[Spice-devel] [PATCH spice-gtk v4 7/7] display-gst: Debug video pipeline on stream-start message

[Pavel Grunt]

On Wed, 2017-06-28 at 14:43 +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.
> 
So this is just for the debug purpose.


> 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'.

When streaming is enabled there is a lot of streams, but just one
file. I'd suggest to put the stream id to the file name.

Pavel

> 
> 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.
> 
> 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>
> Signed-off-by: Victor Toso <me at victortoso.com>
> ---
>  src/channel-display-gst.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/src/channel-display-gst.c b/src/channel-display-gst.c
> index df58de3..04710e8 100644
> --- a/src/channel-display-gst.c
> +++ b/src/channel-display-gst.c
> @@ -298,7 +298,8 @@ 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);
> @@ -312,6 +313,18 @@ 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:
> +        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,
> +                                  "spice-gtk-gst-pipeline-debug");
> +        break;
> +    default:
> +        /* not being handled */
> +        break;
>      }
>      return TRUE;
>  }