[FFmpeg-user] High memory usage when merging videos

[Muhammad Faiz]

On 12/19/16, Jonathan Girven <jonathan.girven at trickbook.com> wrote:
>>> Otherwise there isn't much I can do to improve my FFmpeg
>>> command?
>>
>> I wonder if the (input?) option "-re" can improve your situation...
>
> As I understand it, the "-re" option instructs FFmpeg to read the
> input file at the native frame rate of the file, rather than as fast
> as possible. So the idea would be to slow down the rate at which the
> memory fills with frames waiting to be processed in the hope that the
> complex filters can empty the buffer quickly enough to avoid the out
> of memory problems. Am I right?
>
> Testing this by adding "-re" before each "-i", I am still experiencing
> the same out of memory issues. The speed that FFmpeg quotes it is
> working at is around 0.200x. So in the time 20% of the output file has
> been processed, the inputs have been entirely loaded, 80% of which
> still unprocessed in memory. Is that how it works? It is pretty hacky,
> but I guess if I could specify the rate at which inputs are loaded
> precisely, I could specify fps*0.2, and it would work. Maybe by
> temporarily changing the frame rate ...

How if you move your multiple inputs into movie sources inside filter_complex?

Thx.