Thomas Winter
2011-Mar-24 20:58 UTC
[asterisk-users] Sox and bad quality when converting to 8 kHz
Hi list, I have an 44100 Hz file with human voice, stereo with 16Bit. When convertig this to 8 kHz, mono I loose a lot of quality and have some ground noise. I tried several sox options but without success. Can somebody help.... best regards Thomas
Danny Nicholas
2011-Mar-24 21:05 UTC
[asterisk-users] Sox and bad quality when converting to 8 kHz
-----Original Message----- From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Thomas Winter Sent: Thursday, March 24, 2011 3:59 PM To: asterisk-users at lists.digium.com Subject: [asterisk-users] Sox and bad quality when converting to 8 kHz Hi list, I have an 44100 Hz file with human voice, stereo with 16Bit. When convertig this to 8 kHz, mono I loose a lot of quality and have some ground noise. I tried several sox options but without success. Can somebody help.... best regards Thomas Make sure your "voice talent" is recording in mono or a single stereo channel. This command works for me under these conditions: Sox file44.wav -r 8000 -c 1 -s file8.wav
Steve Edwards
2011-Mar-24 21:13 UTC
[asterisk-users] Sox and bad quality when converting to 8 kHz
On Thu, 24 Mar 2011, Thomas Winter wrote:> I have an 44100 Hz file with human voice, stereo with 16Bit. > When convertig this to 8 kHz, mono I loose a lot of quality and have > some ground noise. I tried several sox options but without success. > Can somebody help....What does your command line look like? I use this with good results: sox "${INPUT}" -c 1 -s -w -r 8000 "${OUTPUT}" -- Thanks in advance, ------------------------------------------------------------------------- Steve Edwards sedwards at sedwards.com Voice: +1-760-468-3867 PST Newline Fax: +1-760-731-3000
Ishfaq Malik
2011-Mar-25 08:53 UTC
[asterisk-users] Sox and bad quality when converting to 8 kHz
On Thu, 2011-03-24 at 21:58 +0100, Thomas Winter wrote:> Hi list, > I have an 44100 Hz file with human voice, stereo with 16Bit. > When convertig this to 8 kHz, mono I loose a lot of quality and have > some ground noise. I tried several sox options but without success. > Can somebody help.... > > best regards Thomas > >The best results I have had have been by using the following mpg123 -q -w "${TEMP}" "${INPUT}" sox "${TEMP}" -c 1 -s -r 8000 "${OUTPUT}" Regards Ish -- Ishfaq Malik Software Developer PackNet Ltd Office: 0161 660 3062
Steve Underwood
2011-Mar-25 13:45 UTC
[asterisk-users] Sox and bad quality when converting to 8 kHz
On 03/25/2011 04:58 AM, Thomas Winter wrote:> Hi list, > I have an 44100 Hz file with human voice, stereo with 16Bit. > When convertig this to 8 kHz, mono I loose a lot of quality and have > some ground noise. I tried several sox options but without success. > Can somebody help.... > > best regards ThomasYou really need to remove the bass end of the spectrum before downsampling to 8k/s. uLaw/ALaw sound pretty muddy and horrible if you don't do that, and the other common 8k/s codecs don't sound any better. Jean-Marc Valin wrote a little filtering utility for this purpose. Steve
Mark Deneen
2011-Mar-28 14:20 UTC
[asterisk-users] Sox and bad quality when converting to 8 kHz
On Thu, Mar 24, 2011 at 4:58 PM, Thomas Winter <thowinter at googlemail.com> wrote:> Hi list, > I have an 44100 Hz file with human voice, stereo with 16Bit. > When convertig this to 8 kHz, mono I loose a lot of quality and have > some ground noise. I tried several sox options but without success. > Can somebody help.... >I have had good results with this: sox in.wav -r 8000 -c 1 out.wav highpass 500 lowpass 4000 resample -ql Play around with the high and low pass numbers because they might need to be changed depending on the properties of your recordings. -M