[Spice-devel] [PATCH spice-gtk 2/2] gstreamer: Fallback to S/W decoder if H/W one is not working

[Kasireddy, Vivek]

Hi Frediano,

> 
> In case the H/W decoder is not able to decode the stream (like too high
> profile) try the S/W version.
> This is done detecting the failure and trying to recreate the pipeline
> in case:
> - we are using a H/W pipeline;
> - we didn't decode any frame (otherwise it means we lost the beginning
>   or it was not a problem of H/W decoder).
> 
> Signed-off-by: Frediano Ziglio <freddy77 at gmail.com>
> ---
>  src/channel-display-gst.c | 43 ++++++++++++++++++++++++++++++++++-----
>  1 file changed, 38 insertions(+), 5 deletions(-)
> 
> diff --git a/src/channel-display-gst.c b/src/channel-display-gst.c
> index 6e126000..1238c943 100644
> --- a/src/channel-display-gst.c
> +++ b/src/channel-display-gst.c
> @@ -48,6 +48,8 @@ typedef struct SpiceGstDecoder {
>      GstElement *pipeline;
>      GstClock *clock;
>      GstBus *bus;
> +    bool is_hw_pipeline;
> +    bool frame_removed;
> 
>      /* ---------- Decoding and display queues ---------- */
> 
> @@ -125,6 +127,7 @@ static void free_gst_frame(SpiceGstFrame *gstframe)
>  /* ---------- GStreamer pipeline ---------- */
> 
>  static void schedule_frame(SpiceGstDecoder *decoder);
> +static void try_sw_pipeline(SpiceGstDecoder *decoder);
> 
>  RECORDER(frames_stats, 64, "Frames statistics");
> 
> @@ -231,6 +234,7 @@ static guint32 pop_up_to_frame(SpiceGstDecoder
> *decoder, const SpiceGstFrame *po
>      SpiceGstFrame *gstframe;
>      guint32 freed = 0;
> 
> +    decoder->frame_removed = true;
>      while ((gstframe = g_queue_pop_head(decoder->decoding_queue)) !=
> popframe) {
>          free_gst_frame(gstframe);
>          freed++;
> @@ -371,6 +375,7 @@ static void free_pipeline(SpiceGstDecoder *decoder)
>      decoder->clock = NULL;
>      gst_object_unref(decoder->pipeline);
>      decoder->pipeline = NULL;
> +    decoder->is_hw_pipeline = false;
>  }
> 
>  static gboolean handle_pipeline_message(GstBus *bus, GstMessage *msg,
> gpointer video_decoder)
> @@ -390,8 +395,12 @@ static gboolean handle_pipeline_message(GstBus
> *bus, GstMessage *msg, gpointer v
>          }
>          g_clear_error(&err);
> 
> -        /* We won't be able to process any more frame anyway */
> -        free_pipeline(decoder);
If you keep the above line, I think you can avoid the else below;
given that you are freeing the pipeline anyway in try_sw_pipeline?

> +        if (decoder->is_hw_pipeline && !decoder->frame_removed) {
> +            try_sw_pipeline(decoder);
> +        } else {
> +            /* We won't be able to process any more frame anyway */
> +            free_pipeline(decoder);
> +        }
>          break;
>      }
>      case GST_MESSAGE_STREAM_START: {
> @@ -670,6 +679,7 @@ static bool try_intel_hw_pipeline(SpiceGstDecoder
> *decoder)
>      }
> 
>      decoder->pipeline = pipeline;
> +    decoder->is_hw_pipeline = true;
>      return launch_pipeline(decoder);
> 
>  err:
> @@ -702,7 +712,7 @@ err:
>      return false;
>  }
> 
> -static gboolean create_pipeline(SpiceGstDecoder *decoder)
> +static gboolean create_pipeline(SpiceGstDecoder *decoder, bool
> try_hw_pipeline)
>  {
>      GstElement *playbin, *sink;
>      SpiceGstPlayFlags flags;
> @@ -712,7 +722,7 @@ static gboolean create_pipeline(SpiceGstDecoder
> *decoder)
> 
>      if (vendor == VENDOR_GPU_DETECTED ||
>          vendor == VENDOR_GPU_UNKNOWN) {
> -        if (try_intel_hw_pipeline(decoder)) {
> +        if (try_hw_pipeline && try_intel_hw_pipeline(decoder)) {
>              return TRUE;
>          }
>      }
> @@ -995,7 +1005,7 @@ VideoDecoder* create_gstreamer_decoder(int
> codec_type, display_stream *stream)
>          g_mutex_init(&decoder->queues_mutex);
>          decoder->decoding_queue = g_queue_new();
> 
> -        if (!create_pipeline(decoder)) {
> +        if (!create_pipeline(decoder, true)) {
>              decoder->base.destroy((VideoDecoder*)decoder);
>              decoder = NULL;
>          }
> @@ -1064,3 +1074,26 @@ gboolean gstvideo_has_codec(int codec_type)
>      gst_plugin_feature_list_free(all_decoders);
>      return TRUE;
>  }
> +
> +static void try_sw_pipeline(SpiceGstDecoder *decoder)
> +{
> +    // try to create a S/W pipeline
> +    free_pipeline(decoder);
> +    if (!create_pipeline(decoder, false)) {
> +        return;
> +    }
> +
> +    // reply the old queue
replay?

Thanks,
Vivek
> +    g_mutex_lock(&decoder->queues_mutex);
> +    GList *l = g_queue_peek_head_link(decoder->decoding_queue);
> +    while (l) {
> +        const SpiceGstFrame *gstframe = l->data;
> +        GstBuffer *buf = gst_buffer_ref(gstframe->encoded_buffer);
> +        if (gst_app_src_push_buffer(decoder->appsrc, buf) != GST_FLOW_OK) {
> +            SPICE_DEBUG("GStreamer error: unable to push frame");
> +            stream_dropped_frame_on_playback(decoder->base.stream);
> +        }
> +        l = l->next;
> +    }
> +    g_mutex_unlock(&decoder->queues_mutex);
> +}
> --
> 2.41.0