/// <summary>
/// CreateNewChunkGroup
/// There is no rule about how many chunks there can be in chunk group. A chunk group may contain ALL chunks
/// in a media file. There's a tradeoff between the resulting size of this SampleToChunkBox, and the size of
/// ChunkOffsetBox. Reducing the size of this SampleToChunkBox (by having less chunk groups) must necessarily
/// increase the size of ChunkOffsetBox. In the degenerate case in which there is one slice in every chunk, all
/// chunks maybe put in a single chunk group, but there would be an entry in the ChunkOffsetBox for every slice.
/// In the other extreme case in which all slices are in one single chunk, there would also be only one chunk group
/// and there would also be only one entry in the ChunkOffsetBox.
///
/// Every chunk group entry created is written out to the ChunkGroupStream. See the Write method also.
/// </summary>
/// <param name="sampleCount"></param>
void CreateNewChunkGroup(uint sampleCount)
{
if (ChunkGroupWriter == null)
{
ChunkGroupFileName = Path.GetTempFileName();
ChunkGroupStream = File.Create(ChunkGroupFileName);
ChunkGroupWriter = new BinaryWriter(ChunkGroupStream);
}
chunk = new ChunkEntry();
chunk.firstChunk = parent.ChunkOffSetBox.EntryCount + 1; // the ChunkOffsetBox is also being built on the fly
chunk.sampleDescriptionIndex = 1; // FIXME: this assumes that for every track there's only one sample description
chunk.samplesPerChunk = sampleCount; // in this chunk group, every chunk has this many slices
ChunkGroupWriter.Write(chunk.firstChunk);
ChunkGroupWriter.Write(chunk.samplesPerChunk);
ChunkGroupWriter.Write(chunk.sampleDescriptionIndex);
EntryCount++;
}
public override void Read(BoxReader reader)
{
using (new SizeChecker(this, reader)) {
base.Read(reader);
EntryCount = reader.ReadUInt32();
ChunkEntries = new ChunkEntry[EntryCount];
for (int i = 0; i < EntryCount; i++)
{
ChunkEntries[i] = new ChunkEntry();
ChunkEntries[i].firstChunk = reader.ReadUInt32();
ChunkEntries[i].samplesPerChunk = reader.ReadUInt32();
ChunkEntries[i].sampleDescriptionIndex = reader.ReadUInt32();
}
}
if (parent.ChunkOffSetBox != null)
{
TotalChunks = parent.ChunkOffSetBox.EntryCount;
}
}
/// <summary>
/// CreateNewChunkGroup
/// There is no rule about how many chunks there can be in chunk group. A chunk group may contain ALL chunks
/// in a media file. There's a tradeoff between the resulting size of this SampleToChunkBox, and the size of
/// ChunkOffsetBox. Reducing the size of this SampleToChunkBox (by having less chunk groups) must necessarily
/// increase the size of ChunkOffsetBox. In the degenerate case in which there is one slice in every chunk, all
/// chunks maybe put in a single chunk group, but there would be an entry in the ChunkOffsetBox for every slice.
/// In the other extreme case in which all slices are in one single chunk, there would also be only one chunk group
/// and there would also be only one entry in the ChunkOffsetBox.
///
/// Every chunk group entry created is written out to the ChunkGroupStream. See the Write method also.
/// </summary>
/// <param name="sampleCount"></param>
void CreateNewChunkGroup(uint sampleCount)
{
if (ChunkGroupWriter == null)
{
ChunkGroupFileName = Path.GetTempFileName();
ChunkGroupStream = File.Create(ChunkGroupFileName);
ChunkGroupWriter = new BinaryWriter(ChunkGroupStream);
}
chunk = new ChunkEntry();
chunk.firstChunk = parent.ChunkOffSetBox.EntryCount + 1; // the ChunkOffsetBox is also being built on the fly
chunk.sampleDescriptionIndex = 1; // FIXME: this assumes that for every track there's only one sample description
chunk.samplesPerChunk = sampleCount; // in this chunk group, every chunk has this many slices
ChunkGroupWriter.Write(chunk.firstChunk);
ChunkGroupWriter.Write(chunk.samplesPerChunk);
ChunkGroupWriter.Write(chunk.sampleDescriptionIndex);
EntryCount++;
}
public override void Read(BoxReader reader)
{
using (new SizeChecker(this, reader)) {
base.Read(reader);
EntryCount = reader.ReadUInt32();
ChunkEntries = new ChunkEntry[EntryCount];
for (int i = 0; i < EntryCount; i++) {
ChunkEntries[i] = new ChunkEntry();
ChunkEntries[i].firstChunk = reader.ReadUInt32();
ChunkEntries[i].samplesPerChunk = reader.ReadUInt32();
ChunkEntries[i].sampleDescriptionIndex = reader.ReadUInt32();
}
}
if (parent.ChunkOffSetBox != null)
TotalChunks = parent.ChunkOffSetBox.EntryCount;
}
