Composer crashes during a show
Composer was running normally, then exited or stopped rendering mid-stream.
First, capture the log. The crash window is in the most recent log file (or the previous one if rotation has cycled). Look for:
- A
fatalentry — names what the runtime tripped over. Encoder init failure (4001), licence verification (4007), out-of-memory. - A burst of
errorentries — encoder/decoder failures piled up until the runtime gave up. warningentries that became more frequent in the minutes before the crash — usually a hint that a resource was running out before it finally failed.
Common causes:
- GPU out of video memory (VRAM) —
cuda out of memoryin the log, often after a particular operator started or a new target attached. Causes: too many concurrent encoders, AI operators allocating large model weights, very high-resolution scenes with many layers. Fix: reduce concurrent target count, switch some targets from x265 to NVENC (lower VRAM footprint), or move to a higher-VRAM GPU. The Performance Report shows VRAM usage per tick. - Encoder hardware busy — NVENC has a per-card concurrent-session limit (varies by GPU; consumer cards cap at 3, workstation cards much higher). Excess targets fail with
nvenc init failed. Fix: reduce concurrent NVENC sessions, or move the GPU up the workstation tier. - Capture card disappeared — a Decklink card briefly drops off the PCIe bus due to a driver glitch or a thermal trip. Fix: check the Decklink driver version, reseat the card, verify the slot has at least PCIe x4 lanes (see Tuning for maximum performance).
- Source dropped — an RTMP / SRT input went quiet and Composer reacted to the dead source for too long. Fix: confirm the upstream source is still alive (
ffprobe rtmp://...from the Composer host); then check the input's reconnect / restart settings in Settings. - Disk full — file recorder targets fail with
write failed; check the target volume's free space and the configured retention policy.
The Performance Report is the single most useful artefact to attach to a crash ticket — capture one immediately after the crash, before anything else changes on the host.