On Thu, 2005-10-06 at 16:38 +0200, Stefan Lucke wrote:
> On Donnerstag, 6. Oktober 2005 16:00, Nicolas Huillard wrote:
> > I just applied the first part of the patch (since I don't mind about
> > field parity), and I get the following result (0.1.3) :
> > 
> > [dfb] Display frame time is 17668 microseconds
> > 
> > (was something like 99950 us before the patch, and video was a
> > succession of 1s fast-paced images and 1s still-image, like someone
> > described on the ML recently)
> > 
> > Since I output on PAL TV @ 50Hz, this timing seems odd (should be 20000
> > us, isn't it ? not 17,668 ms / 56Hz) I'm not in front of the TV so I
> > can't check image quality.
> 
> Yes it should be 20000 or a few counts lower. Do you use Mark Adams'
> unichrome-directfb.diff posted on directfb-user on 2005-09-07 11:27 ?
> There is the following hunk and there is a usleep(2500):
> 
> @@ -240,21 +245,22 @@
>      UcDriverData*  ucdrv = (UcDriverData*) driver_data;
>      UcOverlayData* ucovl = (UcOverlayData*) layer_data;
>      DFBResult    ret;
> -
> -    if (((flags & DSFLIP_WAITFORSYNC) == DSFLIP_WAITFORSYNC) &&
> -        !dfb_config->pollvsync_after)
> -        dfb_layer_wait_vsync( layer );
> +    int field_option;
> +    FBDev *dfb_fbdev = dfb_system_data();
>  
>      dfb_surface_flip_buffers(surface, false);
>  
>      ucovl->field = 0;
>  
> +    field_option = 2;  // wait for bottom field
> +    ioctl(dfb_fbdev->fd, FBIO_WAITFORVSYNC, &field_option);
> +    usleep(2500);      // make sure field has started (so update will happen 
> on next field)
> +
>      ret = uc_ovl_update(ucdrv, ucovl, UC_OVL_FLIP, surface);

I'm sure that this is the source of my problem with softdevice,
DirectFB, and Mark's patches (picture that displays a 'jerk' or dropped
frame every few seconds, i.e. not bad, but the audio stutters quite
badly, although A-V sync isn't that bad for me now).

I have yet to play about with timings properly but a quick go of
hard-coding the frame time to 20000 - 2500 didn't seem to make any
difference.

I will have a deeper look...

Cheers,

Laz


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