I used a Flip Ultra HD which has an excelent audio quality. Now I bought a Sanyo SH1 which records audio which some background "hiss" audio (shame on Sanyo, bad built-in microphone).
Is there a way to remove the background "hiss" audio in Kdenlive? It seems sox can do that:
noiseprof [profile-file]
noisered profile-file [threshold]
Noise reduction filter with profiling. This filter is moderately effective at removing consistent background noise such as hiss or hum. To use it, first
run the noiseprof effect on a section of silence (that is, a section which contains nothing but noise). The noiseprof effect will print a noise profile to
profile-fire-fR, or to stdout if no profile-file is specified. If there is sound output on stdout then the profile will next be directed to stderr.
To actually remove the noise, run SoX again with the noisered filter. The filter needs one argument, profile-file, which contains the noise profile from
noiseprof. thershold specifies how much noise should be removed, and may be between 0 and 1 with a default of 0.5. Higher values will remove more noise
but present a greater possibility of distorting the desired audio signal. Experiment with different threshold values to find the optimal one for your
sample.
