Можно ли изнутри браузера узнать, что проигрываемое видео «тормозит»?

if video_w <= screen_w and video_h <= screen_h:
   нормуль
else:
    разупороться

$ mplayer ШКОЛА\ PDR.\ 1\ УРОК.\ ИНСТРУМЕНТ.\ ЭЛЕМЕНТАРНЫЕ\ ВМЯТИНЫ.\ \[lzYmW4DB6qE\].webm 
MPlayer SVN-r37391-4.8.3 (C) 2000-2015 MPlayer Team
do_connect: could not connect to socket
connect: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.

Playing ШКОЛА PDR. 1 УРОК. ИНСТРУМЕНТ. ЭЛЕМЕНТАРНЫЕ ВМЯТИНЫ. [lzYmW4DB6qE].webm.
libavformat version 56.40.101 (external)
Mismatching header version 56.25.101
libavformat file format detected.
[lavf] stream 0: video (vp9), -vid 0
[lavf] stream 1: audio (opus), -aid 0, -alang eng
VIDEO:  [VP90]  1280x720  0bpp  30.000 fps    0.0 kbps ( 0.0 kbyte/s)
Clip info:
 encoder: Lavf56.40.101
Load subtitles in ./
Failed to open VDPAU backend libvdpau_va_gl.so: cannot open shared object file: No such file or directory
[vdpau] Error when calling vdp_device_create_x11: 1
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
libavcodec version 56.60.100 (external)
Mismatching header version 56.26.100
Selected video codec: [ffvp9] vfm: ffmpeg (FFmpeg VP9)
==========================================================================
==========================================================================
Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
AUDIO: 48000 Hz, 2 ch, floatle, 0.0 kbit/0.00% (ratio: 0->384000)
Selected audio codec: [ffopus] afm: ffmpeg (FFmpeg opus)
==========================================================================
AO: [pulse] 48000Hz 2ch floatle (4 bytes per sample)
Starting playback...
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
VO: [xv] 1280x720 => 1280x720 Planar YV12 
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
VO: [xv] 1280x720 => 1280x720 Planar YV12 
A:   0.2 V:   0.0 A-V:  0.210 ct:  0.003   0/  0 ??% ??% ??,?% 1 0                                                                                                                                                      
[VD_FFMPEG] DRI failure.
A:  19.2 V:  18.7 A-V:  0.499 ct:  0.027   0/  0 68%  5%  3.6% 200 0                                                                                                                                                    


           ************************************************
           **** Your system is too SLOW to play this!  ****
           ************************************************

Possible reasons, problems, workarounds:
- Most common: broken/buggy _audio_ driver
  - Try -ao sdl or use the OSS emulation of ALSA.
  - Experiment with different values for -autosync, 30 is a good start.
- Slow video output
  - Try a different -vo driver (-vo help for a list) or try -framedrop!
- Slow CPU
  - Don't try to play a big DVD/DivX on a slow CPU! Try some of the lavdopts,
    e.g. -vfm ffmpeg -lavdopts lowres=1:fast:skiploopfilter=all.
- Broken file
  - Try various combinations of -nobps -ni -forceidx -mc 0.
- Slow media (NFS/SMB mounts, DVD, VCD etc)
  - Try -cache 8192.
- Are you using -cache to play a non-interleaved AVI file?
  - Try -nocache.
Read DOCS/HTML/en/video.html for tuning/speedup tips.
If none of this helps you, read DOCS/HTML/en/bugreports.html.

A:  31.0 V:  29.2 A-V:  1.856 ct:  0.027   0/  0 79%  4%  3.9% 524 0