[FFmpeg-devel] [PATCH] avfilter/showwaves: add single_pic option

Clément Bœsch u at pkh.me
Thu Dec 25 23:57:47 CET 2014

On Thu, Dec 25, 2014 at 09:07:04PM +0100, Lars Kiesow wrote:
> Hi Clément,


> this is the patch I was looking for... thanks!


> I've applied the patch against the current master and had a first
> glimps at it. It works well. I've tried it successfully on a two minute
> audio file as well as on a several hour long lecture recording.
> One thing I noticed was that with large input files, it was a good idea
> to downsample the input before passing it into the showwaves filter as
> you will need a lot less memory. Though, of course, it still worked with
> the original sample rate. A sample rate of 8000 Hz was what I would
> suggest to use. Dropping the rate too low would change the waveform.
> 8000 Hz looked ok.

Yeah, obviously, hence the warning in the documentation.

> One improvement that's left is to choose the colors, but that's
> something for another patch and you can archive that quite easily with
> some of the other filters already.

Yeah you can just apply a filter on top of it. Adding a color option can
be annoying because of the grayscale logic when you do not use
split_channels option.

> Regards,
> Lars

BTW, please do not top post on this mailing list.

Clément B.
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