[FFmpeg-user] simple bob -- How?

[Mark Filipak (ffmpeg)]

On 12/29/2020 05:07 AM, Paul B Mahol wrote:
> On Tue, Dec 29, 2020 at 10:50 AM Mark Filipak (ffmpeg) <markfilipak at bog.us>
> wrote:
> 
>> On 12/29/2020 04:39 AM, Paul B Mahol wrote:
>>> On Tue, Dec 29, 2020 at 10:32 AM Mark Filipak (ffmpeg) <
>> markfilipak at bog.us>
>>> wrote:
>>>
>>>> On 12/29/2020 04:09 AM, Mark Filipak (ffmpeg) wrote:
>>>>> On 12/29/2020 04:04 AM, Paul B Mahol wrote:
>>>>>> On Tue, Dec 29, 2020 at 9:56 AM Mark Filipak (ffmpeg) <
>>>> markfilipak at bog.us>
>>>>>> wrote:
>>>>>>
>>>>>>> On 12/29/2020 03:41 AM, Paul B Mahol wrote:
>>>>>>>> On Tue, Dec 29, 2020 at 5:51 AM Mark Filipak (ffmpeg) <
>>>>>>> markfilipak at bog.us>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> I seek a way to do simple bob (i.e. repeat fields at 2xFPS) with no
>>>>>>> other
>>>>>>>>> filtering. Can you help me?
>>>> -snip-
>>>>>>>> After so much time you still struggle a lot, buy some GUI tools and
>> be
>>>>>>>> happy ever after.
>>>>
>>>> Here's what I've tried so far:
>>>> -filter_complex
>>>> "split[a][b],[a]separatefields[c],[b]separatefields[d],[c][d]join"
>>>> -filter_complex
>>>> "split[a][b],[a]separatefields[c],[b]separatefields[d],[c][d]interleave"
>>>> -vf "separatefields,shuffleframes=0 0,weave"
>>>> -vf separatefields,scale=720x480
>>>> -vf separatefields,scale=w=iw:h=2*ih
>>>> -filter_complex "split[a][b],[a]separatefields[c],[c][b]scale2ref"
>>>>
>>>
>>> Do you want interlacer or deinterlacer? It is very unclear from your
>>> subject what you need.
>>>
>>> Simple bob deinterlacer takes every single field and than interpolates
>>> missing fields with bilinear interpolation iirc.
>>
>> I think that bob just separates fields (e.g. [720x480] ->
>> [720x240][720x240]), then line doubles
>> (e.g. [720x240][720x240] -> [720x480][720x480]). When it is played back,
>> horizontal lines in the
>> video appear to bob up and down (but at 60Hz, that's not very noticeable).
>>
> 
> Try this filtergraph:
> 
> separatefields,split[a][b],[a][b]vstack,il=l=i:c=i

Ah! I get it. I think that will work. ...I'll be back.