I have put together this script for recording the microphone, the desktop audio and the screen using ffmpeg:
DATE=`which date`
RESO=2560x1440
FPS=30
PRESET=ultrafast
DIRECTORY=$HOME/Video/
FILENAME=videocast`$DATE +%d%m%Y_%H.%M.%S`.mkv
ffmpeg -y -vsync 1 \
-f pulse -ac 2 -i alsa_output.pci-0000_00_1b.0.analog-stereo.monitor \
-f pulse -ac 1 -ar 25000 -i alsa_input.usb-0d8c_C-Media_USB_Headphone_Set-00-Set.analog-mono \
-filter_complex aresample=async=1,amix=duration=shortest,apad \
-f x11grab -r $FPS -s $RESO -i :0.0 \
-acodec libvorbis \
-vcodec libx264 -pix_fmt yuv420p -preset $PRESET -threads 0 \
$DIRECTORY$FILENAME
Everything is recorded and between the screen and the microphone sound there are no issues what so ever, however the desktop audio falls behind badly.
It begins in sync but gets worse over time during playback, also in ffplay. It does not matter what application playing sound: both Youtube-videos in the browser, desktop sounds and Rhythmbox (playing a couple of seconds of song then stops, wait and repeat) gets out of sync.
The terminal output complain about
"ALSA lib pcm.c:7843:(snd_pcm_recover) overrun occurred22.73 bitrate=10384.5kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred"
and similar but I do not know what that means.
Full terminal output here:
ffmpeg version 2.0.1 Copyright (c) 2000-2013 the FFmpeg developers
built on Aug 11 2013 14:52:28 with gcc 4.8.1 (GCC) 20130725 (prerelease)
configuration: --prefix=/usr --disable-debug --disable-static --enable-avresample --enable-dxva2 --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libv4l2 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --enable-pic --enable-postproc --enable-runtime-cpudetect --enable-shared --enable-swresample --enable-vdpau --enable-version3 --enable-x11grab
libavutil 52. 38.100 / 52. 38.100
libavcodec 55. 18.102 / 55. 18.102
libavformat 55. 12.100 / 55. 12.100
libavdevice 55. 3.100 / 55. 3.100
libavfilter 3. 79.101 / 3. 79.101
libavresample 1. 1. 0 / 1. 1. 0
libswscale 2. 3.100 / 2. 3.100
libswresample 0. 17.102 / 0. 17.102
libpostproc 52. 3.100 / 52. 3.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, pulse, from 'alsa_output.pci-0000_00_1b.0.analog-stereo.monitor':
Duration: N/A, start: 0.014093, bitrate: 1536 kb/s
Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Guessed Channel Layout for Input Stream #1.0 : mono
Input #1, pulse, from 'alsa_input.usb-0d8c_C-Media_USB_Headphone_Set-00-Set.analog-mono':
Duration: N/A, start: 0.006172, bitrate: 400 kb/s
Stream #1:0: Audio: pcm_s16le, 25000 Hz, mono, s16, 400 kb/s
[x11grab @ 0x218a6e0] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 2560 height: 1440
[x11grab @ 0x218a6e0] shared memory extension found
Input #2, x11grab, from ':0.0':
Duration: N/A, start: 1379021580.184321, bitrate: N/A
Stream #2:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 2560x1440, -2147483 kb/s, 30 tbr, 1000k tbn, 30 tbc
[libx264 @ 0x21ae560] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x21ae560] profile Constrained Baseline, level 5.0
[libx264 @ 0x21ae560] 264 - core 133 r2339 585324f - H.264/MPEG-4 AVC codec - Copyleft 2003-2013 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=12 lookahead_threads=2 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
Output #0, matroska, to '/home/anders/Video/videocast12092013_23.33.00.mkv':
Metadata:
encoder : Lavf55.12.100
Stream #0:0: Audio: vorbis (libvorbis) (oV[0][0] / 0x566F), 25000 Hz, mono, fltp
Stream #0:1: Video: h264 (libx264) (H264 / 0x34363248), yuv420p, 2560x1440, q=-1--1, 1k tbn, 30 tbc
Stream mapping:
Stream #0:0 (pcm_s16le) -> aresample (graph 0)
Stream #1:0 (pcm_s16le) -> amix:input1 (graph 0)
amix (graph 0) -> Stream #0:0 (libvorbis)
Stream #2:0 -> #0:1 (rawvideo -> libx264)
Press [q] to stop, [?] for help
ALSA lib pcm.c:7843:(snd_pcm_recover) overrun occurred22.73 bitrate=10384.5kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred3.22 bitrate=10423.3kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) overrun occurred25.25 bitrate=11011.0kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred5.76 bitrate=11013.7kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) overrun occurred27.25 bitrate=11175.4kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred7.76 bitrate=11168.7kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred8.24 bitrate=11176.4kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) overrun occurred55.48 bitrate=11243.8kbits/s
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
frame=12871 fps= 30 q=-1.0 Lsize= 542369kB time=00:07:09.31 bitrate=10349.3kbits/s
video:539762kB audio:2363kB subtitle:0 global headers:3kB muxing overhead 0.044476%
[libx264 @ 0x21ae560] frame I:52 Avg QP:15.46 size:725888
[libx264 @ 0x21ae560] frame P:12819 Avg QP:18.26 size: 40172
[libx264 @ 0x21ae560] mb I I16..4: 100.0% 0.0% 0.0%
[libx264 @ 0x21ae560] mb P I16..4: 2.6% 0.0% 0.0% P16..4: 18.1% 0.0% 0.0% 0.0% 0.0% skip:79.3%
[libx264 @ 0x21ae560] coded y,uvDC,uvAC intra: 57.8% 49.8% 25.3% inter: 8.9% 8.7% 2.2%
[libx264 @ 0x21ae560] i16 v,h,dc,p: 23% 29% 32% 16%
[libx264 @ 0x21ae560] i8c dc,h,v,p: 45% 28% 18% 9%
[libx264 @ 0x21ae560] kb/s:10306.26
Please help me, I am really close to get this working!
UPDATE: The desktop audio is out of sync when skipping filter_complex and microphone also, bit in a smaller amount. Using copy
instead of libvorbis
does not change anything either.