ffmpeg transcoding only utilizing 50% CPU.

[poor_red_neck]

Hello,

Not sure if this is a NPVR issue or nDroid issue.

When transcoding live TV, ffmpeg seems to only be using 50% CPU. This is a dedicated box that only does PVR and NAS functions. WinXP Pro SP3 32bit, with all non-essential services cut off. CPU is always at 1% or less unless transcoding is taking place for android playback. I have a P4 3.0Ghz dual core (prescott or northwood, not sure which one) with 2GB RAM, and a GeForce210.

Live playback on my local network is... Ok. I've tweaked all the typical registry tcp settings (sendwindow, globalmaxtcp, etc) to get better throughput but I still get the occasional hesitation from time to time. Transcoding 800kbps and under plays back fine, but above and ffmpeg can't keep up. Process monitor shows ffmpeg maxing out at 50% CPU usage with approximately 48% idle CPU.

Is there a setting somewhere to increase how much processing power ffmpeg can use?

Thanks!
Jon aka poor_red_neck

[poor_red_neck]

Found it!

Had a brain fart and remembered seeing ffmpeg options in the config.xml file of NPVR.

For those that may search for this issue, I did the following to fix the issue:

Open config.xml under C:\Documents and Settings\All Users\Application Data\NPVR (C:\Users\All Users\ for Win 7 I'm assuming)

Find "<TranscodeArgs>"
Add -threads X (where X is the number of cores you want ffmpeg to use. Ex: a 4 core CPU could be set to 3 for ffmpeg to utilize 3 cores instead of 1 With my dual core CPU not having any other tasks running i set -threads 2 to use both. Now CPU usage is ~90%)
Not sure where it matters to add the argument but I put it after -bufsize 96

It's made a little bit of a difference, but still not great. Going to try playing with the other settings)

[bgowland]

Sorry for not to having responded - I'm no expert in ffmpeg anyway so probably couldn't have advised. You may want to search the net for a more recent build of ffmpeg (the one that comes with npvr is dated 2009) - they may have improved things.

Cheers,
Brian