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

[Ulf Zibis]

Am 29.10.23 um 17:04 schrieb Paul B Mahol:
> On Sun, Oct 29, 2023 at 4:52 PM Ulf Zibis <Ulf.Zibis at cosoco.de> wrote:
>
>> 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?
>>
> Could use vfrdet video filter on original input to find minimum, average
> and maximum delay between frames.

So I get this:

[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147394 >= 147394
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147416 >= 147416
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147417 >= 147417
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147418 >= 147418
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147422 >= 147422
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147430 >= 147430
     Last message repeated 1 times
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147441 >= 147441
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147443 >= 147443
     Last message repeated 1 times
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147468 >= 147468
     Last message repeated 1 times
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147469 >= 147469
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147478 >= 147478
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147492 >= 147492
     Last message repeated 1 times
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147493 >= 147493
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147518 >= 147518
     Last message repeated 1 times
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147519 >= 147519
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147532 >= 147532
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147542 >= 147542
     Last message repeated 1 times
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147543 >= 147543
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147568 >= 147568
     Last message repeated 1 times
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147569 >= 147569
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147573 >= 147573
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147574 >= 147574
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147588 >= 147588
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147593 >= 147593
     Last message repeated 1 times
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147599 >= 147599
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147600 >= 147600
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147614 >= 147614
[null @ 0x55a6d94fca80] Application provided invalid, non monotonically increasing dts to muxer in stream 0: 147617 >= 147617
frame=147619 fps=244 q=-0.0 Lsize=N/A time=01:38:24.96 bitrate=N/A speed=9.76x
video:69196kB audio:1107184kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
[Parsed_vfrdet_0 @ 0x55a6d9979b80] VFR:0.232174 (34273/113345) min: 900 max: 14400 avg: 4892

What do the numbers mean, are this nano seconds ? (the ffmpeg docs don't outline this)

-Ulf