[Spice-devel] [PATCH spice-gtk 5/5] display-gst: Use Playbin for GStreamer 1.9.0 onwards

Victor Toso victortoso at redhat.com
Tue May 9 11:08:15 UTC 2017


On Mon, May 08, 2017 at 03:41:59AM +0000, Daimon Wang wrote:
> Hi,
> Is there anything prevent playbin from working with previous versions
> of Gstreamer? I'm trying to use palybin similarly on another program,
> for the vaapi support.

For versions 1.9.0 onwards and if you have supported hw with drivers and
gstreamer1-vaapi (elements) installed, then playbin should be using
either vaapidecodebin or vaapipostproc first, to verify if it can do hw
decoding otherwise it fallback to sw decoding (with avdec_h264 for
instance).

For version before 1.9.0, as far as I understood, it'll not use the
vaapielements first, so it should do sw decoding by default.

I did not test with 1.9.0 or earlier versions to say it for sure.

> Regards,Daimon
>
>     On Thursday, May 4, 2017 9:44 PM, Victor Toso <victortoso at redhat.com> wrote:
>  
> 
>  From: Victor Toso <me at victortoso.com>
> 
> The Playbin can provide the full pipeline which reduces the
> overall maintenance in the code as we don't need to track which
> decoder can work with our stream type.
> 
> We need to maintain the GstCaps per SPICE_VIDEO_CODEC_TYPE in order to
> tell Playbin the type of data we expect. This much should be covered
> by spice-protocol and very likely we will need to extend it in the
> future to allow more settings that might not possible to verify at
> runtime.
> 
> This patch keeps previous code for compatibility reasons.
> 
> Note that we have to wait Playbin to emit "source-setup" in order to
> configure GstAppSrc with the capabilities of input stream. If in the
> unlikely event of frames arriving while GstAppSrc is not setup, we
> will drop those frames.
> 
> Signed-off-by: Victor Toso <victortoso at redhat.com>
> Signed-off-by: Victor Toso <me at victortoso.com>
> ---
>  src/channel-display-gst.c | 88 +++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 86 insertions(+), 2 deletions(-)
> 
> diff --git a/src/channel-display-gst.c b/src/channel-display-gst.c
> index 2a20763..2b14745 100644
> --- a/src/channel-display-gst.c
> +++ b/src/channel-display-gst.c
> @@ -50,6 +50,9 @@ typedef struct SpiceGstDecoder {
>     guint timer_id;
>  } SpiceGstDecoder;
>  
> +/* FIXME: With gstreamer version 1.9.0 and higher, we are using playbin to
> + * create the pipeline for us and for that reason we don't need to keep track of
> + * decoder's name anymore. */
>  static struct {
>     const gchar *dec_name;
>     const gchar *dec_caps;
> @@ -256,10 +259,13 @@ static GstFlowReturn new_sample(GstAppSink *gstappsink, gpointer video_decoder)
>             }
>             l = l->next;
>         }
> +#if !GST_CHECK_VERSION(1,9,0)
> +        /* We down own this sample when using playbin, no need to unref it */
>         if (!l) {
>             spice_warning("got an unexpected decoded buffer!");
>             gst_sample_unref(sample);
>         }
> +#endif
>  
>         g_mutex_unlock(&decoder->queues_mutex);
>         schedule_frame(decoder);
> @@ -276,8 +282,11 @@ static void free_pipeline(SpiceGstDecoder *decoder)
>     }
>  
>     gst_element_set_state(decoder->pipeline, GST_STATE_NULL);
> +#if !GST_CHECK_VERSION(1,9,0)
> +    /* Owned by playbin on 1.9.0 onwards */
>     gst_object_unref(decoder->appsrc);
>     gst_object_unref(decoder->appsink);
> +#endif
>     gst_object_unref(decoder->pipeline);
>     gst_object_unref(decoder->clock);
>     decoder->pipeline = NULL;
> @@ -305,13 +314,79 @@ static gboolean handle_pipeline_message(GstBus *bus, GstMessage *msg, gpointer v
>     return TRUE;
>  }
>  
> +#if GST_CHECK_VERSION(1,9,0)
> +static void app_source_setup(GstElement *pipeline, GstElement *source, SpiceGstDecoder *decoder)
> +{
> +    GstCaps *caps;
> +
> +    /* - We schedule the frame display ourselves so set sync=false on appsink
> +    *  so the pipeline decodes them as fast as possible. This will also
> +    *  minimize the risk of frames getting lost when we rebuild the
> +    *  pipeline.
> +    * - Set max-bytes=0 on appsrc so it does not drop frames that may be
> +    *  needed by those that follow.
> +    */
> +    caps = gst_caps_from_string(gst_opts[decoder->base.codec_type].dec_caps);
> +    g_object_set(source,
> +                "caps", caps,
> +                "is-live", TRUE,
> +                "format", GST_FORMAT_TIME,
> +                "max-bytes", 0,
> +                "block", TRUE,
> +                NULL);
> +    gst_caps_unref(caps);
> +    decoder->appsrc = GST_APP_SRC(source);
> +}
> +#endif
> +
>  static gboolean create_pipeline(SpiceGstDecoder *decoder)
>  {
> -    gchar *desc;
>     GstAppSinkCallbacks appsink_cbs = { NULL };
> -    GError *err = NULL;
>     GstBus *bus;
> +#if GST_CHECK_VERSION(1,9,0)
> +    GstElement *playbin, *sink;
> +    gint flags;
> +    GstCaps *caps;
>  
> +    playbin = gst_element_factory_make("playbin", "playbin");
> +    if (playbin == NULL) {
> +        spice_warning("error upon creation of 'playbin' element");
> +        return FALSE;
> +    }
> +
> +    sink = gst_element_factory_make("appsink", "sink");
> +    if (sink == NULL) {
> +        spice_warning("error upon creation of 'appsink' element");
> +        gst_object_unref(playbin);
> +        return FALSE;
> +    }
> +
> +    caps = gst_caps_from_string("video/x-raw,format=BGRx");
> +    g_object_set(sink,
> +                "caps", caps,
> +                "sync", FALSE,
> +                "drop", FALSE,
> +                NULL);
> +    gst_caps_unref(caps);
> +
> +    g_object_set(playbin,
> +                "uri", "appsrc://",
> +                "video-sink", sink,
> +                NULL);
> +
> +    g_signal_connect(playbin, "source-setup", G_CALLBACK(app_source_setup), decoder);
> +
> +    /* Disable audio in playbin */
> +    g_object_get(playbin, "flags", &flags, NULL);
> +    flags &= ~(1 << 1);
> +    g_object_set(playbin, "flags", flags, NULL);
> +
> +    decoder->appsrc = NULL;
> +    decoder->appsink = GST_APP_SINK(sink);
> +    decoder->pipeline = playbin;
> +#else
> +    gchar *desc;
> +    GError *err = NULL;
>  
>     /* - We schedule the frame display ourselves so set sync=false on appsink
>       *  so the pipeline decodes them as fast as possible. This will also
> @@ -337,6 +412,7 @@ static gboolean create_pipeline(SpiceGstDecoder *decoder)
>  
>     decoder->appsrc = GST_APP_SRC(gst_bin_get_by_name(GST_BIN(decoder->pipeline), "src"));
>     decoder->appsink = GST_APP_SINK(gst_bin_get_by_name(GST_BIN(decoder->pipeline), "sink"));
> +#endif
>  
>     appsink_cbs.new_sample = new_sample;
>     gst_app_sink_set_callbacks(decoder->appsink, &appsink_cbs, decoder, NULL);
> @@ -447,6 +523,14 @@ static gboolean spice_gst_decoder_queue_frame(VideoDecoder *video_decoder,
>         return FALSE;
>     }
>  
> +#if GST_CHECK_VERSION(1,9,0)
> +    if (decoder->appsrc == NULL) {
> +        spice_warning("Error: Playbin has not yet initialized the Appsrc element");
> +        stream_dropped_frame_on_playback(decoder->base.stream);
> +        return TRUE;
> +    }
> +#endif
> +
>     /* ref() the frame_msg for the buffer */
>     spice_msg_in_ref(frame_msg);
>     GstBuffer *buffer = gst_buffer_new_wrapped_full(GST_MEMORY_FLAG_PHYSICALLY_CONTIGUOUS,
> -- 
> 2.12.2
> 
> _______________________________________________
> Spice-devel mailing list
> Spice-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/spice-devel
> 
> 
>    
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/spice-devel/attachments/20170509/5ca7bbf1/attachment.sig>


More information about the Spice-devel mailing list