[FFmpeg-user] Meaning of ffprobe output

Carl Eugen Hoyos ceffmpeg at gmail.com
Sun Jan 13 01:25:41 EET 2019


2019-01-12 22:32 GMT+01:00, Ulf Zibis <Ulf.Zibis at gmx.de>:

> Am 11.01.19 um 01:47 schrieb Carl Eugen Hoyos:
>> 2019-01-11 0:39 GMT+01:00, Ulf Zibis <Ulf.Zibis at gmx.de>:
>>
>>> 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 which is the timebase
for all mpeg streams (and cannot be changed afaik).

>>> -movflags +faststart -c copy CYD_copy.vob
>> Sadly, output option cannot (easily) be checked for correctness.
>> Using options that cannot have an effect may reduce your
>> chance to get good help here (consider the increased time it
>> needs to understand what's going on / what your intentions are).
>
> The probably wrong '+' was taken from the example in the Wiki:
> https://trac.ffmpeg.org/wiki/Encode/H.264#AdditionalInformationTips
> Maybe this is an error?
> Because VOB also is coded with MPEG, I thought this flag may have a
> positive effect.
> Anyway, without the flag I get the same ffprobe data.

The option "movflags" can only have an effect for mov (and friends)
output, not for mpeg streams.

[...]

> 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).

Carl Eugen


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