[FFmpeg-user] x264 thread option

Lou lou at lrcd.com
Tue Nov 20 05:03:05 CET 2012

On Mon, Nov 19, 2012, at 03:54 PM, Young Kim wrote:
> Hello,
> Does anyone know if threads is enabled for libx264 in the latest version
> of ffmpeg? I've experimented with this by using the x264opts parameter to
> set threads, but I can't tell if libx264 is indeed taking advantage of
> it.
> Thanks,
> Young

You can see the x264 info in the console output when encoding. With my
i7 860 I see "threads=12", or you can use the strings command to check
an existing file:

$ strings out.mkv | grep threads
x264 - core 124 - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 -
http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0
analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1
me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11
fast_pskip=1 chroma_qp_offset=-2 threads=1 sliced_threads=0 nr=0
decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3
b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2
keyint=250 keyint_min=23 scenecut=40 intra_refresh=0 rc_lookahead=40
rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4
ip_ratio=1.40 aq=1:1.00

As you can tell my laptop with a Celeron is not a great encoding

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