[FFmpeg-user] bwdif filter question

Mark Filipak (ffmpeg) markfilipak at bog.us
Thu Sep 24 01:01:40 EEST 2020

On 09/23/2020 05:27 PM, Paul B Mahol wrote:
> On Wed, Sep 23, 2020 at 04:26:27PM -0400, Mark Filipak (ffmpeg) wrote:
>> On 09/23/2020 03:53 PM, Carl Eugen Hoyos wrote:
>>> Am Di., 22. Sept. 2020 um 00:47 Uhr schrieb Mark Filipak (ffmpeg)
>>> <markfilipak at bog.us>:
>>>> On 09/21/2020 06:07 PM, Carl Eugen Hoyos wrote:
>>>>> Am Mo., 21. Sept. 2020 um 14:16 Uhr schrieb Mark Filipak (ffmpeg)
>>>>> <markfilipak at bog.us>:
>>>>>> Here is what you wrote:
>>>>>> "The following makes little sense, it is just meant as an example:
>>>>>> $ ffmpeg -f lavfi -i testsrc2,field -vf bwdif -f null -"
>>>>>> That "explains" nothing. Worse, it seems crass and sarcastic.
>>>>> No.
>>>>> This was an example to show you how you can feed one field to
>>>>> a filter in our system, this is what you had asked for ...
>>>> I didn't ask for that.
>>> This is not true:
>>>> How can a frame contain just one field?
>> I did not ask for an example to see "how you can feed one field to a
>> filter". I asked how a frame can contain just one field. You have yet to
>> answer that. I think it's impossible. You may be referring to a frame that
>> is deinterlaced and cut in half (e.g. from 720x576 to 720x288), in which
>> case the frame contains no field.
>> You wrote: "(If you provide only one field, no FFmpeg deinterlacer will
>> produce useful output.)". Of course I agree with the "no...useful output"
>> part, however, how can a person "provide only one field"? That implies that
>> "provide only one field" is an option. I think that's impossible, so I asked
>> you how it was possible. I did not ask how to implement that impossibility
>> on the command line (which I think is likewise impossible). It is along
>> these lines that misunderstanding and confusion and novice angst ensues.
>> Am I nitpicking? I think not. You are an authority. When an authority uses
>> loose language, misunderstanding and confusion and angst must follow. But
>> MPEG and ffmpeg seems to be primed to require loose language. That needs to
>> end.
> Try to read and follow separatefields, weave and doubleweave filters documentation.

Thank you, Paul. I do try to read them. Is there something specific to which you can point?
All inputs are accepted and appreciated. I'm sure we both endeavor to make ffmpeg better.

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