fix linux bambu liveview decoder sink #523

New Issue

MrUnknownDE · 2026-04-05T16:22:11+02:00

MrUnknownDE commented

2026-04-05 16:22:11 +02:00

Originally created by @thomashenauer on 3/1/2026

Description

Related issue: #9280 (Linux Bambu liveview stream stops after a few seconds).

This PR improves Linux Bambu liveview stability by tightening decoder selection behavior and sink timing configuration for jitter-prone RTSP streams.

What this PR changes

In Linux wxMediaCtrl2.cpp:

marks Bambu playback context on the decode path
adds decoder autoplug filtering hooks for uridecodebin / decodebin
in Bambu context:
- prefers software decode (avdec_h264) when available
- avoids hard-blocking decode candidates when software decode is unavailable (keeps fallback path open)
applies sink timing settings for liveview robustness:
- sync=false
- qos=false
- max-lateness=-1

Why this approach

scoped to Linux Bambu liveview only (no global decoder policy change)
addresses the observed Linux instability while minimizing impact to unrelated playback paths
preserves startup behavior in environments where avdec_h264 is not installed
improves tolerance to RTSP timing jitter/freezes without changing protocol handling

Expected result

fewer early liveview freezes/stalls on Linux
no black-screen regression from over-restrictive decoder filtering
improved continuity on Bambu H2D/X1C liveview in tested setups

Screenshots/Recordings/Graphs

N/A (runtime pipeline behavior change).

Tests

Date tested: March 1, 2026
Platform: Arch Linux, kernel 6.18.13-arch1-1, GStreamer 1.28.1.

Build/test status

Full project build: passed
Automated tests: 146/146 passed

Functional verification

Verified liveview start/stop/re-enable behavior on both Bambu H2D and X1C.
Verified decode path behavior with software decoder available.
Verified fallback behavior when software decoder is unavailable (gst-libav removed): stream still starts and hardware decode path is used.
Verified sink timing flags are applied and liveview remains stable under repeated stream control actions.

Notes / known limitation

In no-software-decoder environments, decode-path warnings may still appear depending on GPU/memory negotiation.
This PR does not redesign GStreamer memory negotiation; it focuses on safe decoder choice and robust sink timing behavior.

*Originally created by @thomashenauer on 3/1/2026* # Description Related issue: #9280 (Linux Bambu liveview stream stops after a few seconds). This PR improves Linux Bambu liveview stability by tightening decoder selection behavior and sink timing configuration for jitter-prone RTSP streams. ## What this PR changes In Linux `wxMediaCtrl2.cpp`: - marks Bambu playback context on the decode path - adds decoder autoplug filtering hooks for `uridecodebin` / `decodebin` - in Bambu context: - prefers software decode (`avdec_h264`) when available - avoids hard-blocking decode candidates when software decode is unavailable (keeps fallback path open) - applies sink timing settings for liveview robustness: - `sync=false` - `qos=false` - `max-lateness=-1` ## Why this approach - scoped to Linux Bambu liveview only (no global decoder policy change) - addresses the observed Linux instability while minimizing impact to unrelated playback paths - preserves startup behavior in environments where `avdec_h264` is not installed - improves tolerance to RTSP timing jitter/freezes without changing protocol handling ## Expected result - fewer early liveview freezes/stalls on Linux - no black-screen regression from over-restrictive decoder filtering - improved continuity on Bambu H2D/X1C liveview in tested setups # Screenshots/Recordings/Graphs N/A (runtime pipeline behavior change). ## Tests Date tested: March 1, 2026 Platform: Arch Linux, kernel 6.18.13-arch1-1, GStreamer 1.28.1. ### Build/test status - Full project build: passed - Automated tests: 146/146 passed ### Functional verification - Verified liveview start/stop/re-enable behavior on both Bambu H2D and X1C. - Verified decode path behavior with software decoder available. - Verified fallback behavior when software decoder is unavailable (`gst-libav` removed): stream still starts and hardware decode path is used. - Verified sink timing flags are applied and liveview remains stable under repeated stream control actions. ### Notes / known limitation - In no-software-decoder environments, decode-path warnings may still appear depending on GPU/memory negotiation. - This PR does not redesign GStreamer memory negotiation; it focuses on safe decoder choice and robust sink timing behavior.

MrUnknownDE added the bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix bug-fix labels 2026-04-05 16:22:11 +02:00

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Reference: github/OrcaSlicer#523