topic Re: H264 Encoder and NAL Split in Intel® Integrated Performance Primitives

H264 Encoder and NAL Split

yann_stephan — Tue, 14 Apr 2009 21:22:26 GMT

When I use SLICE_CHECK_LIMIT, the stream is certainly split in NAL with a given size.
I didn't find an accessor in the sample for changing the value of m_MaxSliceSize, so I changed it in the code directly.

My question is the following one:

I use the following code (not optimized for a good understanding)

int nSrcWidth = abs((long) pOutputFormat->bmiHeader.biWidth);
int nSrcHeight = abs((long) pOutputFormat->bmiHeader.biHeight);

// Compared to I420 (YUV) plans are in YV12 (YVU)
LPBYTE pDestY = lpVideoBuffer;
LPBYTE pDestU = pDestY + (nSrcWidth * nSrcHeight);
LPBYTE pDestV = pDestU + ((nSrcWidth * nSrcHeight) / 4);

m_pSrcMediaData->SetPlanePointer(pDestY, 0); // Y
m_pSrcMediaData->SetPlanePointer(pDestU, 1); // U
m_pSrcMediaData->SetPlanePointer(pDestV, 2); // V

m_pDstMediaData->SetBufferPointer(lpCompressedData + sizeof(RTP_INFO_HEADER), lOutDataLen - sizeof(RTP_INFO_HEADER));

if (m_h264VideoEncoder->GetFrame(m_pSrcMediaData, m_pDstMediaData) == UMC::UMC_OK)
{
if (m_pDstMediaData->GetDataSize() > 0)
{
....

The problem is that m_pDstMediaData is a continous stream, how I can access the NAL split in order to send it over the network. I need to split in NAL with a maximum size of the given MTU. The mode used is the single NAL unit.

I found a h264_split but it's not very how I should use it (if I need to use it)

Thanks for your answers.

Re: H264 Encoder and NAL Split

yann_stephan — Tue, 14 Apr 2009 21:33:53 GMT

Quoting - yann.stephan@gmail.com

I found maybe the answer, NAL units are separated by a simple (at least) 4-byte sequence containing a
big-endian 1, i.e. 00 00 00 01. So, by searching them I should be able to send them over the network.

Re: H264 Encoder and NAL Split

Emmanuel_W_ — Tue, 05 May 2009 17:54:31 GMT

Quoting - yann.stephan@gmail.com

This is how I did too.