Capture Bureau (Vidéo + Audio)

Bonjour,

j'essaie de faire une capture de mon bureau et sortir une vidéo avec audio. Je suis assez content du résultat.
Mon écran est en 1680x1050. C'est OK pour cette taille en sortie.
L'audio en sortie est en Stéréo qui je suppose est normale vu l'info donnée dans ma commande: -ac 2
J'utilise pulse. (pour l'instant).
Je visionne une vidéo HD avec un son 5.1 en sortie. Tout fonctionne normalement au niveau speakers (speaker-test -Dplug:surround51 -c6 -l1 -twav)
Le player que j'utilise est MPV et dans son fichier de configuration ao=pulse est bien présent.

INFOS:

pactl list sources | grep Name:
Name: alsa_input.pci-0000_05_01.1.analog-stereo
Name: alsa_output.pci-0000_05_02.0.analog-surround-51.monitor
Name: alsa_input.pci-0000_05_02.0.analog-stereo
 

cat /proc/asound/cards
 0 [Audigy2        ]: Audigy2 - SB Audigy 2 ZS [SB0350]
                      SB Audigy 2 ZS [SB0350] (rev.4, serial:0x20021102) at 0xe880, irq 18
 1 [Bt878          ]: Bt87x - Brooktree Bt878
                      Brooktree Bt878 at 0xfbfff000, irq 17
 

avconv -f pulse -itsoffset 00:00:02.000 -ac 2 -i $(pactl list sources | sed -n '/alsa.*monitor/s/.*: \(.*\)$/\1/p') -f x11grab -s $(xwininfo -root | grep 'geometry' | awk '{print $2;}') -r 10 -i :0.0  -c:v libx264 -qp 0 -preset ultrafast -acodec flac  -compression_level 0 Video-Monitor-$(date +%F-%H-%M-%S).mkv
 

patrick@debian:~/Bureau$ avconv -f pulse -itsoffset 00:00:02.000 -ac 2 -i $(pactl list sources | sed -n '/alsa.*monitor/s/.*: \(.*\)$/\1/p') -f x11grab -s $(xwininfo -root | grep 'geometry' | awk '{print $2;}') -r 10 -i :0.0  -c:v libx264 -qp 0 -preset ultrafast -acodec flac  -compression_level 0 Video-Monitor-$(date +%F-%H-%M-%S).mkv
avconv version 11.4-6:11.4-1~deb8u1, Copyright (c) 2000-2014 the Libav developers
  built on Jun  4 2015 19:39:02 with gcc 4.9.2 (Debian 4.9.2-10)
[pulse @ 0x20ee7c0] Estimating duration from bitrate, this may be inaccurate
Guessed Channel Layout for  Input Stream #0.0 : stereo
Input #0, pulse, from 'alsa_output.pci-0000_05_02.0.analog-surround-51.monitor':
  Duration: N/A, start: 1439185491.263747, bitrate: N/A
    Stream #0.0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
[x11grab @ 0x210cb20] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 1680 height: 1050
[x11grab @ 0x210cb20] shared memory extension  found
[x11grab @ 0x210cb20] Estimating duration from bitrate, this may be inaccurate
Input #1, x11grab, from ':0.0':
  Duration: N/A, start: 1439185491.462941, bitrate: 564480 kb/s
    Stream #1.0: Video: rawvideo, bgra, 1680x1050, 564480 kb/s, 1000k tbn, 10 tbc
[libx264 @ 0x211cf80] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64 SlowShuffle
[libx264 @ 0x211cf80] profile High 4:4:4 Predictive, level 4.0, 4:2:0 8-bit
[libx264 @ 0x211cf80] 264 - core 142 r2431 a5831aa - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://ift.tt/1cmqH4m - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=0 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=0 chroma_qp_offset=0 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=10 scenecut=0 intra_refresh=0 rc=cqp mbtree=0 qp=0
Output #0, matroska, to 'Video-Monitor-2015-08-10-07-44-51.mkv':
  Metadata:
    encoder         : Lavf56.1.0
    Stream #0.0: Video: libx264, yuv420p, 1680x1050, q=-1--1, 1k tbn, 10 tbc
    Metadata:
      encoder         : Lavc56.1.0 libx264
    Stream #0.1: Audio: flac, 48000 Hz, stereo, s16, 200 kb/s
    Metadata:
      encoder         : Lavc56.1.0 flac
Stream mapping:
  Stream #1:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #0:0 -> #0:1 (pcm_s16le (native) -> flac (native))
Press ctrl-c to stop encoding
^Cframe= 2026 fps= 10 q=0.0 Lsize=  273097kB time=202.50 bitrate=11048.0kbits/s    
video:262565kB audio:10458kB other streams:0kB global headers:0kB muxing overhead: 0.027409%
[libx264 @ 0x211cf80] frame I:9     Avg QP: 0.00  size:543511
[libx264 @ 0x211cf80] frame P:2017  Avg QP: 0.00  size:130875
[libx264 @ 0x211cf80] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x211cf80] mb P  I16..4:  7.1%  0.0%  0.0%  P16..4: 15.7%  0.0%  0.0%  0.0%  0.0%    skip:77.2%
[libx264 @ 0x211cf80] coded y,uvDC,uvAC intra: 98.0% 95.7% 95.4% inter: 15.6% 16.7% 16.6%
[libx264 @ 0x211cf80] i16 v,h,dc,p: 57% 41%  2%  0%
[libx264 @ 0x211cf80] i8c dc,h,v,p: 12% 33% 55%  1%
[libx264 @ 0x211cf80] kb/s:10616.61
Received signal 2: terminating.
patrick@debian:~/Bureau$
 

Mais voilà, si je passe l'option -ac 2 en -ac 6 pour capturer l'audio et avoir du 5.1 en sortie, je réussi en partie car le fichier dans ces caractéristiques me donne bien flac 5.1.
Mais on voit dans le terminal en rouge un défilement continu de :

[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
 

patrick@debian:~/Bureau$ avconv -f pulse -itsoffset 00:00:02.000 -ac 6 -i $(pactl list sources | sed -n '/alsa.*monitor/s/.*: \(.*\)$/\1/p') -f x11grab -s $(xwininfo -root | grep 'geometry' | awk '{print $2;}') -r 10 -i :0.0  -c:v libx264 -qp 0 -preset ultrafast -acodec flac  -compression_level 0 Video-Monitor-$(date +%F-%H-%M-%S).mkv
avconv version 11.4-6:11.4-1~deb8u1, Copyright (c) 2000-2014 the Libav developers
  built on Jun  4 2015 19:39:02 with gcc 4.9.2 (Debian 4.9.2-10)
[pulse @ 0x110f7c0] Estimating duration from bitrate, this may be inaccurate
Guessed Channel Layout for  Input Stream #0.0 : 5.1
Input #0, pulse, from 'alsa_output.pci-0000_05_02.0.analog-surround-51.monitor':
  Duration: N/A, start: 1439186951.631960, bitrate: N/A
    Stream #0.0: Audio: pcm_s16le, 48000 Hz, 6 channels, s16, 4608 kb/s
[x11grab @ 0x112db20] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 1680 height: 1050
[x11grab @ 0x112db20] shared memory extension  found
[x11grab @ 0x112db20] Estimating duration from bitrate, this may be inaccurate
Input #1, x11grab, from ':0.0':
  Duration: N/A, start: 1439186951.849089, bitrate: 564480 kb/s
    Stream #1.0: Video: rawvideo, bgra, 1680x1050, 564480 kb/s, 1000k tbn, 10 tbc
[libx264 @ 0x113df80] using cpu capabilities: MMX2 SSE2Fast SSSE3 Cache64 SlowShuffle
[libx264 @ 0x113df80] profile High 4:4:4 Predictive, level 4.0, 4:2:0 8-bit
[libx264 @ 0x113df80] 264 - core 142 r2431 a5831aa - H.264/MPEG-4 AVC codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options: cabac=0 ref=1 deblock=0:0:0 analyse=0:0 me=dia subme=0 psy=0 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=0 chroma_qp_offset=0 threads=3 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=10 scenecut=0 intra_refresh=0 rc=cqp mbtree=0 qp=0
Output #0, matroska, to 'Video-Monitor-2015-08-10-08-09-11.mkv':
  Metadata:
    encoder         : Lavf56.1.0
    Stream #0.0: Video: libx264, yuv420p, 1680x1050, q=-1--1, 1k tbn, 10 tbc
    Metadata:
      encoder         : Lavc56.1.0 libx264
    Stream #0.1: Audio: flac, 48000 Hz, 5.1, s16, 200 kb/s
    Metadata:
      encoder         : Lavc56.1.0 flac
Stream mapping:
  Stream #1:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #0:0 -> #0:1 (pcm_s16le (native) -> flac (native))
Press ctrl-c to stop encoding
Multiple frames in a packet from stream 0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
Error while decoding stream #0:0
[pcm_s16le @ 0x112d720] invalid PCM packet
Error while decoding stream #0:0
^Cframe=    4 fps=  0 q=0.0 Lsize=     927kB time=0.30 bitrate=25310.2kbits/s    
video:918kB audio:8kB other streams:0kB global headers:0kB muxing overhead: 0.091008%
[libx264 @ 0x113df80] frame I:1     Avg QP: 0.00  size:452061
[libx264 @ 0x113df80] frame P:3     Avg QP: 0.00  size:162577
[libx264 @ 0x113df80] mb I  I16..4: 100.0%  0.0%  0.0%
[libx264 @ 0x113df80] mb P  I16..4: 15.7%  0.0%  0.0%  P16..4:  9.2%  0.0%  0.0%  0.0%  0.0%    skip:75.1%
[libx264 @ 0x113df80] coded y,uvDC,uvAC intra: 84.3% 74.0% 73.8% inter: 9.1% 10.4% 10.4%
[libx264 @ 0x113df80] i16 v,h,dc,p: 64% 34%  2%  0%
[libx264 @ 0x113df80] i8c dc,h,v,p: 32% 21% 46%  1%
[libx264 @ 0x113df80] kb/s:18795.82
Received signal 2: terminating.
patrick@debian:~/Bureau$
 

Un connaisseur pourrait-il me guider sur cet option -ac 6 que je voudrais obtenir correctement
? Sur le net, je ne trouve rien sur l'option et sur ce message d'erreurs.

Capture Bureau (Vidéo + Audio)