Opened 6 years ago

Last modified 6 years ago

#6009 new enhancement

[Request] Direct-I/O for ffmpeg output files

Reported by: Tóth F. János Owned by:
Priority: wish Component: avformat
Version: git-master Keywords: directio
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no


Please support Direct-I/O for ffmpeg output files.

Example use case: I have a multi-function home server which (among other things) dumps several continuous video streams to files (surveillance camera recordings). Since Linux file-systems have a shared LRU (least recently used) pagecache replacement logic, this continuous and meaningful amount of I/O tends to "wash out" potentially useful file-system (meta)data from the pagecache (since these video files are 99.9% write-only, I only ever open them on very rare occasions when I have reason to suspect they might recorded something unusual).

So, as I understand, the solution would be opening the output files in DIO (Direct-I/O) mode which is supposed to prevent keeping the file data in the pagecache (well, depending on the actual file-system driver and it's settings, it might goes through some caching still but it should be restricted to write caching and/or very limited in size for read-caching, hence still a lot better than regular buffered IO).

Change History (1)

comment:1 by Carl Eugen Hoyos, 6 years ago

Component: ffmpegavformat
Keywords: direct_io dio removed
Priority: normalwish
Version: unspecifiedgit-master
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