[FFmpeg-user] Problem with astats and adrawgraph

[Paul B Mahol]

On 11/26/19, Michael Koch <astroelectronic at t-online.de> wrote:
> Am 26.11.2019 um 09:55 schrieb Carl Eugen Hoyos:
>>
>>> Am 26.11.2019 um 09:40 schrieb Michael Koch
>>> <astroelectronic at t-online.de>:
>>>
>>>> Am 26.11.2019 um 07:11 schrieb Carl Eugen Hoyos:
>>>>
>>>>> Am 25.11.2019 um 23:36 schrieb Michael Koch
>>>>> <astroelectronic at t-online.de>:
>>>>>
>>>>> [mp4 @ 00000000006288c0] Frame rate very high for a muxer not
>>>>> efficiently supporting it.
>>>>> Please consider specifying a lower framerate, a different muxer
>>>> Did you see this?
>>>> I did not read the whole thread but if your issue is a broken output
>>>> file this is the explanation.
>>>> Test with mkv or -r 25.
>>> The problem does only appear when I use two of the [astats,adrawgraph]
>>> filter chains and combine the outputs with vstack (or hstack or overlay,
>>> it's always the same problem).
>>> If I use only one [astats,adrawgraph] chain, then it works without any
>>> problems with the same input file.
>> How is this related to my suggestions?
>
> Thanks for your suggestion. Adding -r 25 does indeed solve the problem.
> Although I don't understand why it is required. The input framerate is
> 25 and it's detected correctly when I use the simpler filter chain.
>

Ah, I know why this happens, you need to use settb=1/FPS filter after vstack.
This happens because adrawgraph filter it order to not drop output
frames need to have same timebase as input audio. Otherwise you would
get different metadata values.
Also note that your FPS in this case is 48000/1024. ~= 46.xxx