[FFmpeg-user] Same number of frames dropped and duplicated; What does that mean?

[Ulf Zibis]

Am 29.10.23 um 16:00 schrieb Paul B Mahol:
> On Sun, Oct 29, 2023 at 3:29 PM Ulf Zibis <Ulf.Zibis at cosoco.de> wrote:
>
>> Hi,
>>
>> so 18.3 % of the frames were dropped and duplicated at same time.
>>
>> Does that mean, that 8063 frames of the input were dropped and then same
>> (or other) 8064 frames were duplicated to the output?
>>
> Probably variable frame rate input.

When I use "-fps-mode passthroug", then I get messages of frames with the same timestamp, so ffmpeg seems to drop them in normal mode and then fills in duplicates.

Am I right?

So maybe it would be better to correct the timestamps than dropping the frames?

[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 0, current: 0; changing to 1. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 222053, current: 222053; changing to 222054. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 3996954, current: 3996954; changing to 3996955. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 4219007, current: 4219007; changing to 4219008. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 4441060, current: 4441060; changing to 4441061. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 5551325, current: 5551325; changing to 5551326. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 5773378, current: 5773378; changing to 5773379. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 5995431, current: 5995431; changing to 5995432. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 9548279, current: 9548279; changing to 9548280. This may result in incorrect timestamps in the output file.
[mp4 @ 0x561ea7f2ab80] Non-monotonous DTS in output stream 0:0; previous: 9770332, current: 9770332; changing to 9770333. This may result in incorrect timestamps in the output file.