VTDecompressionSessionDecodeFrame fails with code -kVTVideoDecoderBadDataErr - ios

Question

I have been trying to decode H264 using VTDecompressionSessionDecodeFrame but getting errors. The Parameter sets have been created previously and look fine, nothing errors up to this point so it may have something to do with my understanding of Timing information in the CMSampleBufferRef. Any input would be much appreciated
void didDecompress( void *decompressionOutputRefCon, void *sourceFrameRefCon, OSStatus status, VTDecodeInfoFlags infoFlags, CVImageBufferRef imageBuffer, CMTime presentationTimeStamp, CMTime presentationDuration ){
NSLog(#"In decompression callback routine");
}
void decodeH264 {
VTDecodeInfoFlags infoFlags;
[NALPacket appendBytes: NalPacketSize length:4];
[NALPacket appendBytes: &NALCODE length:1];
[NALPacket appendBytes: startPointer length:buflen];
void *samples = (void *)[NALTestPacket bytes];
blockBuffer = NULL;
// add the nal raw data to the CMBlockBuffer
status = CMBlockBufferCreateWithMemoryBlock(
kCFAllocatorDefault,
samples,
[NALPacket length],
kCFAllocatorDefault,
NULL,
0,
[NALPacket length],
0,
&blockBuffer);
const size_t * samplesizeArrayPointer;
size_t sampleSizeArray= buflen;
samplesizeArrayPointer = &sampleSizeArray;
int32_t timeSpan = 1000000;
CMTime PTime = CMTimeMake(presentationTime, timeSpan);
CMSampleTimingInfo timingInfo;
timingInfo.presentationTimeStamp = PTime;
timingInfo.duration = kCMTimeZero;
timingInfo.decodeTimeStamp = kCMTimeInvalid;
status = CMSampleBufferCreate(kCFAllocatorDefault, blockBuffer, YES, NULL, NULL, formatDescription, 1, 1, &timingInfo, 0, samplesizeArrayPointer, &sampleBuffer);
CFArrayRef attachmentsArray = CMSampleBufferGetSampleAttachmentsArray(sampleBuffer, true);
for (CFIndex i = 0; i < CFArrayGetCount(attachmentsArray); ++i) {
CFMutableDictionaryRef attachments = (CFMutableDictionaryRef)CFArrayGetValueAtIndex(attachmentsArray, i);
CFDictionarySetValue(attachments, kCMSampleAttachmentKey_DoNotDisplay, kCFBooleanFalse);
CFDictionarySetValue(attachments, kCMSampleAttachmentKey_DisplayImmediately, kCFBooleanTrue);
}
// I Frame
status = VTDecompressionSessionDecodeFrame(decoder, sampleBuffer, kVTDecodeFrame_1xRealTimePlayback, (void*)CFBridgingRetain(currentTime), &infoFlags);
if (status != noErr) {
NSLog(#"Decode error");
}

Answer 1

Discovered why this wasn't working, I had forgotten to set the CMSampleBufferRef to NULL each time a new sample was captured.
samples = NULL;
status = CMSampleBufferCreate(kCFAllocatorDefault, blockBuffer, YES, NULL, NULL, formatDescription, 1, 1, &timingInfo, 0, samplesizeArrayPointer, &sampleBuffer);