[FFmpeg-user] Screencast looks foggy

Kai Hendry hendry at iki.fi
Sat Nov 17 05:24:52 CET 2012


On 17 November 2012 11:58, Lou <lou at lrcd.com> wrote:
> "-threads 0" does not mean "zero threads" but allows x264 to choose the
> threads value (number of cores * 1.5, rounded down) for frame based
> threads. However, this is now the default behavior so using
> is superfluous.

Is "-threads 0" the same as `-threads auto` then?

My very unscientific (I could have messed this up) test using -d 5
(for 5 seconds) switch on
https://github.com/kaihendry/recordmydesktop2.0/blob/master/r2d2
x220:~/r/2012-11-17$ grep real *.log
auto.log:real   0m1.575s
auto.log:real   0m7.687s
threads-omitted.log:real        0m2.157s
threads-omitted.log:real        0m8.829s
threads-zero.log:real   0m2.160s
threads-zero.log:real   0m9.482s


Sidenote: I did a little investigation and by default things seems to
be treated as 24 FPS.

x220:~/r/2012-11-17$ for i in *.{mp4,webm}; do ffprobe $i 2>&1 | grep
-i fps; done
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 /
0x31637661), yuv420p, 1366x768 [SAR 1:1 DAR 683:384], 967 kb/s, 24
fps, 24 tbr, 24 tbn, 48 tbc
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 /
0x31637661), yuv420p, 1366x768 [SAR 1:1 DAR 683:384], 795 kb/s, 24
fps, 24 tbr, 24 tbn, 48 tbc
    Stream #0:0(und): Video: h264 (Constrained Baseline) (avc1 /
0x31637661), yuv420p, 1366x768 [SAR 1:1 DAR 683:384], 797 kb/s, 24
fps, 24 tbr, 24 tbn, 48 tbc
    Stream #0:0: Video: vp8, yuv420p, 1366x768, SAR 1:1 DAR 683:384,
24 fps, 24 tbr, 1k tbn, 1k tbc (default)
    Stream #0:0: Video: vp8, yuv420p, 1366x768, SAR 1:1 DAR 683:384,
24 fps, 24 tbr, 1k tbn, 1k tbc (default)
    Stream #0:0: Video: vp8, yuv420p, 1366x768, SAR 1:1 DAR 683:384,
24 fps, 24 tbr, 1k tbn, 1k tbc (default)


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