Class MediaSink

Provides a high-level interface for encoding and writing media to an output container.

Inheritance

object

MediaSink

Implements

IDisposable

Inherited Members

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Namespace: FFmpeg

Assembly: FFmpeg.dll

Syntax

public class MediaSink : IDisposable

Remarks

MediaSink combines one or more CodecContext instances with a MuxerContext to simplify media encoding and muxing.

Streams are added using AddStream(CodecContext?) or AddStream(Codec). Frames can then be encoded and written using WriteFrame(AVFrame, int), subtitles using WriteSubtitle(Subtitle, int), or pre-encoded packets using WritePacket(IPacket).

The container header is written automatically before the first packet is written. Close() or Dispose() drains any remaining encoded packets, writes the trailer, and releases all associated resources.

Constructors

MediaSink(MuxerContext)

Initializes a new MediaSink using the specified muxer context.

Declaration

public MediaSink(MuxerContext context)

Parameters

Type	Name	Description
MuxerContext	context	The muxer context used to write the output container.

Properties

CodecContexts

Gets the encoder contexts associated with the output streams.

Declaration

public IReadOnlyList<CodecContext?> CodecContexts { get; }

Property Value

Type	Description
IReadOnlyList<CodecContext>

Remarks

The list contains one entry for each stream in Streams. Entries may be null for streams that are written using pre-encoded packets instead of an encoder.

FormatContext

Gets the underlying muxer context.

Declaration

public MuxerContext FormatContext { get; }

Property Value

Type	Description
MuxerContext

Metadata

Gets the metadata associated with the output container.

Declaration

public AVDictionary_ref Metadata { get; }

Property Value

Type	Description
AVDictionary_ref

Streams

Gets the streams contained in the output media.

Declaration

public IReadOnlyList<AVStream> Streams { get; }

Property Value

Type	Description
IReadOnlyList<AVStream>

Methods

AddStream(Codec)

Adds a new stream for the specified codec.

Declaration

public AVStream AddStream(Codec encoder)

Parameters

Type	Name	Description
Codec	encoder	The codec associated with the stream.

Returns

Type	Description
AVStream	The newly created output stream.

Remarks

No encoder context is created automatically. Call SetCodecContext(CodecContext, int) before encoding frames, or write encoded packets directly using WritePacket(IPacket).

AddStream(CodecContext?)

Adds a new stream using an existing encoder context.

Declaration

public AVStream AddStream(CodecContext? encoderContext)

Parameters

Type	Name	Description
CodecContext	encoderContext	The encoder context used to initialize the stream, or null to create a stream without an associated encoder.

Returns

Type	Description
AVStream	The newly created output stream.

Remarks

The codec parameters and time base are copied from the encoder context when one is supplied.

AddStream(AVStream)

Adds a stream based on the codec parameters of the

Declaration

public AVStream AddStream(AVStream copyStream)

Parameters

Type	Name	Description
AVStream	copyStream	The stream that contains the codec parameters we want to copy

Returns

Type	Description
AVStream	The added stream.

Close()

Finalizes the output container and releases all associated resources.

Declaration

public void Close()

Remarks

This method writes the trailer if it has not already been written and then disposes the MediaSink.

Create(IOContext, OutputFormat)

Creates a new MediaSink using a custom I/O context.

Declaration

public static MediaSink? Create(IOContext ioContext, OutputFormat outputFormat)

Parameters

Type	Name	Description
IOContext	ioContext	The custom I/O context.
OutputFormat	outputFormat	The output format.

Returns

Type	Description
MediaSink	A new MediaSink, or null if the output could not be created.

Create(Stream, OutputFormat, bool)

Creates a new MediaSink for writing media to a managed stream.

Declaration

public static MediaSink? Create(Stream stream, OutputFormat outputFormat, bool leaveOpen = false)

Parameters

Type	Name	Description
Stream	stream	The destination stream.
OutputFormat	outputFormat	The output format.
bool	leaveOpen	False if the stream should be closed when the MediaSink gets disposed.

Returns

Type	Description
MediaSink	A new MediaSink, or null if the output could not be created.

Create(string)

Creates a new MediaSink for writing media to a file.

Declaration

public static MediaSink? Create(string url)

Parameters

Type	Name	Description
string	url	The output filename or URL.

Returns

Type	Description
MediaSink	A new MediaSink, or null if the output could not be created.

Create(string?, OutputFormat?)

Creates a new MediaSink for writing media to a file.

Declaration

public static MediaSink? Create(string? url, OutputFormat? outputFormat)

Parameters

Type	Name	Description
string	url	The output filename or URL.
OutputFormat?	outputFormat	The output format, or null to determine the format from the filename.

Returns

Type	Description
MediaSink	A new MediaSink, or null if the output could not be created.

Exceptions

Type	Condition
ArgumentNullException	Thrown when both url and outputFormat are null.

Dispose()

Releases all resources used by the current instance.

Declaration

public void Dispose()

Remarks

If the trailer has not yet been written, this method attempts to write it before releasing the underlying resources.

Dispose(bool)

Releases the resources used by the current instance.

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
bool	disposing	true to release managed resources; otherwise, false.

OpenCodecs()

Opens all encoder contexts that have not already been opened.

Declaration

public void OpenCodecs()

Remarks

Calling this method is optional. If an encoder has not been opened manually, it will be opened automatically when the first frame is encoded.

SetCodecContext(CodecContext, int)

Associates an encoder context with an existing stream.

Declaration

public void SetCodecContext(CodecContext codec, int streamIndex)

Parameters

Type	Name	Description
CodecContext	codec	The encoder context.
int	streamIndex	The zero-based index of the stream.

Remarks

The codec parameters are copied to the corresponding stream. If either the stream or codec context does not define a valid time base, it is initialized from the other.

WriteFrame(AVFrame, int)

Encodes a frame and writes the resulting packets to the output container.

Declaration

public AVResult32 WriteFrame(AVFrame frame, int streamIndex)

Parameters

Type	Name	Description
AVFrame	frame	The frame to encode.
int	streamIndex	The index of the destination stream.

Returns

Type	Description
AVResult32	An AVResult32 indicating the result of the operation.

Remarks

The frame is sent to the encoder and all immediately available packets are written to the output container.

WriteHeader()

Writes the container header.

Declaration

public AVResult32 WriteHeader()

Returns

Type	Description
AVResult32	An AVResult32 indicating the result of the operation.

Remarks

After the header has been written, the packet time base of each associated encoder is synchronized with the corresponding output stream, since some muxers may adjust stream parameters while writing the header.

WriteHeader(IDictionary<string, string>)

Writes the container header using the specified muxer options.

Declaration

public AVResult32 WriteHeader(IDictionary<string, string> dic)

Parameters

Type	Name	Description
IDictionary<string, string>	dic	A dictionary containing muxer options.

Returns

Type	Description
AVResult32	An AVResult32 indicating the result of the operation.

Remarks

Any options that are not recognized by the muxer remain in the supplied dictionary after the call returns.

WritePacket(IPacket)

Writes an encoded packet to the output container.

Declaration

public AVResult32 WritePacket(IPacket packet)

Parameters

Type	Name	Description
IPacket	packet	The packet to write.

Returns

Type	Description
AVResult32	An AVResult32 indicating the result of the operation.

Remarks

If the container header has not yet been written, it is written automatically before the packet is muxed.

WriteSubtitle(Subtitle, int)

Encodes and writes a subtitle to the output container.

Declaration

public AVResult32 WriteSubtitle(Subtitle subtitle, int streamIndex)

Parameters

Type	Name	Description
Subtitle	subtitle	The subtitle to encode.
int	streamIndex	The destination stream.

Returns

Type	Description
AVResult32	An AVResult32 indicating the result of the operation.

WriteTrailer()

Flushes all encoders and writes the trailer of the output container.

Declaration

public AVResult32 WriteTrailer()

Returns

Type	Description
AVResult32	An AVResult32 indicating the result of the operation.

Remarks

All audio and video encoders are drained before the trailer is written. Subsequent calls after a successful write return immediately without writing the trailer again.

Implements

IDisposable