/// <summary>
/// Start the following reads from the selected timestamp.
/// Seeks all tracks to the block before the position given in seconds.
/// </summary>
/// <returns>Position that was actually possible to seek to or -1 if the position didn't change.</returns>
public override double Seek(double position)
{
long targetTime = (long)(position * sToNs / timestampScale);
Cue cue = Cue.Find(cues, targetTime);
int clusterId = 0;
Cluster cluster;
if (cue != null)
{
clusterId = segments[0].GetIndexByPosition(reader, MatroskaTree.Segment_Cluster, cue.Position);
}
if (clusterId == -1)
{
while (true)
{
cluster = GetCluster(clusterId++);
if (cluster == null)
{
break;
}
if (cluster.TimeStamp > targetTime)
{
break;
}
}
if (cluster == null)
{
return(-1);
}
--clusterId;
}
bool[] trackSet = new bool[Tracks.Length];
int tracksSet = 0;
long audioTime = long.MaxValue, minTime = long.MaxValue;
while (clusterId >= 0 && tracksSet != trackSet.Length)
{
cluster = GetCluster(clusterId);
IReadOnlyList <Block> blocks = cluster.GetBlocks(reader);
for (int block = blocks.Count - 1; block >= 0; --block)
{
long trackId = Tracks.GetIndexByID(blocks[block].Track);
if (trackId == -1 || trackSet[trackId])
{
continue;
}
long time = cluster.TimeStamp + blocks[block].TimeStamp;
if (time <= targetTime)
{
MatroskaTrack trackData = Tracks[trackId] as MatroskaTrack;
trackData.lastCluster = clusterId;
trackData.lastBlock = block;
if (minTime > time)
{
minTime = time;
}
if (trackData.Format.IsAudio() && audioTime > targetTime)
{
audioTime = time;
}
trackSet[trackId] = true;
++tracksSet;
}
}
--clusterId;
}
if (audioTime != long.MaxValue)
{
return(audioTime * timestampScale * nsToS);
}
if (minTime != long.MaxValue)
{
return(minTime * timestampScale * nsToS);
}
return(-1);
}