[Spice-devel] [spice-gtk] gstreamer: Take into account stride information

[Pavel Grunt]

Hi Frediano,

On Tue, 2017-07-25 at 15:31 +0100, Frediano Ziglio wrote:
> Using hardware encoders/decoders is possible that the output
> stride of the image cannot be computed with a fixed formula
> (width * 4). GStreamer in this case should set GstVideoMeta
> information with the correct stride value.
> Consider this value if present.
> This fix a problem using NvDec encoder and Intel decoder.
you mean NVENC encoder

> 
> Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
> ---
>  src/channel-display-gst.c   | 9 ++++++++-
>  src/channel-display-mjpeg.c | 2 +-
>  src/channel-display-priv.h  | 2 +-
>  src/channel-display.c       | 6 ++++--
>  4 files changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/src/channel-display-gst.c b/src/channel-display-gst.c
> index 03c6044..0abe706 100644
> --- a/src/channel-display-gst.c
> +++ b/src/channel-display-gst.c
> @@ -26,6 +26,7 @@
>  #include <gst/gst.h>
>  #include <gst/app/gstappsrc.h>
>  #include <gst/app/gstappsink.h>
> +#include <gst/video/gstvideometa.h>
>  
>  
>  /* GStreamer decoder implementation */
> @@ -102,6 +103,12 @@ static void free_gst_frame(SpiceGstFrame *gstframe)
>  
>  static void schedule_frame(SpiceGstDecoder *decoder);
>  
> +static int gst_buffer_get_stride(GstBuffer *buffer)
I'd prefer to do in our namespace instead on gstreamer's
> +{
> +    GstVideoMeta *video = gst_buffer_get_video_meta(buffer);
> +    return video ? video->stride[0] : 0;
The documentation of GstVideoMeta says that the value of the stride may be
invalid - do you know what is the value in that case?

What about using some constant instead of 0 (respectively the invalid value)
(SPICE_UNKNOWN_STRIDE)


> +}
> +
>  /* main context */
>  static gboolean display_frame(gpointer video_decoder)
>  {
> @@ -145,7 +152,7 @@ static gboolean display_frame(gpointer video_decoder)
>      }
>  
>      stream_display_frame(decoder->base.stream, gstframe->frame,
> -                         width, height, mapinfo.data);
> +                         width, height, gst_buffer_get_stride(buffer),
> mapinfo.data);
>      gst_buffer_unmap(buffer, &mapinfo);
>  
>   error:
> diff --git a/src/channel-display-mjpeg.c b/src/channel-display-mjpeg.c
> index 3ba098c..6082511 100644
> --- a/src/channel-display-mjpeg.c
> +++ b/src/channel-display-mjpeg.c
> @@ -176,7 +176,7 @@ static gboolean mjpeg_decoder_decode_frame(gpointer
> video_decoder)
>  
>      /* Display the frame and dispose of it */
>      stream_display_frame(decoder->base.stream, decoder->cur_frame,
> -                         width, height, decoder->out_frame);
> +                         width, height, 0, decoder->out_frame);

same here

>      free_spice_frame(decoder->cur_frame);
>      decoder->cur_frame = NULL;
>      decoder->timer_id = 0;
> diff --git a/src/channel-display-priv.h b/src/channel-display-priv.h
> index 04cb4d1..72e0840 100644
> --- a/src/channel-display-priv.h
> +++ b/src/channel-display-priv.h
> @@ -192,7 +192,7 @@ 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);
> +void stream_display_frame(display_stream *st, SpiceFrame *frame, uint32_t
> width, uint32_t height, int stride, uint8_t* data);
>  gint64 get_stream_id_by_stream(SpiceChannel *channel, display_stream *st);
>  
>  
> diff --git a/src/channel-display.c b/src/channel-display.c
> index 06ed18a..4eb665f 100644
> --- a/src/channel-display.c
> +++ b/src/channel-display.c
> @@ -1312,9 +1312,11 @@ void stream_dropped_frame_on_playback(display_stream
> *st)
>  /* main context */
>  G_GNUC_INTERNAL
>  void stream_display_frame(display_stream *st, SpiceFrame *frame,
> -                          uint32_t width, uint32_t height, uint8_t *data)
> +                          uint32_t width, uint32_t height, int stride,
> uint8_t *data)
>  {
> -    int stride = width * sizeof(uint32_t);
> +    if (stride == 0) {
and here
> +        stride = width * sizeof(uint32_t);
> +    }
>      if (!(st->flags & SPICE_STREAM_FLAGS_TOP_DOWN)) {
>          data += stride * (height - 1);
>          stride = -stride;