Class CodecContext

Represents a codec context used for encoding or decoding video and audio streams using FFmpeg.

This class wraps the FFmpeg.AutoGen._AVCodecContext structure from the FFmpeg library, providing an interface for configuring and interacting with codec parameters for both encoding and decoding operations.

Inheritance
object
OptionQueryableBase
CodecContext
Implements
IAVPointer<_AVCodecContext>
Inherited Members
Namespace: FFmpeg.Codecs
Assembly: FFmpeg.dll
Syntax
public sealed class CodecContext : OptionQueryableBase, ILoggingContext, IAudioDecoder, IAudioEncoder, IVideoDecoder, IDecoderContext, IVideoEncoder, IEncoderContext, IDisposable, IOptionQueryable, IAVPointer<_AVCodecContext>

Properties

View Source

AlphaMode

Gets or sets how the alpha channel is represented in relation to the color components.

Declaration
public AlphaMode AlphaMode { get; set; }
Property Value
Type Description
AlphaMode
Remarks

Premultiplied indicates that the color components are already multiplied by the alpha value, while Straight indicates that the alpha channel is stored independently of the color components.

View Source

AudioServiceType

Gets or sets the audio service type, which indicates the intended usage of the audio stream (e.g., main audio, commentary, or karaoke).

Encoding: Notify by the user to specify the type of audio service for encoding.

Decoding: This field is set by libavcodec during decoding and cannot be set by the user.

Declaration
public AudioServiceType AudioServiceType { get; set; }
Property Value
Type Description
AudioServiceType
View Source

BitRate

Gets or sets the target bit rate in bits per second, which influences the compression level. The bit rate directly affects the quality and size of the encoded media.

Encoding: Notify by the user. Not used in constant quantizer encoding.

Decoding: Notify by the user. May be overwritten by libavcodec if this information is available in the stream.

Declaration
public long BitRate { get; set; }
Property Value
Type Description
long
View Source

BitRateTolerance

Gets or sets the tolerance for bit rate deviations during encoding.

Encoding: Defines how much the bitstream is allowed to deviate from the target bit rate. This applies to both constant bit rate (CBR) and variable bit rate (VBR) encoding.

Decoding: This field is not used during decoding.

Declaration
public int BitRateTolerance { get; set; }
Property Value
Type Description
int
View Source

ChannelLayout

Gets or sets the channel layout for the audio stream, such as stereo or surround sound.

Encoding: Must be set by the user to specify the desired channel layout for encoding.

Decoding: May be set by the user if known, but the decoder may override it based on the actual stream data.

Declaration
public ChannelLayout_ref ChannelLayout { get; }
Property Value
Type Description
ChannelLayout_ref
View Source

ChromaSampleLocation

Gets or sets the chroma sample location, which defines the position of the chroma samples relative to the luma samples in the video.

Encoding: Must be set by the user to specify the chroma sample location for encoding.

Decoding: Notify by libavcodec during decoding to correctly align chroma samples.

Declaration
public ChromaLocation ChromaSampleLocation { get; set; }
Property Value
Type Description
ChromaLocation
View Source

Codec

Gets the codec associated with the context. Represents the specific codec being used for encoding or decoding.

Declaration
public Codec Codec { get; }
Property Value
Type Description
Codec
View Source

CodecID

Gets or sets the codec ID, which represents the specific codec used. This identifies the codec being used, such as H.264 or AAC.

Declaration
public CodecID CodecID { get; }
Property Value
Type Description
CodecID
View Source

CodecTag

Gets or sets the codec tag, an additional codec identifier used to work around some encoder bugs. The codec tag is a 32-bit identifier used to map codec information, especially when containers store this data in formats that exceed 32 bits. It is commonly represented as a FourCC code.

Encoding: Notify by the user; if not set, a default based on CodecID will be used.

Decoding: Notify by the user; during initialization, libavcodec will convert the value to uppercase.

Declaration
public FourCC CodecTag { get; set; }
Property Value
Type Description
FourCC
View Source

CodecType

Gets or sets the general type of the codec (e.g., video, audio). This property indicates whether the codec is handling audio, video, or other media types.

Declaration
public MediaType CodecType { get; }
Property Value
Type Description
MediaType
View Source

CodedHeight

Gets or sets the coded height of the video frame, which may be larger than the actual display height. This value represents the height of the frame in the bitstream, which may differ from the decoded output height due to cropping or other optimizations.

Encoding: Unused.

Decoding: May be set by the user before opening the decoder if known. The decoder may overwrite this value during parsing.

Declaration
public int CodedHeight { get; set; }
Property Value
Type Description
int
View Source

CodedWidth

Gets or sets the coded width of the video frame, which may be larger than the actual display width. This value represents the width of the frame in the bitstream, which may differ from the decoded output width due to cropping or other optimizations.

Encoding: Unused.

Decoding: May be set by the user before opening the decoder if known. The decoder may overwrite this value during parsing.

Declaration
public int CodedWidth { get; set; }
Property Value
Type Description
int
View Source

ColorPrimaries

Gets or sets the chromaticity coordinates of the source primaries, which define the red, green, and blue components of the video.

Encoding: Must be set by the user to define the chromaticity coordinates for encoding.

Decoding: Notify by libavcodec during decoding to interpret the color information correctly.

Declaration
public ColorPrimaries ColorPrimaries { get; set; }
Property Value
Type Description
ColorPrimaries
View Source

ColorRange

Gets or sets the color range of the video, which defines the range of values for the color components (MPEG vs JPEG YUV range).

Encoding: Can be set by the user to override the default output color range. If not specified, libavcodec sets the color range based on the output format.

Decoding: Notify by libavcodec, but may be set by the user to propagate the color range to other components reading from the decoder context.

Declaration
public ColorRange ColorRange { get; set; }
Property Value
Type Description
ColorRange
View Source

ColorSpace

Gets or sets the YUV colorspace type of the video, which defines how the color components are organized.

Encoding: Must be set by the user to specify the YUV colorspace for encoding.

Decoding: Notify by libavcodec during decoding to interpret the colorspace of the video stream.

Declaration
public ColorSpace ColorSpace { get; set; }
Property Value
Type Description
ColorSpace
View Source

ColorTransferCharacteristic

Gets or sets the color transfer characteristic, which is used for gamma correction and defines how colors are transformed.

Encoding: Must be set by the user to specify the color transfer characteristics for encoding.

Decoding: Notify by libavcodec during decoding to handle color transformation properly.

Declaration
public ColorTransferCharacteristic ColorTransferCharacteristic { get; set; }
Property Value
Type Description
ColorTransferCharacteristic
View Source

CompressionLevel

Gets or sets the compression level for encoding, affecting the tradeoff between speed and quality.

Encoding: Notify by the user to control the level of compression. Higher values may result in slower encoding but potentially better quality.

Decoding: This field is not used during decoding.

Declaration
public int CompressionLevel { get; set; }
Property Value
Type Description
int
View Source

Delay

Gets the delay in frames between the input to the encoder and the output of the decoder. For video, this represents the number of frames delayed between the encoded input and the decoded output. For audio decoding, this is the number of samples that the decoder needs to output before its output is valid.

Encoding: Notify by libavcodec.

Decoding: Notify by libavcodec.

Declaration
public int Delay { get; }
Property Value
Type Description
int
View Source

ExtraData

Gets or sets the extra data, typically codec-specific initialization data required for decoding or encoding. Certain codecs use extradata to store auxiliary information, such as Huffman tables for MJPEG, additional flags for RV10, or global headers for MPEG-4.

Encoding: The data is set, allocated, and freed by libavcodec.

Decoding: The data must be set, allocated, and freed by the user. The allocated memory should be AV_INPUT_BUFFER_PADDING_SIZE bytes larger than the actual extradata to prevent buffer overflows when reading the bitstream.

Declaration
public ReadOnlySpan<byte> ExtraData { get; set; }
Property Value
Type Description
ReadOnlySpan<byte>
View Source

FieldOrder

Gets or sets the field order for interlaced video, which defines whether the top or bottom field is displayed first.

Encoding: Notify by libavcodec during encoding to ensure proper field order in the output stream.

Decoding: Notify by the user if known, to correctly interpret the field order of the input stream.

Declaration
public FieldOrder FieldOrder { get; set; }
Property Value
Type Description
FieldOrder
View Source

Flags

Gets or sets codec flags that determine various encoding or decoding settings. The flags are split between general codec flags (AV_CODEC_FLAG_) and extended flags (AV_CODEC_FLAG2_).

Encoding: Notify by the user.

Decoding: Notify by the user.

Declaration
public CodecFlags Flags { get; set; }
Property Value
Type Description
CodecFlags
View Source

FrameRate

Gets or sets the frame rate of the video stream, in frames per second.

Encoding: Used to signal the constant frame rate (CFR) content to the encoder.

Decoding: May be set by the decoder for codecs that store a frame rate value in the bitstream. If unknown, this value will be { 0, 1 }.

Declaration
public Rational FrameRate { get; set; }
Property Value
Type Description
Rational
View Source

FrameSize

Gets or sets the frame size for audio encoding/decoding, which represents the number of samples per channel in each frame.

Encoding: Notify by libavcodec during encoding to define the number of samples per frame. Each frame submitted must have exactly this number of samples, except the last frame.

Decoding: Some decoders may set this field to indicate a constant frame size.

Declaration
public int FrameSize { get; set; }
Property Value
Type Description
int
View Source

GOPSize

Gets or sets the number of frames in a Group of Pictures (GOP).

Encoding: Notify by the user to specify the number of frames in each GOP. If set to 0, the encoding will be intra-only (I-frames only).

Decoding: This field is unused.

Declaration
public int GOPSize { get; set; }
Property Value
Type Description
int
View Source

GlobalQuality

Gets or sets the global quality factor for codecs that do not adjust quality on a per-frame basis.

Encoding: This value is used to set the global quality for encoding, which is proportional to the MPEG quantization scale (qscale).

Decoding: This field is not used during decoding.

Declaration
public int GlobalQuality { get; set; }
Property Value
Type Description
int
View Source

HardwareDeviceContext

Gets the hardware device context pointer, which represents the device context used for hardware acceleration.

Encoding: Not used.

Decoding: Access this property to interact with the hardware device context when using hardware acceleration.

Declaration
public DeviceContext_ref HardwareDeviceContext { get; }
Property Value
Type Description
DeviceContext_ref
View Source

Height

Gets or sets the height of the video frame in pixels. This field must be set by the user for encoding and may be set for decoding if known.

Encoding: Must be set by the user.

Decoding: May be set by the user before opening the decoder if known, e.g., from the container. The decoder may overwrite this value during parsing.

Declaration
public int Height { get; set; }
Property Value
Type Description
int
View Source

IsOpen

Gets a value indicating whether the codec context is open.

Declaration
public bool IsOpen { get; }
Property Value
Type Description
bool
View Source

MinGOPSize

Gets or sets the minimum size of the Group of Pictures (GOP).

Encoding: Notify by the user to specify the minimum number of frames between keyframes (i.e., I-frames).

Decoding: This field is unused.

Declaration
public int MinGOPSize { get; set; }
Property Value
Type Description
int
View Source

PacketTimeBase

Gets or sets the packet time base, which is used for expressing packet timestamps (pkt_dts/pts) and AVPacket.dts/pts. This defines the time base in which the packet timestamps are calculated.

Encoding: Unused.

Decoding: Notify by the user.

Declaration
public Rational PacketTimeBase { get; set; }
Property Value
Type Description
Rational
View Source

Pass1StatsOutput

Gets the pass1 encoding statistics output buffer as a read-only span of bytes.

This buffer contains encoding statistics collected during the first pass of encoding.

This property is set by libavcodec and cannot be modified by the user.

Declaration
public ReadOnlySpan<byte> Pass1StatsOutput { get; }
Property Value
Type Description
ReadOnlySpan<byte>
View Source

Pass2StatsInput

Gets or sets the pass2 encoding statistics input buffer as a read-only span of bytes.

This buffer should contain the concatenated statistics from the pass1 output, used for the second pass of encoding.

This property can be set by the user for pass2 encoding. If the buffer is being replaced, the old buffer is freed.

Declaration
public ReadOnlySpan<byte> Pass2StatsInput { get; set; }
Property Value
Type Description
ReadOnlySpan<byte>
View Source

PixelFormat

Gets or sets the pixel format of the video, which defines the format of the pixels (e.g., YUV, RGB).

Encoding: Must be set by the user to define the pixel format for encoding.

Decoding: May be set by the user if known from the headers. However, it can be overridden by the decoder during parsing.

Declaration
public PixelFormat PixelFormat { get; set; }
Property Value
Type Description
PixelFormat
View Source

Pointer

Gets the pointer to the underlying FFmpeg.AutoGen._AVCodecContext structure.

Declaration
protected override void* Pointer { get; }
Property Value
Type Description
void*
Overrides
View Source

Profile

Gets or sets the codec profile, which defines the level of compression and quality for the codec.

Encoding: Notify by the user to specify the desired codec profile (e.g., main, high, baseline for H.264).

Decoding: Notify by libavcodec during decoding to reflect the profile used in the encoded stream.

Declaration
public Profile Profile { get; set; }
Property Value
Type Description
Profile
View Source

ReferenceFrames

Gets or sets the number of reference frames used for inter-frame compression.

Encoding: Must be set by the user to specify the number of reference frames for encoding.

Decoding: Notify by libavcodec during decoding to manage reference frame usage.

Declaration
public int ReferenceFrames { get; set; }
Property Value
Type Description
int
View Source

SampleAspectRatio

Gets or sets the sample aspect ratio, which represents the width of a pixel divided by its height. A sample aspect ratio of 0 means the value is unknown. For some video standards, the numerator and denominator must be relatively prime and less than 256.

Encoding: Must be set by the user to specify the sample aspect ratio for encoding.

Decoding: Notify by libavcodec to provide the sample aspect ratio for decoding.

Declaration
public Rational SampleAspectRatio { get; set; }
Property Value
Type Description
Rational
View Source

SampleFormat

Gets or sets the audio sample format, which defines how audio samples are stored (e.g., signed 16-bit, float).

Encoding: Must be set by the user to define the sample format for the audio stream being encoded.

Decoding: Notify by libavcodec based on the audio stream format during decoding.

Declaration
public SampleFormat SampleFormat { get; set; }
Property Value
Type Description
SampleFormat
View Source

SampleRate

Gets or sets the audio sample rate in samples per second (Hz).

Encoding: Must be set by the user to specify the sample rate of the audio stream being encoded.

Decoding: May be set by the user if known, but could be overridden by libavcodec based on the audio stream format.

Declaration
public int SampleRate { get; set; }
Property Value
Type Description
int
View Source

SoftwarePixelFormat

Gets the software pixel format, which represents the nominal unaccelerated pixel format used during decoding.

Encoding: Unused.

Decoding: Notify by libavcodec before calling the format selection function (get_format).

Declaration
public PixelFormat SoftwarePixelFormat { get; }
Property Value
Type Description
PixelFormat
View Source

ThreadCount

Gets or sets the number of threads used for encoding or decoding operations.

Encoding: Notify by the user to determine the number of threads for parallel encoding tasks.

Decoding: Notify by the user to determine the number of threads for parallel decoding tasks.

Declaration
public int ThreadCount { get; set; }
Property Value
Type Description
int
View Source

TimeBase

Gets or sets the time base, representing the unit of time in terms of frame duration. This is the fundamental unit used to express timestamps in the media stream (e.g., 1/25 for 25 fps).

Encoding: The time base is unused.

Decoding: Notify by the user to define the base time unit for timestamps.

Declaration
public Rational TimeBase { get; set; }
Property Value
Type Description
Rational
View Source

Width

Gets or sets the width of the video frame in pixels. This field must be set by the user for encoding and may be set for decoding if known.

Encoding: Must be set by the user.

Decoding: May be set by the user before opening the decoder if known, e.g., from the container. The decoder may overwrite this value during parsing.

Declaration
public int Width { get; set; }
Property Value
Type Description
int

Methods

View Source

Allocate(Codec?)

Allocates a new CodecContext instance for the specified codec.

Declaration
public static CodecContext Allocate(Codec? codec)
Parameters
Type Name Description
Codec? codec

The codec for which to allocate the context. If null, a context is allocated without a specific codec.
Returns
Type Description
CodecContext

A new CodecContext instance.
Exceptions
Type Condition
OutOfMemoryException

Thrown if the codec context cannot be allocated due to insufficient memory.
View Source

CopyParameters(CodecContext)

Copies codec parameters from the current codec context to another CodecContext.

Declaration
public void CopyParameters(CodecContext dst)
Parameters
Type Name Description
CodecContext dst

The destination CodecContext to which the codec parameters will be copied.
Exceptions
Type Condition
OutOfMemoryException

Thrown if there is insufficient memory to create the temporary ICodecParameters object.
FFmpegException

Thrown if the FFmpeg function to copy parameters returns an error.
View Source

Decode(AVPacket?, AVFrame)

Decodes an encoded packet and returns the next available decoded frame.

Declaration
public AVResult32 Decode(AVPacket? packet, AVFrame frame)
Parameters
Type Name Description
AVPacket packet

The packet to submit to the decoder, or null to signal the end of the input stream and enter draining mode.
AVFrame frame

Receives the decoded frame if one is available.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation.
Remarks

This convenience method combines SendPacket(AVPacket?) and ReceiveFrame(AVFrame) into a single operation.

Passing null for packet flushes the decoder. Continue calling this method with null until EndOfFile is returned, indicating that all buffered frames have been retrieved.

Under normal circumstances this method never returns TryAgain. If the decoder reports this condition while accepting a packet, an FFmpegException is thrown instead. Applications that need to handle TryAgain explicitly should use SendPacket(AVPacket?) and ReceiveFrame(AVFrame) directly.

View Source

DecodeSubtitle(AVPacket, Subtitle)

Decodes a subtitle from the given AVPacket and outputs the result as a Subtitle.

Declaration
public AVResult32 DecodeSubtitle(AVPacket packet, Subtitle subtitle)
Parameters
Type Name Description
AVPacket packet

The AVPacket containing the encoded subtitle data.
Subtitle subtitle

The decoded subtitle output as a Subtitle.
Returns
Type Description
AVResult32

The result of the decoding operation as AVResult32. This result indicates whether the operation was successful or if an error occurred.
Remarks

This method is specific to subtitle codecs. If the codec type is not set to Subtitle, the operation will throw a NotSupportedException.

Exceptions
Type Condition
NotSupportedException

Thrown if the codec is not of type subtitle.
View Source

Dispose()

Declaration
public void Dispose()
View Source

DrainDecoder()

Enters draining mode for the decoder at the end of a stream, ensuring that any internally buffered frames are processed. This is required when no more input packets are available for decoding, but the codec may still have frames to output.

Declaration
public AVResult32 DrainDecoder()
Returns
Type Description
AVResult32
Remarks

The draining process for decoding works as follows:

  • Instead of passing a valid packet, call SendPacket(AVPacket?) with a null packet, which enters draining mode.
  • Then, call ReceiveFrame(AVFrame) repeatedly to retrieve any remaining decoded frames until AVERROR_EOF is returned, indicating that all buffered frames have been processed.
  • Before decoding can be resumed, call FlushBuffers() to clear the codec's internal buffers and reset its state.

During draining mode, ReceiveFrame(AVFrame) will not return AVERROR(EAGAIN) unless the draining mode was not properly initiated.

View Source

DrainEncoder()

Enters draining mode for the encoder at the end of a stream, ensuring that any internally buffered packets are processed. This is required when no more input frames are available for encoding, but the codec may still have frames to output.

Declaration
public AVResult32 DrainEncoder()
Returns
Type Description
AVResult32
Remarks

The draining process for encoding works as follows:

  • Instead of passing a valid frame, call SendFrame(AVFrame?) with a null frame, which enters draining mode.
  • Then, call ReceivePacket(AVPacket) repeatedly to retrieve any remaining encoded packets until AVERROR_EOF is returned, indicating that all buffered packets have been processed.
  • Before encoding can be resumed, call FlushBuffers() to clear the codec's internal buffers and reset its state.

During draining mode, ReceivePacket(AVPacket) will not return AVERROR(EAGAIN) unless the draining mode was not properly initiated.

View Source

Encode(AVFrame?, AVPacket)

Encodes a frame and returns the next available encoded packet.

Declaration
public AVResult32 Encode(AVFrame? frame, AVPacket packet)
Parameters
Type Name Description
AVFrame frame

The frame to submit to the encoder, or null to signal the end of the input stream and enter draining mode.
AVPacket packet

Receives the encoded packet if one is available.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation.
Remarks

This convenience method combines SendFrame(AVFrame?) and ReceivePacket(AVPacket) into a single operation.

Passing null for frame flushes the encoder. Continue calling this method with null until EndOfFile is returned, indicating that all buffered packets have been retrieved.

Under normal circumstances this method never returns TryAgain. If the encoder reports this condition while accepting a frame, an FFmpegException is thrown instead. Applications that need to handle TryAgain explicitly should use SendFrame(AVFrame?) and ReceivePacket(AVPacket) directly.

View Source

EncodeSubtitle(AVPacket, Subtitle)

Encodes a subtitle into the provided AVPacket and returns the result.

Declaration
public AVResult32 EncodeSubtitle(AVPacket packet, Subtitle subtitle)
Parameters
Type Name Description
AVPacket packet

The AVPacket that will contain the encoded subtitle data. This method will modify and return a fresh packet with the encoded data.
Subtitle subtitle

The Subtitle to encode into the packet.
Returns
Type Description
AVResult32

The result of the encoding operation as AVResult32. A successful result indicates that the subtitle was encoded into the packet successfully.
Remarks

After encoding the subtitle, the returned AVPacket will be freshly created. Important settings, such as StreamIndex, must be set accordingly after the encoding process completes. The AVPacket will have a maximum size of 1MB (1024 * 1024 bytes).

Exceptions
Type Condition
NotSupportedException

Thrown if the codec is not of type subtitle.
View Source

~CodecContext()

Finalizer for CodecContext to ensure resources are released.

This finalizer calls the FFmpeg.Codecs.CodecContext.Dispose(System.Boolean) method with disposing set to false. It is called by the garbage collector if the object is not explicitly disposed.

Declaration
protected ~CodecContext()
View Source

FlushBuffers()

Resets the internal codec state and flushes internal buffers.

This method should be called, for example, when seeking or when switching to a different stream. It clears any cached data and prepares the codec for new data.

Declaration
public void FlushBuffers()
View Source

GetCodecParameters()

Retrieves the codec parameters from the current codec context.

Declaration
public CodecParameters GetCodecParameters()
Returns
Type Description
CodecParameters

An ICodecParameters object containing the codec parameters retrieved from the context.
Exceptions
Type Condition
OutOfMemoryException

Thrown if there is insufficient memory to allocate the ICodecParameters object.
FFmpegException

Thrown if the FFmpeg function to retrieve parameters returns an error.
View Source

Open(Codec)

Opens a codec and initializes a CodecContext for it.

Declaration
public static CodecContext Open(Codec codec)
Parameters
Type Name Description
Codec codec

The codec to open.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec.
View Source

Open(Codec, ICodecParameters?)

Opens a codec, sets codec parameters, and initializes a CodecContext for it.

Declaration
public static CodecContext Open(Codec codec, ICodecParameters? codecParams)
Parameters
Type Name Description
Codec codec

The codec to open.
ICodecParameters codecParams

The codec parameters to set. Can be null.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec or setting parameters.
View Source

Open(Codec, ICodecParameters?, DeviceType)

Opens a codec, sets codec parameters, and initializes a CodecContext for it with hardware acceleration support.

Declaration
public static CodecContext Open(Codec codec, ICodecParameters? codecParams, DeviceType deviceType)
Parameters
Type Name Description
Codec codec

The codec to open.
ICodecParameters codecParams

The codec parameters to set. Can be null.
DeviceType deviceType

The type of hardware device to use for acceleration.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec, setting parameters, or configuring hardware acceleration.
View Source

Open(Codec, AVDictionary?)

Opens a codec and initializes a CodecContext for it with additional options from a dictionary.

Declaration
public static CodecContext Open(Codec codec, AVDictionary? dictionary)
Parameters
Type Name Description
Codec codec

The codec to open.
AVDictionary dictionary

A dictionary of additional codec options. Can be null.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec.
View Source

Open(Codec, AVDictionary?, DeviceType)

Opens a codec, sets hardware device type, and initializes a CodecContext for it with additional options from a dictionary.

Declaration
public static CodecContext Open(Codec codec, AVDictionary? dictionary, DeviceType deviceType)
Parameters
Type Name Description
Codec codec

The codec to open.
AVDictionary dictionary

A dictionary of additional codec options. Can be null.
DeviceType deviceType

The type of hardware device to use for acceleration.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec or setting hardware device type.
View Source

Open(Codec, AVMultiDictionary?)

Opens a codec and initializes a CodecContext for it with additional options from a multi-dictionary.

Declaration
public static CodecContext Open(Codec codec, AVMultiDictionary? dictionary)
Parameters
Type Name Description
Codec codec

The codec to open.
AVMultiDictionary dictionary

A multi-dictionary of additional codec options. Can be null.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec.
View Source

Open(Codec, AVMultiDictionary?, DeviceType)

Opens a codec, sets hardware device type, and initializes a CodecContext for it with additional options from a multi-dictionary.

Declaration
public static CodecContext Open(Codec codec, AVMultiDictionary? dictionary, DeviceType deviceType)
Parameters
Type Name Description
Codec codec

The codec to open.
AVMultiDictionary dictionary

A multi-dictionary of additional codec options. Can be null.
DeviceType deviceType

The type of hardware device to use for acceleration.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec or setting hardware device type.
View Source

Open(Codec, DeviceType)

Opens a codec and initializes a CodecContext for it with hardware acceleration support.

Declaration
public static CodecContext Open(Codec codec, DeviceType deviceType)
Parameters
Type Name Description
Codec codec

The codec to open.
DeviceType deviceType

The type of hardware device to use for acceleration.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec or setting hardware device type.
View Source

Open(Codec, IDictionary<string, string>?)

Opens a codec and initializes a CodecContext for it with additional options from a dictionary of string key-value pairs.

Declaration
public static CodecContext Open(Codec codec, IDictionary<string, string>? dictionary)
Parameters
Type Name Description
Codec codec

The codec to open.
IDictionary<string, string> dictionary

A dictionary of additional codec options. Can be null.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec.
View Source

Open(Codec, IDictionary<string, string>?, DeviceType)

Opens a codec, sets hardware device type, and initializes a CodecContext for it with additional options from a dictionary of string key-value pairs.

Declaration
public static CodecContext Open(Codec codec, IDictionary<string, string>? dictionary, DeviceType deviceType)
Parameters
Type Name Description
Codec codec

The codec to open.
IDictionary<string, string> dictionary

A dictionary of additional codec options. Can be null.
DeviceType deviceType

The type of hardware device to use for acceleration.
Returns
Type Description
CodecContext

An open CodecContext instance.
Exceptions
Type Condition
Exception

Thrown if an error occurs while opening the codec or setting hardware device type.
View Source

Open(Codec?)

Opens the codec context with the specified codec.

Declaration
public AVResult32 Open(Codec? codec)
Parameters
Type Name Description
Codec? codec

The codec to be used to open the codec context. If null, the context is opened with the currently set codec.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

Open(Codec?, ICodecParameters?)

Opens the codec context with the specified codec and codec parameters.

Declaration
public AVResult32 Open(Codec? codec, ICodecParameters? codecParameters)
Parameters
Type Name Description
Codec? codec

The codec to be used to open the codec context. If null, the context is opened with the currently set codec.
ICodecParameters codecParameters

Optional ICodecParameters to set before opening the codec. If null, only the codec is used.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

Open(Codec?, AVDictionary?)

Opens the codec context with the specified codec and optional dictionary of codec options.

Declaration
public AVResult32 Open(Codec? codec, AVDictionary? dictionary)
Parameters
Type Name Description
Codec? codec

The codec to be used to open the codec context. If null, the context is opened with the currently set codec.
AVDictionary dictionary

An optional AVDictionary containing codec-specific options. If null, defaults are used.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

Open(Codec?, AVMultiDictionary?)

Opens the codec context with the specified codec and optional multi-dictionary of codec options.

Declaration
public AVResult32 Open(Codec? codec, AVMultiDictionary? dictionary)
Parameters
Type Name Description
Codec? codec

The codec to be used to open the codec context. If null, the context is opened with the currently set codec.
AVMultiDictionary dictionary

An optional AVMultiDictionary containing codec-specific options. If null, defaults are used.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

Open(Codec?, IDictionary<string, string>?)

Opens the codec context with the specified codec and an IDictionary<TKey, TValue> of codec options.

Declaration
public AVResult32 Open(Codec? codec, IDictionary<string, string>? dictionary)
Parameters
Type Name Description
Codec? codec

The codec to be used to open the codec context. If null, the context is opened with the currently set codec.
IDictionary<string, string> dictionary

An optional IDictionary<TKey, TValue> containing codec-specific options. If null, defaults are used.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

OpenEncoder(AVStream)

Creates and opens an encoder configured from the specified stream.

Declaration
public static CodecContext OpenEncoder(AVStream stream)
Parameters
Type Name Description
AVStream stream

The stream whose codec identifier, codec parameters, time base, and frame rate are used to configure the encoder.
Returns
Type Description
CodecContext

An opened CodecContext configured for encoding the specified stream.
Exceptions
Type Condition
FFmpegException

Thrown if the encoder cannot be found, allocated, configured, or opened.
View Source

ReceiveFrame(AVFrame)

Receives a frame from the codec and transfers it to the provided AVFrame.

If the codec context uses hardware acceleration, the frame will be transferred from hardware memory (GPU) to system memory (RAM).

Declaration
public AVResult32 ReceiveFrame(AVFrame frame)
Parameters
Type Name Description
AVFrame frame

The AVFrame to receive from the codec. This frame will be populated with the decoded data.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

ReceiveHWFrame(AVFrame)

Receives a hardware-accelerated frame from the codec.

If the frame is in RAM, this method behaves the same as ReceiveFrame(AVFrame). If the frame is in GPU memory, this method will return the frame without transferring it to RAM first.

Declaration
public AVResult32 ReceiveHWFrame(AVFrame frame)
Parameters
Type Name Description
AVFrame frame

The AVFrame to receive from the codec.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

ReceivePacket(AVPacket)

Receives a packet from the codec after encoding or decoding.

Declaration
public AVResult32 ReceivePacket(AVPacket packet)
Parameters
Type Name Description
AVPacket packet

The AVPacket to receive from the codec.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

SendFrame(AVFrame?)

Sends a frame to the codec for encoding or decoding.

Declaration
public AVResult32 SendFrame(AVFrame? frame)
Parameters
Type Name Description
AVFrame frame

The AVFrame to send to the codec.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

SendPacket(AVPacket?)

Sends a packet to the codec for encoding or decoding.

Declaration
public AVResult32 SendPacket(AVPacket? packet)
Parameters
Type Name Description
AVPacket packet

The AVPacket to send to the codec.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation. Check for errors using ThrowIfError().
View Source

SetCodecParameters(ICodecParameters)

Sets the codec parameters for the current codec context using the specified parameters.

Declaration
public void SetCodecParameters(ICodecParameters parameters)
Parameters
Type Name Description
ICodecParameters parameters

An ICodecParameters object containing the codec parameters to be set in the context.
Exceptions
Type Condition
FFmpegException

Thrown if the FFmpeg function to set parameters returns an error.
View Source

SetHWDeviceType(DeviceType)

Sets the hardware device type for the codec context.

This method configures the hardware acceleration device type to be used by the codec context. It must be set before opening the codec. If the codec context is already open, an exception will be thrown.

Declaration
public AVResult32 SetHWDeviceType(DeviceType deviceType)
Parameters
Type Name Description
DeviceType deviceType

The type of hardware device to use for acceleration.
Returns
Type Description
AVResult32

An AVResult32 indicating the result of the operation.
Exceptions
Type Condition
NotSupportedException

Thrown if the codec context is already open when attempting to set the hardware device type.
View Source

ToString()

Declaration
public override string ToString()
Returns
Type Description
string
Overrides

Implements

Extension Methods