[Spice-devel] [PATCH spice-gtk 2/2] display-gst: Debug video pipeline on stream-start message

[Christophe Fergeau]

On Mon, Jul 10, 2017 at 05:52:07PM +0200, Victor Toso wrote:
> From: Victor Toso <me at victortoso.com>
> 
> On GST_MESSAGE_STREAM_START our stream is about to start and it seems
> a good moment to debug GStreamer pipeline if requested.
> 
> That we can do with GST_DEBUG_BIN_TO_DOT_FILE() which iterates
> recursively in the whole pipeline and generates a dot file with all
> the information, the filename is 'spice-gtk-gst-pipeline-debug.dot'.
> 
> One can generate png image out of this dot file with the command:
>   dot -Tpng -oimage.png spice-gtk-gst-pipeline-debug.dot
> 
> Not that GST_DEBUG_BIN_TO_DOT_FILE() will only work if Gstreamer was
> configured with --gst-enable-gst-debug and the environment variable
> GST_DEBUG_DUMP_DOT_DIR was properly set.

Ah missed that initially, I was wondering where the file would go, and
if this was always enabled :) Good to have these details in the log!

> 
> Full example:
> 
> 1) GST_DEBUG_DUMP_DOT_DIR=/tmp remote-viewer ...
> 2) dot -Tpng -oimage.png spice-gtk-gst-pipeline-debug.dot
> 
> Signed-off-by: Victor Toso <victortoso at redhat.com>
> ---
>  src/channel-display-gst.c  | 21 ++++++++++++++++++++-
>  src/channel-display-priv.h |  1 +
>  src/channel-display.c      | 17 +++++++++++++++++
>  3 files changed, 38 insertions(+), 1 deletion(-)
> 
> diff --git a/src/channel-display-gst.c b/src/channel-display-gst.c
> index acea4a2..ef63078 100644
> --- a/src/channel-display-gst.c
> +++ b/src/channel-display-gst.c
> @@ -265,7 +265,8 @@ static gboolean handle_pipeline_message(GstBus *bus, GstMessage *msg, gpointer v
>  {
>      SpiceGstDecoder *decoder = video_decoder;
>  
> -    if (GST_MESSAGE_TYPE(msg) == GST_MESSAGE_ERROR) {
> +    switch(GST_MESSAGE_TYPE(msg)) {
> +    case GST_MESSAGE_ERROR: {
>          GError *err = NULL;
>          gchar *debug_info = NULL;
>          gst_message_parse_error(msg, &err, &debug_info);
> @@ -279,6 +280,24 @@ static gboolean handle_pipeline_message(GstBus *bus, GstMessage *msg, gpointer v
>  
>          /* We won't be able to process any more frame anyway */
>          free_pipeline(decoder);
> +        break;
> +    }
> +    case GST_MESSAGE_STREAM_START: {
> +        gchar *filename = g_strdup_printf("spice-gtk-gst-pipeline-debug-%ld-%s",
> +                                          get_stream_id_by_stream(decoder->base.stream->channel,
> +                                                                  decoder->base.stream),
> +                                          gst_opts[decoder->base.codec_type].name);
> +        GST_DEBUG_BIN_TO_DOT_FILE(GST_BIN(decoder->pipeline),
> +                                  GST_DEBUG_GRAPH_SHOW_ALL
> +                                    | GST_DEBUG_GRAPH_SHOW_FULL_PARAMS
> +                                    | GST_DEBUG_GRAPH_SHOW_STATES,
> +                                    filename);
> +        g_free(filename);
> +        break;
> +    }
> +    default:
> +        /* not being handled */
> +        break;
>      }
>      return TRUE;
>  }
> diff --git a/src/channel-display-priv.h b/src/channel-display-priv.h
> index 00f71f8..407145f 100644
> --- a/src/channel-display-priv.h
> +++ b/src/channel-display-priv.h
> @@ -196,6 +196,7 @@ G_STATIC_ASSERT(G_N_ELEMENTS(gst_opts) <= SPICE_VIDEO_CODEC_TYPE_ENUM_END);
>  guint32 stream_get_time(display_stream *st);
>  void stream_dropped_frame_on_playback(display_stream *st);
>  void stream_display_frame(display_stream *st, SpiceFrame *frame, uint32_t width, uint32_t height, uint8_t* data);
> +gint64 get_stream_id_by_stream(SpiceChannel *channel, display_stream *st);
>  
>  
>  G_END_DECLS
> diff --git a/src/channel-display.c b/src/channel-display.c
> index e51064a..f226988 100644
> --- a/src/channel-display.c
> +++ b/src/channel-display.c
> @@ -1164,6 +1164,23 @@ static display_stream *get_stream_by_id(SpiceChannel *channel, uint32_t id)
>      return NULL;
>  }
>  
> +G_GNUC_INTERNAL
> +gint64 get_stream_id_by_stream(SpiceChannel *channel, display_stream *st)
> +{
> +    SpiceDisplayChannelPrivate *c = SPICE_DISPLAY_CHANNEL(channel)->priv;
> +    guint i;
> +
> +    g_return_val_if_fail(c->streams != NULL, -1);
> +    g_return_val_if_fail(c->nstreams != 0, -1);

You could even go for
+    g_return_val_if_fail(c->nstreams > 0, -1);

Acked-by: Christophe Fergeau <cfergeau at redhat.com>
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