# AV1 Encoders

Video Capture SDK .Net Video Edit SDK .Net Media Blocks SDK .Net

VideoCaptureCoreX VideoEditCoreX MediaBlocksPipeline

VisioForge supports multiple AV1 encoder implementations, each with its own unique features and capabilities. This document covers the available encoders and their configuration options.

Currently, AV1 encoder are supported in the cross-platform engines: VideoCaptureCoreX, VideoEditCoreX, and Media Blocks SDK.

# Available Encoders

You can use AV1 encoder with WebM output or for network streaming.

# AMD AMF AV1 Encoder

The AMD AMF AV1 encoder provides hardware-accelerated encoding using AMD graphics cards.

# Features

Multiple quality presets
Variable bitrate control modes
GOP size control
QP (Quantization Parameter) control
Smart Access Video support

# Rate Control Modes

Default: Depends on Usage
CQP: Constant QP
LCVBR: Latency Constrained VBR
VBR: Peak Constrained VBR
CBR: Constant Bitrate

# Sample Usage

var encoderSettings = new AMFAV1EncoderSettings
{
    Bitrate = 3000,                              // 3 Mbps
    GOPSize = 30,                                // GOP size of 30 frames
    Preset = AMFAV1EncoderPreset.Quality,        // Quality preset
    RateControl = AMFAV1RateControlMode.VBR,     // Variable Bitrate mode
    Usage = AMFAV1EncoderUsage.Transcoding,      // Transcoding usage
    MaxBitrate = 5000,                           // 5 Mbps max bitrate
    QpI = 26,                                    // I-frame QP
    QpP = 26,                                    // P-frame QP
    RefFrames = 1,                               // Number of reference frames
    SmartAccessVideo = false                     // Smart Access Video disabled
};

# NVIDIA NVENC AV1 Encoder

NVIDIA's NVENC AV1 encoder provides hardware-accelerated encoding using NVIDIA GPUs.

# Features

Multiple encoding presets
Adaptive B-frame support
Temporal AQ (Adaptive Quantization)
VBV (Video Buffering Verifier) buffer control
Spatial AQ support

# Rate Control Modes

Default: Default mode
ConstQP: Constant Quantization Parameter
CBR: Constant Bitrate
VBR: Variable Bitrate
CBR_LD_HQ: Low-delay CBR, high quality
CBR_HQ: CBR, high quality (slower)
VBR_HQ: VBR, high quality (slower)

# Sample Usage

var encoderSettings = new NVENCAV1EncoderSettings
{
    Bitrate = 3000,                          // 3 Mbps
    Preset = NVENCPreset.HighQuality,        // High quality preset
    RateControl = NVENCRateControl.VBR,      // Variable Bitrate mode
    GOPSize = 75,                            // GOP size of 75 frames
    MaxBitrate = 5000,                       // 5 Mbps max bitrate
    BFrames = 2,                             // 2 B-frames between I and P
    RCLookahead = 8,                         // 8 frames lookahead
    TemporalAQ = true,                       // Enable temporal AQ
    Tune = NVENCTune.HighQuality,            // High quality tuning
    VBVBufferSize = 6000                     // 6000k VBV buffer
};

# Intel QuickSync AV1 Encoder

Intel's QuickSync AV1 encoder provides hardware-accelerated encoding using Intel GPUs.

# Features

Low latency mode support
Configurable target usage
Reference frame control
Flexible GOP size settings

# Rate Control Modes

CBR: Constant Bitrate
VBR: Variable Bitrate
CQP: Constant Quantizer

# Sample Usage

var encoderSettings = new QSVAV1EncoderSettings
{
    Bitrate = 2000,                              // 2 Mbps
    LowLatency = false,                          // Standard latency mode
    TargetUsage = 4,                             // Balanced quality/speed
    GOPSize = 30,                                // GOP size of 30 frames
    MaxBitrate = 4000,                           // 4 Mbps max bitrate
    QPI = 26,                                    // I-frame QP
    QPP = 28,                                    // P-frame QP
    RateControl = QSVAV1EncRateControl.VBR,      // Variable Bitrate mode
    RefFrames = 1                                // Number of reference frames
};

# AOM AV1 Encoder

The Alliance for Open Media (AOM) AV1 encoder is a software-based reference implementation.

# Features

Buffer control settings
CPU usage optimization
Frame dropping support
Multi-threading capabilities
Super-resolution support

# Rate Control Modes

VBR: Variable Bit Rate Mode
CBR: Constant Bit Rate Mode
CQ: Constrained Quality Mode
Q: Constant Quality Mode

# Sample Usage

var encoderSettings = new AOMAV1EncoderSettings
{
    BufferInitialSize = TimeSpan.FromMilliseconds(4000),
    BufferOptimalSize = TimeSpan.FromMilliseconds(5000),
    BufferSize = TimeSpan.FromMilliseconds(6000),
    CPUUsed = 4,                                   // CPU usage level
    DropFrame = 0,                                 // Disable frame dropping
    RateControl = AOMAV1EncoderEndUsageMode.VBR,   // Variable Bitrate mode
    TargetBitrate = 256,                           // 256 Kbps
    Threads = 0,                                   // Auto thread count
    UseRowMT = true,                               // Enable row-based threading
    SuperResMode = AOMAV1SuperResolutionMode.None  // No super-resolution
};

# RAV1E Encoder

RAV1E is a fast and safe AV1 encoder written in Rust.

# Features

Speed preset control
Quantizer settings
Key frame interval control
Low latency mode
Psychovisual tuning

# Sample Usage

var encoderSettings = new RAV1EEncoderSettings
{
    Bitrate = 3000,                               // 3 Mbps
    LowLatency = false,                           // Standard latency mode
    MaxKeyFrameInterval = 240,                    // Maximum keyframe interval
    MinKeyFrameInterval = 12,                     // Minimum keyframe interval
    MinQuantizer = 0,                             // Minimum quantizer value
    Quantizer = 100,                              // Base quantizer value
    SpeedPreset = 6,                              // Speed preset (0-10)
    Tune = RAV1EEncoderTune.Psychovisual          // Psychovisual tuning
};

# General Usage Notes

All encoders implement the IAV1EncoderSettings interface, providing a consistent way to create encoder blocks.
Each encoder has its own specific set of optimizations and trade-offs.
Hardware encoders (AMF, NVENC, QSV) generally provide better performance but may have specific hardware requirements.
Software encoders (AOM, RAV1E) offer more flexibility but may require more CPU resources.

# Recommendations

For AMD GPUs: Use AMF encoder
For NVIDIA GPUs: Use NVENC encoder
For Intel GPUs: Use QSV encoder
For maximum quality: Use AOM encoder
For CPU-efficient encoding: Use RAV1E encoder

# Best Practices

Always check encoder availability before using it
Set appropriate bitrates based on your target resolution and framerate
Use appropriate GOP sizes based on your content type
Consider the trade-off between quality and encoding speed
Test different rate control modes to find the best fit for your use case