$ ffmpeg -loglevel verbose -f x11grab -s "1920x1080" -i :0.0 -aq 128k \
 -f alsa -ac 2 -i pulse -vcodec libx264 -crf 30 \
 -acodec libmp3lame -ar 44100 -threads 2 \
 -f flv out.mkv

ffmpeg version 0.11.1 Copyright (c) 2000-2012 the FFmpeg developers
  built on Jun  9 2012 13:50:13 with gcc 4.7.0 20120505 (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-libv4l2 --enable-gpl --enable-version3 --enable-runtime-cpudetect --disable-debug --disable-static
  libavutil      51. 54.100 / 51. 54.100
  libavcodec     54. 23.100 / 54. 23.100
  libavformat    54.  6.100 / 54.  6.100
  libavdevice    54.  0.100 / 54.  0.100
  libavfilter     2. 77.100 /  2. 77.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[x11grab @ 0x1568220] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 1920 height: 1080
[x11grab @ 0x1568220] shared memory extension found
[x11grab @ 0x1568220] Estimating duration from bitrate, this may be inaccurate
Input #0, x11grab, from ':0.0':
  Duration: N/A, start: 1344968991.991578, bitrate: 1988667 kb/s
    Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1920x1080, 1988667 kb/s, 29.97 tbr, 1000k tbn, 29.97 tbc
[alsa @ 0x157b8a0] Estimating duration from bitrate, this may be inaccurate
Guessed Channel Layout for  Input Stream #1.0 : stereo
Input #1, alsa, from 'pulse':
  Duration: N/A, start: 1344968992.026006, bitrate: 1536 kb/s
    Stream #1:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
File 'out.mkv' already exists. Overwrite ? [y/N] y
w:1920 h:1080 pixfmt:bgr0 tb:1/1000000 sar:0/1 sws_param:flags=2
[buffersink @ 0x1565280] No opaque field provided
[format @ 0x1566ee0] auto-inserting filter 'auto-inserted scaler 0' between the filter 'src' and the filter 'format'
[scale @ 0x1565440] w:1920 h:1080 fmt:bgr0 sar:0/1 -> w:1920 h:1080 fmt:yuv420p sar:0/1 flags:0x4
[abuffer @ 0x15f2580] tb:1/1000000 samplefmt:s16 samplerate: 48000 ch layout:0x3
[aformat @ 0x163f580] auto-inserting filter 'auto-inserted resampler 0' between the filter 'src' and the filter 'aformat'
[aresample @ 0x161f5c0] chl:stereo fmt:s16 r:48000Hz -> chl:stereo fmt:s16 r:44100Hz
[libx264 @ 0x1563b40] using cpu capabilities: MMX2 SSE2Fast FastShuffle SSEMisalign LZCNT
[libx264 @ 0x1563b40] profile High, level 4.0
[libx264 @ 0x1563b40] 264 - core 124 - H.264/MPEG-4 AVC codec - Copyleft 2003-2012 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=30.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, flv, to 'out.mkv':
  Metadata:
    encoder         : Lavf54.6.100
    Stream #0:0: Video: h264 ([7][0][0][0] / 0x0007), yuv420p, 1920x1080, q=-1--1, 1k tbn, 29.97 tbc
    Stream #0:1: Audio: mp3 ([2][0][0][0] / 0x0002), 44100 Hz, stereo, s16
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo -> libx264)
  Stream #1:0 -> #0:1 (pcm_s16le -> libmp3lame)
Press [q] to stop, [?] for help
*** drop!16 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s    
*** drop!32 fps= 30 q=0.0 size=       0kB time=00:00:00.00 bitrate=   0.0kbits/s dup=0 drop=1    
DTS 27417033, next:27417119 st:0 invalid dropping0:00:25.49 bitrate= 428.3kbits/s dup=0 drop=2    
PTS 27417033, next:27417119 invalid dropping st:0
DTS 27579850, next:27579970 st:0 invalid dropping
PTS 27579850, next:27579970 invalid dropping st:0
DTS 33899007, next:33899075 st:0 invalid dropping0:00:31.23 bitrate= 382.2kbits/s dup=0 drop=2    
PTS 33899007, next:33899075 invalid dropping st:0
DTS 44107651, next:44107722 st:0 invalid dropping0:00:41.50 bitrate= 366.4kbits/s dup=0 drop=2    
PTS 44107651, next:44107722 invalid dropping st:0
DTS 49376019, next:49376220 st:0 invalid dropping0:00:47.44 bitrate= 344.8kbits/s dup=0 drop=2    
PTS 49376019, next:49376220 invalid dropping st:0
DTS 64479227, next:64479259 st:0 invalid dropping0:01:00.62 bitrate= 396.8kbits/s dup=0 drop=2    
PTS 64479227, next:64479259 invalid dropping st:0
DTS 78840186, next:78840216 st:0 invalid dropping0:01:15.17 bitrate= 416.6kbits/s dup=0 drop=2    
PTS 78840186, next:78840216 invalid dropping st:0