Mencoderを使用したビデオ録画

mencoderビデオを録画するために使用しようとしています。次のコマンドは次から取得されます。オンラインチュートリアル:

mencoder tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0:forceaudio:adevice=/dev/dsp -ovc lavc -oac mp3lame -lameopts cbr:br=64:mode=3 -o filename.avi

出力は次のとおりです。

MEncoder SVN-r37379 (C) 2000-2015 MPlayer Team
210 audio & 441 video codecs
success: format: 9  data: 0x0 - 0x0
TV file format detected.
Selected driver: v4l2
 name: Video 4 Linux 2 input
 author: Martin Olschewski <[email protected]>
 comment: first try, more to come ;-)
v4l2: your device driver does not support VIDIOC_G_STD ioctl, VIDIOC_G_PARM was used instead.
Selected device: UVC Camera (046d:0825)
 Capabilities:  video capture  streaming
 supported norms:
 inputs: 0 = Camera 1;
 Current input: 0
 Current format: YUYV
tv.c: norm_from_string(pal): Bogus norm parameter, setting default.
v4l2: ioctl enum norm failed: Inappropriate ioctl for device
Error: Cannot set norm!
Selected input hasn't got a tuner!
Unable to open '/dev/dsp': No such file or directory
Unable to open '/dev/dsp': No such file or directory
Unable to open '/dev/dsp': No such file or directory
v4l2: ioctl set mute failed: Invalid argument
v4l2: 0 frames successfully processed, 0 frames dropped.
============ Sorry, this file format is not recognized/supported =============
=== If this file is an AVI, ASF or MPEG stream, please contact the author! ===
Cannot open demuxer.

Exiting...
user@ArchBox:~/Dropbox$ mencoder tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0:forceaudio:ade[15838:17998:0117/045341:ERROR:cert_verify_proc_nss.cc(922)] CERT_PKIXVerifyCert for api.tldr.io failed err=-8181

これらのエラーをどのように解決できますか？