Steam’s Remote Play host crashes in Steam’s own encoder, and Valve merged a second report

Steam’s Remote Play host is crashing with a SIGSEGV inside the FFmpeg encoder that Steam ships with itself, and Valve has merged a second report into the first. Issue 13704, opened on October 8 and carrying Valve’s own Streaming and SteamOS labels, puts the fault in heap corruption “inside Steam’s bundled FFmpeg video encoder, hit while freeing an AVFrame during avcodec_send_frame”.

The reported path is a Steam Machine host streaming to a Steam Frame. Image: Valve Image: Valve

The reported path is a Steam Machine streaming to a Steam Frame. The host runs SteamOS 3.8.28 on the stable branch with an AMD Navi 33 GPU, capturing through PipeWire and VAAPI, on Steam’s bundled libavcodec 62.28.102, and the report says the codec choice changes only how often it happens: “H.264 crashes within minutes of streaming; HEVC can run for hours”.

Valve merged a second machine’s report on October 13

The second report, issue 13731, came off different hardware: a Ryzen 7 7800X3D with a Radeon RX 9070 XT, encoding on the integrated GPU, with Steam Link on an iPad as the client. Valve closed it within 13 minutes: “this looks like the same issue as #13704. Closing as a duplicate.”

Its author counted “7 times in a row on Oct 13”, on both H.264 and HEVC, each crash a few seconds after connecting. They put the trigger on Steam’s one-time hardware-codec probe, which the client logs as it tries CUDA, fails to load libcuda and falls back to VAAPI, and which “appears to run only once per Steam process”.

The kernel log line names CGameStreamVideo segfaulting in libc, and the fault addresses across the seven crashes were 0x440, 0x441, 0x10 and 0xc51. The stack above it runs through Steam’s libvideo into av_freep and avcodec_send_frame.

Two reports is where the evidence stops

Valve has labelled 13704 and judged the second report the same bug, which is the whole of its public position. It has not said what corrupts the heap, or whether the fault sits in Steam’s own libvideo or in the FFmpeg copy Steam bundles, and 13704 was still open on October 14.

Two machines is two machines. Both hosts run SteamOS on AMD graphics and both encode through Steam’s own bundled copy of FFmpeg, and that is as far as the pattern goes with the reports that exist.

It is also the pairing Valve has been pushing. Valve called the Steam Machine the perfect host for a Steam Frame in September, when VR game streaming between the two was not working yet, and flat-game Remote Play is the route both of these reports use.

Remote Play’s own settings have been moving fast: the beta client raised its ceiling to 1 Gbit/s on October 3, with Valve’s own warning about the latency cost. The piece neither reporter can swap out is the encoder Steam brings with it.

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