public AVIOContextWrapper(ulong bufferSize, ReadPacket readPacket)
{
buffer = (byte *)Interop.FFmpeg.av_mallocz(bufferSize);
this.readPacket = readPacket;
readFunctionDelegate = ReadPacket;
var readFunction = new avio_alloc_context_read_packet_func
{
Pointer = Marshal.GetFunctionPointerForDelegate(readFunctionDelegate)
};
var writeFunction = new avio_alloc_context_write_packet_func {
Pointer = IntPtr.Zero
};
var seekFunction = new avio_alloc_context_seek_func {
Pointer = IntPtr.Zero
};
context = Interop.FFmpeg.avio_alloc_context(buffer,
(int)bufferSize,
0,
(void *)GCHandle.ToIntPtr(
GCHandle.Alloc(
this)),
readFunction,
writeFunction,
seekFunction);
if (context == null)
{
throw new FFmpegException("Cannot allocate AVIOContext");
}
context->seekable = 0;
context->write_flag = 0;
}
public unsafe ByteReader()
{
_currentPosition = 0;
_readDelegate = Read;
_seekDelegate = Seek;
ReadFunc = new avio_alloc_context_read_packet_func {
Pointer = Marshal.GetFunctionPointerForDelegate(_readDelegate)
};
SeekFunc = new avio_alloc_context_seek_func {
Pointer = Marshal.GetFunctionPointerForDelegate(_seekDelegate)
};
}
private static extern AVIOContext *avio_alloc_context(byte *buffer, int buffer_size, int write_flag, void *opaque, avio_alloc_context_read_packet_func read_packet, avio_alloc_context_write_packet_func write_packet, avio_alloc_context_seek_func seek);
/// <summary>
/// Allocate and initialize an AVIOContext for buffered I/O. It must be later freed with avio_context_free().
/// </summary>
/// <param name="buffer">
/// Memory block for input/output operations via AVIOContext. The buffer must be allocated with av_malloc() and friends.
/// It may be freed and replaced with a new buffer by libavformat. AVIOContext.buffer holds the buffer currently in use, which must be later freed with av_free().
/// </param>
/// <param name="buffer_size">
/// The buffer size is very important for performance. For protocols with fixed blocksize it should be set to this blocksize. For others a typical size is a cache page, e.g. 4kb.
/// </param>
/// <param name="write_flag">
/// Set to 1 if the buffer should be writable, 0 otherwise.
/// </param>
/// <param name="opaque">
/// An opaque pointer to user-specific data.
/// </param>
/// <param name="read_packet">
/// A function for refilling the buffer, may be NULL. For stream protocols, must never return 0 but rather a proper AVERROR code.
/// </param>
/// <param name="write_packet">
/// A function for writing the buffer contents, may be NULL. The function may not change the input buffers content.
/// </param>
/// <param name="seek">
/// A function for seeking to specified byte position, may be NULL.
/// </param>
/// <returns>
/// Allocated AVIOContext.
/// </returns>
public NativeAVIOContext *AllocAVIOContext(byte *buffer, int buffer_size, int write_flag, void *opaque, avio_alloc_context_read_packet_func read_packet, avio_alloc_context_write_packet_func write_packet, avio_alloc_context_seek_func seek)
{
var avio_ctx = ffmpeg.avio_alloc_context(buffer, buffer_size, write_flag, opaque, read_packet, write_packet, seek);
if (avio_ctx == null)
{
throw new OutOfMemoryException();
}
return(avio_ctx);
}
