[MEncoder-users] x264 file playback is too slow!

The Wanderer inverseparadox at comcast.net
Thu Mar 23 00:47:29 CET 2006

Raphael wrote:

> Corey Hickey wrote:
>> Raphael wrote:
>>> How do you get mencoder to output the audio in a format another
>>> audio encoder can use?
>>> mencoder k3b_image.iso -oac pcm  -ovc frameno  -endpos 120 -o
>>> k3b.wav
>>> is not usable by oggenc for example.
>> That's because it's not really a wave file, even though you call it
>> one. It's still an avi file.
>> $ mplayer k3b_image.iso -ao pcm:file=k3b.wav \ -vc null -vo null -benchmark
> Thanks. I tried that method first but it has two problems.
> 1) I don't see how to do the equivalent of -endpos 120

Add '-frames X', where X is '<FPS of source file> * 120'.

> and/join
> 2) It runs very slowly and is generally rather odd. Here is the full
> mplayer -v output attached. See how it complains that I don't have
> -vo null etc.

No, I don't see where it does that.

The only messages I see involving the word 'null' are standard,
unremarkable (if overly verbose) status information. The only
complaining messages I see in the initialization section are the ones
involving trying to detect various container formats and failing on the
first several (which makes sense, since the file isn't in any of those
formats). The only message I see in the initialization section which you
might - or might not - want to pay any attention to is the informational
one about the "waveheader" suboption.

> and then says my system is too slow to play the file!

This is quite strange, since with '-vo null' and '-vc null' you have
eliminated two of the biggest CPU-hogging parts of playback. The only
remaining plausible cause I can think of offhand is slow media - in
other words, that the drive you are reading the file from is not
providing the data to MPlayer quickly enough, and MPlayer's internal
buffers are emptying out. To work around this, the only thing I know of
which you can do which is not too complicated for me to go over on a
mailing list is play around with the '-cache' option.

>            ************************************************
>            **** Your system is too SLOW to play this!  ****
>            ************************************************
> Possible reasons, problems, workarounds:
> - Most common: broken/buggy _audio_ driver

This is no longer remotely true. (There has been discussion of revamping
and/or removing this "system too slow" message, but nothing has ever
gotten very far.) The most common reason by far, in my experience (both
playing things for myself and reading others' reports) is:

>   - 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.

this. The second most common, of course, is "slow CPU", but as I've
noted above that doesn't seem likely to be the case here.

       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.

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