/// <summary>
/// Loads M4ESDAtom atom from the input bitstream.
/// </summary>
/// <param name="bitstream">The input bitstream.</param>
/// <returns>The number of bytes loaded.</returns>
public long create_esd_atom(Mp4DataStream bitstream)
{
create_full_atom(bitstream);
esd_descriptor = Mp4Descriptor.CreateDescriptor(bitstream);
_bytesRead += esd_descriptor.BytesRead;
return(_bytesRead);
}
/// <summary>
/// Loads the MP4ES_Descriptor from the input bitstream.
/// </summary>
/// <param name="bitstream">The input bitstream.</param>
public void CreateESDescriptor(Mp4DataStream bitstream)
{
int ES_ID = (int)bitstream.ReadBytes(2);
int flags = (int)bitstream.ReadBytes(1);
bool streamDependenceFlag = (flags & (1 << 7)) != 0;
bool urlFlag = (flags & (1 << 6)) != 0;
bool ocrFlag = (flags & (1 << 5)) != 0;
_bytesRead += 3;
if (streamDependenceFlag)
{
bitstream.SkipBytes(2);
_bytesRead += 2;
}
if (urlFlag)
{
int str_size = (int)bitstream.ReadBytes(1);
bitstream.ReadString(str_size);
_bytesRead += str_size + 1;
}
if (ocrFlag)
{
bitstream.SkipBytes(2);
_bytesRead += 2;
}
while (_bytesRead < _size)
{
Mp4Descriptor descriptor = CreateDescriptor(bitstream);
_children.Add(descriptor);
_bytesRead += descriptor.BytesRead;
}
}
/// <summary>
/// Looks up a child descriptor with the specified <code>type</code>, skips the <code>number</code> children with the same type before retrieving.
/// </summary>
/// <param name="type">The type of the descriptor.</param>
/// <param name="number">The number of child descriptors to skip.</param>
/// <returns>The descriptor if found, otherwise null.</returns>
public Mp4Descriptor Lookup(int type, int number)
{
int position = 0;
for (int i = 0; i < _children.Count; i++)
{
Mp4Descriptor descriptor = _children[i];
if (descriptor.Type == type)
{
if (position >= number)
{
return(descriptor);
}
position++;
}
}
return(null);
}
/// <summary>
/// Loads the MP4DecoderConfigDescriptor from the input bitstream.
/// </summary>
/// <param name="bitstream">The input bitstream.</param>
public void CreateDecoderConfigDescriptor(Mp4DataStream bitstream)
{
int objectTypeIndication = (int)bitstream.ReadBytes(1);
int value = (int)bitstream.ReadBytes(1);
bool upstream = (value & (1 << 1)) > 0;
byte streamType = (byte)(value >> 2);
value = (int)bitstream.ReadBytes(2);
int bufferSizeDB = value << 8;
value = (int)bitstream.ReadBytes(1);
bufferSizeDB |= value & 0xff;
int maxBitRate = (int)bitstream.ReadBytes(4);
int minBitRate = (int)bitstream.ReadBytes(4);
_bytesRead += 13;
if (_bytesRead < _size)
{
Mp4Descriptor descriptor = CreateDescriptor(bitstream);
_children.Add(descriptor);
_bytesRead += descriptor.BytesRead;
}
}
public static Mp4Descriptor CreateDescriptor(Mp4DataStream bitstream)
{
int tag = (int)bitstream.ReadBytes(1);
int bytesRead = 1;
int size = 0;
int b = 0;
do
{
b = (int)bitstream.ReadBytes(1);
size <<= 7;
size |= b & 0x7f;
bytesRead++;
} while ((b & 0x80) == 0x80);
Mp4Descriptor descriptor = new Mp4Descriptor(tag, size);
switch (tag)
{
case MP4ES_DescriptorTag:
descriptor.CreateESDescriptor(bitstream);
break;
case MP4DecoderConfigDescriptorTag:
descriptor.CreateDecoderConfigDescriptor(bitstream);
break;
case MP4DecSpecificInfoDescriptorTag:
descriptor.CreateDecSpecificInfoDescriptor(bitstream);
break;
default:
break;
}
bitstream.SkipBytes(descriptor._size - descriptor._bytesRead);
descriptor._bytesRead = bytesRead + descriptor._size;
return(descriptor);
}
