// Calls fileStream.Position and fileStream.Write only.
//
// Usually trackSamples has 2 elements: a video track and an audio track.
//
// Uses trackEntries and trackSamples only as a read-only argument, doesn't modify their contents.
//
// Starts with the initial cue points specified in cuePoints, and appends subsequent cue points in place.
private static void WriteClustersAndCues(FileStream fileStream,
ulong segmentOffset,
int videoTrackIndex,
IList<bool> isAmsCodecs,
IMediaDataSource mediaDataSource,
MuxStateWriter muxStateWriter,
IList<CuePoint> cuePoints,
ref ulong minStartTime,
ulong timePosition,
out ulong seekHeadOffsetMS,
out ulong cuesOffsetMS)
{
int trackCount = mediaDataSource.GetTrackCount();
if (isAmsCodecs.Count != trackCount) {
throw new Exception("ASSERT: isAmsCodecs vs mediaDataSource length mismatch.");
}
if (trackCount > 13) { // 13 is because a..m and n..z in MuxStateWriter checkpointing.
throw new Exception("Too many tracks to mux.");
}
// For each track, contains the data bytes of a media sample ungot (i.e. pushed back) after reading.
// Initializes items to null (good).
MediaDataBlock[] ungetBlocks = new MediaDataBlock[trackCount];
ulong minStartTime0 = minStartTime;
if (timePosition == ulong.MaxValue) {
timePosition = 0;
ulong maxStartTime = ulong.MaxValue;
for (int i = 0; i < trackCount; ++i) {
if ((ungetBlocks[i] = mediaDataSource.PeekBlock(i)) != null) {
if (maxStartTime == ulong.MaxValue || maxStartTime < ungetBlocks[i].StartTime) {
maxStartTime = ungetBlocks[i].StartTime;
}
mediaDataSource.ConsumeBlock(i); // Since it was moved to ungetBlocks[i].
}
}
for (int i = 0; i < trackCount; ++i) {
MediaDataBlock block = mediaDataSource.PeekBlock(i);
while (block != null && block.StartTime <= maxStartTime) {
ungetBlocks[i] = block; // Takes ownership.
mediaDataSource.ConsumeBlock(i);
}
// We'll start each track (in ungetMediaSample[i]) from the furthest sample within maxStartTime.
}
int trackIndex2;
if ((trackIndex2 = GetNextTrackIndex(mediaDataSource, ungetBlocks)) < 0) {
throw new Exception("ASSERT: Empty media file, no samples.");
}
minStartTime = minStartTime0 = ungetBlocks[trackIndex2] != null ? ungetBlocks[trackIndex2].StartTime :
mediaDataSource.PeekBlock(trackIndex2).StartTime;
muxStateWriter.WriteUlong('A', minStartTime0);
}
List<ArraySegment<byte>> output = new List<ArraySegment<byte>>();
ulong[] lastOutputStartTimes = new ulong[trackCount]; // Items initialized to zero.
int trackIndex;
// timePosition is the beginning StartTime of the last output block written by fileStream.Write.
while ((trackIndex = GetNextTrackIndex(mediaDataSource, ungetBlocks)) >= 0) {
ulong timeCode; // Will be set below.
bool isKeyFrame; // Will be set below.
MediaDataBlock block0; // Will be set below.
MediaDataBlock block1 = null; // May be set below.
int mediaDataBlockTotalSize; // Will be set below.
{
if ((block0 = ungetBlocks[trackIndex]) == null &&
(block0 = mediaDataSource.PeekBlock(trackIndex)) == null) {
throw new Exception("ASSERT: Reading from a track already at EOF.");
}
// Some kind of time delta for this sample.
timeCode = block0.StartTime - timePosition - minStartTime0;
if (block0.StartTime < timePosition + minStartTime0) {
throw new Exception("Bad start times: block0.StartTime=" + block0.StartTime +
" timePosition=" + timePosition + " minStartTime=" + minStartTime0);
}
isKeyFrame = block0.IsKeyFrame;
mediaDataBlockTotalSize = block0.Bytes.Count;
if (ungetBlocks[trackIndex] != null) {
ungetBlocks[trackIndex] = null;
} else {
mediaDataSource.ConsumeBlock(trackIndex);
}
}
if (timeCode > 327670000uL) {
throw new Exception("timeCode too large: " + timeCode); // Maybe that's not fatal?
}
if (isAmsCodecs[trackIndex]) { // Copy one more MediaSample if available.
// TODO: Test this.
block1 = ungetBlocks[trackIndex];
if (block1 != null) {
mediaDataBlockTotalSize += block1.Bytes.Count;
ungetBlocks[trackIndex] = null;
} else if ((block1 = mediaDataSource.PeekBlock(trackIndex)) != null) {
mediaDataBlockTotalSize += block1.Bytes.Count;
mediaDataSource.ConsumeBlock(trackIndex);
}
}
// TODO: How can be timeCode so large at this point?
if ((output.Count != 0 && trackIndex == videoTrackIndex && isKeyFrame) || timeCode > 327670000uL) {
ulong outputOffset = (ulong)fileStream.Position - segmentOffset;
cuePoints.Add(new CuePoint(timePosition / 10000uL, (ulong)(videoTrackIndex + 1), outputOffset));
muxStateWriter.WriteUlong('C', timePosition);
muxStateWriter.WriteUlong('D', outputOffset);
int totalSize = 0;
for (int i = 0; i < output.Count; ++i) {
totalSize += output[i].Count;
}
// We do a single copy of the media stream data bytes here. That copy is inevitable, because it's
// faster to save to file that way.
byte[] bytes = Utils.CombineByteArraysAndArraySegments(
new byte[][]{GetDataSizeBytes((ulong)ID.Cluster), GetDataSizeBytes((ulong)totalSize)}, output);
output.Clear();
// The average bytes.Length is 286834 bytes here, that's large enough (>8 kB), and it doesn't warrant a
// a buffered output stream for speedup.
fileStream.Write(bytes, 0, bytes.Length);
fileStream.Flush();
for (int i = 0; i < trackCount; ++i) {
muxStateWriter.WriteUlong((char)('a' + i), lastOutputStartTimes[i]);
}
muxStateWriter.WriteUlong('P', (ulong)bytes.Length);
muxStateWriter.Flush();
}
if (output.Count == 0) {
timePosition += timeCode;
timeCode = 0uL;
output.Add(new ArraySegment<byte>(
GetEEBytes(ID.Timecode, GetVintBytes(timePosition / 10000uL))));
}
output.Add(new ArraySegment<byte>(GetSimpleBlockBytes(
(ulong)(trackIndex + 1), (short)(timeCode / 10000uL), isKeyFrame, isAmsCodecs[trackIndex],
mediaDataBlockTotalSize)));
output.Add(block0.Bytes);
if (block1 != null) output.Add(block1.Bytes);
lastOutputStartTimes[trackIndex] = block1 != null ? block1.StartTime : block0.StartTime;
}
// Write remaining samples (from output to fileStream), and write cuePoints.
{
ulong outputOffset = (ulong)fileStream.Position - segmentOffset;
cuePoints.Add(new CuePoint(timePosition / 10000uL, (ulong)(videoTrackIndex + 1), outputOffset));
muxStateWriter.WriteUlong('C', timePosition);
muxStateWriter.WriteUlong('D', outputOffset);
if (output.Count == 0) {
throw new Exception("ASSERT: Expecting non-empty output at end of mixing.");
}
int totalSize = 0;
for (int i = 0; i < output.Count; ++i) {
totalSize += output[i].Count;
}
byte[] bytes = Utils.CombineByteArraysAndArraySegments(
new byte[][]{GetDataSizeBytes((ulong)ID.Cluster), GetDataSizeBytes((ulong)totalSize)}, output);
output.Clear(); // Save memory.
cuesOffsetMS = outputOffset + (ulong)bytes.Length;
byte[] bytes2 = GetCueBytes(cuePoints); // cues are about 1024 bytes per 2 minutes.
seekHeadOffsetMS = cuesOffsetMS + (ulong)bytes2.Length;
SeekBlock[] seekBlocks = new SeekBlock[cuePoints.Count];
for (int i = 0; i < cuePoints.Count; ++i) {
seekBlocks[i] = new SeekBlock(ID.Cluster, cuePoints[i].CueClusterPosition);
}
byte[] bytes3 = GetSeekBytes(seekBlocks, -1);
bytes = Utils.CombineBytes(bytes, bytes2, bytes3);
fileStream.Write(bytes, 0, bytes.Length);
}
}
// Returns trackIndex with the smallest StartTime, or -1.
private static int GetNextTrackIndex(IMediaDataSource mediaDataSource, MediaDataBlock[] ungetBlocks)
{
int trackCount = ungetBlocks.Length; // == mediaDataSource.GetTrackCount().
ulong minUnconsumedStartTime = 0; // No real need to initialize it here.
int trackIndex = -1;
for (int i = 0; i < trackCount; ++i) {
MediaDataBlock block = ungetBlocks[i];
if (block == null) block = mediaDataSource.PeekBlock(i);
if (block != null && (trackIndex == -1 || minUnconsumedStartTime > block.StartTime)) {
trackIndex = i;
minUnconsumedStartTime = block.StartTime;
}
}
return trackIndex;
}