[FFmpeg-user] Meaning of ffprobe output

[Ulf Zibis]

Hi Carl Eugen,

Am 19.01.19 um 14:02 schrieb Carl Eugen Hoyos:
>> $ ffmpeg -i CYD_copy.vob -vf idet -f null -
>> ffmpeg version 4.1-static https://johnvansickle.com/ffmpeg/  Copyright
> Not supported here!
>
>> (c) 2000-2018 the FFmpeg developers
>>   built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
> Not ok!
This recommendation comes from here:
https://trac.ffmpeg.org/ticket/7623#comment:5
So I used the release version 4.1 from here:
https://johnvansickle.com/ffmpeg/
in the assumption, that it is more stable as the git build.

>> [Parsed_idet_0 @ 0x6e71900] Repeated Fields: Neither:114683 Top:     1
>> Bottom:     0
>> [Parsed_idet_0 @ 0x6e71900] Single frame detection: TFF: 18738 BFF:
>> 12770 Progressive: 42496 Undetermined: 40680
>> [Parsed_idet_0 @ 0x6e71900] Multi frame detection: TFF: 36759 BFF: 19705
>> Progressive: 58193 Undetermined:    27
> This is not conclusive, possibly mixed progressive - interlaced or
> interlaced with many scenes without movement.
> Visual inspection should clarify.
Does that mean, that my vob stream is partly interlaced and partly
progressive?
I guess, TFF means top first frame and BFF bottom first frame, right?

This is weird, as the stream comes from a DVD which was recorded from a
VHS cassette with a hardware DVD recorder.

Also I do not understand, that after the transcoding to mp4 the numbers
are different. I interpret this, that the transcoding process does some
deinterlacing, but you say, the encoder does not. The vob with 114684
frames at 25 fps results in 76:27.36 length, but the resulting mp4 with
114502 frames is 76:20.08.

How can I understand all this?

-Ulf