[FFmpeg-user] ffmpeg create wrong time information

[Cecil Westerhof]

Bouke / Videotoolshed <bouke at videotoolshed.com> writes:

>> On 21 Dec 2021, at 19:37, Cecil Westerhof via ffmpeg-user <ffmpeg-user at ffmpeg.org> wrote:
>> 
>> Cecil Westerhof via ffmpeg-user <ffmpeg-user at ffmpeg.org> writes:
>> 
>> After some experiments I solved it by putting -ss and -to behind -i
>> and not forgetting to alter the between values.
>> But this takes about a third more time.
>> Is there be a better solution?
>> 
>> I am now using:
>>    ffmpeg -y                                         \
>>        -i input.mp4                                  \
>>        -ss 00:26:05                                  \
>>        -to 00:44:04                                  \
>>        -vf "
>>             drawbox=enable='between(t, 1565, 1566.6)':
>>                color     = black                     :
>>                w         = in_w                      :
>>                h         = in_h                      :
>>                thickness = fill
>>        "                                             \
>>        -acodec copy                                  \
>>        -vcodec libx264                               \
>>        -crf 23                                       \
>>        -preset veryfast                              \
>>        output.mkv
>
> I think you are inserting black, not overlaying (blanking) the
> video. Try -vf overlay.

If I look at overlay, it says:
    Overlay one video on top of another.

I only want to block video for a short while because someone who
should not be visible is visible.


> With -ss before input, it will do a faster search, you might have to do
> a bit of math on the enable= range, but that will become very obvious
> with a small test.

The problem is that (in this case, I have used it without problems)
with -ss before the video there is 27 seconds of (hidden) audio. If
the video started 27 seconds I could understand it.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof