Experimental Physics and
Industrial Control System

<[email protected]> · Thu, 9 Sep 2010 17:23:07 +0100

Hi all,

I've now released ffmpegServer (mentioned in the below thread) to the
diamond controls website:
http://controls.diamond.ac.uk/downloads/support/ffmpegServer/

ffmpegServer is a windows and Linux areaDetector 1-6 plugin wrapping the
ffmpeg libraries that provides 2 functions:
    * ffmpegStream: Compression into an mjpg stream which is made
available over http.
    * ffmpegFile: Compression to disk into any file format that ffmpeg
supports.

In a previous message, Emmanuel mentioned that he was using axis servers
producing mjpg and mpeg4 streams. ffmpegServer will produce the same
format mjpg stream as this, and I would like to get it to produce mpeg4
video over an rtsp:// connection. It can produce mpeg4 video at the
moment, but only write it to file. The old module mjpgServer has been
deprecated.

Thanks,
Tom Cobb,
Diamond Light Source Ltd.
Diamond House
Harwell Science and Innovation Campus
Didcot
Oxfordshire
OX11 0DE
Tel +44 (0) 1235 778582

> -----Original Message-----
> From: [email protected] 
> [mailto:[email protected]] On Behalf Of Mark Rivers
> Sent: 01 September 2010 19:48
> To: J. Lewis Muir; EPICS Tech-Talk
> Subject: RE: areaDetector video (Was: network video)
> 
> If multiple cameras are being used each areaDetector Prosilica driver
> runs in its own thread.  But their driver library actually creates a
> thread that calls back the areaDetector drivers.  It's possible that
> they only create one thread even for multiple cameras, I'm not sure.
> 
> Mark
> 
> 
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of J. Lewis Muir
> Sent: Wednesday, September 01, 2010 11:06 AM
> To: EPICS Tech-Talk
> Subject: Re: areaDetector video (Was: network video)
> 
> On 9/1/10 10:37 AM, [email protected] wrote:
> > Lewis,
> > 
> > No, the software is multithreaded. The images I mentioned were black
> and
> > white and if you switch to colour compression (which is more
> expensive)
> > the CPU load goes up to around 220% at times.
> > 
> > This is all implemented as an areaDetector plugin in a single IOC. I
> > don't know what would happen if you tried to use two IOC's on one
> host,
> > but I suspect the gains would be minimal. Clearly, if you used a
> second
> > host system you would get a doubling of everything.
> > 
> > As I understand it the frames are lost before they leave 
> the Prosilica
> > driver. The GigE standard is real-time UDP and since we 
> have multiple
> > independent data sources with no bandwidth allocation I think if you
> > looked carefully you would see data bits all over the floor. I feel
> > having the system die reasonably gracefully when the 
> incoming Ethernet
> > pipe chokes is the best we can do - even if the choke point is
> > significantly less than the full theoretical bandwidth.
> 
> Hi, Nick.
> 
> If you think frames are lost before they leave the Prosilica driver,
> then perhaps the Prosilica driver is not multithreaded?  It seems like
> something must not be multithreaded since you have one core completely
> idle.  Of course, not all tasks are easily split into smaller 
> tasks that
> could be run on different cores, but in this case, I would think it
> could.
> 
> Lewis
> 
> 

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System