/// <summary>
/// Search video stream using passed MpegStreamManager
/// </summary>
public bool Parse(ref MpegStreamManager msManager)
{
videoStream = new MpegVideoStream();
long offset = 0;
// Search 0x00 0x00 0x01 0xB3 marker [Sequence header]
bool isSeqHeader = msManager.SearchMarker(ref offset,
new byte[4]{0x00, 0x00, 0x01, 0xB3});
if (!isSeqHeader)
{
// Sequence header not founded
return false;
}
// skip marker bytes
offset += 4;
// read height and width
videoStream.Width = msManager.GetSize(offset) >> 4;
videoStream.Height = msManager.GetSize(offset + 1) & 0x0FFF;
offset += 3;
// read framerate
int frameRateIndex = msManager.GetByte(offset) & 0x0F;
if (frameRateIndex > 8)
{
// Reserved
videoStream.FrameRate = 0.0d;
}
else
{
// Retrieve value from table
videoStream.FrameRate = MpegConstants.FrameRateTable[frameRateIndex];
}
// read aspectratio
int aspectRatioIndex = (msManager.GetByte(offset) & 0xF0) >> 4;
if (aspectRatioIndex <=4)
{
videoStream.AspectRatio = MpegConstants.AspectRatio[aspectRatioIndex];
}
else
{
videoStream.AspectRatio = "Unknow";
}
offset += 1;
// read BitRate
int bitRate = ((msManager.GetByte(offset) * 0x10000) +
(msManager.GetByte(offset + 1) * 0x100) +
msManager.GetByte(offset + 2) ) >> 6;
videoStream.BitRate = bitRate;
// calculate Duration
videoStream.Duration = msManager.StreamSize / ((bitRate * 400) / 8.0);
// Extract video format and chroma format
GetVideoFormat(ref msManager, offset);
return true;
}
