VideoEncoder

VideoEncoder node is used to encode ImgFrame into either H264, H265, or MJPEG streams. Only NV12 or GRAY8 (which gets converted to NV12) format is supported as an input. All codecs are lossy (except lossless MJPEG), for more information please see encoding quality docs.Encoded bitstream (either MJPEG, H264, or H265) from the device can also be saved directly into .mp4 container with no computational overhead on the host computer. See demo here. for more information.MatroskaBesides ffmpeg and .mp4 video container (which is patent encumbered), you could also use the mkvmerge (see MKVToolNix for GUI usage) and .mkv video container to mux encoded stream into video file that is supported by all major video players (eg. VLC).

Command Line

1mkvmerge -o vid.mkv video.h265

How to place it

Python

C++

Python

1pipeline = dai.Pipeline()
2encoder = pipeline.create(dai.node.VideoEncoder)

Inputs and Outputs

React Flow

Note

Output message types bitstream and out are mutually exclusive.

Usage

Python

C++

Python

1pipeline = dai.Pipeline()
2
3# Create ColorCamera beforehand
4# Set H265 encoding for the ColorCamera video output
5videoEncoder = pipeline.create(dai.node.VideoEncoder)
6videoEncoder.setDefaultProfilePreset(cam.getFps(), dai.VideoEncoderProperties.Profile.H265_MAIN)
7videoEncoder.setBitrateKbps(500) # 0.5 Mbps
8
9# Create MJPEG encoding for still images
10stillEncoder = pipeline.create(dai.node.VideoEncoder)
11stillEncoder.setDefaultProfilePreset(1, dai.VideoEncoderProperties.Profile.MJPEG)
12# stillEncoder.setLossless(True) # Lossless only for MJPEG
13stillEncoder.setQuality(90) # 0-100, 100 being the best quality (not lossless though)
14
15cam.still.link(stillEncoder.input)
16cam.video.link(videoEncoder.input)

Limitations

For H.264 / H.265 encoding, we have the following limits:

248 million pixels/second (4K@30) limit for the encoder. The resolution and frame rate can be divided into multiple streams - but the sum of all the pixels/second needs to be below 248 million.
Due to a HW constraint, video encoding can be done only on frames whose width values are multiples of 32.
4096 pixel max width for a frame.

The MJPEG encoder is capable of 16384x8192 resolution at 450 MPix/sec. From our testing, we were able to encode 4K at 30FPS and 2x 800P at 55FPS.Note the processing resources of the encoder are shared between H.26x and JPEG.

Examples of functionality

Reference

class

dai::node::VideoEncoder

#include VideoEncoder.hpp

variable

Input input

Input for NV12 ImgFrame to be encoded

variable

Output bitstream

Outputs ImgFrame message that carries BITSTREAM encoded (MJPEG, H264 or H265) frame data. Mutually exclusive with out.

variable

Output out

Outputs EncodedFrame message that carries encoded (MJPEG, H264 or H265) frame data. Mutually exclusive with bitstream.

function

std::shared_ptr< VideoEncoder > build(Node::Output & input)

function

void setDefaultProfilePreset(float fps, Properties::Profile profile)

Sets a default preset based on specified frame rate and profile

Parameters

fps: Frame rate in frames per second
profile: Encoding profile

function

void setNumFramesPool(int frames)

Set number of frames in pool

Parameters

frames: Number of pool frames

function

int getNumFramesPool()

Get number of frames in pool

Returns

Number of pool frames

function

void setRateControlMode(Properties::RateControlMode mode)

function

void setProfile(Properties::Profile profile)

function

void setBitrate(int bitrate)

function

void setBitrateKbps(int bitrateKbps)

function

void setKeyframeFrequency(int freq)

Set keyframe frequency. Every Nth frame a keyframe is inserted.Applicable only to H264 and H265 profilesExamples:

30 FPS video, keyframe frequency: 30. Every 1s a keyframe will be inserted
60 FPS video, keyframe frequency: 180. Every 3s a keyframe will be inserted

function

void setNumBFrames(int numBFrames)

function

void setQuality(int quality)

Set quality

Parameters

quality: Value between 0-100%. Approximates quality

function

void setLossless(bool lossless)

Set lossless mode. Applies only to [M]JPEG profile

Parameters

lossless: True to enable lossless jpeg encoding, false otherwise

function

void setFrameRate(float frameRate)

Sets expected frame rate

Parameters

frameRate: Frame rate in frames per second

function

void setMaxOutputFrameSize(int maxFrameSize)

Specifies maximum output encoded frame size

function

Properties::RateControlMode getRateControlMode()

function

Properties::Profile getProfile()

function

int getBitrate()

function

int getBitrateKbps()

function

int getKeyframeFrequency()

function

int getNumBFrames()

function

int getQuality()

function

float getFrameRate()

function

bool getLossless()

function

int getMaxOutputFrameSize()

inline function

DeviceNodeCRTP()

inline function

DeviceNodeCRTP(const std::shared_ptr< Device > & device)

inline function

DeviceNodeCRTP(std::unique_ptr< Properties > props)

inline function

DeviceNodeCRTP(std::unique_ptr< Properties > props, bool confMode)

inline function

DeviceNodeCRTP(const std::shared_ptr< Device > & device, std::unique_ptr< Properties > props, bool confMode)

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ON THIS PAGE

VideoEncoder

How to place it

Python

Inputs and Outputs

Usage

Python

Limitations

Examples of functionality

Reference

dai::node::VideoEncoder

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