Dithering in 'aresample' has no effect

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

Dithering in 'aresample' has no effect

林至善
Hi all,

I am trying to compare the wav file with/without dithering, but it seems
that my command doesn't work. Here's my command line and console output:

[1] *ffmpeg -i Fsweep96.wav -af
aresample=8000:dither_scale=0:dither_method=0 Fsweep8_NoDither.wav* (I
would assume this would generate a file *without *dither,
Fsweep8_NoDither.wav)
[image: 1.JPG]

[2]* ffmpeg -i Fsweep96.wav -af
aresample=8000:dither_scale=1:dither_method=rectangular Fsweep8_Dither.wav *(I
would assume this would generate a file *with *dither, Fsweep8_Dither.wav)
[image: 2.JPG]

But the output file Fsweep8_NoDither.wav/Fsweep8_Dither.wav are totally the
same, both the wav header and the PCM value(it should be
increased/decreased by a small value like +-1 in Fsweep8_Dither.wav).

The question is :
*It seems that my command doesn't work. Is that correct? If I want to
enable/disable dithering, what command should I use?
*Command line mentioned above uses the default resampler, 'swr'. Can I
enable/disable dithering when using resampler 'soxr'?

Thanks a lot for any help!


LCS

_______________________________________________
ffmpeg-user mailing list
[hidden email]
http://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".

1.JPG (205K) Download Attachment
2.JPG (224K) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: Dithering in 'aresample' has no effect

Michael Niedermayer-2
On Tue, Dec 04, 2018 at 11:56:18AM +0800, 林至善 wrote:

> Hi all,
>
> I am trying to compare the wav file with/without dithering, but it seems
> that my command doesn't work. Here's my command line and console output:
>
> [1] *ffmpeg -i Fsweep96.wav -af
> aresample=8000:dither_scale=0:dither_method=0 Fsweep8_NoDither.wav* (I
> would assume this would generate a file *without *dither,
> Fsweep8_NoDither.wav)
> [image: 1.JPG]
>
> [2]* ffmpeg -i Fsweep96.wav -af
> aresample=8000:dither_scale=1:dither_method=rectangular Fsweep8_Dither.wav *(I
> would assume this would generate a file *with *dither, Fsweep8_Dither.wav)
> [image: 2.JPG]
>
> But the output file Fsweep8_NoDither.wav/Fsweep8_Dither.wav are totally the
> same, both the wav header and the PCM value(it should be
> increased/decreased by a small value like +-1 in Fsweep8_Dither.wav).
>
> The question is :
> *It seems that my command doesn't work. Is that correct? If I want to
> enable/disable dithering, what command should I use?
try choosing a more precisse internal sample format, for example:
"-internal_sample_fmt fltp"

[...]


--
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle

_______________________________________________
ffmpeg-user mailing list
[hidden email]
http://ffmpeg.org/mailman/listinfo/ffmpeg-user

To unsubscribe, visit link above, or email
[hidden email] with subject "unsubscribe".

signature.asc (188 bytes) Download Attachment