From 2af4bc8562f970207e3b1f6fc0b377ecf116a69c Mon Sep 17 00:00:00 2001 From: Tushar Darote Date: Mon, 8 Jun 2026 18:05:51 +0530 Subject: [PATCH] wayland: handle padded buffers in wl_shm buffer creation Use GstBuffer metadata when constructing wl_shm buffers so stride and size reflect the actual buffer layout. This fixes incorrect rendering with DMA-backed buffers that include padding or custom strides. gst_wl_shm_memory_construct_wl_buffer() now takes a GstBuffer instead of a GstMemory. It derives the video layout from the buffer's GstVideoMeta when present (width, height, stride and offset), falling back to the caps-derived GstVideoInfo otherwise, and computes the real memory footprint (plane_offset + stride * height) rather than the unpadded GstVideoInfo size. The single-memory and fd-memory checks that used to live in the callers are now performed inside the function. All callers in gstwlwindow, waylandsink and gtkwaylandsink are updated accordingly. Upstream-Status: Backport [adapted from https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/11370 due to API differences] Signed-off-by: Tushar Darote --- ext/gtk/gstgtkwaylandsink.c | 11 ++--- ext/wayland/gstwaylandsink.c | 11 ++--- gst-libs/gst/wayland/gstwlshmallocator.c | 59 ++++++++++++++++++------ gst-libs/gst/wayland/gstwlshmallocator.h | 2 +- gst-libs/gst/wayland/gstwlwindow.c | 4 +- 5 files changed, 52 insertions(+), 35 deletions(-) diff --git a/ext/gtk/gstgtkwaylandsink.c b/ext/gtk/gstgtkwaylandsink.c index 0660b30..81bcd7f 100644 --- a/ext/gtk/gstgtkwaylandsink.c +++ b/ext/gtk/gstgtkwaylandsink.c @@ -1179,7 +1179,6 @@ gst_gtk_wayland_sink_show_frame (GstVideoSink * vsink, GstBuffer * buffer) gst_gtk_wayland_sink_get_instance_private (self); GstBuffer *to_render; GstWlBuffer *wlbuffer; - GstMemory *mem; struct wl_buffer *wbuf = NULL; GstFlowReturn ret = GST_FLOW_OK; @@ -1240,8 +1239,6 @@ gst_gtk_wayland_sink_show_frame (GstVideoSink * vsink, GstBuffer * buffer) } /* update video info from video meta */ - mem = gst_buffer_peek_memory (buffer, 0); - GST_LOG_OBJECT (self, "buffer %" GST_PTR_FORMAT " does not have a wl_buffer from our " "display, creating it", buffer); @@ -1301,9 +1298,8 @@ gst_gtk_wayland_sink_show_frame (GstVideoSink * vsink, GstBuffer * buffer) handle_shm: if (!wbuf && gst_wl_display_check_format_for_shm (priv->display, &priv->render_info)) { - if (gst_buffer_n_memory (buffer) == 1 && gst_is_fd_memory (mem)) - wbuf = gst_wl_shm_memory_construct_wl_buffer (mem, priv->display, - &priv->render_info); + wbuf = gst_wl_shm_memory_construct_wl_buffer (buffer, priv->display, + &priv->render_info); /* If nothing worked, copy into our internal pool */ if (!wbuf) { @@ -1328,8 +1324,7 @@ handle_shm: /* attach a wl_buffer if there isn't one yet */ if (G_UNLIKELY (!wlbuffer)) { - mem = gst_buffer_peek_memory (to_render, 0); - wbuf = gst_wl_shm_memory_construct_wl_buffer (mem, priv->display, + wbuf = gst_wl_shm_memory_construct_wl_buffer (to_render, priv->display, &priv->render_info); if (G_UNLIKELY (!wbuf)) diff --git a/ext/wayland/gstwaylandsink.c b/ext/wayland/gstwaylandsink.c index 443db24..60aa11d 100644 --- a/ext/wayland/gstwaylandsink.c +++ b/ext/wayland/gstwaylandsink.c @@ -1011,7 +1011,6 @@ gst_wayland_sink_show_frame (GstVideoSink * vsink, GstBuffer * buffer) GstWaylandSink *self = GST_WAYLAND_SINK (vsink); GstBuffer *to_render; GstWlBuffer *wlbuffer; - GstMemory *mem; struct wl_buffer *wbuf = NULL; GstFlowReturn ret = GST_FLOW_OK; @@ -1086,8 +1085,6 @@ gst_wayland_sink_show_frame (GstVideoSink * vsink, GstBuffer * buffer) } /* update video info from video meta */ - mem = gst_buffer_peek_memory (buffer, 0); - GST_LOG_OBJECT (self, "buffer %" GST_PTR_FORMAT " does not have a wl_buffer from our " "display, creating it", buffer); @@ -1147,9 +1144,8 @@ gst_wayland_sink_show_frame (GstVideoSink * vsink, GstBuffer * buffer) handle_shm: if (!wbuf && gst_wl_display_check_format_for_shm (self->display, &self->render_info)) { - if (gst_buffer_n_memory (buffer) == 1 && gst_is_fd_memory (mem)) - wbuf = gst_wl_shm_memory_construct_wl_buffer (mem, self->display, - &self->video_info); + wbuf = gst_wl_shm_memory_construct_wl_buffer (buffer, self->display, + &self->video_info); /* If nothing worked, copy into our internal pool */ if (!wbuf) { @@ -1173,8 +1169,7 @@ handle_shm: /* attach a wl_buffer if there isn't one yet */ if (G_UNLIKELY (!wlbuffer)) { - mem = gst_buffer_peek_memory (to_render, 0); - wbuf = gst_wl_shm_memory_construct_wl_buffer (mem, self->display, + wbuf = gst_wl_shm_memory_construct_wl_buffer (to_render, self->display, &self->video_info); if (G_UNLIKELY (!wbuf)) diff --git a/gst-libs/gst/wayland/gstwlshmallocator.c b/gst-libs/gst/wayland/gstwlshmallocator.c index 671f2b7..11fb22c 100644 --- a/gst-libs/gst/wayland/gstwlshmallocator.c +++ b/gst-libs/gst/wayland/gstwlshmallocator.c @@ -76,32 +76,60 @@ gst_wl_shm_validate_video_info (const GstVideoInfo * vinfo) } struct wl_buffer * -gst_wl_shm_memory_construct_wl_buffer (GstMemory * mem, GstWlDisplay * display, - const GstVideoInfo * info) +gst_wl_shm_memory_construct_wl_buffer (GstBuffer * buf, + GstWlDisplay * display, const GstVideoInfo * info) { + GstMemory *mem; + GstVideoMeta *vmeta; + GstVideoInfo vinfo; gint width, height, stride; - gsize offset, size, memsize, maxsize; + gsize plane_offset = 0; + gsize mem_offset = 0; + gsize size, memsize, maxsize; enum wl_shm_format format; struct wl_shm_pool *wl_pool; struct wl_buffer *wbuffer; - if (!gst_wl_shm_validate_video_info (info)) { + /* Ensure the buffer has exactly one memory block */ + if (gst_buffer_n_memory (buf) != 1) + return NULL; + + /* Retrieve the memory and ensure it is FD backed */ + mem = gst_buffer_peek_memory (buf, 0); + if (!gst_is_fd_memory (mem)) + return NULL; + + /* Start from caps-derived video info */ + vinfo = *info; + + /* Override layout using GstVideoMeta if present */ + vmeta = gst_buffer_get_video_meta (buf); + if (vmeta) { + vinfo.width = vmeta->width; + vinfo.height = vmeta->height; + vinfo.stride[0] = vmeta->stride[0]; + vinfo.offset[0] = vmeta->offset[0]; + } + + /* Validate the final video layout */ + if (!gst_wl_shm_validate_video_info (&vinfo)) { GST_DEBUG_OBJECT (display, "Unsupported strides and offsets."); return NULL; } - width = GST_VIDEO_INFO_WIDTH (info); - height = GST_VIDEO_INFO_HEIGHT (info); - stride = GST_VIDEO_INFO_PLANE_STRIDE (info, 0); - size = GST_VIDEO_INFO_SIZE (info); - format = gst_video_format_to_wl_shm_format (GST_VIDEO_INFO_FORMAT (info)); + width = GST_VIDEO_INFO_WIDTH (&vinfo); + height = GST_VIDEO_INFO_HEIGHT (&vinfo); + stride = GST_VIDEO_INFO_PLANE_STRIDE (&vinfo, 0); + plane_offset = GST_VIDEO_INFO_PLANE_OFFSET (&vinfo, 0); + + /* wl_shm requires the actual memory footprint of the buffer */ + size = plane_offset + (stride * height); + format = gst_video_format_to_wl_shm_format (GST_VIDEO_INFO_FORMAT (&vinfo)); - memsize = gst_memory_get_sizes (mem, &offset, &maxsize); - offset += GST_VIDEO_INFO_PLANE_OFFSET (info, 0); + memsize = gst_memory_get_sizes (mem, &mem_offset, &maxsize); - g_return_val_if_fail (gst_is_fd_memory (mem), NULL); g_return_val_if_fail (size <= memsize, NULL); - g_return_val_if_fail (gst_wl_display_check_format_for_shm (display, info), + g_return_val_if_fail (gst_wl_display_check_format_for_shm (display, &vinfo), NULL); GST_DEBUG_OBJECT (display, "Creating wl_buffer from SHM of size %" @@ -110,8 +138,9 @@ gst_wl_shm_memory_construct_wl_buffer (GstMemory * mem, GstWlDisplay * display, wl_pool = wl_shm_create_pool (gst_wl_display_get_shm (display), gst_fd_memory_get_fd (mem), memsize); - wbuffer = wl_shm_pool_create_buffer (wl_pool, offset, width, height, stride, - format); + wbuffer = + wl_shm_pool_create_buffer (wl_pool, mem_offset + plane_offset, width, + height, stride, format); wl_shm_pool_destroy (wl_pool); return wbuffer; diff --git a/gst-libs/gst/wayland/gstwlshmallocator.h b/gst-libs/gst/wayland/gstwlshmallocator.h index 4309bd7..38f3ba5 100644 --- a/gst-libs/gst/wayland/gstwlshmallocator.h +++ b/gst-libs/gst/wayland/gstwlshmallocator.h @@ -33,7 +33,7 @@ GST_WL_API void gst_wl_shm_init_once (void); GST_WL_API -struct wl_buffer * gst_wl_shm_memory_construct_wl_buffer (GstMemory * mem, +struct wl_buffer * gst_wl_shm_memory_construct_wl_buffer (GstBuffer * buf, GstWlDisplay * display, const GstVideoInfo * info); G_END_DECLS diff --git a/gst-libs/gst/wayland/gstwlwindow.c b/gst-libs/gst/wayland/gstwlwindow.c index 3c5c3cc..cd9c964 100644 --- a/gst-libs/gst/wayland/gstwlwindow.c +++ b/gst-libs/gst/wayland/gstwlwindow.c @@ -985,9 +985,7 @@ gst_wl_window_update_borders (GstWlWindow * self) buf = gst_buffer_new_allocate (alloc, info.size, NULL); gst_buffer_memset (buf, 0, 0, info.size); - wlbuf = - gst_wl_shm_memory_construct_wl_buffer (gst_buffer_peek_memory (buf, 0), - priv->display, &info); + wlbuf = gst_wl_shm_memory_construct_wl_buffer (buf, priv->display, &info); g_object_unref (alloc); } -- 2.34.1