[FFmpeg-devel] [PATCH] Work around msvc (c99wrap) build failure

[Pavel Koshevoy]

On 8/25/13 10:16 PM, Michael Niedermayer wrote:
> On Sun, Aug 25, 2013 at 09:57:45PM -0600, Pavel Koshevoy wrote:
>> On 8/25/13 9:13 PM, Michael Niedermayer wrote:
>>> On Sun, Aug 25, 2013 at 06:30:35PM -0600, pkoshevoy at gmail.com wrote:
>>>> From: Pavel Koshevoy <pkoshevoy at gmail.com>
>>>>
>>>> c99wrap choked on initialization of .dbl start_time option with
>>>> AV_NOPTS_VALUE: Unable to parse int64_t as expression primary
>>>>
>>>> Signed-off-by: Pavel Koshevoy <pkoshevoy at gmail.com>
>>>> ---
>>>>   libavfilter/vf_fps.c |    6 ++++--
>>>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/libavfilter/vf_fps.c b/libavfilter/vf_fps.c
>>>> index e30e90b..219bcd1 100644
>>>> --- a/libavfilter/vf_fps.c
>>>> +++ b/libavfilter/vf_fps.c
>>>> @@ -25,6 +25,8 @@
>>>>    * a filter enforcing given constant framerate
>>>>    */
>>>> +#include <float.h>
>>>> +
>>>>   #include "libavutil/common.h"
>>>>   #include "libavutil/fifo.h"
>>>>   #include "libavutil/mathematics.h"
>>>> @@ -61,7 +63,7 @@ typedef struct FPSContext {
>>>>   #define F AV_OPT_FLAG_FILTERING_PARAM
>>>>   static const AVOption fps_options[] = {
>>>>       { "fps", "A string describing desired output framerate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, { .str = "25" }, .flags = V|F },
>>>> -    { "start_time", "Assume the first PTS should be this value.", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, { .dbl = AV_NOPTS_VALUE}, INT64_MIN, INT64_MAX, V },
>>>> +    { "start_time", "Assume the first PTS should be this value.", OFFSET(start_time), AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX }, -DBL_MAX, DBL_MAX, V },
>>> does INT64_MIN work as well ?
>>> if so i think its preferable as it has the same nummeric value as
>>> AV_NOPTS_VALUE, introducing no change except the fix/workaround
>>> (vf_fps.c could check by assert that the 2 match)
>>>
>> No, INT64_MIN triggers the same error from c99wrap: Unable to parse
>> int64_t as expression primary
>>
>> I suspect c99wrap chokes on the typecast statement.
>>
>> If I change it to { .dbl = 0 } it compiles fine.
>> If I change it to { .dbl = (double)0 } it complains:  Unable to
>> parse double as expression primary
> next try:
> -9223372036854775808.0
>
>
>> I don't see why there is any particular attachment to AV_NOPTS_VALUE
>> as initial value for start_time.  It's appears to be just that -- an
> its the "not set" value throughout the codebase, also some user
> app could be setting that intentionally or unintenionally

changing { .dbl = AV_NOPTS_VALUE} to { .dbl = -9223372036854775808.0 } 
compiles successfully.

     Pavel.