[FFmpeg-user] Meaning of ffprobe output

Ulf Zibis Ulf.Zibis at gmx.de
Tue Feb 5 00:29:19 EET 2019

Am 04.02.19 um 01:00 schrieb Carl Eugen Hoyos:
> 2019-02-03 21:16 GMT+01:00, Ulf Zibis <Ulf.Zibis at gmx.de>:
>> Am 03.02.19 um 21:06 schrieb Carl Zwanzig:
>>> It's a shortening of "Top Field First" (TFF). With interlaced video
>>> you have a choice of whether the top or bottom field (odd numbered
>>> lines/even numbered lines) comes before the other in the digital stream.
>> I know this, but Carl Eugen said, that my video is not interlaced
Now I've checked the files with mediainfo:
- The vob file is stated as interlaced top first. (I know, this does
nothing say about the content, only the flag is evaluated.)
- The transcoded mp4 is stated as progressive.
I don't know, why libx264 doesn't retain the flag, maybe it evaluates
the content and decides to remove it. Carl Eugen stated, that libx264
makes an interlaced output, if the input is interlaced, so I would
think, it shouldn't change the interlace state, if I understood right.

> FFmpeg cannot know if the video is interlaced.
> (It was encoded interlaced which is not unusual for mpeg2video)

I still must admid, that I don't really understand what is meant by
"encoded interlaced", is it the same than "has the interlaced flag set"?
I see no reason why ffmpeg "cannot know" this flag.


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