Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Fri, Sep 20, 2019 at 02:09:58PM +0100, Mick wrote > > I suggest you give jackd a spin. There appear to be "media-sound/jack" and "media-sound/jack2" ebuilds. Both of them are tagged "~amd64". There's also media-sound/jack-audio-connection-kit Which one(s) do I use? > It should what you want, but may I ask why you need to record off > your browser whatever youtube shows? Can't you use youtube-dl to > download the youtube video/audio? Youtube is a bad example to use. There are various other HTML5 streaming websites, which don't work with youtube-dl. Plus I also want to be able to record video games and any other desktop app in general. What I want is to "tee" the audio output so that I can record while monitoring it. -- Walter Dnes I don't run "desktop environments"; I run useful applications
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
Mick wrote: > On Thursday, 19 September 2019 15:19:57 BST Walter Dnes wrote: >> On Wed, Sep 18, 2019 at 07:57:51PM -0400, Walter Dnes wrote >> >>> I did some further digging. It appears that the instructions I >>> followed are for capture devices (USB microphones, etc). According to >>> https://trac.ffmpeg.org/wiki/Capture/ALSA if I want to record from a >>> running application, I need to load the "snd_aloop" module and mention >>> it in a local .asoundrc. According to the linux kernel config help... >>> >>> CONFIG_SND_ALOOP: >>> | Say 'Y' or 'M' to include support for the PCM loopback device. | >>> | This module returns played samples back to the user space using | >>> | the standard ALSA PCM device| >>> | >>> Oh well, there is a new kernel, so I'll build it with the module, and >>> >>> get back later to see how things work. >> That failed differently. With the local .asoundrc present, I loaded >> the snd_aloop module. It showed up as a capture device in alsamixer. >> But I had no sound on the speakers when playing Youtube. Even worse, I >> was unable to unload the snd_aloop module. When trying to do so, I got >> >> FATAL ERROR: Module in use. >> >> The normal way around that is to unload any other modules using it. >> But I have everything, except snd_aloop, built into the kernel. So >> there was nothing to unload to release snd_aloop. I ended up renaming >> .asoundrc, and rebooting. > I suggest you give jackd a spin. It should what you want, but may I ask why > you need to record off your browser whatever youtube shows? Can't you use > youtube-dl to download the youtube video/audio? > I use a add-on to download videos from sites youtube-dl doesn't work with. I think it is called Video Download Helper. It works pretty well. It also allows you to pick what resolution you want if there is more than one available. My DSL isn't fast enough for HD videos but I can use the download tool to select a HD stream when I want to. Just another option. Dale :-) :-)
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Thursday, 19 September 2019 15:19:57 BST Walter Dnes wrote: > On Wed, Sep 18, 2019 at 07:57:51PM -0400, Walter Dnes wrote > > > I did some further digging. It appears that the instructions I > > followed are for capture devices (USB microphones, etc). According to > > https://trac.ffmpeg.org/wiki/Capture/ALSA if I want to record from a > > running application, I need to load the "snd_aloop" module and mention > > it in a local .asoundrc. According to the linux kernel config help... > > > > CONFIG_SND_ALOOP: > > | Say 'Y' or 'M' to include support for the PCM loopback device. | > > | This module returns played samples back to the user space using | > > | the standard ALSA PCM device| > > | > > Oh well, there is a new kernel, so I'll build it with the module, and > > > > get back later to see how things work. > > That failed differently. With the local .asoundrc present, I loaded > the snd_aloop module. It showed up as a capture device in alsamixer. > But I had no sound on the speakers when playing Youtube. Even worse, I > was unable to unload the snd_aloop module. When trying to do so, I got > > FATAL ERROR: Module in use. > > The normal way around that is to unload any other modules using it. > But I have everything, except snd_aloop, built into the kernel. So > there was nothing to unload to release snd_aloop. I ended up renaming > .asoundrc, and rebooting. I suggest you give jackd a spin. It should what you want, but may I ask why you need to record off your browser whatever youtube shows? Can't you use youtube-dl to download the youtube video/audio? -- Regards, Mick signature.asc Description: This is a digitally signed message part.
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Wed, Sep 18, 2019 at 07:57:51PM -0400, Walter Dnes wrote > > I did some further digging. It appears that the instructions I > followed are for capture devices (USB microphones, etc). According to > https://trac.ffmpeg.org/wiki/Capture/ALSA if I want to record from a > running application, I need to load the "snd_aloop" module and mention > it in a local .asoundrc. According to the linux kernel config help... > > CONFIG_SND_ALOOP: > > | Say 'Y' or 'M' to include support for the PCM loopback device. | > | This module returns played samples back to the user space using | > | the standard ALSA PCM device| > > Oh well, there is a new kernel, so I'll build it with the module, and > get back later to see how things work. That failed differently. With the local .asoundrc present, I loaded the snd_aloop module. It showed up as a capture device in alsamixer. But I had no sound on the speakers when playing Youtube. Even worse, I was unable to unload the snd_aloop module. When trying to do so, I got FATAL ERROR: Module in use. The normal way around that is to unload any other modules using it. But I have everything, except snd_aloop, built into the kernel. So there was nothing to unload to release snd_aloop. I ended up renaming .asoundrc, and rebooting. -- Walter Dnes I don't run "desktop environments"; I run useful applications
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Thursday, 19 September 2019 03:45:59 BST Adam Carter wrote: > On Thu, Sep 19, 2019 at 9:58 AM Walter Dnes wrote: > > On Wed, Sep 18, 2019 at 09:14:44PM +0100, Mick wrote > > > > > Yes, you only have one card 0. The first device (default) is the > > > > analogue. > > > > > What does 'arecord -l' show? > > > > List of CAPTURE Hardware Devices > > card 0: PCH [HDA Intel PCH], device 0: CX20641 Analog [CX20641 Analog] > > > > Subdevices: 1/1 > > Subdevice #0: subdevice #0 > > > > card 0: PCH [HDA Intel PCH], device 2: CX20641 Alt Analog [CX20641 Alt > > Analog] > > > > Subdevices: 1/1 > > Subdevice #0: subdevice #0 > > > > I don't run "desktop environments"; I run useful applications > > I think for what you are trying to do, the capture devices/mic are not > relevant - there will be no signal on them. The playback device have the > signal, and ffmpeg needs to capture of those signals. > > > -i hw:0,1 > > > > or > > > > -i hw:0,0,1 > > Both fail with No such file or directory. > > FWIW audacity has a drop down list of the output devices, and on my system > they're all shown as hw:X,Y. There's no hw:X or hw:X,Y,Z. I also notice > that the same hw:X,Y is used for both an playback and capture device, so i > guess that means that '-i hw:0.1' is using the hw:0,1 capture device, which > for you has no signal, and therefore ffmpeg doesnt capture anything. > > Hopefully there's some way to capture the output digitally, but if not, a > cable connecting the analogue out to the analogue in should work. I'm sorry - I had misunderstood the original requirement! I thought Walter wanted to capture the whole desktop (not a single application window within it) and record voice along with it - not the sound of the application. The command shown does that - records a screencast of the desktop and voice from the microphone. Having read the first email to the list once more, I can confirm the ffmpeg command will work, but only with the audio loopback configured. It should also work nicely with jackd - which along with qjackctl would be my preference. https://qjackctl.sourceforge.io/qjackctl-index.html -- Regards, Mick signature.asc Description: This is a digitally signed message part.
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Thu, Sep 19, 2019 at 9:58 AM Walter Dnes wrote: > On Wed, Sep 18, 2019 at 09:14:44PM +0100, Mick wrote > > > Yes, you only have one card 0. The first device (default) is the > analogue. > > > > What does 'arecord -l' show? > > List of CAPTURE Hardware Devices > card 0: PCH [HDA Intel PCH], device 0: CX20641 Analog [CX20641 Analog] > Subdevices: 1/1 > Subdevice #0: subdevice #0 > card 0: PCH [HDA Intel PCH], device 2: CX20641 Alt Analog [CX20641 Alt > Analog] > Subdevices: 1/1 > Subdevice #0: subdevice #0 > I don't run "desktop environments"; I run useful applications > > I think for what you are trying to do, the capture devices/mic are not relevant - there will be no signal on them. The playback device have the signal, and ffmpeg needs to capture of those signals. > -i hw:0,1 > > or > > -i hw:0,0,1 Both fail with No such file or directory. FWIW audacity has a drop down list of the output devices, and on my system they're all shown as hw:X,Y. There's no hw:X or hw:X,Y,Z. I also notice that the same hw:X,Y is used for both an playback and capture device, so i guess that means that '-i hw:0.1' is using the hw:0,1 capture device, which for you has no signal, and therefore ffmpeg doesnt capture anything. Hopefully there's some way to capture the output digitally, but if not, a cable connecting the analogue out to the analogue in should work.
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Wed, Sep 18, 2019 at 09:14:44PM +0100, Mick wrote > Yes, you only have one card 0. The first device (default) is the analogue. > > What does 'arecord -l' show? List of CAPTURE Hardware Devices card 0: PCH [HDA Intel PCH], device 0: CX20641 Analog [CX20641 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 2: CX20641 Alt Analog [CX20641 Alt Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 > Let's try something else, specifying a sub-device. What happens with: > > -i hw:0,1 > > or > > -i hw:0,0,1 Both fail with No such file or directory. > The ffmpeg output seems noisy and you're getting alsa buffer > over/under runs. Try this: > > -f alsa -thread_queue_size 2048 That gets rid of the warnings and Alsa xrun messages. But still no help. I did some further digging. It appears that the instructions I followed are for capture devices (USB microphones, etc). According to https://trac.ffmpeg.org/wiki/Capture/ALSA if I want to record from a running application, I need to load the "snd_aloop" module and mention it in a local .asoundrc. According to the linux kernel config help... CONFIG_SND_ALOOP: | Say 'Y' or 'M' to include support for the PCM loopback device. | | This module returns played samples back to the user space using | | the standard ALSA PCM device| Oh well, there is a new kernel, so I'll build it with the module, and get back later to see how things work. -- Walter Dnes I don't run "desktop environments"; I run useful applications
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Wednesday, 18 September 2019 19:03:02 BST Walter Dnes wrote: > On Wed, Sep 18, 2019 at 11:16:41AM +0100, Mick wrote > > > On Wednesday, 18 September 2019 10:10:16 BST Walter Dnes wrote: > > > ffmpeg -f alsa -ac 2 -i hw:0 -video_size 1920x1080 -framerate 25 -f > > > x11grab > > > -i :0.0 output.mp4 > > > > The above should work, but only if your active audio card has Card > > ID 0. If your PC uses HDMI as the first card you'll need to adjust > > /etc/asound.conf accordingly to switch to your analogue audio device, > > or perhaps try hw:1 in the above incantation instead. > > "aplay -l" outputs > > List of PLAYBACK Hardware Devices > card 0: PCH [HDA Intel PCH], device 0: CX20641 Analog [CX20641 Analog] > Subdevices: 0/1 > Subdevice #0: subdevice #0 > card 0: PCH [HDA Intel PCH], device 3: Generic Digital [Generic Digital] > Subdevices: 1/1 > Subdevice #0: subdevice #0 > > If I try "hw:1" it dies immediately (No such file or directory) Yes, you only have one card 0. The first device (default) is the analogue. What does 'arecord -l' show? > No /etc/asound.conf or $HOME/.asoundrc on my system. But there is a > large (9596 bytes) /usr/share/alsa/alsa.conf You would need to create a asound.conf card to switch from the HDMI to analogue as the default card, if your hardware was like mine - but it is not. Let's try something else, specifying a sub-device. What happens with: -i hw:0,1 or -i hw:0,0,1 Adjust the above according to what arecord shows. > The console I launch ffmpeg from shows a lot of stuff like... > > [alsa @ 0x559c480c94c0] ALSA buffer xrun. > frame= 2337 fps= 25 q=28.0 size= 11008kB time=00:01:33.05 bitrate= > 969.1kbits/frame= 2350 fps= 25 q=28.0 size= 11008kB time=00:01:33.05 > bitrate= 969.1kbits/frame= 2362 fps= 25 q=28.0 size= 11008kB > time=00:01:33.05 bitrate= 969.1kbits/frame= 2375 fps= 25 q=28.0 size= > 11008kB time=00:01:33.05 bitrate= 969.1kbits/[alsa @ 0x559c480c94c0] ALSA > buffer xrun. frame= 2387 fps= 25 q=28.0 size= 11264kB time=00:01:35.21 > bitrate= 969.2kbits/frame= 2400 fps= 25 q=28.0 size= 11264kB > time=00:01:35.21 bitrate= 969.2kbits/frame= 2412 fps= 25 q=28.0 size= > 11264kB time=00:01:35.21 bitrate= 969.2kbits/frame= 2425 fps= 25 q=28.0 > size= 11264kB time=00:01:35.21 bitrate= 969.2kbits/[alsa @ > 0x559c480c94c0] ALSA buffer xrun. > > When I playback with mplayer and exit, there's a bunch of diagnostics. > Towards the end it says... > > == > Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders > AUDIO: 48000 Hz, 2 ch, floatle, 0.1 kbit/0.00% (ratio: 17->384000) > Selected audio codec: [ffaac] afm: ffmpeg (FFmpeg AAC (MPEG-2/MPEG-4 Audio)) > == > AO: [alsa] 48000Hz 2ch floatle (4 bytes per sample) > Starting playback... > Could not find matching colorspace - retrying with -vf scale... > Opening video filter: [scale] > Movie-Aspect is undefined - no prescaling applied. > [swscaler @ 0x7f28e3f20100]bicubic scaler, from yuv444p to yuv420p using > MMXEXT VO: [xv] 1920x1080 => 1920x1080 Planar YV12 > A: 38.9 V: 35.9 A-V: 3.003 ct: 3.588 0/ 0 17% 12% 0.0% 0 0 > Timing looks severely broken, resetting > A: 38.9 V: 39.6 A-V: -0.717 ct: 3.805 0/ 0 17% 12% 0.0% 0 0 > > The message about timing may be a clue. I think timing issues should not affect the audio (it could be out of sync with the video). The ffmpeg output seems noisy and you're getting alsa buffer over/under runs. Try this: -f alsa -thread_queue_size 2048 or use 1024, if 2048 takes too long to allow the recording to start. This should do away with the message 'ALSA buffer xrun'. The mplayer output shows you have an audio stream alright and I bet ffprobe will show the same. Unless you're trying to record frequencies not audible by the human ear, I can think of one more thing. Maximise the Mic's capture volume and any boost settings available. Once I was trying to perform a voice recording using the built in microphone on a lesser quality laptop, not understanding why I couldn't hear any audio on playback. Well, I had to push the capture volume all the way up to 100% before I heard audio being played back. What a relief! I thought I was going deaf. LOL!! HTH. -- Regards, Mick signature.asc Description: This is a digitally signed message part.
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Wed, Sep 18, 2019 at 11:16:41AM +0100, Mick wrote > On Wednesday, 18 September 2019 10:10:16 BST Walter Dnes wrote: > > > > ffmpeg -f alsa -ac 2 -i hw:0 -video_size 1920x1080 -framerate 25 -f x11grab > > -i :0.0 output.mp4 > > The above should work, but only if your active audio card has Card > ID 0. If your PC uses HDMI as the first card you'll need to adjust > /etc/asound.conf accordingly to switch to your analogue audio device, > or perhaps try hw:1 in the above incantation instead. "aplay -l" outputs List of PLAYBACK Hardware Devices card 0: PCH [HDA Intel PCH], device 0: CX20641 Analog [CX20641 Analog] Subdevices: 0/1 Subdevice #0: subdevice #0 card 0: PCH [HDA Intel PCH], device 3: Generic Digital [Generic Digital] Subdevices: 1/1 Subdevice #0: subdevice #0 If I try "hw:1" it dies immediately (No such file or directory) No /etc/asound.conf or $HOME/.asoundrc on my system. But there is a large (9596 bytes) /usr/share/alsa/alsa.conf > Also, check your Mic is not muted with alsamixer, or your desktop GUI > equivalent. Enabled them, but no difference. > Did you try USE="alsa, -speex"? "emerge -pv mlayer" shows that speex is disabled. The console I launch ffmpeg from shows a lot of stuff like... [alsa @ 0x559c480c94c0] ALSA buffer xrun. frame= 2337 fps= 25 q=28.0 size= 11008kB time=00:01:33.05 bitrate= 969.1kbits/frame= 2350 fps= 25 q=28.0 size= 11008kB time=00:01:33.05 bitrate= 969.1kbits/frame= 2362 fps= 25 q=28.0 size= 11008kB time=00:01:33.05 bitrate= 969.1kbits/frame= 2375 fps= 25 q=28.0 size= 11008kB time=00:01:33.05 bitrate= 969.1kbits/[alsa @ 0x559c480c94c0] ALSA buffer xrun. frame= 2387 fps= 25 q=28.0 size= 11264kB time=00:01:35.21 bitrate= 969.2kbits/frame= 2400 fps= 25 q=28.0 size= 11264kB time=00:01:35.21 bitrate= 969.2kbits/frame= 2412 fps= 25 q=28.0 size= 11264kB time=00:01:35.21 bitrate= 969.2kbits/frame= 2425 fps= 25 q=28.0 size= 11264kB time=00:01:35.21 bitrate= 969.2kbits/[alsa @ 0x559c480c94c0] ALSA buffer xrun. When I playback with mplayer and exit, there's a bunch of diagnostics. Towards the end it says... == Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders AUDIO: 48000 Hz, 2 ch, floatle, 0.1 kbit/0.00% (ratio: 17->384000) Selected audio codec: [ffaac] afm: ffmpeg (FFmpeg AAC (MPEG-2/MPEG-4 Audio)) == AO: [alsa] 48000Hz 2ch floatle (4 bytes per sample) Starting playback... Could not find matching colorspace - retrying with -vf scale... Opening video filter: [scale] Movie-Aspect is undefined - no prescaling applied. [swscaler @ 0x7f28e3f20100]bicubic scaler, from yuv444p to yuv420p using MMXEXT VO: [xv] 1920x1080 => 1920x1080 Planar YV12 A: 38.9 V: 35.9 A-V: 3.003 ct: 3.588 0/ 0 17% 12% 0.0% 0 0 Timing looks severely broken, resetting A: 38.9 V: 39.6 A-V: -0.717 ct: 3.805 0/ 0 17% 12% 0.0% 0 0 The message about timing may be a clue. -- Walter Dnes I don't run "desktop environments"; I run useful applications
Re: [gentoo-user] [OT] ffmpeg video+audio capture question
On Wednesday, 18 September 2019 10:10:16 BST Walter Dnes wrote: > I'm trying to do a video+audio capture of my desktop, e.g. a Youtube > video playing, or whatever. I've got video capture working, but not > audio. I've compiled ffmpeg with both "alsa" and "oss" USE flags and > tried the commands... > > ffmpeg -f alsa -ac 2 -i hw:0 -video_size 1920x1080 -framerate 25 -f x11grab > -i :0.0 output.mp4 The above should work, but only if your active audio card has Card ID 0. If your PC uses HDMI as the first card you'll need to adjust /etc/asound.conf accordingly to switch to your analogue audio device, or perhaps try hw:1 in the above incantation instead. Also, check your Mic is not muted with alsamixer, or your desktop GUI equivalent. > ffmpeg -f oss -i /dev/dsp -video_size 1920x1080 -framerate 25 -f x11grab -i > :0.0 output.mp4 I don't have oss experience and as I understand it pre-OSS4 is mono only(?), but again the above ought to work, as long as there is no clash with alsa. You may need jackd to plug in/out the requisite input devices and sinks - too complicated for just a simple audio recording. > In both case the video capture works, and ffmpeg claims to be > capturing audio, but I don't get any audio capture at all. What am I > doing wrong? Any more USE flags to set? Did you try USE="alsa, -speex"? -- Regards, Mick signature.asc Description: This is a digitally signed message part.
