FFmpeg registra l'output video ma non l'output audio

[Sargon6]

Salve a tutti, sono Sargon6.
Volendo creare un video di ciò che compare sullo schermo, pensavo di usare FFmpeg, ed ho fatto una ricerca in tal senso.
Mi sono quindi imbattuto in questa pagina web:
https://computer-acquisti.com/blog/come-...st-ffmpeg/
che sembrava fare il caso mio, ma non funziona.
Se impartisco il comando
ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 25 -s 1366x768 -i :0.0 -vcodec libx264 -vpre lossless_ultrafast -crf 22 -acodec libmp3lame -ar 44100 -ab 126k -threads 3 screencast.mp4
non produce alcun video, e l'output del terminale è il seguente:

Codice:

lmde3c@asus-f555y:/mnt/Dati2/Video/Schermo01$ ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 25 -s 1366x768 -i :0.0 -vcodec libx264 -vpre lossless_ultrafast -crf 22 -acodec libmp3lame -ar 44100 -ab 126k -threads 3 screencast.mp4
ffmpeg version 3.3.9 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
  configuration: --disable-decoder=amrnb --disable-decoder=libopenjpeg --disable-mips32r2 --disable-mips32r6 --disable-mips64r6 --disable-mipsdsp --disable-mipsdspr2 --disable-mipsfpu --disable-msa --disable-libopencv --disable-podpages --disable-stripping --enable-avfilter --enable-avresample --enable-gcrypt --enable-gnutls --enable-gpl --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libfdk-aac --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libilbc --enable-libkvazaar --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx265 --enable-libxvid --enable-libzvbi --enable-nonfree --enable-opengl --enable-openssl --enable-postproc --enable-pthreads --enable-shared --enable-version3 --incdir=/usr/include/x86_64-linux-gnu --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --toolchain=hardened --enable-frei0r --enable-chromaprint --enable-libx264 --enable-libiec61883 --enable-libdc1394 --enable-vaapi --disable-opencl --enable-libmfx --disable-altivec --shlibdir=/usr/lib/x86_64-linux-gnu
  libavutil      55. 58.100 / 55. 58.100
  libavcodec    57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter    6. 82.100 /  6. 82.100
  libavresample  3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample  2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, alsa, from 'pulse':
  Duration: N/A, start: 1595247455.114958, bitrate: 1536 kb/s
    Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
[x11grab @ 0x555e4ffddd80] Stream #0: not enough frames to estimate rate; consider increasing probesize
Input #1, x11grab, from ':0.0':
  Duration: N/A, start: 1595247455.158403, bitrate: N/A
    Stream #1:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1366x768, 25 fps, 1000k tbr, 1000k tbn, 1000k tbc
File for preset 'lossless_ultrafast' not found
lmde3c@asus-f555y:/mnt/Dati2/Video/Schermo01$

Se invece impartisco il comando
ffmpeg -f alsa -ac 2 -i pulse -f x11grab -r 25 -s 1366x768 -i :0.0 -vcodec libx264 -crf 22 -acodec libmp3lame -ar 44100 -ab 126k -threads 3 screencast.mp4
ottengo un video senza audio.

Avevo provato anche coi comandi
ffmpeg -video_size 1366x768 -framerate 25 -f x11grab -i :0.0+0,0 -f pulse -ac 2 -i default output01.mkv # registra audio e video
e
ffmpeg -video_size 1366x768 -framerate 25 -f x11grab -i :0.0+0,0 -f alsa -ac 2 -i default output02.mkv # registra audio e video
trovati in un'altra pagina WEB; con entrambi registro ciò che appare sullo schermo del PC, ma, riproducendo il file multimediale così ottenuto, non trovo traccia del sonoro (effetti grafici o altro).
Come risolvo?

[dxgiusti]

ffmpeg -f x11grab -s $(xdpyinfo | grep dimensions | awk '{print $2;}') -i :0.0 -f alsa -i default output.mp4

ho inserito il comando per registrare audio nella stringa per registrare il video. fonte

[stonehenge]

Ciao
A me non funzionano nessuno dei comandi dati.I file li crea ma non partono.
Poi come si ferma? Si chiude brutalmente il terminale?
ok

Codice:

Premere q o CTRL+C in qualsiasi momento per interrompere lo screencast

Adesso funziona.
PS.Accertarsi che il volume di ingresso della nostra scheda audio sia ad un livello accettabile (non muto).

[Sargon6]

Ho lanciato

Codice:

lmde3c@asus-f555y:/mnt/Dati2/Video/Schermo01$ ffmpeg -f x11grab -s $(xdpyinfo | grep dimensions | awk '{print $2;}') -i :0.0 -f alsa -i default output03.mp4
ffmpeg version 3.3.9 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
  configuration: --disable-decoder=amrnb --disable-decoder=libopenjpeg --disable-mips32r2 --disable-mips32r6 --disable-mips64r6 --disable-mipsdsp --disable-mipsdspr2 --disable-mipsfpu --disable-msa --disable-libopencv --disable-podpages --disable-stripping --enable-avfilter --enable-avresample --enable-gcrypt --enable-gnutls --enable-gpl --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libfdk-aac --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libilbc --enable-libkvazaar --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libx265 --enable-libxvid --enable-libzvbi --enable-nonfree --enable-opengl --enable-openssl --enable-postproc --enable-pthreads --enable-shared --enable-version3 --incdir=/usr/include/x86_64-linux-gnu --libdir=/usr/lib/x86_64-linux-gnu --prefix=/usr --toolchain=hardened --enable-frei0r --enable-chromaprint --enable-libx264 --enable-libiec61883 --enable-libdc1394 --enable-vaapi --disable-opencl --enable-libmfx --disable-altivec --shlibdir=/usr/lib/x86_64-linux-gnu
  libavutil      55. 58.100 / 55. 58.100
  libavcodec    57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter    6. 82.100 /  6. 82.100
  libavresample  3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample  2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[x11grab @ 0x55e688f35c40] Stream #0: not enough frames to estimate rate; consider increasing probesize
Input #0, x11grab, from ':0.0':
  Duration: N/A, start: 1595278963.165009, bitrate: N/A
    Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1366x768, 29.97 fps, 1000k tbr, 1000k tbn, 1000k tbc
Guessed Channel Layout for Input Stream #1.0 : stereo
Input #1, alsa, from 'default':
  Duration: N/A, start: 1595278963.296309, bitrate: 1536 kb/s
    Stream #1:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  Stream #1:0 -> #0:1 (pcm_s16le (native) -> aac (native))
Press [q] to stop, [?] for help
[swscaler @ 0x55e688f71aa0] Warning: data is not aligned! This can lead to a speedloss
No pixel format specified, yuv444p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[libx264 @ 0x55e688f621e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX BMI1 SlowPshufb
[libx264 @ 0x55e688f621e0] profile High 4:4:4 Predictive, level 3.2, 4:4:4 8-bit
[libx264 @ 0x55e688f621e0] 264 - core 150 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - 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=4 threads=6 lookahead_threads=1 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=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[alsa @ 0x55e688f3ff20] Thread message queue blocking; consider raising the thread_queue_size option (current value: 8)
Output #0, mp4, to 'output03.mp4':
  Metadata:
    encoder        : Lavf57.71.100
    Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv444p(progressive), 1366x768, q=-1--1, 29.97 fps, 30k tbn, 29.97 tbc
    Metadata:
      encoder        : Lavc57.89.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1: Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, fltp, 128 kb/s
    Metadata:
      encoder        : Lavc57.89.100 aac
[x11grab @ 0x55e688f35c40] Thread message queue blocking; consider raising the thread_queue_size option (current value: 8)
Past duration 0.691154 too large
Past duration 0.919609 too large
frame=  16 fps=0.0 q=0.0 size=      0kB time=00:00:00.00 bitrate=N/A dup=2 droframe=  37 fps= 37 q=0.0 size=      0kB time=00:00:00.00 bitrate=N/A dup=2 droframe=  49 fps= 32 q=0.0 size=      0kB time=00:00:00.00 bitrate=N/A dup=2 droframe=  60 fps= 29 q=29.0 size=    160kB time=00:00:00.23 bitrate=5569.4kbits/Past duration 0.609947 too large
Past duration 0.959221 too large
frame=  75 fps= 29 q=29.0 size=    332kB time=00:00:00.74 bitrate=3640.6kbits/frame=  94 fps= 30 q=29.0 size=    338kB time=00:00:01.36 bitrate=2025.1kbits/frame=  112 fps= 31 q=29.0 size=    346kB time=00:00:01.96 bitrate=1440.2kbits/frame=  130 fps= 32 q=29.0 size=    354kB time=00:00:02.56 bitrate=1129.8kbits/frame=  145 fps= 31 q=29.0 size=    368kB time=00:00:03.09 bitrate= 976.0kbits/frame=  161 fps= 31 q=29.0 size=    374kB time=00:00:03.60 bitrate= 850.8kbits/frame=  175 fps= 31 q=29.0 size=    380kB time=00:00:04.07 bitrate= 764.5kbits/frame=  190 fps= 31 q=29.0 size=    385kB time=00:00:04.57 bitrate= 689.8kbits/frame=  206 fps= 31 q=29.0 size=    393kB time=00:00:05.10 bitrate= 630.4kbits/frame=  221 fps= 31 q=29.0 size=    549kB time=00:00:05.61 bitrate= 801.1kbits/frame=  234 fps= 30 q=29.0 size=    551kB time=00:00:06.03 bitrate= 747.3kbits/frame=  250 fps= 30 q=29.0 size=    558kB time=00:00:06.57 bitrate= 696.0kbits/frame=  265 fps= 29 q=29.0 size=    561kB time=00:00:07.08 bitrate= 649.1kbits/Past duration 0.684654 too large
Past duration 0.624748 too large
Past duration 0.827690 too large
frame=  280 fps= 29 q=29.0 size=    566kB time=00:00:07.57 bitrate= 612.6kbits/Past duration 0.686028 too large
Past duration 0.988091 too large
frame=  292 fps= 29 q=29.0 size=    569kB time=00:00:07.97 bitrate= 584.0kbits/Past duration 0.743401 too large
frame=  299 fps= 28 q=29.0 size=    571kB time=00:00:08.21 bitrate= 569.4kbits/Past duration 0.693352 too large
frame=  306 fps= 27 q=29.0 size=    571kB time=00:00:08.44 bitrate= 554.4kbits/frame=  314 fps= 27 q=29.0 size=    577kB time=00:00:08.70 bitrate= 542.6kbits/frame=  324 fps= 26 q=29.0 size=    579kB time=00:00:09.04 bitrate= 524.4kbits/frame=  334 fps= 25 q=29.0 size=    581kB time=00:00:09.38 bitrate= 507.5kbits/frame=  354 fps= 26 q=29.0 size=    583kB time=00:00:10.04 bitrate= 475.2kbits/frame=  370 fps= 26 q=29.0 size=    585kB time=00:00:10.57 bitrate= 452.8kbits/frame=  399 fps= 27 q=29.0 size=    613kB time=00:00:11.54 bitrate= 434.8kbits/frame=  426 fps= 28 q=29.0 size=    629kB time=00:00:12.44 bitrate= 414.0kbits/frame=  448 fps= 28 q=29.0 size=    700kB time=00:00:13.17 bitrate= 435.1kbits/frame=  468 fps= 28 q=29.0 size=    708kB time=00:00:13.84 bitrate= 418.9kbits/frame=  491 fps= 29 q=29.0 size=    710kB time=00:00:14.61 bitrate= 398.1kbits/frame=  515 fps= 29 q=29.0 size=    714kB time=00:00:15.41 bitrate= 379.4kbits/frame=  534 fps= 29 q=29.0 size=    719kB time=00:00:16.04 bitrate= 367.0kbits/frame=  556 fps= 29 q=29.0 size=    722kB time=00:00:16.78 bitrate= 352.6kbits/frame=  566 fps= 29 q=29.0 size=    723kB time=00:00:17.11 bitrate= 346.1kbits/Past duration 0.732811 too large
frame=  578 fps= 29 q=29.0 size=    725kB time=00:00:17.51 bitrate= 339.2kbits/Past duration 0.609978 too large
Past duration 0.929497 too large
frame=  596 fps= 28 q=29.0 size=    726kB time=00:00:18.11 bitrate= 328.4kbits/Past duration 0.604149 too large
Past duration 0.950188 too large
frame=  613 fps= 29 q=29.0 size=    794kB time=00:00:18.68 bitrate= 348.3kbits/frame=  635 fps= 29 q=29.0 size=    795kB time=00:00:19.41 bitrate= 335.6kbits/frame=  651 fps= 29 q=29.0 size=    930kB time=00:00:19.95 bitrate= 381.8kbits/frame=  676 fps= 29 q=29.0 size=    943kB time=00:00:20.79 bitrate= 371.3kbits/frame=  700 fps= 29 q=29.0 size=    951kB time=00:00:21.58 bitrate= 360.7kbits/Past duration 0.776817 too large
Past duration 0.707756 too large
Past duration 0.836266 too large
Past duration 0.667503 too large
frame=  722 fps= 30 q=29.0 size=    966kB time=00:00:22.32 bitrate= 354.6kbits/Past duration 0.828575 too large
Past duration 0.880363 too large
Past duration 0.787102 too large
Past duration 0.738731 too large
Past duration 0.647545 too large
frame=  736 fps= 30 q=29.0 size=    979kB time=00:00:22.80 bitrate= 351.5kbits/Past duration 0.860222 too large
frame=  750 fps= 30 q=29.0 size=    984kB time=00:00:23.25 bitrate= 346.5kbits/Past duration 0.792900 too large
Past duration 0.638451 too large
frame=  764 fps= 30 q=29.0 size=    986kB time=00:00:23.72 bitrate= 340.4kbits/Past duration 0.677269 too large
frame=  779 fps= 30 q=29.0 size=    989kB time=00:00:24.22 bitrate= 334.5kbits/frame=  798 fps= 30 q=29.0 size=    992kB time=00:00:24.85 bitrate= 327.1kbits/Past duration 0.865471 too large
Past duration 0.695580 too large
frame=  809 fps= 29 q=29.0 size=    1002kB time=00:00:25.22 bitrate= 325.5kbits/Past duration 0.649834 too large
Past duration 0.927452 too large
Past duration 0.735710 too large
frame=  830 fps= 29 q=29.0 size=    1018kB time=00:00:25.92 bitrate= 321.7kbits/Past duration 0.634026 too large
frame=  852 fps= 30 q=29.0 size=    1080kB time=00:00:26.66 bitrate= 331.8kbits/Past duration 0.743584 too large
Past duration 0.840782 too large
frame=  871 fps= 30 q=29.0 size=    1086kB time=00:00:27.29 bitrate= 326.1kbits/Past duration 0.637169 too large
Past duration 0.911736 too large
Past duration 0.908165 too large
Past duration 0.660362 too large
Past duration 0.740379 too large
frame=  886 fps= 30 q=29.0 size=    1188kB time=00:00:27.79 bitrate= 350.2kbits/Past duration 0.911369 too large
Past duration 0.820488 too large
Past duration 0.940239 too large
Past duration 0.874687 too large
frame=  905 fps= 30 q=29.0 size=    1198kB time=00:00:28.43 bitrate= 345.1kbits/Past duration 0.683311 too large
Past duration 0.731529 too large
Past duration 0.998802 too large
frame=  915 fps= 30 q=29.0 size=    1199kB time=00:00:28.76 bitrate= 341.4kbits/frame=  931 fps= 30 q=29.0 size=    1206kB time=00:00:29.31 bitrate= 337.1kbits/Past duration 0.867699 too large
frame=  944 fps= 30 q=29.0 size=    1210kB time=00:00:29.73 bitrate= 333.3kbits/frame=  953 fps= 29 q=29.0 size=    1211kB time=00:00:30.03 bitrate= 330.3kbits/frame=  960 fps= 29 q=29.0 size=    1212kB time=00:00:30.27 bitrate= 327.9kbits/frame=  971 fps= 29 q=29.0 size=    1220kB time=00:00:30.63 bitrate= 326.3kbits/frame=  985 fps= 29 q=29.0 size=    1232kB time=00:00:31.09 bitrate= 324.7kbits/frame= 1002 fps= 29 q=29.0 size=    1237kB time=00:00:31.66 bitrate= 320.0kbits/frame= 1014 fps= 28 q=29.0 size=    1240kB time=00:00:32.06 bitrate= 316.7kbits/frame= 1023 fps= 28 q=29.0 size=    1278kB time=00:00:32.36 bitrate= 323.4kbits/frame= 1039 fps= 28 q=29.0 size=    1284kB time=00:00:32.89 bitrate= 319.7kbits/frame= 1048 fps= 27 q=29.0 size=    1341kB time=00:00:33.19 bitrate= 330.9kbits/frame= 1057 fps= 27 q=29.0 size=    1341kB time=00:00:33.50 bitrate= 328.0kbits/frame= 1082 fps= 27 q=29.0 size=    1384kB time=00:00:34.33 bitrate= 330.2kbits/frame= 1106 fps= 26 q=29.0 size=    1453kB time=00:00:35.13 bitrate= 338.8kbits/frame= 1140 fps= 26 q=29.0 size=    1498kB time=00:00:36.26 bitrate= 338.4kbits/frame= 1151 fps= 26 q=29.0 size=    1629kB time=00:00:36.63 bitrate= 364.2kbits/frame= 1171 fps= 26 q=29.0 size=    1675kB time=00:00:37.30 bitrate= 367.9kbits/frame= 1230 fps= 26 q=29.0 size=    1679kB time=00:00:39.27 bitrate= 350.1kbits/frame= 1264 fps= 26 q=29.0 size=    1768kB time=00:00:40.40 bitrate= 358.5kbits/frame= 1316 fps= 26 q=29.0 size=    1771kB time=00:00:42.14 bitrate= 344.2kbits/frame= 1334 fps= 26 q=29.0 size=    1782kB time=00:00:42.74 bitrate= 341.6kbits/frame= 1368 fps= 26 q=29.0 size=    1785kB time=00:00:43.87 bitrate= 333.3kbits/frame= 1435 fps= 26 q=29.0 size=    1816kB time=00:00:46.11 bitrate= 322.6kbits/frame= 1469 fps= 26 q=29.0 size=    2062kB time=00:00:47.24 bitrate= 357.5kbits/frame= 1511 fps= 26 q=29.0 size=    2065kB time=00:00:48.64 bitrate= 347.7kbits/frame= 1527 fps= 26 q=29.0 size=    2099kB time=00:00:49.18 bitrate= 349.7kbits/frame= 1558 fps= 27 q=29.0 size=    2122kB time=00:00:50.21 bitrate= 346.2kbits/More than 1000 frames duplicated
frame= 1647 fps= 27 q=-1.0 Lsize=    2417kB time=00:00:54.85 bitrate= 361.0kbits/s dup=1013 drop=2 speed=0.883x   
video:2331kB audio:14kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 3.064659%
[libx264 @ 0x55e688f621e0] frame I:8    Avg QP:15.42  size: 92375
[libx264 @ 0x55e688f621e0] frame P:419  Avg QP:20.32  size:  3477
[libx264 @ 0x55e688f621e0] frame B:1220  Avg QP:32.36  size:  156
[libx264 @ 0x55e688f621e0] consecutive B-frames:  0.8%  1.0%  1.1% 97.1%
[libx264 @ 0x55e688f621e0] mb I  I16..4: 37.3% 37.0% 25.7%
[libx264 @ 0x55e688f621e0] mb P  I16..4:  1.3%  1.2%  0.8%  P16..4:  1.4%  0.3%  0.1%  0.0%  0.0%    skip:94.8%
[libx264 @ 0x55e688f621e0] mb B  I16..4:  0.1%  0.1%  0.0%  B16..8:  1.5%  0.0%  0.0%  direct: 0.0%  skip:98.3%  L0:44.8% L1:54.9% BI: 0.3%
[libx264 @ 0x55e688f621e0] 8x8 transform intra:37.0% inter:59.4%
[libx264 @ 0x55e688f621e0] coded y,u,v intra: 24.6% 16.2% 15.4% inter: 0.1% 0.1% 0.0%
[libx264 @ 0x55e688f621e0] i16 v,h,dc,p: 54% 42%  1%  2%
[libx264 @ 0x55e688f621e0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 16% 40%  1%  2%  1%  3%  1%  2%
[libx264 @ 0x55e688f621e0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 33% 30% 14%  3%  4%  4%  5%  3%  4%
[libx264 @ 0x55e688f621e0] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0x55e688f621e0] ref P L0: 64.0%  6.1% 23.3%  6.6%
[libx264 @ 0x55e688f621e0] ref B L0: 63.8% 34.7%  1.5%
[libx264 @ 0x55e688f621e0] ref B L1: 93.7%  6.3%
[libx264 @ 0x55e688f621e0] kb/s:347.45
[aac @ 0x55e688f63680] Qavg: 65536.000
lmde3c@asus-f555y:/mnt/Dati2/Video/Schermo01$

sono passato da una finestra all'altra, ho aperto firefox, ho aperto un video che aveva un audio che io ho sentito distintamente, poi, dopo un po', ho premito il tasto [q] per terminare la registrazione.
Quando ho cliccato sul video così ottenuto, ho potuto vederlo, ma non sentivo nè gli effetti sonori del passaggio da una finestra all'altra, nè l'audio del video visualizzato durante la registrazione.
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Effettivamente ho dovuto attivare il "volume in ingresso"...
Ora sento tutto, compreso l'audio del televisore acceso che è entrato nel PC dal microfono incorporato...
Questa non me l'aspettavo...
Ora che lo so, agirò di conseguenza.

[stonehenge]

Bene
E' una forza questo ffmpeg, sembra una cosa da niente quando lo installi  ma invece può fare tutto.
Dalle immagini alla musica hai video una grande scoperta per me.

[Sargon6]

Ok, ho verificato: se prima, da
[Volume] > [Impostazioni audio] > [Ingresso]
si verifica che l'ingresso sia attivo, ognuno dei tre comandi

Codice:

ffmpeg -video_size 1366x768 -framerate 25 -f x11grab -i :0.0+0,0 -f pulse -ac 2 -i default outputVideo01.MP4 # registra audio e video

ffmpeg -video_size 1366x768 -framerate 25 -f x11grab -i :0.0+0,0 -f alsa -ac 2 -i default outputVideo02.MP4 # registra audio e video

ffmpeg -f x11grab -s $(xdpyinfo | grep dimensions | awk '{print $2;}') -i :0.0 -f alsa -i default outputVideo03.MP4 # registra audio e video

funziona perfettamente.
Ma come faccio ad escludere l'ingresso del microfono integrato, dall'audio registrato con ciascuno di questi 3 comandi?