stalls / pauses in video every 30 seconds.
|Reported by:||TroyWorks||Owned by:|
|Version:||unspecified||Keywords:||pause, stall, freeze, capture, xllgrab, xvfb|
|Blocking:||Reproduced by developer:||no|
|Analyzed by developer:||no|
Summary of the bug:
We are using fllgrab for screencapture in the cloud.
Every 30 seconds for about 1-2 seconds in duration, are pauses in only the video. Audio and Audio Video sync is perfectly fine despite stalls.
EXAMPLEs: with a four color frame counter drop frame test case
WITH lossless x264 dropped frames around 25-26 and significant stall errors at 30 and 60 seconds
We get this trying even different options, like keyframes, bitrate.
WITH flashsrv, which shows similar pause around 23 and 53 seconds, and indicates it's not a libx264 specific issue.
This is running on an instance with 16 vcpu + 16gb ram, on the Amazon AWS there is no noticeable background process that we can see at least that would explain
It happens regardless if it's debian, or ubuntu.
How to reproduce:
Using XVFB open chrome with this test
START CAPTURE USING:
ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 30 -s 1024x768 -i :0.0 -acodec libvorbis -ar 44100 -vcodec libx264 -preset ultrafast -gp 0 -threads 0 ffg4.mkv
ffmpeg version 0.11.1 Copyright (c) 2000-2012 the FFmpeg developers
built on Jun 26 2012 12:42:06 with gcc 4.7.1
configuration: --arch=x86_64 --enable-avfilter --enable-vdpau --enable-bzlib --enable-libgsm --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --disable-stripping --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libdc1394 --enable-shared --disable-static --enable-libx264 --enable-libvpx --enable-libmp3lame --enable-libfaac --enable-nonfree --enable-libopencore-amrwb --enable-libopencore-amrnb --enable-version3
Ubuntu (several versions) and Debian, with hardware accelerated virtualization (HVM). We've also tried several xwindows and xvfb/xenth with same issue.