<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> </head> <body bgcolor="#ffffff" text="#000000"> Hello, I am trying to build an element that is a video transformer. It will transform in a way that depends on downstream elements (external dependencies). The sink pad has voxelVideo as caps and the two src pads have video/x-raw-rgb and video/x-raw-short respectively. The video/x-raw-short is just a 16bit/pixel 1 channel video used for a disparity map. When I try to get negotiated caps in the chain function, this fails. Code: ----- static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",                                                                     GST_PAD_SINK,                                                                     GST_PAD_ALWAYS,                    GST_STATIC_CAPS ("videoVoxel/x-raw-gray, "                    "width = (int) [ 16, 4096 ], "                                    "height = (int) [ 16, 4096 ], "                                    "voxelDepth = (int) [ 1, 4096 ], "                                    "framerate = (fraction) [ 0/1, 2147483647/1 ]")); static GstStaticPadTemplate src_factory_rgb = GST_STATIC_PAD_TEMPLATE("src_rgb",                                                                   GST_PAD_SRC,                                                                   GST_PAD_REQUEST,                    GST_STATIC_CAPS ("video/x-raw-rgb, "                    "width = (int) [ 16, 4096 ], "                     "bpp = (int) 24, "                                    "height = (int) [ 16, 4096 ], "                                    "framerate = (fraction) [ 0/1, 2147483647/1 ]")); static GstStaticPadTemplate src_factory_short = GST_STATIC_PAD_TEMPLATE("src_short",                                                                   GST_PAD_SRC,                                                                   GST_PAD_REQUEST,                    GST_STATIC_CAPS ("video/x-raw-short, "                    "width = (int) [ 16, 4096 ], "                     "bpp = (int) 16, "                                    "height = (int) [ 16, 4096 ], "                                    "framerate = (fraction) [ 0/1, 2147483647/1 ]")); ----- /* initialize the plugin's class */ static void gst_tidvoxelrend_class_init (GsttidvoxelrendClass * klass) { ...    gstelement_class->request_new_pad = gst_vrender_request_new_pad; .... } --------- static void gst_tidvoxelrend_base_init (gpointer gclass) { ...    gst_element_class_add_pad_template(element_class, gst_static_pad_template_get (&sink_factory));     gst_element_class_add_pad_template(element_class, gst_static_pad_template_get (&src_factory_rgb));     gst_element_class_add_pad_template(element_class, gst_static_pad_template_get (&src_factory_short));     gst_element_class_set_details(element_class, &element_details); ... } ------------ static GstPad * gst_vrender_request_new_pad (GstElement * element,     GstPadTemplate * templ, const gchar * req_name) {     Gsttidvoxelrend *vrender = GST_TIDVOXELREND (element);     GstElementClass *klass = GST_ELEMENT_GET_CLASS (element);     GstPad *pad;     GST_DEBUG("RENDER :::::::::: new pad");     g_return_val_if_fail (templ != NULL, NULL);     if (templ->direction != GST_PAD_SRC) {     GST_WARNING_OBJECT (vrender, "request pad is not a SRC pad");     return NULL;     }     if (templ == gst_element_class_get_pad_template (klass, "src_rgb")) {     if (vrender->srcpad_rgb)         return NULL;     vrender->srcpad_rgb = gst_pad_new_from_template (templ, "src_rgb");     gst_pad_set_setcaps_function (vrender->srcpad_rgb,                       GST_DEBUG_FUNCPTR (gst_tidvoxelrend_set_caps_rgb));     pad = vrender->srcpad_rgb;     } else if (templ == gst_element_class_get_pad_template (klass, "src_short")) {     if (vrender->srcpad_short)         return NULL;     vrender->srcpad_short = gst_pad_new_from_template (templ, "src_short");     gst_pad_set_setcaps_function (vrender->srcpad_short,                       GST_DEBUG_FUNCPTR (gst_tidvoxelrend_set_caps_short));     pad = vrender->srcpad_short;     } else {     g_return_val_if_reached (NULL);     }     gst_element_add_pad (element, pad);     return pad; } ----- static void gst_tidvoxelrend_init(Gsttidvoxelrend * filter, GsttidvoxelrendClass * gclass) {   GstElementClass *klass = GST_ELEMENT_GET_CLASS (filter);   GST_DEBUG("In gst_tidvoxelrend_init");   goodtimestamp                 = GOODTIMESTAMP;   goodduration                  = GOODDURATION;   gst_tidvoxelrend_pad_id      = GST_TIDVOXELREND_PAD_ID;   /* Src pad config */   filter->sinkpad = gst_pad_new_from_template (gst_element_class_get_pad_template (klass, "sink"), "sink");   gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);   gst_pad_set_chain_function (filter->sinkpad, gst_tidvoxelrend_chain); .... } --------------- static GstFlowReturn gst_tidvoxelrend_chain (GstPad * pad, GstBuffer * buf) {   GstCaps *debugcaps = NULL;   GstStructure *structure;   GList *pads;   GstBuffer *outbuf = NULL;   size_t outsize = 0;   int rgb = 0;   Gsttidvoxelrend *vrender = (Gsttidvoxelrend *) gst_pad_get_parent (pad);   pads = GST_ELEMENT_CAST (vrender)->srcpads;   while (pads) {       GstPad *pad;     pad = GST_PAD_CAST (pads->data);       GST_DEBUG("RENDER :::::::::: pad name = %s", GST_PAD_NAME(pad));       /* We get the already negotiated caps to reapply them on the src pad */       debugcaps = gst_pad_get_negotiated_caps(pad);       GST_DEBUG("RENDER :::::::::: after get_negotiated_caps");       /* Get output buffer size */       structure = gst_caps_get_structure (debugcaps, 0);       GST_DEBUG("RENDER :::::::::: after caps_get_structure");       if (strstr (GST_PAD_NAME(pad), "src_rgb")) {           outsize = vrender->out_width * vrender->out_height * 3;           rgb = 1;       }       else {           outsize = vrender->out_width * vrender->out_height * 2;           rgb = 0;       }       if( gst_pad_alloc_buffer_and_set_caps (pad,                                              GST_BUFFER_OFFSET_NONE,                                              outsize,                                              debugcaps,                                              &outbuf) != GST_FLOW_OK ) ................ } ---------------- When I try to run this element with one fakesink afterwards: gstlaunch someplugins !  tidvoxelrend  name=rend rend. ! fakesink dump=true I get: 0:00:01.427001861 25832 0x7fd6b0002f00 DEBUG         tidvoxelrend voxelRenderer/gsttidvoxelrend.c:606:gst_tidvoxelrend_chain: RENDER :::::::::: pad name = src_rgb 0:00:01.427033240 25832 0x7fd6b0002f00 DEBUG         tidvoxelrend voxelRenderer/gsttidvoxelrend.c:611:gst_tidvoxelrend_chain: RENDER :::::::::: after get_negotiated_caps (gst-launch-0.10:25832): GStreamer-CRITICAL **: gst_caps_get_structure: assertion `GST_IS_CAPS (caps)' failed 0:00:01.427112209 25832 0x7fd6b0002f00 DEBUG         tidvoxelrend voxelRenderer/gsttidvoxelrend.c:617:gst_tidvoxelrend_chain: RENDER :::::::::: after caps_get_structure What could be wrong here, please? Thanks in advance, Mattias <pre class="moz-signature" cols="72">-- Mattias Frank Barthel Vía Augusta 177 08021 Barcelona (Spain) Video & Multimedia technologies TELEFÓNICA R&D T. 0034-93-365-3309 </pre> </body> </html>