[FFmpeg-user] should I shoot the dog?

Paul B Mahol onemda at gmail.com
Tue Sep 29 22:43:04 EEST 2020


On Tue, Sep 29, 2020 at 10:26:20AM -0400, Mark Filipak (ffmpeg) wrote:
> On 09/29/2020 09:37 AM, Michael Koch wrote:
> > Am 29.09.2020 um 14:58 schrieb Mark Filipak (ffmpeg):
> > > 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!
> > 
> > As far as I know, this is not described in the official documentation.
> > You can find it for example here:
> > https://video.stackexchange.com/questions/16374/ffmpeg-pixel-format-definitions
> 
> Thanks for that. It saved me some time. ...So, what does "planar" mean? What does "packed" mean?
> 
> > > 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.
> > There is no single consistent format used internally. See Gyan's answer here:
> > http://ffmpeg.org/pipermail/ffmpeg-user/2020-September/050031.html
> 
> And thanks for that. So, ffmpeg really is a Tower of Babel, eh? That does
> not seem wise to me. That seems like a great way to generate bugs in
> addition to confusion.

Now if that is not trolling out of pure ignorance I dunno what is.

I'm really asking mysefl why are there still people feeding this poor troll.

> 
> Now, I imagine that converting to a lingua franca would blow up processing
> time, so it isn't done. However, if there are format-to-format regular
> expressions for conversions, may I suggest that those regular expressions be
> published? Also, if Y Cb & Cr are separate buffers, may I suggest that
> ffmpeg publish that?
> 
> In school, I learned that inputs and outputs should be fully characterized,
> not suggested, not implied, but fully characterized as structures. That
> takes time, and it takes review and perfection by informed people, but that
> time is worth the investment.
> 
> -- 
> 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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