[FFmpeg-devel] avfilter/showvolume : various "fix"

[Paul B Mahol]

On 3/30/18, Martin Vignali <martin.vignali at gmail.com> wrote:
> Hello,
>
> After discussion in user mailing list,
> several patchs, trying to fix various "issue" with showvolume filter
>
> A wav example can be found here (1000 hz with -12 db, then -18 db then 0
> db) :
> https://we.tl/X6L69kEWAN
>
> Command line to test (vertical)
> ./ffmpeg -i inputFile.wav -filter_complex
> "[0:a]showvolume=w=340:h=5:o=v:f=1.:p=1.:t=0:m=p:v=0[v]"
> -map "[v]" -c:v qtrle resAudioMeter004.mov
>
> Command line to test (horizontal)
> ./ffmpeg -i inputFile.wav -filter_complex
> "[0:a]showvolume=w=340:h=5:o=h:f=1.:p=1.:t=0:m=p:v=0[v]"
> -map "[v]" -c:v qtrle resAudioMeter004.mov
>
>
>
> 001 : add comments to help to remember the orientation value inside func
>
> 002 : calculate fade only if fade option is not set to 1.
> 003 : indent
>
> 004 : clear buffer at each frame (not sure it's the best way to fix)
> with this patch the wav sample at the start of this email, show a correct
> audio meter
> (the -18 db part of the wav, is correctly display)
> 005 : indent
>
> 006 : use another scale for display (some kind of log scale), more close to
> a classic audio meter display. IMHO, it's better, but if need, i will add
> and option, for choosing the scale display.
>
> 007 : Fix doc, for orientation parameter (possible value are h or v, not
> horizontal or vertical)
>
>
> I think the result of rms mode is still not right, but need more work.
>
> Comments welcome
>
> Martin
>

I applied what I considered useful.
For different scale, please implement it as another option.

Just use f=0 if you want instant output without fading.
With some of your patches this option wouldn no longer do anything.