⚿ Sign in
OWLOWL  ← Home

Video Transcode Energy Test

Greening of Streaming · OWL · GoS1
First time here? Try the Guided Tour →  ·  Encode is half the story: Decode rig — client-device energy → Lab only
betaSome initial findings: browse the OWL findings catalog →
⚡ Transcode options for a set energy budget →
How many hours of video fit a given Wh budget, by hardware & codec at a target VMAF.
ⓘ About this test (click to expand)
Transcode a source video and measure the server's wall-power draw during the encode.
Accepted: MP4, MOV, MKV, AVI, WebM, TS · Max 1GB.
Baseline measured 10s before each run · P110 + thermals at 1s intervals.
All GPU presets use the full VAAPI pipeline (hardware decode + encode + scale) — representative of live encoding workflows.
Rate control is ABR (constant bitrate target) across all 6 presets so CPU and GPU receive identical tasks.
Scope: device layer only — network, CDN, and client devices (CPE) excluded.
H.264

H.264 CPU

libx264 · ABR · 1080p

detailsSoftware encode across all 24 cores.

H.264 GPU

h264_nvenc · ABR · 1080p · full pipeline

detailsHardware decode + encode. Full GPU pipeline — representative of live encoding.

H.264 Both

CPU then GPU · same file

detailsSide-by-side energy + thermal report with analysis.
H.265

H.265 CPU

libx265 · ABR · 1080p

detailsSoftware HEVC encode.

H.265 GPU

hevc_nvenc · ABR · 1080p · full pipeline

detailsHardware decode + encode. Full GPU pipeline.

H.265 Both

CPU then GPU · same file

detailsSide-by-side H.265 CPU vs GPU comparison.
AV1

AV1 CPU

libsvtav1 · ABR · 1080p

detailsSVT-AV1 software encode.

AV1 GPU

av1_nvenc · ABR · 1080p · full pipeline

detailsHardware decode + AV1 encode on the GPU's dedicated AV1 engine.

AV1 Both

CPU then GPU · same file

detailsSide-by-side AV1 CPU vs GPU comparison.
🔒 All-codecs sweep — Members only · Join GoS ↗
Compare codecs · CPU (software)
H.264 · H.265 · AV1 on CPU · same source · same target bitrate — which codec is cheapest in software
~3× longer · locks queue
Compare codecs · GPU (hardware)
H.264 · H.265 · AV1 on GPU · same source · same target bitrate — which codec is cheapest in hardware
~3× longer · locks queue
Compare all (CPU vs GPU)
H.264 · H.265 · AV1 · CPU + GPU · same source · same target bitrate — full matrix
~6× longer · locks queue
Source
GoS promo
Promo / motion graphics — text & sharp edges, very high spatial detail (SI ~57, TI ~8)
Meridian 4K · CC BY 4.0
Cinematic live-action — soft, shallow depth-of-field, dark scenes; low spatial detail (SI ~13, TI ~2), compresses easily
Big Buck Bunny 4K · CC BY 3.0
3D animation — sharp edges, flat gradients, high detail & motion (SI ~33, TI ~6); banding-prone, harder to compress to a VMAF target
Downhill MTB (Kranjska Gora) · CC BY 3.0
Fast-action sport — POV downhill mountain biking; extreme spatial & temporal complexity (SI ~101, TI ~45), the hardest-to-compress source on the bench · © Maks Berc (CC BY 3.0)
Upload your own
🔒 Upload — Members only · Join GoS ↗
After upload
Scored after the measurement window closes — never part of the energy figure, but it adds minutes of wall time. Uncheck for a faster energy-only run. Single-preset runs never score.
— · CPU — · GPU —