https://bugs.kde.org/show_bug.cgi?id=476186
Bug ID: 476186 Summary: Screen recording quality is terrible Classification: Frameworks and Libraries Product: KPipeWire Version: unspecified Platform: Other OS: Linux Status: REPORTED Severity: normal Priority: NOR Component: general Assignee: plasma-b...@kde.org Reporter: mar...@marcan.st CC: aleix...@kde.org Target Milestone: --- Screen recording quality in Spectacle is bad to the point of being unusable for anything more than casual use. Selecting quality is a codec, specific issue, but for x264 in particular, the current code is very questionable: https://invent.kde.org/plasma/kpipewire/-/blob/master/src/libx264encoder.cpp This sets `m_avCodecContext->global_quality` from some weird formula, but it's unclear how that maps to encoder settings in the end within ffmpeg. What I see in the resulting files is that Average Bitrate mode is being used (rc=abr), with bitrate somehow varying based on dimensions. This is a very bad choice for x264. The correct "just give me a given quality please" mode in x264 is CRF (constant rate factor) mode, which does not force any given bitrate but rather targets a specific visual quality. If the quality settings are not configurable (or not configurable beyond a simple quality slider), then that mode should be the default to give decent output without more fuss. CRF mode is resolution-independent, and will automatically scale bitrate depending on the requirements (video size, motion complexity, etc.). It's the best option to default to for most users. -- You are receiving this mail because: You are watching all bug changes.