[FFmpeg-user] Awful audio distortion with line input capture

[MrNice]

Hello,

I want to record audio from line input with ffmpeg.
I have a player connected to the line input and run the below command.

I get the file but there is an awful distortion even when I reduce the
recording level with PulseAudio Volume Control and Mate Volume Control.
Direct listening is good.
I tried with Audacity and gnome-sound-recorder V 3.4.0, sound is good.

My system is Asrock 970 Extrem4 MOBO
Fedora 20 Mate 1.6.2
Kernel 3.14.5-200.fc20.x86_64

Could you help me to find out what could do this?

Many thanks

====================
$ ffmpeg -f alsa -channel_layout stereo -i hw:0,0 -vn -b:a 320k
Documents/test_`date +%Y%m%d_%H%M`.mp3
ffmpeg version 2.1.4 Copyright (c) 2000-2014 the FFmpeg developers
  built on Feb 25 2014 08:24:47 with gcc 4.8.2 (GCC) 20131212 (Red Hat
4.8.2-7)
  configuration: --prefix=/usr --bindir=/usr/bin
--datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg
--libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64
--optflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
-fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches
-m64 -mtune=generic' --enable-bzlib --disable-crystalhd --enable-frei0r
--enable-gnutls --enable-libass --enable-libcdio --enable-libcelt
--enable-libdc1394 --disable-indev=jack --enable-libfreetype
--enable-libgsm --enable-libmp3lame --enable-openal --enable-libopencv
--enable-libopenjpeg --enable-libopus --enable-libpulse
--enable-libschroedinger --enable-libsoxr --enable-libspeex
--enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvpx
--enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter
--enable-avresample --enable-postproc --enable-pthreads --disable-static
--enable-shared --enable-gpl --disable-debug --disable-stripping
--shlibdir=/usr/lib64 --enable-runtime-cpudetect
  libavutil      52. 48.101 / 52. 48.101
  libavcodec     55. 39.101 / 55. 39.101
  libavformat    55. 19.104 / 55. 19.104
  libavdevice    55.  5.100 / 55.  5.100
  libavfilter     3. 90.100 /  3. 90.100
  libavresample   1.  1.  0 /  1.  1.  0
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
  libpostproc    52.  3.100 / 52.  3.100
Input #0, alsa, from 'hw:0,0':
  Duration: N/A, start: 1402662681.666032, bitrate: 1536 kb/s
    Stream #0:0: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s
Output #0, mp3, to 'Documents/test_20140613_1331.mp3':
  Metadata:
    TSSE            : Lavf55.19.104
    Stream #0:0: Audio: mp3 (libmp3lame), 48000 Hz, stereo, s16p, 320 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le -> libmp3lame)
Press [q] to stop, [?] for help
size=     399kB time=00:00:10.17 bitrate= 321.5kbits/s
video:0kB audio:398kB subtitle:0 global headers:0kB muxing overhead
0.246324%
=====================

More info
======================
$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: SB [HDA ATI SB], device 0: ALC892 Analog [ALC892 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: SB [HDA ATI SB], device 1: ALC892 Digital [ALC892 Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 7: HDMI 1 [HDMI 1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: SB [HDA ATI SB], device 0: ALC892 Analog [ALC892 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: SB [HDA ATI SB], device 2: ALC892 Alt Analog [ALC892 Alt Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

=======================