[FFmpeg-user] Meaning of ffprobe output

Carl Eugen Hoyos ceffmpeg at gmail.com
Fri Jan 18 17:44:02 EET 2019

2019-01-18 15:58 GMT+01:00, Ulf Zibis <Ulf.Zibis at gmx.de>:

> Am 15.01.19 um 12:54 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.
> Timebase without unit? What does it serve for?
> If it's 1/90000 h, then it would be equal to 1/25 s, which would
> perfectly align with the fps 25 of the file.

So it's 1/90000 sec.


>>> 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.
> You may be right. Technically I don't see an obstacle for a software
> player to feed the video display buffer with 50 half-frames per second,
> as most displays refresh rate is at least 50 per sec.

I do though.
(It is simply not possible, you can only send frames to your
driver / display.)

>> The "idet" filter can do this.
> I have tried that with:
> $ ffmpeg -i CYD_atadenoise_H.264_mp3-q4.mp4 -vf idet
> and get:
> Trailing options were found on the commandline.
> At least one output file must be specified.
> Now I'm confused what to do, as I don't want to create another big file.
> How is the correct syntax?

One possibility is to add "-f null -".

Carl Eugen

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