fauxstream VS recordmydesktop

There is also the very useful project fauxstream which encapsulates this knowledge.

https://github.com/rfht/fauxstream

I was testing a stream over ipfs proof of concept. and the trickiest thing for me was figuring out what ffmpeg arcana was needed to grab the desktop and audio. And fauxstream proved very valuable in providing a known working config.

I was able to use fauxstream as a starting point for part of my streaming project.

My experiment was streaming via a ipfs transport layer.

fauxstream is a very thin wrapper around ffmpeg, it proved invaluable in providing a reference command I could iterate off of to get my stream working.

https://github.com/rfht/fauxstream

One of the things I improved in my recordMyDesktop fork [0] was an awful tendency for the frame cache writer to accumulate heaps of dirty pages until background writeback would flush them out.

I had 16GiB of RAM which meant quite large swaths of dirty pages would become buffered while the SSD sat idle until writeback began. This would cause high-FPS full-screen recordings in particular to just become backlogged and start dropping frames / audio dropouts. Just generally broken behavior for a desktop recorder, especially for a defferred-encode mode that's supposed to be optimized for minimizing system-wide effects/overheads during the recording.

The simple solution I found was to proactively initiate writeback regularly via fdatasync() on the cache fd. [1] I haven't decided yet if more should be done to constrain its buffer cache effects though. The cache files will be read back during encoding in post, so if there's enough RAM it can be desirable to enable reading them back entirely from memory instead of having to hit the disks again... but it would also be nice to let the rest of the system's processes keep their stuff in the page cache. memcg can probably be used to find a balanced solution, but I haven't done any experiments yet. Have any of you handled similar scenarios? What did you do?

[0] https://github.com/recordmydesktop/recordmydesktop

[1] https://github.com/recordmydesktop/recordmydesktop/commit/42...

recordMyDesktop[0] should work on any *NIX w/OSS+X, and it defaults to a cached mode with deferred encoding so there's less load on the system during* the recording.

In my experience using Linux+XOrg+ALSA on an X220 ThinkPad it works pretty well, at least in its current form.

Disclaimer: I'm the maintainer of the linked fork, prior to this fork it was ~useless.

[0] https://github.com/recordmydesktop/recordmydesktop