/// <summary>
/// GetDurationFromLastAudioQBox
/// This is necessary for a dynamically growing stream.
/// It needs to be threadsafe because we set and then reset the stream Position.
/// Remove mutex and call this from LazyRead to avoid deadlocks.
/// </summary>
/// <returns></returns>
public ulong GetDurationFromLastQBox()
{
if (Stream.CanSeek == false)
{
return(0);
}
lock (base.Stream) {
long currentPos = Stream.Position; // store where we are at currently...
// try to find an audio qbox...
BinaryReader br = new BinaryReader(base.Stream);
br.BaseStream.Position = br.BaseStream.Length - 8;
while (true)
{
if (QBox.SeekPrevQBox(br))
{
QBox box = new QBox();
long boxPos = br.BaseStream.Position;
box.Read(br);
// if (box.mSampleStreamType == QBox.QBOX_SAMPLE_TYPE_AAC)
if (box.mStreamDuration != 0)
{
br.BaseStream.Position = currentPos;
ulong ans = MediaTimes[box.mSampleStreamId].TicksToTime(box.mStreamDuration, MediaTimeUtils.TimeUnitType.OneHundredNanoSeconds);
return(ans);
}
else
{
if (br.BaseStream.Position - 8 <= 0)
{
// no more data to read...
br.BaseStream.Position = currentPos;
}
br.BaseStream.Position = boxPos - 8; // rewind a bit...
}
}
else
{
//DurationIn100NanoSecs = 0; // return value assigned to DurationIn100NanoSecs
break; // can't find a previous qbox!!
}
}
br.BaseStream.Position = currentPos;
}
return(0U);
}
//nbl; removed as we shouldn't 'fix' bframe time stamps
//private Dictionary<ushort, ulong> PrevTimeStamps = new Dictionary<ushort, ulong>();
//private Dictionary<ushort, int> PrevIndices = new Dictionary<ushort, int>();
public override void LazyRead(int requestedBoxCount)
{
QBox qbox = null;
int i = 0;
int boxCount = 0;
lock (_binaryReader.BaseStream) {
// clear out all qbox lists
// we expect the payload buffers to stay intact because these are now referenced in Slices
_audioBoxes.Clear();
_videoBoxes.Clear();
while ((boxCount < requestedBoxCount) && (_binaryReader.BaseStream.Position < _binaryReader.BaseStream.Length))
{
try {
qbox = new QBox();
qbox.Read(_binaryReader);
if (MediaTimes[qbox.mSampleStreamId] == null)
{
MediaTimes[qbox.mSampleStreamId] = new MediaTimeUtils();
}
MediaTimes[qbox.mSampleStreamId].SetClockRate(((qbox.mSampleFlags & QBox.QBOX_SAMPLE_FLAGS_120HZ_CLOCK) != 0U));
//nbl; we can't fill in duration for bframes as this doesn't make sense... the CTTS info is presentation time used for mp4 stuff
//qbox.FixTimeStamp(PrevTimeStamps, PrevIndices); // <---- Kludge! Some qboxes may have mStreamDuration reset, fix it here
boxCount++;
}
// for the moment we catch two different exceptions, yet all we do is break our while loop
catch (EndOfStreamException eos) {
string msg = eos.Message;
break;
} catch (Exception ex) {
throw ex;
}
switch (qbox.SampleStreamTypeString())
{
case "AAC":
case "PCM":
case "MP2A":
case "Q711":
case "Q722":
case "Q726":
case "Q728":
_audioBoxes.Add(qbox);
break;
case "H264":
case "H264_SLICE":
case "JPEG":
case "MPEG2_ELEMENTARY":
if (!_videoTrackIDs.Contains(qbox.mSampleStreamId))
{
_videoTrackIDs.Add(qbox.mSampleStreamId);
}
_videoBoxes.Add(qbox);
break;
case "VIN_STATS_GLOBAL":
case "VIN_STATS_MB":
case "USER_METADATA":
case "DEBUG":
default:
System.Diagnostics.Debug.WriteLine("Unknown QBox: {0}", qbox.SampleStreamTypeString());
break;
}
i++;
} // end of while
}
// define the tracks, if we haven't already
// note that for qboxes, we really only care about formats (QBoxTrackFormat), and tracks are just generic.
if (MediaTracks.Count == 0 && qbox != null)
{
if (_audioBoxes.Count > 0)
{
ushort audioTrackID = _audioBoxes[0].mSampleStreamId;
QBoxTrackFormat audioTrackFormat = new QBoxTrackFormat(_audioBoxes, audioTrackID, MediaTimes[audioTrackID]);
QBoxAudioTrack audioTrack = new QBoxAudioTrack(audioTrackFormat, this);
// audioTrack.NextIndexToRead = tempIndices[audioTrackID];
//GenericAudioTrack audioTrack = new GenericAudioTrack(audioTrackFormat, this);
//this.Duration = audioTrack.TrackDuration;
//this.TimeScale = (uint)audioTrack.SampleRate;
base.AddTrack(audioTrack);
}
foreach (ushort trackID in _videoTrackIDs)
{
QBoxTrackFormat videoTrackFormat = new QBoxTrackFormat(_videoBoxes, trackID, MediaTimes[trackID]);
QBoxVideoTrack videoTrack = new QBoxVideoTrack(videoTrackFormat, this);
videoTrack.NextIndexToRead = (int)(qbox.mBoxContinuityCounter + 1);
if (DurationIn100NanoSecs < videoTrack.TrackDurationIn100NanoSecs)
{
this.DurationIn100NanoSecs = videoTrack.TrackDurationIn100NanoSecs;
}
//this.TimeScale = videoTrack.TrackFormat.TimeScale;
base.AddTrack(videoTrack);
}
}
else if (_audioBoxes.Count > 0 && _videoBoxes.Count > 0)
{
// add qboxes to existing track formats
foreach (GenericMediaTrack track in this.MediaTracks)
{
QBoxTrackFormat format = track.TrackFormat as QBoxTrackFormat;
if (track is GenericAudioTrack)
{
format.AddMore(_audioBoxes);
}
else
{
format.AddMore(_videoBoxes);
}
}
}
if (currStreamLength < Stream.Length)
{
currStreamLength = Stream.Length;
// if the duration we're getting from the last audio qbox is shorter than we already have, then don't bother
ulong liveDuration = (ulong)GetDurationFromLastQBox(); // seek all the way forward and back, just to determine duration
if (liveDuration > DurationIn100NanoSecs)
{
DurationIn100NanoSecs = liveDuration;
}
// might as well set audio and video durations
foreach (IMediaTrack track in MediaTracks)
{
track.TrackDurationIn100NanoSecs = DurationIn100NanoSecs;
}
}
}
