[MPlayer-dev-eng] MNG support for MPlayer

[Diego Biurrun]

On Fri, Sep 19, 2008 at 03:39:20PM +0200, Stefan Schuermans wrote:
> Diego Biurrun wrote:
>> On Thu, Sep 18, 2008 at 10:47:00PM +0200, Stefan Schuermans wrote:
>>> --- configure	(revision 27638)
>>> +++ configure	(working copy)
>>> @@ -4683,6 +4687,33 @@
>>>  +echocheck "MNG support"
>>> +if test "$_mng" = auto ; then
>>> +  _mng=no
>>> +  cat > $TMPC << EOF
>>> +#include <libmng.h>
>>> +int main(void) {
>>> +  const char * p_ver = mng_version_text() ?: "";
>>> +  printf("libmng: %s\n", p_ver);
>>> +  return p_ver[0] == 0;
>>> +}
>>> +EOF
>>> +  if cc_check -lmng -lz $_ld_lm ; then
>>> +    if tmp_run ; then
>>> +      _mng=yes
>>> +    else
>>> +      _res_comment="no library version"
>>> +    fi
>>> +  fi
>>> +fi
>>
>> I wonder why tmp_run is necessary?  And yes, I know that the libpng test
>> does it as well...
>
> If I've understood this correctly, cc_check tries to compile and link  
> the C source and tmp_run tries to run the result. I think it is  
> neccessary to run the code to detect if linking against libmng works.  
> I've seen it at least once (with some broken libmng installation) that  
> compiling and linking worked, but the binary did not run. I'm not sure  
> any more if it crashed or did not load due to not finding libmng.so.

I think the the test in the libpng test is already suspicious.  Just
drop it.  As Reimar said, it will be problematic if cross-compiling.

> --- configure	(revision 27638)
> +++ configure	(working copy)
> @@ -4683,6 +4687,32 @@
>  
> +if test "$_mng" = yes ; then
> +  _def_mng='#define HAVE_MNG 1'

CONFIG_MNG

> --- libmpdemux/demux_mng.c	(revision 0)
> +++ libmpdemux/demux_mng.c	(revision 0)
> @@ -0,0 +1,622 @@
> +
> + * start time must be > 0 for the variable frame time mechanism
> + * (GIF, MATROSKA, MNG) in video.c to work for the first frame

When you have complete sentences like this, you should ideally
capitalize the first word and end in a period, same below.

> + * This structure is used as private data for MPlayer demuxer
> + * als also as private data for the MNG library.

als also?

> +/**
> + * \brief MNG library callback: (a part of) the canvas should be shown
> + * \param[in] h_mng MNG library image handle
> + * \param[in] x rectangle's left edge
> + * \param[in] y rectangle's top edge
> + * \param[in] width rectangle's width
> + * \param[in] height rectangle's heigt
> + * \return \p MNG_TRUE on success, \p MNG_FALSE on error (never happens)

What are all those rectangles?  I may be missing something obvious
here..

> +  // save number of milliseconds after which to call MNG library again

the MNG

> + * \return demuxer sructure on success, \p NULL on error

sTructure

Diego