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• Linux : Create a file for writing with controlled flushing to disk in large chunks [closed]

  12 août 2023, par Pete

  On Linux I have a process (ffmpeg) that writes very slowly (even slower than 1kb / s sometimes) to disk. Ffmpeg can buffer this to 256kb chunks that get written infrequently but ffmpeg hangs occasionally and if I try to detect these hangs by checking that the file is being updated I need to wait a long time between updates, up to 10 or 15 mins, otherwise I can sometimes mistakenly kill the ffmpeg process when it appears to have stopped writing when it fact its still filling its internal buffer.

  


  Theres no way to detect this it seems unless I use strace (that I can find anyway). So I am wondering about turning off buffering in ffmpeg and writing unbuffered to disk from ffmpeg.

  


  This will result in the disk constantly making tiny writes and wasting power (and probably, if I use a SSD, mess with wear levelling too).

  


  So I would like to make ffmpeg write to a 'virtual file' (in memory - either kernel memory or a process) which I can specify the flushing characteristics of. The idea being to perhaps specify flush every 2 minutes, then I can keep an eye on the file size and make sure its still being written.

  


  I don't think I've missed any other ways to do this job - even if I could watch the socket stream incoming to ffpmeg the process itself could still stop writing and lose data. Doing the buffering outside of ffmpeg seems like the best way.

  


  Is there a built in way to do this in Linux or does it mean a custom process ? I guess I know how to do this with a small C program and pipe the data in but I wonder if theres a neater way.

  


• How to compile FFProbe as stand-alone application ? (Mac/Linux/Win)

  16 janvier 2016, par Hanzaplastique

  I’m trying to compile FFMPEG (I’m actually only looking for FFProbe, which is included in the FFMPEG tools) as a standalone application for MacOS X, Linux and possibly Windows.
  With standalone I mean that the libraries (x264, OpenJPEG, etc) are "embedded" into the executable so that I have to distribute only one executable for FFProbe - I apologize that I don’t know the proper lingo for this (please let me know), I’m a newbie when it comes to this.

  I have started by trying to do this under MacOS X, without any luck, but plan to do this for Linux and MacOS X as well.

  I did see a few pre-compiled binaries that do this, and do not depend on extra libraries, but the versions I have found so far are either not the current version (1.x) or do not included the libraries in the executable (evermeet).

  I followed several guides (for example : FFMpeg MacOSX Compilation Guide, reneVolution), with or without the use of Brew, but none of these show me how to embed the libraries in the executable.
  I assume this is an option to be set for linking.

  I’m not sure if it’s appropriate to ask this question for Win, Mac and Linux at the same time - if it’s not appropriate : I’d like to start with doing this for the Mac version.

  My system runs MacOS X 10.9, XCode 5.0.2, with commandline tools and brew installed. I’m only looking for an Intel binary, so not a universal or PowerPC binary.

  For Windows I can use either Windows 8.1 or XP, for Linux I currently use Ubuntu 12, all of which are virtual machines.

• ffmpeg / node-js-ffmpeg No device found

  20 juillet 2020, par Nikola Lukic

  I get list of devices on my windows mashine.
Looks like :

  


  Device Name = Realtek High Definition Audio - Device Id = HDAUDIO\FUNC_01&VEN_10EC&DEV_0887&SUBSYS_10438445&REV_1003\4&3AD857FA&0&0001 - Status = OK
Device Name = USB Audio Device - Device Id = USB\VID_0C45&PID_6340&MI_02\6&313CDC8E&0&0002 - Status = OK
Device Name = NVIDIA High Definition Audio - Device Id = HDAUDIO\FUNC_01&VEN_10DE&DEV_0041&SUBSYS_1458356D&REV_1001\5&27AB1F0A&0&0001 - Status = OK
Device Name = NVIDIA Virtual Audio Device (Wave Extensible) (WDM) - Device Id = ROOT\UNNAMED_DEVICE\0000 - Status = OK
Device Name = NVIDIA GeForce GTX 650 Ti BOOST - Device Id = VideoController1 - Status = OK


  


  After :

  


   ffmpeg -f dshow -i video="NVIDIA GeForce GTX 650 Ti BOOST"  -framerate 30 -video_size 640x480 -f mpegts -codec:v mpeg2video -s 640x480 -rtbufsize 100M -b:v 1000k -bf 0 http://localhost:8081/supersecret


  


  I try also divice ID = VideoController1
I got error log :

  


   Could not find video device with name [NVIDIA GeForce GTX 650 Ti 
BOOST] among source devices of type video.
video=NVIDIA GeForce GTX 650 Ti BOOST: I/O error


  


  Any suggestion...