[MPlayer-users] Recording from tv:// isn't realtime

Marc MERLIN marc_mplayer at merlins.org
Wed Jul 16 19:35:34 CEST 2014

I have an 8 core CPU that seems fast enough for encoding (I can encode at
more than realtime speed with x264).

But with tv:// recording, I only record at about 0.3x of realtime.

I've tried stuff like
time mencoder tv:// -tv driver=v4l2:norm=PAL:width=720:height=576:outfmt=uyvy:device=/dev/video1:input=0:fps=25:alsa:amode=1:forcechan=2:audiorate=48000:forceaudio:immediatemode=0 -ovc x264 -x264encopts threads=8:subq=5:8x8dct:frameref=2:bframes=3:b_pyramid=normal:weight_b -oac mp3lame -lameopts cbr:br=128   -o test.avi 

It works fine, but if I stop it after 1mn, I only get about 20 seconds

I've tried some options to improve speed, but none seem to help.

Is my speed being throttled by the source somehow?
I can play tv:// with mplayer realtime.

Actually I'd love to use mplayer with -dumpstream, but that doesn't work
for this source type.

Any ideas?

This is what mencoder says when I stop it (video bitrate is low because it's a blue image for testing):

Pos:   5.1s    309f ( 0%) 24.89fps Trem:   0min   0mb  A-V:0.000 [4:128]
Flushing video frames.
Writing index...
Writing header...
ODML: vprp aspect is 16384:13107.
Setting audio delay to 0.080s.
Video stream:    6.387 kbit/s  (798 B/s)  size: 4056 bytes  5.080 secs  309 frames
Audio stream:  128.000 kbit/s  (16000 B/s)  size: 81408 bytes  5.088 secs
x264 [info]: frame I:1     Avg QP: 9.00  size:   848
x264 [info]: frame P:32    Avg QP: 9.22  size:    31
x264 [info]: frame B:94    Avg QP:12.67  size:    24
x264 [info]: consecutive B-frames:  0.8%  1.6%  0.0% 97.6%
x264 [info]: mb I  I16..4: 99.9%  0.0%  0.1%
x264 [info]: mb P  I16..4:  0.0%  0.0%  0.0%  P16..4:  0.0%  0.0%  0.0%  0.0%  0.0%    skip:100.0%
x264 [info]: mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.0%  0.0%  0.0%  direct: 0.0%  skip:100.0%
x264 [info]: 8x8 transform intra:0.0%
x264 [info]: coded y,uvDC,uvAC intra: 0.0% 0.1% 0.0% inter: 0.0% 0.0% 0.0%
x264 [info]: i16 v,h,dc,p: 97%  0%  3%  0%
x264 [info]: i4 v,h,dc,ddl,ddr,vr,hd,vl,hu:  0%  0% 100%  0%  0%  0%  0%  0%  0%
x264 [info]: i8c dc,h,v,p: 100%  0%  0%  0%
x264 [info]: Weighted P-Frames: Y:0.0% UV:0.0%
x264 [info]: kb/s:6.39
v4l2: 312 frames successfully processed, 0 frames dropped.

real	0m12.796s
user	0m0.800s
sys	0m0.300s

"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/  

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