[Ffmpeg-devel] Mac OSX debug build problems

Anders Moden ffmpeg
Tue Oct 24 23:39:50 CEST 2006

24 okt 2006 kl. 23.19 skrev Michael Niedermayer:

> Hi
> On Tue, Oct 24, 2006 at 11:04:00PM +0200, Anders Moden wrote:
>> 24 okt 2006 kl. 22.23 skrev Guillaume Poirier:
>>> On Oct 24, 2006, at 9:37 , Anders Moden wrote:
>>>> Hi !
>>>> Why is it always a lot of problems using --disable-strip --disable-
>>>> opts
>>>> I am always stuck in a situation where I need to debug the code.
>>>> On OSX I always get
>>>> cc -I/Users/amo/ffmpeg/libswscale   -DHAVE_AV_CONFIG_H -
>>>> Users/amo/ffmpeg -I/Users/amo/ffmpeg -I/Users/amo/ffmpeg/libavutil
>>>> -I/Users/amo/faad2/include -no-cpp-precomp -pipe -
>>>> force_cpusubtype_ALL -Wno-sign-compare -g -Wdeclaration-after-
>>>> statement -Wall -Wno-switch -Wdisabled-optimization -Wpointer-
>>>> arith -Wredundant-decls -Winline -mdynamic-no-pic  -c -o cabac.o
>>>> cabac.c
>>>> In file included from cabac.c:32:
>>>> cabac.h: In function 'get_cabac_noinline':
>>>> cabac.h:525: error: can't find a register in class 'GENERAL_REGS'
>>>> while reloading 'asm'
>>>> make[1]: *** [cabac.o] Error 1
>>>> make: *** [lib] Error 2
>>>> somewhere. Either mmx or swscale. The mmx stuff can be disabled,
>>>> but the swscale can not.
>>> CFLAGS+=-fomit-pointer
>> Nope. I can get it to compile without using -O3 on some files
> -O0 with the x86 asm or mmx code does NOT compile, ask the gcc  
> developers
> why, its a known issue, there is no solution except the obvious  
> dont use
> -O0, dont use mmx/asm, fix/change the compiler, i also dont think
> -fomit-frame-pointer will help, though yes its mandatory if you  
> want asm/mmx
> again its a gcc issue, if you have any other solutions patches  
> would be
> welcome as long as there is _no_ speedloss
>>> Oh, and btw, user questions belong to the users ml
>> Thanx. I must say that it is pretty hard to get into this project as
>> many questions on the user forum never get answered and on the devel
>> forum you must be part of some elite...
> there are many many questions and too few people who have the time and
> knowledeg to awnser them, theres also the issue that most questions  
> lack
> 90% of the information needed to awnsr them
> volunteers to help the ffmpeg users are certainly welcome ...
>> Anyway. Its a great library but perhaps not that friendly to external
>> developers...
> do you have any suggestions how we could improve that (note  
> spending more
> time isnt an option we dont have more ...)

My suggestion is to have some kind of design document. Maybe there is  
something like that already but I haven't found it. I have been  
single stepping a lot to find out how muxers and protocols work. What  
flags to be used and how to structure members for frames, time base  
etc work. How yuv formats can be converted to rgba etc. All these  
issues could have been described in some kind of design document.  
perhaps one overall part that describes the overall architecture and  
some sub parts for more complicated stuff like h264 encoders,rtsp  
control,sap/sdp etc.

/Anders Mod?n
Saab Training Systems AB
CTO ToolTech Software

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