[Ffmpeg-devel] ffmpeg & postprocess_internal.h (colorspace issue)
Kris A. Wotipka
Mon Jul 25 01:26:19 CEST 2005
Michael Niedermayer wrote:
> and what do you do if someone picks a completely unrelated and unused part and
> ask you to explain it? will you tell him its not going to help him with his
> problem even if he understands that part? or what else?
I guess that being a teacher first and an engineer second, I am more use
to these things. True I am not a programmer but I am trying to 1) Wrap
my brain around the new digital formats and how they relate to my
issues. It's not like you can go to Books a million and buy a MPEG
standards book off of the shelf. Trust me I have looked. The one I
ordered never came in. So, yes, I am trying to learn.
> lets see the lines you quoted:
> /// select between full y range (255-0) or standart one (234-16)
> #define FULL_Y_RANGE 0x8000 // 32768
> the first line is a comment as it starts with //
understand that. Now you have to understand that I have truged through
most of the code to find this line that looked like a glimmer of hope
for my issue.
> the second is a preprocessor directive which has the effect that all
> occurances of FULL_Y_RANGE later in the program will be replaced by 0x8000
> now what is that FULL_Y_RANGE thing? its a flag and 0x8000 is the bit for that
> flag, change 0x8000 to another unused bit and recompile everything and
> nothing will change, change it to a bit which is used for something else and
> things will break thats it
> now what does the flag/bit thing actually switch between? it switches between
> the output range of the brightness/contrast correcture filter
> what does that filter do? it guesses the maximum and minimum brightness and
> adjusts brightness&contrast so the guessed values are changed to the wanted
> output ones
Sounds like exactly what I want to do. Find everything that is <16 &
>235 and make it fit, clamp it, resample it, whatever to 16-235 space.
So you can see why I was harping on this.
> how to use the filter in ffmpeg, sorry its not supported currently you would
> need to add support for that first
Bummer. That statement alone would have been just fine with me. I work
with several developers so I know about code fragments that were put
there and never really done anything with. Again, I am not a programmer
but I am a good end user.
> did any of that help you?
Yes, I apologize if my lack of knowledge frustrates you. I too get
frustrated with people who want it done for them.
Like I said before, I would be more than happy to RTFM. That is what I
have started doing with Mplayer/coder. As it turns out, if I can pipe
the output of this instead of playing it on the screen, then some of my
issues may be figured out.
I beg of the development team to come up with more complete docs.
FFMPEG is a great program and I use it for other simpler stuff. I will
post this request to the list in another e-mail.
Hope you have enjoyed your weekend
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