public AsfPacket(AsfFileConfiguration asfConfig, byte[] packetData, uint packetID = 0, int payloadIdOffset = 0)
{
if (asfConfig.AsfPacketSize != packetData.Length)
throw new ArgumentException("Packet data length doesn't match packet configuration");
_asfConfig = asfConfig;
Size = packetData.Length;
PacketID = packetID;
PayloadIdOffset = payloadIdOffset;
Payload = new List<PayloadInfo>();
_packet = packetData;
ParsePacket();
}
private void Init(AsfStreamType streamType, double startOffset, double endOffset)
{
StreamType = streamType;
if (StreamType == AsfStreamType.asfImage)
{
endOffset = 0; //use all available data
}
if (startOffset < 0 || endOffset < 0 || ((streamType != AsfStreamType.asfStream && streamType != AsfStreamType.asfImage && streamType != AsfStreamType.asfAudio) && endOffset < startOffset))
throw new ArgumentOutOfRangeException();
if (streamType == AsfStreamType.asfImage && _asfFile.PacketConfiguration.ImageWidth == 0)
{
throw new AsfStreamException("Cannot create image stream for audio file");
}
_streamInfo = new AsfStreamInfo(StreamType);
FilePosition fileStartPos;
FilePosition fileEndPos;
bool status = _asfFile.SetOffsetRange(startOffset, endOffset, out fileStartPos, out fileEndPos, streamType);
if (!status)
throw new AsfStreamException("Asf stream data within required offsets not found"); // could not find file data covering the requested start and end offsets
_asfConfig = _asfFile.PacketConfiguration;
_streamInfo.StartTimeOffset = fileStartPos.TimeOffset;
_streamInfo.EndTimeOffset = fileEndPos.TimeOffset;
if (StreamType == AsfStreamType.asfStream)
_length = Math.Min(int.MaxValue, _asfFile.Length + _asfConfig.AsfHeaderSize);
else if (StreamType == AsfStreamType.asfUnaltered)
_length = _asfFile.Length;
else
_length = _asfFile.Length + _asfConfig.AsfHeaderSize;
}
public void CreateAsfObject()
{
AsfFile asfFile = new AsfFile(testVideoFileName);
AsfFileConfiguration config = new AsfFileConfiguration();
AsfFileHeader asfFileHeader;
using (FileStream fs = new FileStream(testVideoFileName, FileMode.Open, FileAccess.Read))
{
asfFileHeader = (AsfFileHeader)AsfObject.CreateAsfObject(AsfGuid.ASF_Header_Object, fs, config);
}
Assert.IsNotNull(asfFileHeader);
Assert.AreEqual<uint>(5292, asfFileHeader.HeaderSize);
}
/// <summary>
/// Correct presentation and send time stamps based on the stream info
/// <param name="configuration">The ASF configuration</param>
/// <param name="asfStream">The stream info</param>
/// </summary>
public bool SetStart(AsfFileConfiguration configuration, AsfStreamInfo asfStream)
{
if (asfStream.StreamType != AsfStreamType.asfAudio) //nothing to do for audio
{
//determine keyframe
PayloadInfo keyframeInfo = (from payload in Payload where (payload.StreamId == configuration.AsfVideoStreamId && payload.IsKeyframeStart) select payload).LastOrDefault();
if (keyframeInfo == null)
return false;
//now cut out everything before that presentation time
for (int idx = 0; idx < Payload.Count; idx++)
{
if (Payload[idx].StreamId == configuration.AsfVideoStreamId && !Payload[idx].IsKeyframeStart && Payload[idx].PresentationTime < keyframeInfo.PresentationTime)
{
byte streamId = Payload[idx].StreamId;
if (Payload[idx].MediaObjectNumber < keyframeInfo.MediaObjectNumber && asfStream.StreamType != AsfStreamType.asfUnaltered) //this is a B or P-frame that comes before the key frame, so it must be disabled
streamId += AsfConstants.ASF_PRIVATE_STREAM_OFFSET;
Payload[idx].StreamId = streamId;
Buffer.SetByte(_packet, Payload[idx].StreamIDOffset, streamId);
//fix media offset as well
UInt32 mediaOffset = 0;
Payload[idx].OffsetIntoMedia = mediaOffset;
Buffer.BlockCopy(BitConverter.GetBytes(mediaOffset), 0, _packet, Payload[idx].MediaOffset, sizeof(UInt32));
}
}
}
return true;
}
/// <summary>
/// Correct presentation and send time stamps based on the stream info
/// <param name="configuration">The ASF configuration</param>
/// <param name="asfStreamInfo">The stream info</param>
/// </summary>
public void SetFollowup(AsfFileConfiguration configuration, AsfStreamInfo asfStreamInfo)
{
Int64 packetSendTime = (Int64)SendTime - asfStreamInfo.StartSendTime;
if (packetSendTime - AsfConstants.ASF_SEND_SAFTEY_THRESHOLD > 0)
packetSendTime -= AsfConstants.ASF_SEND_SAFTEY_THRESHOLD;
else
packetSendTime = 0;
SendTime = (uint)packetSendTime;
//base payload on packet send time, add delta to zero based send time
for (int i = 0; i < Payload.Count; i++)
{
Int64 payloadPresentationTime = (Int64)Payload[i].PresentationTime - asfStreamInfo.StartTimeOffset;
if (payloadPresentationTime < _asfConfig.AsfPreroll)
{
//an audio payload before the preroll must be eliminated, in this case we assign it a private stream id
if (Payload[i].StreamId == configuration.AsfAudioStreamId && asfStreamInfo.StreamType != AsfStreamType.asfUnaltered)
{
payloadPresentationTime = SendTime + _asfConfig.AsfPreroll;
MovePayloadPrivate(Payload[i], (uint)payloadPresentationTime);
}
else
{
//set the time slightly before the preroll time - not used by renderer, but decoded so first frame (seek point) can be delta frame
payloadPresentationTime = asfStreamInfo.StreamType == AsfStreamType.asfImage ? (_asfConfig.AsfPreroll - 100) : _asfConfig.AsfPreroll;
}
}
//remove unnecesscary audio data for image stream, that means only one stream is remaining which sets the timeline
if (asfStreamInfo.StreamType == AsfStreamType.asfImage && Payload[i].StreamId == configuration.AsfAudioStreamId)
{
MovePayloadPrivate(Payload[i], SendTime + _asfConfig.AsfPreroll);
}
//Packet Sendtime must be earlier than Payload presentation times
if (payloadPresentationTime < SendTime)
SendTime = Math.Max((uint)payloadPresentationTime, asfStreamInfo.MinPacketSendTime);
SetPayloadPresentationTime(Payload[i], (uint)payloadPresentationTime);
if ((asfStreamInfo.StreamType != AsfStreamType.asfUnaltered) && asfStreamInfo.StreamType != AsfStreamType.asfImage && Payload[i].PresentationTime > _asfConfig.AsfPreroll && Payload[i].PresentationTime - _asfConfig.AsfPreroll > (asfStreamInfo.EndTimeOffset - asfStreamInfo.StartTimeOffset))
{
//Crop both audio and video at the end of the segment
payloadPresentationTime = (asfStreamInfo.EndTimeOffset - asfStreamInfo.StartTimeOffset) + _asfConfig.AsfPreroll;
MovePayloadPrivate(Payload[i], (uint)payloadPresentationTime);
}
//Handle media object id's: must be consecutive, starting at zero, roll over at 255
uint maxPresentationTime = 0;
asfStreamInfo.MaxPresentationTime.TryGetValue(Payload[i].StreamId, out maxPresentationTime);
if (maxPresentationTime < Payload[i].PresentationTime)
asfStreamInfo.MaxPresentationTime[Payload[i].StreamId] = Payload[i].PresentationTime;
if ((asfStreamInfo.MediaObjectId[Payload[i].StreamId] == 0 && asfStreamInfo.PrevMediaObjectId[Payload[i].StreamId] == 0) || asfStreamInfo.PrevMediaObjectId[Payload[i].StreamId] != Payload[i].MediaObjectNumber)
{
asfStreamInfo.MediaObjectId[Payload[i].StreamId]++;
}
asfStreamInfo.PrevMediaObjectId[Payload[i].StreamId] = Payload[i].MediaObjectNumber;
SetMediaObjectNumber(i, asfStreamInfo.MediaObjectId[Payload[i].StreamId]);
}
//the send time of the next packet must be larger or equal than the send time of the current packet, keep track of send time
asfStreamInfo.MinPacketSendTime = SendTime;
}