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v0.3.0: H.265/HEVC Compute Encoder, Vulkan Motion Estimation, Quality Presets & 32-bit Steam Link Support

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@github-actions github-actions released this 16 Sep 03:23
· 244 commits to main since this release
v0.3.0
31e0f06

🎮 AMD BC-250 Custom Driver & VA-API Video Encoder v0.3.0

Hardware-accelerated video encoding and DisplayPort/HDMI audio fixes for the AMD BC-250 ("Cyan Skillfish" / PS5 "Oberon" APU) on Linux (Bazzite, ChimeraOS, CachyOS, Fedora, Ubuntu, Arch, SteamOS).

🚀 What's New in v0.3.0

⚡ Full H.265 / HEVC Compute Video Encoder

  • Complete HEVC Encoding Pipeline: Produces fully spec-compliant H.265/HEVC bitstreams (VPS, SPS, PPS, IDR, and P-slices) matching ITU-T H.265.
  • 4x4 Intra DST-VII & DCT-II Transforms: Real intra prediction with 3 MPM candidate derivation, directional modes, and CABAC syntax binarization.
  • P-Frame Temporal Prediction & RPS: Full Reference Picture Set (RPS) management with short-term reference picture signaling and decoded picture buffer (DPB) tracking.
  • Vulkan Compute Motion Estimation: Leverages the BC-250's 40 RDNA2 Compute Units via motion_estimation.comp for CTU motion search on P-frames, with host staging readback.
  • SSE2 SIMD Vectorization: Fully vectorized 8x8 luma and 4x4 chroma Sum of Absolute Differences (SAD) using _mm_sad_epu8 (psadbw), cutting CPU motion estimation time by ~10x.
  • Hierarchical Diamond Search & Spatial Merge Mode: Evaluates ITU-T Section 8.5.3.2.2 merge candidates ($A_1, B_1, B_0, A_0, B_2$) with spatial deduplication and coarse diamond search bypass.
  • Zero Chroma Drift Mathematical Invariant: All motion vectors strictly enforce even integer displacements ($dx, dy \equiv 0 \pmod 2$), guaranteeing zero chroma rounding error and bit-exact reconstruction against standard HEVC decoders.

🎯 Quality Presets & Streaming Latency Optimization (Issue #10)

  • VA-API Quality Levels (1..7): Advertises and implements VAConfigAttribEncQualityRange and VAEncMiscParameterTypeQualityLevel (Level 1 = Quality, Level 4 = Balanced, Level 7 = Speed).
  • Speed Preset Fast Paths:
    • H.264: Negligible chroma residual detection ($|\Delta| \le 1$) enables P_Skip when luma residual is zero, bypassing expensive CAVLC AC coefficient entropy coding.
    • HEVC: Relaxed early-exit SAD thresholds and skipped 8-point refinement for low-residual blocks, significantly reducing host CPU time in fast-motion scenes.
  • Max Frame Size Constraint: Handles VAEncMiscParameterTypeMaxFrameSize to suppress network bandwidth spikes and prevent buffer bloat in Sunshine/Moonlight streaming sessions.

📈 Leaky-Bucket Rate Control & Dynamic Adaptation

  • Multi-Mode Rate Control: Full CQP, CBR, VBR, and Low-Latency rate control models.
  • Dynamic Feedback: Real-time frame SAD motion distortion feeds directly into QP decisions.
  • Mid-Stream Adaptation: Verified dynamic runtime switching of bitrate and framerate without restarting encoding sessions.

🎮 32-bit (i386) Companion Driver for Steam Link (Issues #8 & #14)

  • Dedicated 32-bit Package: Provides bc250-driver-linux-i386.tar.gz built for 32-bit VA-API runtimes such as Steam Link.
  • SELinux & Hardening Compatible: Built with shared libgomp1:i386 to eliminate text relocations (DT_TEXTREL), ensuring clean loading under SELinux deny_execmod.
  • Multiarch Installer & Diagnostics: Updated tools/bc250_diagnose.sh and added tools/bc250_uninstall.sh for safe driver lifecycle management.

🔊 Audio DTO Driver v0.3.0 (bc250_audio_fix)

  • Synchronized DKMS package version to 0.3.0 with automated kernel rebuilds.
  • Direct DCN Display Controller Clock Generator (DCCG) register programming for 48 kHz / 44.1 kHz DisplayPort and HDMI audio.

🛡️ Automated CI & External Reference Oracle Verification

  • 5 Passing Test Suites: Bitstream, CAVLC, H.264 Encode, VA-API Backend, and HEVC Encode test suites run on every commit.
  • FFmpeg Reference Decoder Oracle: Every build verifies that external FFmpeg decodes 30/30 frames of both H.264 and H.265/HEVC with 100% zero errors.

📥 Installation Instructions

1. 64-bit Driver (Main Package — OBS, Sunshine, Games, Desktop)

tar -xzvf bc250-driver-linux-x86_64.tar.gz
cd bc250-driver
sudo ./build_and_install.sh

2. 32-bit Companion Driver (For Steam Link Users)

Install the 64-bit package first (for shaders and configuration), then install the 32-bit companion driver:

tar -xzvf bc250-driver-linux-i386.tar.gz
sudo install -Dm755 bc250-driver-i386/bc250_drv_video.so /usr/lib32/dri/bc250_drv_video.so
# On Debian/Ubuntu multiarch:
# sudo install -Dm755 bc250-driver-i386/bc250_drv_video.so /usr/lib/i386-linux-gnu/dri/bc250_drv_video.so

⚡ Recommended Sunshine / Moonlight Settings

Add these environment variables to your Sunshine service or launch script:

export LIBVA_DRIVER_NAME=bc250
export BC250_FAST_MODE=1

In Sunshine Web UI:

  • Encoder: VA-API
  • Quality Preset: speed (Preset 7) or balanced (Preset 4)
  • Codec: H.264 or HEVC (H.265)
Assets 4
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