Description
In the editor, seeking to the last frame of a recording fails to decode and the preview falls back to "Preview unavailable on this machine". The message suggests a machine/driver problem, but the index in the error is exactly nb_frames - 1, which points to an off-by-one in the seek/decode path rather than a hardware issue.
Everything else on this machine works on hardware: VAAPI encode is accepted with no rejections, the Vulkan/dmabuf path is active, and Whisper STT runs on Vulkan at 11.4x real-time.
Error
[live] render thread error: decode_at(frame_idx=2434) : aucune frame reçue
native bridge compositor.readFrame failed: Error: decode_at(frame_idx=2434) : aucune frame reçue
at CP.readFrame (app.asar/dist-electron/main-FolZ9gtb.js:30644:18)
at app.asar/dist-electron/main-FolZ9gtb.js:77279:27
code: 'GenericFailure'
Why it looks like off-by-one
ffprobe on the recording that produced the error:
codec_name=h264
profile=High
width=1920
height=1080
pix_fmt=yuv420p
r_frame_rate=60/1
nb_frames=2435
duration=40.576000
nb_frames = 2435, so valid indices are 0..2434. The failing request is frame_idx=2434 — the last valid frame. The decoder returns no frame for it.
Reproduce
- Record ~40s at 1920x1080 60fps on Linux/Wayland (VAAPI encode).
- Open the recording in the editor.
- Drag the playhead to the very end of the timeline.
- Preview goes to "Preview unavailable on this machine"; the log shows
decode_at(frame_idx=<nb_frames-1>) : aucune frame reçue.
Seeking back to any earlier point recovers, so it is specific to the final frame.
Capture pipeline (all healthy)
[capture-linux] encoder {"video":"vaapi","rejected":[]}
[d3d] adaptateur Vulkan : AMD Radeon RX 6600 (RADV NAVI23) (DiscreteGpu, Vulkan)
-> backend Hardware, export dmabuf actif
[whisper-stt] model loaded; backend=whispercpp-vulkan
[stt] done on whispercpp-vulkan: 40.6s audio in 3.6s (0.09 rtf, 11.4x real-time)
Cursor telemetry is complete as well — 1115 move + 31 click samples spanning the full 40.559s, so the portal + evdev path is working correctly on GNOME Wayland.
Environment
|
|
| OpenScreen |
1.11.0 (AppImage) |
| OS |
Ubuntu 26.04 LTS, kernel 7.0.0-31-generic |
| Desktop |
GNOME 50.1, Wayland |
| GPU |
AMD Radeon RX 6600 (radeonsi, navi23, RADV NAVI23) |
| Mesa |
26.0.3 |
| Electron |
Chrome/146.0.7680.188 |
| Encoder |
VAAPI (hardware), dmabuf export active |
Note on the message
"Preview unavailable on this machine" reads as a capability problem and sent me looking at drivers and portals first. Since the underlying failure here is a single-frame decode error, surfacing the frame index (or a "could not decode frame N" wording) would point at the real cause much faster.
Description
In the editor, seeking to the last frame of a recording fails to decode and the preview falls back to "Preview unavailable on this machine". The message suggests a machine/driver problem, but the index in the error is exactly
nb_frames - 1, which points to an off-by-one in the seek/decode path rather than a hardware issue.Everything else on this machine works on hardware: VAAPI encode is accepted with no rejections, the Vulkan/dmabuf path is active, and Whisper STT runs on Vulkan at 11.4x real-time.
Error
Why it looks like off-by-one
ffprobeon the recording that produced the error:nb_frames = 2435, so valid indices are0..2434. The failing request isframe_idx=2434— the last valid frame. The decoder returns no frame for it.Reproduce
decode_at(frame_idx=<nb_frames-1>) : aucune frame reçue.Seeking back to any earlier point recovers, so it is specific to the final frame.
Capture pipeline (all healthy)
Cursor telemetry is complete as well — 1115
move+ 31clicksamples spanning the full 40.559s, so the portal + evdev path is working correctly on GNOME Wayland.Environment
Note on the message
"Preview unavailable on this machine" reads as a capability problem and sent me looking at drivers and portals first. Since the underlying failure here is a single-frame decode error, surfacing the frame index (or a "could not decode frame N" wording) would point at the real cause much faster.