h.264硬件解码

//  H264HWDecoder.m
//  H264EncoderDecoder
//
//  Created by lujunjie on 2016/11/28.
//  Copyright © 2016年 陆俊杰. All rights reserved.
//

#import "H264HWDecoder.h"

@implementation H264HWDecoder

- (void)dealloc
{
    if(self.decompressionSession != NULL){
        VTDecompressionSessionInvalidate(self.decompressionSession);
        CFRelease(self.decompressionSession);
        self.decompressionSession=NULL;
    }
}
- (int)DecodeH264Frames:(unsigned char *)frame withLength:(int)frameSize
{
    OSStatus status = -;

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

    int startCodeIndex = ;
    int secondStartCodeIndex = ;
    int thirdStartCodeIndex = ;

    long blockLength = ;

    CMSampleBufferRef sampleBuffer = NULL;
    CMBlockBufferRef blockBuffer = NULL;

    int nalu_type = (frame[startCodeIndex + ] & 0x1F);

    if (nalu_type !=  && _formatDesc == NULL)
    {
        NSLog(@"Video error: Frame is not an I Frame and format description is null");
        return -;
    }

    if (nalu_type == )
    {
//        NSLog(@"=================================================");
//        for (int i = 0; i<frameSize; i++) {
//            printf(" %x",frame[i]);
//        }
        for (int i = startCodeIndex + ; i < startCodeIndex + ; i++)
        {
            if (frame[i] == 0x00 && frame[i+] == 0x00 && frame[i+] == 0x00 && frame[i+] == 0x01)
            {
                secondStartCodeIndex = i;
                _spsSize = secondStartCodeIndex;
                break;
            }
        }
        nalu_type = (frame[secondStartCodeIndex + ] & 0x1F);

    }

    if(nalu_type == )
    {

        for (int i = _spsSize + ; i < _spsSize + ; i++)
        {
            if (frame[i] == 0x00 && frame[i+] == 0x00 && frame[i+] == 0x00 && frame[i+] == 0x01)
            {
                thirdStartCodeIndex = i;
                _ppsSize = thirdStartCodeIndex - _spsSize;
                break;
            }
        }

        sps = malloc(_spsSize - );
        pps = malloc(_ppsSize - );

        memcpy (sps, &frame[], _spsSize-);
        memcpy (pps, &frame[_spsSize+], _ppsSize-);

        uint8_t*  parameterSetPointers[] = {sps, pps};
        size_t parameterSetSizes[] = {_spsSize-, _ppsSize-};

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

        if(status != noErr){
            NSLog(@"MVideoFormatDescriptionCreateFromH264ParameterSets ERROR type: %d", (int)status);
        }

        nalu_type = (frame[thirdStartCodeIndex + ] & 0x1F);
    }

    if(nalu_type ==  )
    {

        int offset = _spsSize + _ppsSize;
        blockLength = frameSize - offset;
        data = malloc(blockLength);
        data = memcpy(data, &frame[offset], blockLength);

        uint32_t dataLength32 = htonl (blockLength - );
        memcpy (data, &dataLength32, sizeof (uint32_t));

        status = CMBlockBufferCreateWithMemoryBlock(NULL, data,
                                                    blockLength,
                                                    kCFAllocatorNull, NULL,
                                                    ,
                                                    blockLength,
                                                    , &blockBuffer);
        if(status != noErr){
            NSLog(@"I Frame: CMBlockBufferCreateWithMemoryBlock Error type: %d", (int)status);
        }

    }

    if (nalu_type == )
    {

        blockLength = frameSize;
        data = malloc(blockLength);
        data = memcpy(data, &frame[], blockLength);

        uint32_t dataLength32 = htonl (blockLength - );
        memcpy (data, &dataLength32, sizeof (uint32_t));

        status = CMBlockBufferCreateWithMemoryBlock(NULL, data,
                                                    blockLength,
                                                    kCFAllocatorNull, NULL,
                                                    ,
                                                    blockLength,
                                                    , &blockBuffer);
        if(status != noErr){
            NSLog(@"P Frame: CMBlockBufferCreateWithMemoryBlock Error type: %d", (int)status);
        }

    }

    if(status == noErr)
    {
        const size_t sampleSize = blockLength;
        status = CMSampleBufferCreate(kCFAllocatorDefault,
                                      blockBuffer, true, NULL, NULL,
                                      _formatDesc, , , NULL, ,
                                      &sampleSize, &sampleBuffer);
        if(status != noErr){
            NSLog(@"CMSampleBufferCreate Error type: %d", (int)status);
        }

    }

    if(status == noErr)
    {

        CFArrayRef attachments = CMSampleBufferGetSampleAttachmentsArray(sampleBuffer, YES);
        CFMutableDictionaryRef dict = (CFMutableDictionaryRef)CFArrayGetValueAtIndex(attachments, );
        CFDictionarySetValue(dict, kCMSampleAttachmentKey_DisplayImmediately, kCFBooleanTrue);

        if([self.updateDelegate respondsToSelector:@selector(updateDecodedSampleBuffer:)]){
            [self.updateDelegate updateDecodedSampleBuffer:sampleBuffer];

        }

    }

    if (data != NULL)
    {
        free (data);
        data = NULL;
    }
    if(sps != NULL)
    {
        free(sps);
        sps = NULL;
    }
    if(pps != NULL)
    {
        free(pps);
        pps = NULL;
    }

    return ;
}
@end