#9461 closed defect (worksforme)
Showpectrumpic: scale doesn't work anymore
| Reported by: | RKleinert | Owned by: | |
|---|---|---|---|
| Priority: | normal | Component: | avfilter |
| Version: | git-master | Keywords: | |
| Cc: | Blocked By: | ||
| Blocking: | Reproduced by developer: | no | |
| Analyzed by developer: | no |
Description (last modified by )
Summary of the bug:
In https://trac.ffmpeg.org/ticket/8919 I had adressed a bug that would mess up the scaling of the frequency-axis in showspectrum() and showspectrumpic() when choosing a starting-frequency that is not zero. This bug is now supposedly fixed.
Now after the fix Showspectrum() seems to work just fine. On the other hand showspectrumpic() won't work anymore at all when used with my prevousily used arguments. Especialy defining an output size (which is crucial) seems to lead to a never ending loop where ffmepg doesn't get anywhere. My batch-script doesn't end and no output is written.
Secondly I noticed, that the argument "legend" doesn't default to 0 (as it states in the doc) but to 1 - so the legend and axes are always enabled if not actively disabled.
How to reproduce:
The Sample Code:
ffmpeg -i input.wav -filter_complex "showspectrumpic=size=700x400:mode=combined:color=rainbow:scale=sqrt:fscale=log:legend=1:start=500:stop=20000" output.png
leads into an endless loop. Whereas the code without the size-argument:
ffmpeg -i input.wav -filter_complex "showspectrumpic=mode=combined:color=rainbow:scale=sqrt:fscale=log:legend=1:start=500:stop=20000" output.png
does the trick (although it takes quite some time to run)
ffmpeg version 2021-10-18-git-d04c005021-full built from gyan.dev
I supplied the input.wav file which is a test-sample with a 1kHz-Sinewave
Attachments (1)
Change History (7)
by , 3 years ago
comment:1 by , 3 years ago
| Description: | modified (diff) |
|---|---|
| Summary: | Showpectrum scale doesn't work anymore → Showpectrumpic: scale doesn't work anymore |
follow-up: 3 comment:2 by , 3 years ago
It still works just fine, just no longer trims upper frequencies if user have supplied non power of 2 height or width (for vertical orientation).
Contrary to your claims, it does not loop forever, it just executes really slow because of current very slow and naive fft implementation for sizes you set.
comment:3 by , 3 years ago
Replying to Elon Musk:
It still works just fine, just no longer trims upper frequencies if user have supplied non power of 2 height or width (for vertical orientation).
Contrary to your claims, it does not loop forever, it just executes really slow because of current very slow and naive fft implementation for sizes you set.
Thanks for your quick reply. As I don't really have insight in the workings of the function could you tell me, which sizes would work and which won't? So far I've gotten it to work with 1024x768 for instance. 1000x768 works as well, but 1024x700 doesn't. So it works with a height of 768 but not 700 although 768 is not a power of 2.
comment:4 by , 3 years ago
It works for width you set, not for output width with included legend pad.
comment:5 by , 3 years ago
| Resolution: | → worksforme |
|---|---|
| Status: | new → closed |
comment:6 by , 17 months ago
Speed for sizes other than power of 2 have dramatically improved in latest git version.
Also there is new filter, showcwt that supports log and other scales natively.
1kHz-Sinewave for testing