[FFmpeg-user] Meaning of ffprobe output

[Carl Eugen Hoyos]

2019-01-15 3:13 GMT+01:00, Ulf Zibis <Ulf.Zibis at gmx.de>:

> 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?

I suspect timebase is a fraction and has no unit but I may
be wrong.

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

MPEG program and MPEG transport streams are (also)
defined in the MPEG-2 standard (that also defines
several other things).

> My MPEG-4 stream has
>
> 12800 tbn

Command line and complete, uncut console output missing.

[...]

>>>>  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?

Probably "-flags +ilme+ildct"

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

x264 is an encoder and knows nothing about de-interlacing,
it does not de-interlace.

> I'm interested in that, because I imagine, that it would be better
> for the quality to retain the interlacing

This is correct: If you use progressive encoding for interlaced
content, it either costs (a lot of) quality or bitrate.

> 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.

Only (old!) CRTs can do this, so I assume this has no
relevance here.

> 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?

The "idet" filter can do this.

Carl Eugen