/// <summary>
/// Return the next frame of a stream.
/// </summary>
/// <param name="formatContext">
/// The format context.
/// </param>
/// <returns>
/// Value indicating wheter a frame was received.
/// </returns>
public bool ReadFrame(AVFormatContext formatContext)
{
int ret = this.client.ReadFrame(formatContext, this);
if (ret == 0)
{
return(true);
}
else if (ret == NativeFFmpeg.AVERROR_EOF)
{
return(false);
}
else
{
this.client.ThrowOnAVError(ret, postiveIndicatesSuccess: false);
return(false);
}
}
/// <summary>
/// Close an opened input AVFormatContext. Free it and all its contents and set *s to NULL.
/// </summary>
/// <param name="formatContext">
/// The format context.
/// </param>
public virtual void CloseFormatContext(AVFormatContext formatContext)
{
var native = formatContext.NativeObject;
ffmpeg.avformat_close_input(&native);
}
/// <summary>
/// Return the next frame of a stream.
/// </summary>
/// <param name="context">
/// The context.
/// </param>
/// <param name="packet">
/// The packet.
/// </param>
/// <returns>
/// 0 if OK, negative on error or end of file.
/// </returns>
public virtual int ReadFrame(AVFormatContext context, AVPacket packet)
{
return(ffmpeg.av_read_frame(context.NativeObject, packet.NativeObject));
}
/// <summary>
/// Open an input stream and read the header. The codecs are not opened. The stream must be closed with avformat_close_input().
/// </summary>
/// <param name="context">
/// Pointer to user-supplied AVFormatContext (allocated by avformat_alloc_context).
/// May be a pointer to NULL, in which case an AVFormatContext is allocated by this
/// function and written into ps. Note that a user-supplied AVFormatContext will
/// be freed on failure.
/// </param>
/// <param name="url">
/// URL of the stream to open.
/// </param>
/// <param name="fmt">
/// If non-NULL, this parameter forces a specific input format. Otherwise the format is autodetected.
/// </param>
/// <param name="options">
/// A dictionary filled with AVFormatContext and demuxer-private options.On return
/// this parameter will be destroyed and replaced with a dict containing options
/// that were not found. May be NULL.
/// </param>
/// <returns>
/// 0 on success, a negative AVERROR on failure.
/// </returns>
public int avformat_open_input(AVFormatContext context, string?url, NativeAVInputFormat *fmt, AVDictionary **options)
{
var ctx = context.NativeObject;
return(ffmpeg.avformat_open_input(&ctx, url, fmt, options));
}
/// <summary>
/// Decodes the current stream and blocks until decoding is done.
/// </summary>
/// <param name="cancellationToken">
/// A <see cref="CancellationToken"/> which can be used to cancel the asynchronous operation.
/// </param>
public virtual unsafe void Decode(CancellationToken cancellationToken = default)
{
if (this.disposed)
{
throw new ObjectDisposedException(nameof(H264Decoder));
}
var readDelegate = new NativeReadPacket(this.Read);
var readFunc = new NativeReadPacketFunc()
{
Pointer = Marshal.GetFunctionPointerForDelegate(readDelegate),
};
using (var ioContext = new AVIOContext(this.client, ReadBufferSize, readFunc, null))
using (var formatContext = new AVFormatContext(this.client, ioContext))
{
formatContext.OpenInputStream("h264");
var stream = formatContext.GetVideoStream();
using (var codec = new AVCodec(this.client, stream))
using (var frame = new AVFrame(this.client))
using (var packet = new AVPacket(this.client))
{
int frameNumber = 0;
while (packet.ReadFrame(formatContext))
{
this.logger.LogDebug($"Got a frame for stream {packet.StreamIndex}");
if (packet.NativeObject->stream_index != stream.Index)
{
continue;
}
this.logger.LogDebug("Sending packet");
codec.SendPacket(packet);
int framesInPacket = 0;
while (codec.ReceiveFrame(frame))
{
this.logger.LogDebug("Receiving frame");
framesInPacket += 1;
if (frame.PictureType != NativeAVPictureType.AV_PICTURE_TYPE_NONE)
{
this.logger.LogDebug($"Got a picture of {frame.Width}x{frame.Height} in color space {frame.Format}");
// decode frame
this.FrameBuffer.DecompresFrame(
frame.Width,
frame.Height,
frame.Width,
frame.Height,
frame.Width * 4,
new Span <byte>(frame.NativeObject->data[0], frame.NativeObject->linesize[0]),
new Span <byte>(frame.NativeObject->data[1], frame.NativeObject->linesize[1]),
new Span <byte>(frame.NativeObject->data[2], frame.NativeObject->linesize[2]),
new int[] { frame.NativeObject->linesize[0], frame.NativeObject->linesize[1], frame.NativeObject->linesize[2] });
}
}
this.logger.LogInformation($"Add {framesInPacket} frames in packet.");
frameNumber++;
}
}
}
GC.KeepAlive(readDelegate);
}
