[FFmpeg-devel] avcodec/proresdec : add 12b decoding support

[Martin Vignali]

Le dim. 18 nov. 2018 à 01:57, Carl Eugen Hoyos <ceffmpeg at gmail.com> a
écrit :

> 2018-11-18 0:28 GMT+01:00, Martin Vignali <martin.vignali at gmail.com>:
>
> > 012 : Add 12b support for 444 by default,
>
> Is it slower?
> I believe that once 12 bit decoding is not slower, it should
> be the default for 422.
>

Yes 12b is much slower

On a 422 HQ file :
10b decoding precision :
frame= 3316 fps=280 q=-0.0 Lsize=N/A time=00:02:12.64 bitrate=N/A
speed=11.2x
bench: utime=88.741s stime=1.257s rtime=11.833s

12b decoding precision :
frame= 3316 fps=176 q=-0.0 Lsize=N/A time=00:02:12.64 bitrate=N/A
speed=7.02x
bench: utime=145.096s stime=0.769s rtime=18.894s


>
> > and add user option for setting decoding precision
>
> I wonder if this is necessary and correct: Calling applications
> should choose the bit depth depending on their use case, if
> ffmpeg (the cli) really doesn't support that, it is a missing
> feature, different pix_fmts for one decoder (and input file) is
> not new in FFmpeg, MPlayer had used this feature since
> forever.
>
>

I don't know, how to get the "wanted" pix_fmt output using ffmpeg cli, and
I don't know, what the general "rules" of this project for multiple pix_fmt
output for the same input file.

If user option for decoding precision need to be remove,
i think 422 need to stay in 10b decoding, and 444 need to be decode in 12b.

Martin