I have a USB audio-video capture device, something used to digitize video cassettes. I want to record both the video and audio from the device to a video file that has dimensions 720x576 and video codec H.264 and good audio quality.
I am able to record video from the device using ffmpeg and I am able to see video from the device using MPlayer. I am able also to see that audio is being delivered from the device to the computer by looking at Input tab of the Sound Preferences window or by recording the audio using Audacity, however the audio gets delivered from the device apparently only when the video is being accessed using ffmpeg or MPlayer.
I have tried to get ffmpeg to record the audio and I have tried to get MPlayer to play the audio and my efforts have not been successful.
The device is "Pinnacle Dazzle DVC 90/100/101" (as returned by v4l2-ctl --list-devices). The sound cards listing shows it as "DVC100":
$ cat /proc/asound/cards
0 [PCH ]: HDA-Intel - HDA Intel PCH
HDA Intel PCH at 0x601d118000 irq 171
1 [DVC100 ]: USB-Audio - DVC100
Pinnacle Systems GmbH DVC100 at usb-0000:00:14.0-4, high speed
29 [ThinkPadEC ]: ThinkPad EC - ThinkPad Console Audio Control
ThinkPad Console Audio Control at EC reg 0x30, fw N2LHT33W
The PulseAudio listing for the device is as follows:
$ pactl list cards short
0 alsa_card.pci-0000_00_1f.3 module-alsa-card.c
14 alsa_card.usb-Pinnacle_Systems_GmbH_DVC100-01 module-alsa-card.c
The following ffmpeg command successfully records video, but records severely distorted, broken and out-of-sync audio:
ffmpeg -y -f rawvideo -f alsa -thread_queue_size 2048 -ar 48000 -i hw:0
-c:a aac -video_size 720x576 -pixel_format uyvy422 -i /dev/video2 out.mp4
The following MPlayer command successfully displays the video but does not play the audio:
mplayer -tv driver=v4l2:norm=PAL:device=/dev/video2:width=720:height=576
-ao alsa:device=hw=1.0 -vf pp=lb tv://
Now, when the above MPlayer command is running (not the ffmpeg command) and displaying the input video in a window, Audacity can be opened and set recording audio, and it records the audio from the device clearly and in good quality. While Audacity is doing this, the input device is listed in pavucontrol as "Dazzle DVC Audio Device Analogue Stereo". Equivalently, arecord can be used also to record the audio using the following command (with output shown):
$ arecord -vv -D plughw:DVC100 -fdat out.wav
Recording WAVE 'out.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Plug PCM: Hardware PCM card 1 'DVC100' device 0 subdevice 0
Its setup is:
stream : CAPTURE
access : RW_INTERLEAVED
format : S16_LE
subformat : STD
channels : 2
rate : 48000
exact rate : 48000 (48000/1)
msbits : 16
buffer_size : 24000
period_size : 6000
period_time : 125000
tstamp_mode : NONE
tstamp_type : MONOTONIC
period_step : 1
avail_min : 6000
period_event : 0
start_threshold : 1
stop_threshold : 24000
silence_threshold: 0
silence_size : 0
boundary : 6755399441055744000
appl_ptr : 0
hw_ptr : 0
Looking at the output of arecord -L, I tried a variety of audio device input names with ffmpeg and none of them seemed to work. So, for example, I tried commands like the following:
ffmpeg -y -f rawvideo -f alsa -i plughw:DVC100
-video_size 720x576 -pixel_format uyvy422 -i /dev/video2 out.mp4
And tried the following audio device names:
plughw:DVC100
plughw:CARD=DVC100,DEV=0
hw:CARD=DVC100,DEV=0
plughw:CARD=DVC100
sysdefault:CARD=DVC100
iec958:CARD=DVC100,DEV=0
dsnoop:CARD=DVC100,DEV=0
So, how might I get ffmpeg to record the audio successfully to the video file? Is there some alternative approach to this problem?
EDIT: The relevant output from the command pactl list sources is as follows:
Source #20
State: SUSPENDED
Name: alsa_input.usb-Pinnacle_Systems_GmbH_DVC100-01.analog-stereo
Description: Dazzle DVC100 Audio Device Analogue Stereo
Driver: module-alsa-card.c
Sample Specification: s16le 2ch 48000Hz
Channel Map: front-left,front-right
Owner Module: 45
Mute: no
Volume: front-left: 99957 / 153% / 11.00 dB, front-right: 99957 / 153% / 11.00 dB
balance 0.00
Base Volume: 35466 / 54% / -16.00 dB
Monitor of Sink: n/a
Latency: 0 usec, configured 0 usec
Flags: HARDWARE HW_MUTE_CTRL HW_VOLUME_CTRL DECIBEL_VOLUME LATENCY
Properties:
alsa.resolution_bits = "16"
device.api = "alsa"
device.class = "sound"
alsa.class = "generic"
alsa.subclass = "generic-mix"
alsa.name = "USB Audio"
alsa.id = "USB Audio"
alsa.subdevice = "0"
alsa.subdevice_name = "subdevice #0"
alsa.device = "0"
alsa.card = "1"
alsa.card_name = "DVC100"
alsa.long_card_name = "Pinnacle Systems GmbH DVC100 at usb-0000:00:14.0-4, high speed"
alsa.driver_name = "snd_usb_audio"
device.bus_path = "pci-0000:00:14.0-usb-0:4:1.1"
sysfs.path = "/devices/pci0000:00/0000:00:14.0/usb1/1-4/1-4:1.1/sound/card1"
udev.id = "usb-Pinnacle_Systems_GmbH_DVC100-01"
device.bus = "usb"
device.vendor.id = "2304"
device.vendor.name = "Pinnacle Systems, Inc."
device.product.id = "021a"
device.product.name = "Dazzle DVC100 Audio Device"
device.serial = "Pinnacle_Systems_GmbH_DVC100"
device.string = "front:1"
device.buffering.buffer_size = "352800"
device.buffering.fragment_size = "176400"
device.access_mode = "mmap+timer"
device.profile.name = "analog-stereo"
device.profile.description = "Analogue Stereo"
device.description = "Dazzle DVC100 Audio Device Analogue Stereo"
alsa.mixer_name = "USB Mixer"
alsa.components = "USB2304:021a"
module-udev-detect.discovered = "1"
device.icon_name = "audio-card-usb"
Ports:
analog-input-linein: Line In (priority: 8100)
Active Port: analog-input-linein
Formats:
pcm
I tested the name from this with ffmpeg (version 4.3.1, compiled with -enable-libpulse) in the following way:
ffmpeg -y -f video4linux2 -f pulse
-i alsa_input.usb-Pinnacle_Systems_GmbH_DVC100-01.analog-stereo
-video_size 720x576 -pixel_format uyvy422 -i /dev/video2 out.mp4
Unfortunately this hasn't worked.
