[FFmpeg-user] Alternative to Dynamic Text

Marton Balint cus at passwd.hu
Sun Nov 7 11:26:03 EET 2021

On Sun, 7 Nov 2021, Gyan Doshi wrote:

> On 2021-11-07 03:58 am, Anatoly wrote:
>>  On Thu, 4 Nov 2021 20:14:16 +0800
>>  LianCheng <tanlccc at gmail.com> wrote:
>>>  Yes, would like to know in ffmpeg, under drawtext, the textfile
>>>  (reload=1) is using read-write or read-only mode?
>>  I think "procmon.exe" from Microsoft
>>  https://docs.microsoft.com/en-us/sysinternals/downloads/procmon
>>  can help you to find the answer (and maybe somehow "debug" the
>>  situation).
> FFmpeg opens the file with O_RDONLY mode.
>>  Btw, I think following approach may help (or may not, I have no windows
>>  system by hand to test it myself). Let's say I want to atomically
>>  replace file a.txt with file b.txt
>>  mklink /h wrk.txt a.txt
>>  open wrk.txt with ffmpeg
>>  update b.txt as needed
>>  mklink /h next.txt b.txt
>>  move /y next.txt wrk.txt
>>  now update a.txt as needed or may delete a, b and create new b.
>>  hardlink again and move again
>>  and so on in loop
> This can work until it doesn't. The filter doesn't tolerate any load 
> failures.
> I'll see if I can add a short sleep and retry. If it still fails, we continue 
> with the old text.

I am not a fan of this to be honest. There is a proper way to do atomic 
renames even in windows, see the referenced stackoverflow articles, so it 
should just work.


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