[solved]ffmpeg x11grab fail (screencast/streaming)

Question

So I decided to try and do some live streaming and quickly found a couple of not too complicated guides using ffmpeg, but I get an error and can't seem to find an explanation.
Command (one of many I've tried):
ffmpeg -f x11grab -s 1920x1080 -r 30 -i :0.0 -f alsa -ac 2 -i pulse -vcodec libx264 -vpre fast -s 1280x720 -acodec libmp3lame -ab 96k -vol 4096 -ar 22050 -threads 0 -f flv "rtmp://live.justin.tv/app/live_blablablablabla"
Output:
ffmpeg version N-37208-g01fcbdf Copyright (c) 2000-2012 the FFmpeg developers
built on Feb 7 2012 10:34:18 with gcc 4.6.2 20120120 (prerelease)
configuration: --prefix=/usr --enable-libmp3lame --enable-libvorbis --enable-libxvid --enable-libx264 --enable-libvpx --enable-libtheora --enable-libgsm --enable-libspeex --enable-postproc --enable-shared --enable-x11grab --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libschroedinger --enable-libopenjpeg --enable-librtmp --enable-libpulse --enable-gpl --enable-version3 --enable-runtime-cpudetect --disable-debug --disable-static
libavutil 51. 34.101 / 51. 34.101
libavcodec 53. 60.100 / 53. 60.100
libavformat 53. 31.100 / 53. 31.100
libavdevice 53. 4.100 / 53. 4.100
libavfilter 2. 60.100 / 2. 60.100
libswscale 2. 1.100 / 2. 1.100
libswresample 0. 6.100 / 0. 6.100
libpostproc 52. 0.100 / 52. 0.100
[x11grab @ 0x92b5e0] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 1920 height: 1080
[x11grab @ 0x92b5e0] shared memory extension found
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 142 (MIT-SHM)
Minor opcode of failed request: 4 (X_ShmGetImage)
Serial number of failed request: 11
Current serial number in output stream: 11
I've tried doing this in a multitude of ways, but the error is always the same:
[x11grab @ 0x92b5e0] shared memory extension found
X Error of failed request: BadMatch (invalid parameter attributes)
Major opcode of failed request: 142 (MIT-SHM)
Minor opcode of failed request: 4 (X_ShmGetImage)
Serial number of failed request: 11
Current serial number in output stream: 11[
Quite frankly I haven't got a clue, so please let me know if you've got an explanation.
So far the only idea I've been able to come up with is that the fact that I run openbox instead of gnome/kde, may have something to do with it. Possibly the proprietary nvidia drivers I'm using could have something to do with it as well I suppose, though I should think it rather odd.
Best regards.
Last edited by zacariaz (2012-03-10 04:45:19)

Answer 1

Wow, a lot of help and I just now got a notice on my email. How is that? Is it only send out once a day or something?
Anyway, thanks a bunch. I figured out by my self that I didn't have pulseaudio, but whether I want it or need it... Well, I haven't got a clue. I did assume that I could do it without pulse, but I'm still somewhat confused. Worst case scenario I could probably just get pulseaudio up and running, but of course it's confusing as always, messing around with openbox.
The badmatch error do not imply that the resolution is wrong (at least in my case) and is sorted out by putting the params in the proper order. It's odd but it works.
Also thanks for the preset tip. I assumed it was something like that, but the manpages are confusing at best, at least for me, so thanks again.
An no,l do not want lossless video, but my resources are limited. I suppose I misinterpreted the the option.
So to wrap it all up, it will properly be a few days before I have time to mess around with this again, but I will return whether it goes well or not.
For those who may wish to offer further advise, here's a few pointers.
I'm running on a machine with an aging core2 duo (E7400), 4GB RAM, SSD, no swap and a somewhat limited upload (1-1.5 Mbit), so there are a few issues to consider.
Any advice will be very much appreciated, but for now I'll assume that I can at least get it to work, albeit maybe not great.
Also would it be wise to encode mp3 instead of aac and how would it be done?
Best regards.
Last edited by zacariaz (2012-03-09 10:05:49)