[FFmpeg-devel] vc1test silly fps check
Reimar Döffinger
Reimar.Doeffinger
Tue Sep 15 12:07:16 CEST 2009
On Tue, Sep 15, 2009 at 12:56:50PM +0300, Kostya wrote:
> On Tue, Sep 15, 2009 at 11:48:50AM +0200, Reimar D?ffinger wrote:
> > Hello,
> > vc1test has this code:
> > fps = get_le32(pb);
> > if(fps == -1)
> > av_set_pts_info(st, 32, 1, 1000);
> > else{
> > av_set_pts_info(st, 24, 1, fps);
> > st->duration = frames;
> > }
> > Seriously? Is it _supposed_ to be possible to set time_base to 1/0?
>
> From SMPTE 421m:
>
> J.2.3 Integer Frame Rate (FRAMERATE)
> FRAMERATE is a 32-bit unsigned word in the bitstream which may signal
> the rounded frame rate (fps) of the encoded
> clip. FRAMERATE should be set to 0xffffffff if it is not known,
> unspecified, or non-constant.
> Note: This value is usually not used by the decoder.
How does that justify av_set_pts_info(st, 24, 1, 0); that the above code
allows? A time base of 1/0 seconds still makes no sense.
I'd also like to point out that fps == -1 assumes that int is no more
than 32 bits, since get_le32 returns something unsigned.
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