[Libav-user] Frame number

[Michael Zucchi]

I'm pretty sure you shouldn't use approximate numbers (floats or 
doubles) for this.

There's a bunch of AVRational related and exact-precision arithmetic 
functions in libavutil for this purpose.  see libavutil/mathematics.h 
libavutil/rational.h.

On 29/06/12 21:51, Hector Alonso wrote:
> Hi,
> I've made myself one LibAvUtils class with this two functions
> implemented like this:
>
>
> int64_t  LibAvUtils::frameNumberToPts(uint  uiFrameNum,  float  fFps)
>
> {
>
>      if  (fFps  <=  0)  return  0;
>
>      return  (int64_t)uiFrameNum  *  (int64_t)(((float)AV_TIME_BASE)  /  fFps);
>
> }
>
> //-----------------------------------------------------------------------------
>
> uint  LibAvUtils::ptsToFrameNumber(int64_t  iPts,  float  fFps)
>
> {
>
>      if  (fFps  <=  0)  return  0;
>
>      return  (uint)(iPts  /  (((float)AV_TIME_BASE)  /  fFps));
>
> }