1. frame# as n, or at playback and pressing the keys for back to
beginning, does not start until 0.566 for frame # 0 because (I think)
the source video has an audio offset. This makes problem#1 affect all
2. overlay:between appears at frame# 446 15.433 sec which is not as
requested at 511 a difference of 65 frames early.
3. overlay:between disappears early also, last frame# 1092 37.000 which
is not 1224. A difference of 132 frames. My math on the drift makes that
a factor of 90.6%, but  is 30 fps. The cause is because the gif file
 is 30ms per frame, not 33.333ms, which accounts for the 90% figure.
So question#2 is:
How can I override the timing, and just copy frame by frame ignoring the
timestamps of ?
4. overlay appears a second time for one frame at frame# 1207 40.799 sec
Acts like it ignored it's own timestamp calculations and included one
frame at the end of the requested range, plus the audio offset.
S Andreason wrote:
> 1. frame# as n, or at playback and pressing the keys for back to
> beginning, does not start until 0.566 for frame # 0 because (I think)
> the source video has an audio offset. This makes problem#1 affect all
> future edits.
> 2. How can I override the timing, and just copy frame by frame
> ignoring the timestamps of ?
Step 1. clip desired video. I want to start at 22.0 seconds, (where the
blue sign is visible on left) but the nearest I-frame appears to be at
21.933 sec according to mpv.
$ ffprobe -show_frames says 21.566 for nearest pict_type=I
Giving a -ss 22 or -ss 21.97 results in a 0.566 gap in video, where the
audio is not cut at the same place as the video, so it was not cut at
-ss 21.933 results in a 0.114 sec gap.
-ss 21.566 results in a 0.497 sec gap.
-ss 21.96 results in 0.092 sec gap, which seems to be the best I can
get. Too many of these concat together later will result in audio sync
problems, so there is a good reason to ask how to improve the cut here.
Notice frame 1 overlay doesn't start at 0.0 I really need frame 0 to be
0 for all later calculations to work without adding offsets.
Notice the gif frame starts at 24 or 0.900 sec.
Notice the last gif frame is 105 at 3.600 sec.
I can work around this limitation (unless you have a solution) by
recalculating the start and stop points for n. x/30/0.03=n
I can't duplicate problem 3 on such a short file, so let's focus on the
Thank you, Stewart