinationImageBufferAttributes)
                                                    &callBackRecord, &_decompressionSession);
    NSLog(@"Video Decompression Session Create: \t %@", (status == noErr) ? @"successful!" : @"failed...");
    if(status != noErr) NSLog(@"\t\t VTD ERROR type: %d", (int)status);
}

现在，这个方法被调用每一个VTD完成后解压你发送给它的任何帧时间。此方法被调用，即使有错误，或者如果丢弃该帧。

void decompressionSessionDecodeFrameCallback(void *decompressionOutputRefCon,
                                             void *sourceFrameRefCon,
                                             OSStatus status,
                                             VTDecodeInfoFlags infoFlags,
                                             CVImageBufferRef imageBuffer,
                                             CMTime presentationTimeStamp,
                                             CMTime presentationDuration)
{
    THISCLASSNAME *streamManager = (__bridge THISCLASSNAME *)decompressionOutputRefCon;

    if (status != noErr)
    {
        NSError *error = [NSError errorWithDomain:NSOSStatusErrorDomain code:status userInfo:nil];
        NSLog(@"Decompressed error: %@", error);
    }
    else
    {
        NSLog(@"Decompressed sucessfully");

        // do something with your resulting CVImageBufferRef that is your decompressed frame
        [streamManager displayDecodedFrame:imageBuffer];
    }
}

这是我们实际发送sampleBuffer关闭的VTD进行解码。

- (void) render:(CMSampleBufferRef)sampleBuffer
{
    VTDecodeFrameFlags flags = kVTDecodeFrame_EnableAsynchronousDecompression;
    VTDecodeInfoFlags flagOut;
    NSDate* currentTime = [NSDate date];
    VTDecompressionSessionDecodeFrame(_decompressionSession, sampleBuffer, flags,
                                      (void*)CFBridgingRetain(currentTime), &flagOut);

    CFRelease(sampleBuffer);

    // if you're using AVSampleBufferDisplayLayer, you only need to use this line of code
    // [videoLayer enqueueSampleBuffer:sampleBuffer];
}

如果您使用AVSampleBufferDisplayLayer ，一定要初始化层像这样，在viewDidLoad中或内部的一些其他init方法。

-(void) viewDidLoad
{
    // create our AVSampleBufferDisplayLayer and add it to the view
    videoLayer = [[AVSampleBufferDisplayLayer alloc] init];
    videoLayer.frame = self.view.frame;
    videoLayer.bounds = self.view.bounds;
    videoLayer.videoGravity = AVLayerVideoGravityResizeAspect;

    // set Timebase, you may need this if you need to display frames at specific times
    // I didn't need it so I haven't verified that the timebase is working
    CMTimebaseRef controlTimebase;
    CMTimebaseCreateWithMasterClock(CFAllocatorGetDefault(), CMClockGetHostTimeClock(), &controlTimebase);

    //videoLayer.controlTimebase = controlTimebase;
    CMTimebaseSetTime(self.videoLayer.controlTimebase, kCMTimeZero);
    CMTimebaseSetRate(self.videoLayer.controlTimebase, 1.0);

    [[self.view layer] addSublayer:videoLayer];
}

Answer 2:

如果你无法找到该框架VTD中的错误代码，我决定只包括他们在这里。（同样，所有这些错误，更可以在里面找到VideoToolbox.framework本身在项目导航，在文件VTErrors.h 。）

您将获得无论是在VTD中解码帧回调或当您创建VTD会话，如果你做了一些错误，这些错误代码之一。

kVTPropertyNotSupportedErr              = -12900,
kVTPropertyReadOnlyErr                  = -12901,
kVTParameterErr                         = -12902,
kVTInvalidSessionErr                    = -12903,
kVTAllocationFailedErr                  = -12904,
kVTPixelTransferNotSupportedErr         = -12905, // c.f. -8961
kVTCouldNotFindVideoDecoderErr          = -12906,
kVTCouldNotCreateInstanceErr            = -12907,
kVTCouldNotFindVideoEncoderErr          = -12908,
kVTVideoDecoderBadDataErr               = -12909, // c.f. -8969
kVTVideoDecoderUnsupportedDataFormatErr = -12910, // c.f. -8970
kVTVideoDecoderMalfunctionErr           = -12911, // c.f. -8960
kVTVideoEncoderMalfunctionErr           = -12912,
kVTVideoDecoderNotAvailableNowErr       = -12913,
kVTImageRotationNotSupportedErr         = -12914,
kVTVideoEncoderNotAvailableNowErr       = -12915,
kVTFormatDescriptionChangeNotSupportedErr   = -12916,
kVTInsufficientSourceColorDataErr       = -12917,
kVTCouldNotCreateColorCorrectionDataErr = -12918,
kVTColorSyncTransformConvertFailedErr   = -12919,
kVTVideoDecoderAuthorizationErr         = -12210,
kVTVideoEncoderAuthorizationErr         = -12211,
kVTColorCorrectionPixelTransferFailedErr    = -12212,
kVTMultiPassStorageIdentifierMismatchErr    = -12213,
kVTMultiPassStorageInvalidErr           = -12214,
kVTFrameSiloInvalidTimeStampErr         = -12215,
kVTFrameSiloInvalidTimeRangeErr         = -12216,
kVTCouldNotFindTemporalFilterErr        = -12217,
kVTPixelTransferNotPermittedErr         = -12218,

Answer 3:

多大的一个很好的例子斯威夫特在乔希·贝克的Avios积分库中找到： https://github.com/tidwall/Avios

需要注意的是Avios积分目前预计用户在NAL起始码来处理分块数据，但并处理来自该点向前的数据进行解码。

另外值得一看就是基于雨燕RTMP库HaishinKit（前身为“LF”），它有自己的解码执行，包括更强大的NALU解析： https://github.com/shogo4405/lf.swift

Answer 4:

除了上述VTErrors，我认为这是值得补充说，则在尝试李维的例子遇到CMFormatDescription，CMBlockBuffer，CMSampleBuffer错误。

kCMFormatDescriptionError_InvalidParameter  = -12710,
kCMFormatDescriptionError_AllocationFailed  = -12711,
kCMFormatDescriptionError_ValueNotAvailable = -12718,

kCMBlockBufferNoErr                             = 0,
kCMBlockBufferStructureAllocationFailedErr      = -12700,
kCMBlockBufferBlockAllocationFailedErr          = -12701,
kCMBlockBufferBadCustomBlockSourceErr           = -12702,
kCMBlockBufferBadOffsetParameterErr             = -12703,
kCMBlockBufferBadLengthParameterErr             = -12704,
kCMBlockBufferBadPointerParameterErr            = -12705,
kCMBlockBufferEmptyBBufErr                      = -12706,
kCMBlockBufferUnallocatedBlockErr               = -12707,
kCMBlockBufferInsufficientSpaceErr              = -12708,

kCMSampleBufferError_AllocationFailed             = -12730,
kCMSampleBufferError_RequiredParameterMissing     = -12731,
kCMSampleBufferError_AlreadyHasDataBuffer         = -12732,
kCMSampleBufferError_BufferNotReady               = -12733,
kCMSampleBufferError_SampleIndexOutOfRange        = -12734,
kCMSampleBufferError_BufferHasNoSampleSizes       = -12735,
kCMSampleBufferError_BufferHasNoSampleTimingInfo  = -12736,
kCMSampleBufferError_ArrayTooSmall                = -12737,
kCMSampleBufferError_InvalidEntryCount            = -12738,
kCMSampleBufferError_CannotSubdivide              = -12739,
kCMSampleBufferError_SampleTimingInfoInvalid      = -12740,
kCMSampleBufferError_InvalidMediaTypeForOperation = -12741,
kCMSampleBufferError_InvalidSampleData            = -12742,
kCMSampleBufferError_InvalidMediaFormat           = -12743,
kCMSampleBufferError_Invalidated                  = -12744,
kCMSampleBufferError_DataFailed                   = -16750,
kCMSampleBufferError_DataCanceled                 = -16751,

Answer 5:

@Livy之前删除内存泄漏CMVideoFormatDescriptionCreateFromH264ParameterSets你应该增加以下内容：

if (_formatDesc) {
    CFRelease(_formatDesc);
    _formatDesc = NULL;
}

如何使用VideoToolbox解压缩的H.264视频流如何使用VideoToolbox解压缩的H.

Answer 1:

概念：

程序：

其他说明：

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