[FFmpeg-user] Filter documentation -- PTSs

[Mark Filipak (ffmpeg)]

On 02/14/2021 08:28 PM, Paul B Mahol wrote:
> On Mon, Feb 15, 2021 at 2:23 AM Mark Filipak (ffmpeg) <markfilipak at bog.us>
> wrote:
> 
>> On 02/14/2021 08:13 PM, Paul B Mahol wrote:
>>> On Mon, Feb 15, 2021 at 1:46 AM Mark Filipak (ffmpeg) <
>> markfilipak at bog.us>
>>> wrote:
>>>
>>>> On 02/14/2021 07:34 PM, Paul B Mahol wrote:
>>>>> On Mon, Feb 15, 2021 at 12:50 AM Mark Filipak (ffmpeg) <
>>>> markfilipak at bog.us>
>>>>> wrote:
>>>>>
>>>>>> Disclosure: Everything that follows may be wrong.
>>>>>>
>>>>>> I reckon that, except for a few filters, the important metric is PTS,
>>>> not
>>>>>> the frame #s assigned at a
>>>>>> filter's input node nor its wall-clock arrival time at a filter's
>> input
>>>>>> node. For example,
>>>>>> 'interleave' performs frame interleaves based on the PTSs of incoming
>>>>>> frames -- at least, that's
>>>>>> what I think.
>>>>>>
>>>>>> Am I correct?
>>>>>>
>>>>>> If so, wouldn't it be helpful if filter documentation included how it
>>>>>> generates PTSs?
>>>>>>
>>>>>
>>>>> PTS are not generated.
>>>>
>>>> ffmpeg -i SOURCE -vf telecine TARGET
>>>>
>>>> What are the PTSs of the first 5 frames at the output of the filter?
>>>>
>>>>
>>> Interpolated by very complex formula.
>>
>> So, the PTSs are generated.
>>
>> What is the formula? Certainly it can't be anywhere nearly as complex as
>> the differential equations
>> and boundary conditions that control air flow through a duct of arbitrary
>> shape or the air flow
>> across an aircraft wing of arbitrary profile. I guess if I can handle
>> those, I'll be able to handle
>> the generated PTSs of a periodic series of frames, eh?
>>
> 
> You need TB aka timebase too.
> 
> TB is rational.
> PTS is 64bit integer.

Thank you, Paul. I promise I can handle it. What is the formula?