private void WriteCodecDescriptor(Stream target, MediaDescriptor descriptor)
{
MemoryStream memoryStream = new MemoryStream();
BitstreamWriter writer = new BitstreamWriter(memoryStream);
writer.Put32BitsAligned((uint)descriptor.Codec);
writer.PutAlignedByte((byte)descriptor.CodecType);
writer.Put32BitsAligned(descriptor.Bitrate);
writer.Put32BitsAligned((uint)descriptor.Flags);
writer.Put32BitsAligned(0); // flags2
writer.Put32BitsAligned(0); // debug
if (((uint)descriptor.Flags & (uint)CodecFlagsEnum.AV_CODEC_FLAG_GLOBAL_HEADER) != 0)
{
int extraDataSize = descriptor.ExtraData == null ? 0 : descriptor.ExtraData.Length;
writer.Put32BitsAligned((uint)extraDataSize);
if (extraDataSize > 0)
{
writer.PutAlignedBytes(descriptor.ExtraData);
}
}
WriteHeaderChunk(
target,
new ArraySegment<byte>(memoryStream.GetBuffer(), 0, (int)memoryStream.Position),
FourCC.Make("COMM")
);
if (!string.IsNullOrEmpty(descriptor.RecommendedEncoderConfiguration))
{
switch (descriptor.CodecType)
{
case CodecTypeEnum.Video: WriteRecommendedConfiguration(target, descriptor.RecommendedEncoderConfiguration, FourCC.Make("S2VI")); break;
case CodecTypeEnum.Audio: WriteRecommendedConfiguration(target, descriptor.RecommendedEncoderConfiguration, FourCC.Make("S2AU")); break;
default: throw new InvalidOperationException(string.Format("unsupported codec type: {0}", descriptor.CodecType));
}
}
}
private void WriteFFM2Chunk(Stream target)
{
BitstreamWriter writer = new BitstreamWriter(target);
writer.Put32BitsAligned(FourCC.Make("FFM2"));
writer.Put32BitsAligned(FFM.FFM_PACKET_SIZE);
writer.Put64BitsAligned(0); //current write position
}
private void WriteMAINChunk(Stream target)
{
MemoryStream memoryStream = new MemoryStream();
BitstreamWriter writer = new BitstreamWriter(memoryStream);
writer.Put32BitsAligned((uint)m_tracks.Count());
uint bitrate = 0;
for (int i = 0; i < m_tracks.Count(); i++)
{
bitrate += m_tracks.ElementAt(i).Bitrate;
}
writer.Put32BitsAligned(bitrate);
WriteHeaderChunk(
target,
new ArraySegment<byte>(memoryStream.GetBuffer(), 0, (int)memoryStream.Position),
FourCC.Make("MAIN")
);
}
private void WriteHeaderChunk(Stream target, ArraySegment<byte> chunkData, uint id)
{
BitstreamWriter writer = new BitstreamWriter(target);
writer.Put32BitsAligned(id);
writer.Put32BitsAligned((uint)chunkData.Count);
writer.PutAlignedBytes(chunkData.Array, chunkData.Offset, chunkData.Count);
}
private void WriteRecommendedConfiguration(Stream target, string config, uint tag)
{
MemoryStream memoryStream = new MemoryStream();
BitstreamWriter writer = new BitstreamWriter(memoryStream);
writer.PutNullTerminatedStringAligned(config);
WriteHeaderChunk(
target,
new ArraySegment<byte>(memoryStream.GetBuffer(), 0, (int)memoryStream.Position),
tag
);
}