[FFmpeg-user] Picture jerky when screencasting?

lugoteehalt lugoteehalt at yahoo.co.uk
Sun Jun 5 03:31:24 CEST 2011


Etienne Buira wrote:
> 
> On Fri, Jun 03, 2011 at 09:14:21PM -0700, lugoteehalt wrote:
>> Great thanks.  Seems to be an exact copy.  It now works with:
> 
> Make sure of it (you can use diff -s file1 file2).
> 
>> ffmpeg -f alsa -ac 2 -i pulse -f x11grab -s cif -r 25 -s `xdpyinfo | grep
>> 'dimensions:'| awk '{print $2}'` -fpre
>> /usr/local/share/ffmpeg/libx264-lossless_ultrafast.ffpreset -i :0.0
>> ~/out.mkv
>> 
>> The picture no longer jerks on iplayer fullscreen, nor is it much
>> webcammy. 
>> But the quality, while acceptable for most things, is not high.  Colour
>> gradients are stepped for instance.  Hope this not off topic but could
>> you
>> suggest how to tweek the quality - it is a complex piece of software for
>> someone new?
> 
> The command you give is not the initial one, and here, you don't use
> libx264 at all. Use your initial command, with only -vpre changed to
> -fpre pointing to a file you know for sure is an exact copy of the
> original preset.
> Bear in mind that options ordering matters.
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> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
> 
Great thanks.  Did as you asked but the result was the same as before with 

[libx264 @ 0x9093f40] constant rate-factor is incompatible with 2pass.

in red.  The command was:

ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 25 -s 1360x768 -i :0.0 -acodec
pcm_s16le -vcodec libx264 -fpre
/usr/local/share/ffmpeg/libx264-lossless_ultrafast.ffpreset output.mkv

The preset files are the same used diff like you said.

Tried strace, don't remotely know if this is relevant but did:

grep '= -1' strace.txt
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
futex(0xbf9f2360, FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 1, NULL,
bf9f2370) = -1 EAGAIN (Resource temporarily unavailable)
access("/home/eric/.asoundrc", R_OK)    = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or
directory)
open("/home/eric/.pulse/client.conf", O_RDONLY|O_LARGEFILE) = -1 ENOENT (No
such file or directory)
read(7, 0xa3f3e10, 8)                   = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(7, 0xa3eece0, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
kill(3206, SIG_0)                       = -1 ESRCH (No such process)
send(6, "W", 1, MSG_NOSIGNAL)           = -1 ENOTSOCK (Socket operation on
non-socket)
ioctl(2, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbf9f1c38) = -1 ENOTTY
(Inappropriate ioctl for device)
ioctl(2, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbf9f1c38) = -1 ENOTTY
(Inappropriate ioctl for device)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)
stat64("output.mkv", 0xbf9f20e0)        = -1 ENOENT (No such file or
directory)
futex(0xa3edba4, FUTEX_WAIT_PRIVATE, 11, NULL) = -1 EAGAIN (Resource
temporarily unavailable)
read(8, 0xa3f2b48, 4096)                = -1 EAGAIN (Resource temporarily
unavailable)

Also strace said:

open("/usr/local/share/ffmpeg/libx264-lossless_ultrafast.ffpreset",
O_RDONLY|O_LARGEFILE) = 9

so seems like it is going to the correct preset.

Had not realised I was not using libx264 in the most recent command that
works, above.  Do not remotely know what I'm talking about but looked for
libx264 and the only files the thing can presumably find are:

/usr/lib/libx264.so.112
/usr/local/lib/libx264.a

Is it possible it simply has no libx264?  Thanks again.


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