[FFmpeg-user] simple bob -- How?

[Mark Filipak (ffmpeg)]

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?
>>>>
>>>> I suppose I could do something like this:
>>>> -filter_complex
>>>>
>>>>
>> "split[s1][s2],[s1]separatefields[A1][a1],[s2]separatefields[A2][a2],[A1][A2]weave[Ao],[a1][a2]weave[ao],[Ao][ao]merge"
>>>> (Kindly forgive any mistakes -- I haven't done anything like this in a
>>>> couple of months.)
>>>> But I thought I'd ask here for an easier way.
>>>>
>>>> These gave pretty good results. They're listed from best to worst:
>>>> bwdif
>>>> yadif=send_field_nospatial
>>>> yadif=send_field
>>>>
>>>> However, I suspect that, in addition to mechanical frame changes,
>> they're
>>>> also making some
>>>> (unwanted) cosmetic changes.
>>>>
>>>> Based on what's written in the documention, these seemed promising:
>>>> separatefields,doubleweave
>>>> separatefields,tinterlace=mergex2
>>>>
>>>> But they produced surprising and undesired results.
>>>>
>>>> Optional Reading:
>>>>
>>>> I also tried this:
>>>>
>>>> separatefields,select=eq(mod(n,4),0)+eq(mod(n,4),3),weave
>>>>
>>>> It's not what I actually want, but I tried it because it doesn't make
>>>> sense to me -- weave together
>>>> fields N%4==0 and N%4==3? (Really? Modulo-4? fields 0 & 3?) -- so,
>> because
>>>> it doesn't make sense to
>>>> me, I thought I might learn something interesting. So, what happened?
>>>> "Conversion failed!" is what
>>>> happened. Why it's cited as an example (
>>>> https://ffmpeg.org/ffmpeg-filters.html#Examples-121) in the
>>>> documentation is a mystery to me.
>>>>
>>>
>>> After so much time you still struggle a lot, buy some GUI tools and be
>>> happy ever after.
>>
>> You're not helping, Paul.
>>
> 
> I'm helping you so you can help yourself.
> 
> 
>>
>>> You probably missing \ to escape every , inside expressions.
>>
>> I'm running in Windows.
>>
> 
> That is not important. Either escape ',' inside expressions or do not ask
> for help if you gonna ignore help.

Ah! "inside expressions". Sorry. Yes, I '\,' inside expressions. I'm not using any expressions.