public IDataPacket GetVideoData(IResultNode resultNode)
{
if (!IsIntraSlice(resultNode))
{
return(null);
}
if (resultNode.Parent == null)
{
// Slice without headers (won't decode!)
return(resultNode.Append(resultNode));
}
uint?firstMacroblockInSlice = GetFirstMacroblockInSlice(resultNode);
if (!firstMacroblockInSlice.HasValue)
{
return(resultNode.Append(resultNode));
}
int index = GetParentIndex(resultNode);
IList <IResultNode> siblings = resultNode.Parent.Children;
IDataPacket dataPacket = resultNode;
for (int i = (index + 1); i < siblings.Count; i++)
{
IResultNode sibling = siblings[i];
if (!IsIntraSlice(sibling))
{
break; // Not an intra-coded slice, so not part of the same IDR picture
}
uint?nextFirstMacroblockInSlice = GetFirstMacroblockInSlice(sibling);
if (!nextFirstMacroblockInSlice.HasValue || (nextFirstMacroblockInSlice <= firstMacroblockInSlice))
{
break; // Slice is not part of the same picture
}
firstMacroblockInSlice = nextFirstMacroblockInSlice.Value;
dataPacket = dataPacket.Append(sibling);
}
// Duplicate the frame data, because otherwise, FFmpeg won't decode it.
return(dataPacket.Append(dataPacket));
}
public IDataPacket FindReferenceHeader(IDataReader dataReader, ICodecParametersSpec codecParameters)
{
// Note: Loop to detect reference headers preceeded by a block of video frames
// (e.g. for 3GP files with 'mdat' before the 'moov' atom, so that the slices are located before the SPS/PPS pair)
while (dataReader.State == DataReaderState.Ready)
{
IScanContext scanContext = new ReferenceHeaderScanContext {
Detectors = new[] { this }
};
var dataBlock = _carver.Carve(new BitStreamDataReader(dataReader), new ReferenceHeaderDataBlockBuilder(), scanContext);
if (dataBlock == null)
{
break; // No (more) data blocks detected
}
IResultNode sequenceParameterSet = scanContext.Results.FindChild(SequenceParameterSet.Name);
if (sequenceParameterSet != null)
{
IResultNode pictureParameterSet = sequenceParameterSet.FindChild(PictureParameterSet.Name);
if (pictureParameterSet != null)
{
// TODO: perhaps we need to include the headers between the SPS and PPS !?
IDataPacket data = sequenceParameterSet.Append(pictureParameterSet);
// Report codec parameters for reference header
codecParameters.Codec = CodecID.H264;
codecParameters.Width = GetWidth(sequenceParameterSet);
codecParameters.Height = GetHeight(sequenceParameterSet);
var entropyCodingMode = GetAttributeValue <bool>(pictureParameterSet, PictureParameterSet.Attribute.EntropyCodingMode);
codecParameters["EntropyCodingMode"] = entropyCodingMode ? "CABAC" : "CAVLC";
// TODO: codecParameters["FrameRate"] = GetAttributeStringValue(sequenceParameterSet, ???);
return(data);
}
}
// Sequence- or Picture Parameter Set is missing: Continue scanning after current data block ...
dataReader.Position = dataBlock.EndOffset;
}
return(null); // No reference header detected
}
public IDataPacket Append(IDataPacket dataPacket)
{
return(_result.Append(dataPacket));
}