[FFmpeg-user] Generete one second of black video and relative silence audio with the same duration

[Moritz Barsnick]

On Sat, Jan 25, 2020 at 22:26:31 +0000, Gian Maria Allibrante wrote:
> Hi Moritz, thanks for reply, this one, im always unable to get round match duration:
>
> echo VIDEO FORMAT CONTAINER DURATION:
> ffprobe -v error -show_entries format=duration \
>   -of default=noprint_wrappers=1:nokey=1 output.mp4
> echo VIDEO STREAM DURATION:
> ffprobe -v error -select_streams v:0 -show_entries stream=duration \
>   -of default=noprint_wrappers=1:nokey=1 output.mp4

Ah, I think I understand now. You are trying to get the same duration
from the container as from the video stream.

Honestly, I was looking for a totally different problem:

> > VIDEO FORMAT CONTAINER DURATION: 3.026000
> > VIDEO STREAM DURATION: 3.000000

You showed us *three* seconds results, not one second. This totally
distracted from your actual issue! ;-)

Regarding the approx 0.026 extra seconds:
For some reason, ffmpeg creates an additional initial audio packet,
marked with
side_data_type=Skip Samples
skip_samples=1105

If those initial samples are skipped, the total length is exactly okay.
I'm not sure whether ffmpeg does this due to restrictions regaring the
audio packet size.

Moritz