[FFmpeg-user] should I shoot the dog?

Mark Filipak (ffmpeg) markfilipak at bog.us
Tue Sep 29 15:58:26 EEST 2020


On 09/29/2020 04:06 AM, Michael Koch wrote:
> Am 29.09.2020 um 04:28 schrieb Mark Filipak (ffmpeg):
>>
>> I just want to understand the frame structures that ffmpeg creates, and that ffmpeg uses in 
>> processing and filtering. Are Y, Cb, Cr separate buffers? That would be logical. Or are the Y, Cb, 
>> Cr values combined and organized similarly to macroblocks? I've found some code that supports 
>> that. Or are the Y, Cb, Cr values thrown together, pixel-by-pixel. That would be logical, too.
> 
> As far as I understood it, that depends on the pixel format.
> For example there are "packed" pixel formats rgb24, bgr24, argb, rgba, abgr, bgra,rgb48be, rgb48le, 
> bgr48be, bgr48le.
> And there are "planar" pixel formats gbrp, bgrp16be, bgrp16le.

Hi Michael,

"Packed" and "planar", eh? What evidence do you have? ...Share the candy!

Now, I'm not talking about streams. I'm talking about after decoding. I'm talking about the buffers. 
I would think that a single, consistent format would be used.

? ? ? ? ?
So, why am I interested in ffmpeg's internal video buffer format? ...I've been here for about 1/2 
year now, watching the ffmpeg, slow motion train wreck. It seems to me that the ffmpeg patricians 
assume that everyone knows the formats just because the patricians do, and have documented based on 
that assumption. Because we plebians don't know the format, and we don't know that we don't know, 
the patricians get frustrated with us and become short tempered and then the word "troll" flies.

I'm just a simple engineer. To understand an architecture, all I need is the structures, preferably 
as pictures, and maybe a bit of the processing flow, preferably via flow diagrams (i.e. step '1', 
then step '2', then step '3', etc.) -- I'm a visual kinda guy -- but I usually don't need to know 
the processing.

Examining the source code doesn't work for me. 'C' code is just too cryptic and I'm too ignorant.

-- 
The U.S. political problem? Amateurs are doing the street fighting.
The Princeps Senatus and the Tribunus Plebis need their own armies.


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