AMF Options
Parameters and options are written as such in the config window:
Usage=transcoding Quality=speed
Parameter types:
- i = int (whole number),
- enum is also whole number. technically means something non-numeric, but...
- b = boolean (true/false),
- s = string
This table is currently only reasonably complete for H.264. Reasonably, as in "options that matter".
H.264
General
| Parameter | Options | Default | Explanation |
|---|---|---|---|
| Usage | transcoding, ultralowlatency, lowlatency, webcam, hq, hqll | Transcoding | Changes a lot of settings based on usage. Highly recommend sticking to "transcoding". |
| Quality | speed, balanced, quality | Quality | Controls the speed vs quality. Note: Can fall back to faster presets if throughput is too high vs max throughput. |
| Profile | main, high, constrained_baseline, constrained_high | High | h264 profile. "High" should work for all modern devices (think iphone 4 and later). |
| ProfileLevel | i (10-62) | 42 (4.2) | H264 profile level. Specifies constraints for decode. |
| MaxNumRefFrames | i | 4 | Limits the max number of reference frames (0-16). This max is also limited by hardware and h264 levels. More ref frames means more encoder work, but potentially better compression. Stick to 4 or less, for the sake of compatibility and profile conformity. The encoder is currently likely to use a single reference frame unless b-frames are active. |
Rate Control
| Parameter | Options | Default | Explanation |
|---|---|---|---|
| RateControlPreanalysisEnable | enum (0 or 1) | 1 (enabled) | Pre-encode assisted rate control. |
| EnforceHRD | b | True | Enforce Hypothetical Reference Decoder. Constraints on QP variation within a picture to meet HRD requirements. |
| FillerDataEnable | b | False (True if CBR) | Filler data. Useful for strict CBR encoding, like live streaming. |
| VBVBufferSize | i | N/A | Note: in bits (bps) |
| InitialVBVBufferFullness | i | 64 (100%) | Note: 0=0%, 64=100% |
| PeakBitrate | i | N/A | Note: in bits (bps) |
| MinQP | i | 0 | |
| MaxQP | i | 51 |
B-Frames
B-Frames and its features currently require RDNA2 (RX 6000 and higher). Seems to currently cause some issues, try BPicturesPattern set to 1 or 2. Only H.264 has B-frame support.
Parameter | Options | Default | Explanation
-- | -- | -- | --
MaxConsecutiveBPictures | I (0-3) | 3 (if supported) | Max consecutive b-frames. Is overridden by BPicturesPattern=0.
BPicturesPattern | i (0-3) | 0 | Sets the number of consecutive b-frames per GOP (area between two i-frames). 0=off.
AdaptiveMiniGOP | b | False | Variable amount of b-frames between p-frames. Note: Might require Pre-Analysis, or at least works better with it.
BReferenceEnable | b | True | Enable/Disable the use of b-frames as reference frames.
Psy
| Parameter | Options | Default | Explanation |
|---|---|---|---|
| DeBlockingFilter | b | True | Enable/Disable the de-blocking filter. Only for H.264. |
| EnableVBAQ | b | True (Unless CQP) | Adaptive quantization (H.264). Prioritize bits to parts of the image humans care about. |
| HighMotionQualityBoostEnable | b | False |
Motion Estimation
| Parameter | Options | Default | Explanation |
|---|---|---|---|
| HalfPixel | b | True | |
| QuarterPixel | b | True |
H.265
| Parameter | Options | Default | Explanation |
|---|---|---|---|
| Usage | transcoding, ultralowlatency, lowlatency, webcam, hq, hqll | Transcoding | Changes a lot of settings based on usage. Highly recommend sticking to "transcoding". |
| Quality | speed, balanced, quality | Quality | Controls the speed vs quality. Note: Can fall back to faster presets if throughput is too high vs max throughput. |
| Profile | main, main10 | main | h265 profile. main10 is for 10-bit (HDR). |
| Tier | main, high | high | h265 tier. |
| ProfileLevel | i (10-62) | 62 (6.2) | H264 profile level. Specifies constraints for decode. |
This above is a (still incomplete) list of main options. Some are really specific to H.265. Others are basically the same, but with an annoying name prefix. For example, EnableVBAQ becomes HevcEnableVBAQ. Use the AMF documentation linked below in "See also".
AV1
| Parameter | Options | Default | Explanation |
|---|---|---|---|
| Usage | transcoding, ultralowlatency, lowlatency, webcam, hq, hqll | Transcoding | Changes a lot of settings based on usage. Highly recommend sticking to "transcoding". |
| Quality | speed, balanced, quality | Quality | Controls the speed vs quality. Note: Can fall back to faster presets if throughput is too high vs max throughput. |
| Profile | main | main | av1 profile. Can only be main. |
| ProfileLevel | i (20-73) | 62 (6.2) | AV1 profile level. Specifies constraints for decode. |
Same deal here: some options really specific, others renamed.
Pre-Analysis
| Parameter | Options | Default | Explanation |
|---|---|---|---|
| EnablePreAnalysis | b | False | Pseudo 2-pass for a certain number of frames. Enabling will disable VBAQ. GPU load hit (spends traditional 3d/render resources). This is the only PA property that gets affected by codec names (EnablePreAnalysis for H.264, HevcEnablePreAnalysis for H.265,Av1EnablePreAnalysis` for AV1). |
| PASceneChangeDetectionEnable | b | True | Akin to scenecut (adaptive I-frame insertion). Safest to disable for HLS transcode platforms, as is potentially risky for muxer segment/split. |
| PAFrameSadEnable | b | True | Frame SAD (Sum of Absolute Difference) algorithm |
| PALookAheadBufferDepth | i | 0 | Pre-Analysis lookahead buffer size |
| PAPerceptualAQMode | Enum 0/1 | 0 (None, off) | PA Perceptual adaptive quantization mode. |
| PATemporalAQMode | Enum 0-2 | 0 (None, off) | PA Temporal adaptive quantization mode. 1 for non-gaming applications, 2 gaming applications. |
| PAHighMotionQualityBoostMode | Enum 0/1 | 0 (None, off) | PA High motion quality boost mode |
| PACAQStrength | Enum (0-2) | 1 (medium) | 0=low, 1=med, 2=high. Content Adaptive Quantization (CAQ) strength |
References
AMF documentation
All the parameter names come directly from the AMD AMF library at https://github.com/GPUOpen-LibrariesAndSDKs/AMF/tree/master/amf. For example, to find how PATemporalAQMode is defined, simply use the search box on top to look for PATemporalAQMode in the code. That will bring you to a #define AMF_PA_TAQ_MODE, so you go on and search for AMF_PA_TAQ_MODE in the documentation.
AMF documentation corresponding to sections of this page:
- "General", "Rate Control", "B frame", "Psy", "Motion Estimation" are documented in codec-specific pages. See AMF_Video_Encode_API.md, AMF_Video_Encode_HEVC_API.md, AMF_Video_Encode_AV1_API.md
- "Pre-Analysis" is its own component, documented in AMF_Video_PreAnalysis_API.md. It is not dependent on the choice of codec.
The AMF documentation uses #define names for parameters and values. Use the search box on top to convert them into the L"string" names.
TODOs
- Evaluate the "HQ" usage mode, which sacrifices throughput for quality.