1 |
luis jure <ljc@××××××××××××.uy> [11-12-10 13:28]: |
2 |
> on 2011-12-09 at 13:55 Michael Mol wrote: |
3 |
> |
4 |
> >I couldn't tell you if it's necessarily "good", but Audacity has a |
5 |
> >noise filter. |
6 |
> |
7 |
> that's exactly what i was about to reply. |
8 |
> |
9 |
> and if you want to try a CLI tool, sox provides a similar utility. |
10 |
> |
11 |
> noiseprof [profile-file] |
12 |
> Calculate a profile of the audio for use in noise reduction. |
13 |
> See the description of the noisered effect for details. |
14 |
> |
15 |
> noisered [profile-file [amount]] |
16 |
> Reduce noise in the audio signal by profiling and filtering. This |
17 |
> effect is moderately effective at removing consistent background |
18 |
> noise such as hiss or hum. To use it, first run SoX with the |
19 |
> noise‐ prof effect on a section of audio that ideally would contain |
20 |
> silence but in fact contains noise - such sections are typically |
21 |
> found at the beginning or the end of a recording. noiseprof will |
22 |
> write out a noise profile to profile-file, or to stdout if no |
23 |
> profile-file or if `-' is given. E.g. sox speech.wav -n trim 0 1.5 |
24 |
> noiseprof speech.noise-profile To actually remove the noise, run |
25 |
> SoX again, this time with the noisered effect; noisered will |
26 |
> reduce noise according to a noise profile (which was generated by |
27 |
> noiseprof), from profile-file, or from stdin if no profile-file or |
28 |
> if `-' is given. E.g. sox speech.wav cleaned.wav noisered |
29 |
> speech.noise-profile 0.3 How much noise should be removed is |
30 |
> specified by amount-a number between 0 and 1 with a default of |
31 |
> 0.5. Higher numbers will remove more noise but present a greater |
32 |
> likelihood of removing wanted components of the audio signal. |
33 |
> Before replacing an original recording with a noise-reduced |
34 |
> version, experiment with different amount values to find the |
35 |
> optimal one for your audio; use headphones to check that you are |
36 |
> happy with the results, paying particular attention to quieter |
37 |
> sections of the audio. |
38 |
> |
39 |
> On most systems, the two stages - profiling and reduction |
40 |
> - can be combined using a pipe, e.g. sox noisy.wav -n |
41 |
> trim 0 1 noiseprof | play noisy.wav noisered |
42 |
> |
43 |
> never compared the results, if you do, i for one would be very interested |
44 |
> in your experience. |
45 |
> |
46 |
> IMO, it's much better to remove noise by small amounts in successive |
47 |
> passes (taking a new profile each time, of course), than trying to remove |
48 |
> too much noise in one pass. |
49 |
> |
50 |
> let us know how it went! |
51 |
> |
52 |
> lj |
53 |
> |
54 |
|
55 |
Thanks for all your replies ! :) |
56 |
|
57 |
|
58 |
In the net I read about audacities denoise and that it is not /that/ |
59 |
good. I didnt checked it myself though. At the same place "Gnome Wave |
60 |
Cleaner" (gwc) was recommended instead of audacities denoiser. On its |
61 |
homepage there is also linked a downloadable book about digital signal |
62 |
processing (34 chapters) which looks quite proefessional. |
63 |
|
64 |
Gwc is ... not the youngest software and development seems to have |
65 |
stopped. Now I trying to get this beast working under Gentoo. |
66 |
The alsa-problem with "snd_pcm_write" can be workarounded ;) with |
67 |
installing pulseaudio and playing the sound with gwc via pulseaudio |
68 |
instead of with alsa directly. |
69 |
While compiling gwc you need to enable alsa and pulseaudio with |
70 |
./configure. |
71 |
|
72 |
When gwc is running I wll report more. |
73 |
See my other posting sent just before this one. |
74 |
|
75 |
Gwc is the first denoise I will try. |
76 |
|
77 |
Have a nice, denoised weekend! :) |
78 |
Best regards, |
79 |
mcc |