[FFmpeg-devel] [PATCH] fbdev: simplify logic in fbdev_read_packet()

[Stefano Sabatini]

On date Monday 2011-04-11 03:02:33 +0200, Michael Niedermayer encoded:
> Hi
> 
> ive seen this in libav (and skiped it because its obviosuly
> buggy) but seem to have missed it here :(
> sorry, for the (too) late review
> 
> On Sat, Mar 12, 2011 at 03:28:40PM +0100, Stefano Sabatini wrote:
> > ---
> >  libavdevice/fbdev.c |   18 ++++++++----------
> >  1 files changed, 8 insertions(+), 10 deletions(-)
> > 
> > diff --git a/libavdevice/fbdev.c b/libavdevice/fbdev.c
> > index 121f02c..37bba3d 100644
> > --- a/libavdevice/fbdev.c
> > +++ b/libavdevice/fbdev.c
> > @@ -190,22 +190,20 @@ static int fbdev_read_packet(AVFormatContext *avctx, AVPacket *pkt)
> >          fbdev->time_frame = av_gettime();
> >  
> >      /* wait based on the frame rate */
> > -    while (1) {
> > -        curtime = av_gettime();
> > -        delay = fbdev->time_frame - curtime;
> > -        av_dlog(avctx,
> > -                "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
> > -                fbdev->time_frame, curtime, delay);
> > -        if (delay <= 0) {
> > -            fbdev->time_frame += INT64_C(1000000) * av_q2d(fbdev->time_base);
> > -            break;
> > -        }
> > +    curtime = av_gettime();  <-------------------------- time read
> > +    delay = fbdev->time_frame - curtime;
> > +    av_dlog(avctx,
> > +            "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
> > +            fbdev->time_frame, curtime, delay);
> > +    if (delay > 0) {
> >          if (avctx->flags & AVFMT_FLAG_NONBLOCK)
> >              return AVERROR(EAGAIN);
> >          ts.tv_sec  =  delay / 1000000;
> >          ts.tv_nsec = (delay % 1000000) * 1000;
> >          while (nanosleep(&ts, &ts) < 0 && errno == EINTR); <--------------------wait
> >      }
> > +    /* compute the time of the next frame */
> > +    fbdev->time_frame += INT64_C(1000000) * av_q2d(fbdev->time_base);
> >  
> >      if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
> >          return ret;
> 
> some point later <-------------------- read frame
> even later   <------------------- curtime from above used, but its no
>                                   longer correct due to the wait

Ah I see it now, I suppose we could put a curtime = av_gettime() after
the nanosleep call, or simply leave the code as it is now.
-- 
FFmpeg = Fundamental & Formidable Murdering Picky Eretic Guide