[FFmpeg-devel] [PATCH] avutil/timestamp: avoid possible FPE when 0 is passed to av_ts_make_time_string2()

[Marton Balint]

On Tue, 18 Jun 2024, Marton Balint wrote:

>
>
> On Tue, 18 Jun 2024, Rémi Denis-Courmont wrote:
>
>> 
>>
>>  Le 17 juin 2024 22:33:01 GMT+02:00, Marton Balint <cus at passwd.hu> a
>>  écrit :
>>>  Signed-off-by: Marton Balint <cus at passwd.hu>
>>>  ---
>>>  libavutil/timestamp.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>>  diff --git a/libavutil/timestamp.c b/libavutil/timestamp.c
>>>  index 2a3e3012a4..6c231a517d 100644
>>>  --- a/libavutil/timestamp.c
>>>  +++ b/libavutil/timestamp.c
>>>  @@ -24,7 +24,7 @@ char *av_ts_make_time_string2(char *buf, int64_t ts,
>>>  AVRational tb)
>>>          snprintf(buf, AV_TS_MAX_STRING_SIZE, "NOPTS");
>>>      } else {
>>>          double val = av_q2d(tb) * ts;
>>>  -        double log = floor(log10(fabs(val)));
>>>  +        double log = (fpclassify(val) == FP_ZERO ? -INFINITY :
>>>  floor(log10(fabs(val))));
>>>          int precision = (isfinite(log) && log < 0) ? -log + 5 : 6;
>>
>>  Can the log be infinite anymore?
>
> Yes, in case of zero value we explicitly set it to -INFINITY, but implicit 
> infinity or NaN is also possible, because av_q2d can return both.

Will apply.

Regards,
Marton