[FFmpeg-user] Meaning of ffprobe output

Ulf Zibis Ulf.Zibis at gmx.de
Tue Jan 15 04:13:21 EET 2019


Am 13.01.19 um 00:25 schrieb Carl Eugen Hoyos:
>>>> tbn
>>> This is the container timebase, 90k for mpeg streams.
>> For what stands 90k? For 90,000 milli seconds?
> It stands for a timebase of 1/90000

Is it 1/90000 second?

> which is the timebase
> for all mpeg streams (and cannot be changed afaik).
Do you mean MPEG-2 with "mpeg"?
My MPEG-4 stream has

12800 tbn

>> Does 50 tbc mean, that I still have 50 interlaced half-frames per
>> second, or why is the codecs timebase 50?
> No, it means that the codec timebase is 1/50.
> (The reason that these answers do not really help you
> is that the values are not necessarily meant for you,
> they typically have more meaning for developers.)
> [...]
>>>  libx264 does not support PAFF encoding.
>> What is PAFF?
> H.264 field-encoding, another method of h.264 interlaced
> encoding exists, MBAFF (which is supported by libx264).

So if I want to retain the interlacing from the vob file, I should use
MBAFF. What is the ffmpeg option for this?

Which is the de-interlacing method, libx264 uses by default?

I'm interested in that, because I imagine, that it would be better for
the quality to retain the interlacing, i.e. then the video player is
able to write 50 half-frames per second to the output display, which
provides better quality than 25 merged progressive frames per second.
Does my assumption hold?
But unfortunately I do not know, if my video (DVD-R recorded from a VHS
cassette) originally was telecined from an analogue celluloid film or
was produced directly on video tape (which should be true interlaced).
Any idea, how I can detect this? It was a low budget production in 1982.


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