ffmpeg help needed
 

Greeting Guru.

I would like to record the sound output in a file from google translate and I follow the instruction in this thread
and give me the error of Unknown input format: 'alsa'

Thanks for your kind attention

ffmpeg -f alsa -i hw:0 -ar 44100 -ac 2 -ab 128k output.mp3
ffmpeg version git-2013-08-19-818ebe9 Copyright (c) 2000-2013 the FFmpeg developers
built on Aug 19 2013 21:10:52 with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-3)
configuration: --prefix=/home/ec2-user/ffmpeg_build --extra-cflags=-I/home/ec2-user/ffmpeg_build/include --extra-ldflags=-L/home/ec2-user/ffmpeg_build/lib --bindir=/home/ec2-user/bin --extra-libs=-ldl --enable-gpl --enable-nonfree --enable-libfdk_aac --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264
libavutil 52. 42.100 / 52. 42.100
libavcodec 55. 28.100 / 55. 28.100
libavformat 55. 13.103 / 55. 13.103
libavdevice 55. 3.100 / 55. 3.100
libavfilter 3. 82.100 / 3. 82.100
libswscale 2. 5.100 / 2. 5.100
libswresample 0. 17.103 / 0. 17.103
libpostproc 52. 3.100 / 52. 3.100
Unknown input format: 'alsa'

You need to have alsa libraries installed to use. They may be missing, try running the command below.

nothing show up when I do

ldconfig -p | grep i alsa

My os is

CentOS Release 6.3 Final

I try to follow this thread

https://www.google.com/url?sa=t&rct=...50952593,d.aWc


but it gives me this error

Error: Package: alsa-kmdl-2.6.32-220.23.1.el6-1.0.24-93.el6.x86_64 (atrpms)
Requires: /boot/vmlinuz-2.6.32-220.23.1.el6.x86_64

does it matter if it is an amazon AMI so maybe it will not work ??

You must still be missing some alsa libraries and files.

Instead of installing the kernel-specific kmdl try using a generic one and see if that still throws you an error

Requires: /boot/vmlinuz-2.6.32-358.11.1.el6.centos.plus.x86_64
Error: Package: alsa-kmdl-2.6.32-220.23.1.el6-1.0.24-93.el6.x86_64 (atrpms)
Requires: /boot/vmlinuz-2.6.32-220.23.1.el6.x86_64
Error: Package: alsa-kmdl-2.6.32-358.14.1.el6.centos.plus-1.0.22.1-83.el6.x86_64 (atrpms)
Requires: /boot/vmlinuz-2.6.32-358.14.1.el6.centos.plus.x86_64
Error: Package: alsa-kmdl-2.6.32-279.22.1.el6-1.0.23-85.el6.x86_64 (atrpms)
Requires: /boot/vmlinuz-2.6.32-279.22.1.el6.x86_64
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest
[ec2-user@ec2-54-221-219-253 ~]$

I try --skip-broken but no luck

I'm wondering which version of vmlinuz you have since yum should take care of the dependencies.
First locate your vmlinuz file(s)
Then update your repos and show the active repos
Your alsa-kmdl package should match your vmlinuz kernel version.
Hope that helps...

An Amazon AMI is made for use on the Amazon EC2 service and is a virtualized environment. I really doubt that it contains sound hardware, so this will not work on this machine.
Try it on a machine that has sound hardware.