[vlc-devel] [PATCH 3/4] video_output: try to create a decoder device even if creating the window failed
Thomas Guillem
thomas at gllm.fr
Mon Jan 13 16:03:00 CET 2020
On Mon, Jan 13, 2020, at 15:59, Steve Lhomme wrote:
>
> On 2020-01-13 15:54, Thomas Guillem wrote:
> >
> > On Mon, Jan 13, 2020, at 15:47, Rémi Denis-Courmont wrote:
> >> Hi,
> >>
> >> Does VA require an actual window? I'd think it only requires a
> >> display, so a vout_window_t in disabled state should suffice.
> >
> > Indeed, we don't have any API that require an enabled window.
> > VA only need:
> > Display *x11dpy = XOpenDisplay(window->display.x11);
> > VADisplay vadpy = *vadpyp = vaGetDisplay(x11dpy);
> >
> > So, I think we could simplify everything by not requiring an enabled
> > window. I that case, you can load the window module, and create the
> > decoder device without a valid size.
>
> Luckily that may be what this patch does. It's using
> sys->display_cfg.window regarless of its state. It may be NULL or set
> but not enabled.
I disagree with this patch. It add one more complexity, different bugs because the decoder device was created with or without a window because the decoder probed it during Open() or when the size was known...
What not requiring the window to be enabled ?
>
> >>
> >> Le 13 janvier 2020 15:56:43 GMT+02:00, Thomas Guillem <thomas at gllm.fr>
> >> a écrit :
> >>
> >>
> >> On Mon, Jan 13, 2020, at 13:35, Steve Lhomme wrote:
> >>
> >> "In some cases (nvdec, mmal, mediacodec ?) the actual size of
> >> the video
> >> to decode is known only after data have been processed, long
> >> after the
> >> device is setup to use with this API. There are hacks to try
> >> to guess
> >> the size early but in the end it's just a hack."
> >>
> >>
> >> What to we do when we have a hw decoder that doesn't know its
> >> actual size but a window is required ? (vaapi).
> >>
> >> >
> >>
> >> This removes the need for these hacks for those using a
> >> decoder device
> >> that doesn't need a window.
> >>
> >> On 2020-01-13 13:27, Alexandre Janniaux wrote:
> >>
> >> Hi,
> >>
> >> This looks dangerous if it is expected to have an enabled
> >> window at decoder device creation. vout_window handle
> >> values will basically be undefined without any way for the
> >> decoder device to know it. Why do you need this?
> >>
> >> Regards,
> >> --
> >> Alexandre Janniaux
> >> Videolabs
> >>
> >> On Mon, Jan 13, 2020 at 12:07:33PM +0100, Steve Lhomme wrote:
> >>
> >> ------------------------------------------------------------------------
> >> src/video_output/video_output.c | 20 +++++++++-----------
> >> 1 file changed, 9 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/src/video_output/video_output.c
> >> b/src/video_output/video_output.c
> >> index 5d583dbe0ca..9540707ab2b 100644
> >> --- a/src/video_output/video_output.c
> >> +++ b/src/video_output/video_output.c
> >> @@ -2099,20 +2099,18 @@ vlc_decoder_device
> >> *vout_GetDevice(const vout_device_configuration_t *cfg)
> >> assert(cfg->fmt != NULL);
> >> vout_thread_sys_t *sys = cfg->vout->p;
> >>
> >> - if (!VoutCheckFormat(cfg->fmt))
> >> - return NULL;
> >> -
> >> - video_format_t original;
> >> - VoutFixFormat(&original, cfg->fmt);
> >> -
> >> vlc_mutex_lock(&sys->window_lock);
> >> - int res = EnableWindowLocked(cfg->vout, &original);
> >> - if (res == 0 && sys->dec_device == NULL)
> >> + if (VoutCheckFormat(cfg->fmt))
> >> + {
> >> + video_format_t original;
> >> + VoutFixFormat(&original, cfg->fmt);
> >> +
> >> + EnableWindowLocked(cfg->vout, &original);
> >> + video_format_Clean(&original);
> >> + }
> >> + if (sys->dec_device == NULL)
> >> sys->dec_device =
> >> vlc_decoder_device_Create(&cfg->vout->obj,
> >> sys->display_cfg.window);
> >> dec_device = sys->dec_device ?
> >> vlc_decoder_device_Hold( sys->dec_device ) : NULL;
> >> vlc_mutex_unlock(&sys->window_lock);
> >> - video_format_Clean(&original);
> >> - if (res != 0)
> >> - return NULL;
> >> return dec_device;
> >> }
> >> --
> >> 2.17.1
> >> ------------------------------------------------------------------------
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> >> --
> >> Envoyé de mon appareil Android avec Courriel K-9 Mail. Veuillez
> >> excuser ma brièveté.
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