[FFmpeg-user] toggle between two streams

[Michael Koch]

Am 03.09.2021 um 15:09 schrieb Paul B Mahol:
> On Fri, Sep 3, 2021 at 3:07 PM Michael Koch <astroelectronic at t-online.de>
> wrote:
>
>> Am 03.09.2021 um 14:21 schrieb Michael Koch:
>>> I have two video streams and want to toggle between them in 1 second
>>> intervals. I did try this command:
>>>
>>> ffmpeg -i in1.mp4 -i in2.mp4 -lavfi streamselect=map='mod(t,2)' -t 30
>>> out.mp4
>>>
>>> This doesn't work because streamselect doesn't accept expressions.
>>> Who has an idea for a workaround?
>> Found a workaround myself:
>>
>> blend=all_expr='if(lt(mod(T,2),1),A,B)'
>>
>>
> Slow, doesnt it supports commands?

In this case I didn't want to use commands because I wanted it to toggle 
for a very long (or infinite) time. It would be nice if streamselect 
accepts expressions.

Michael