Created attachment 247771 [details] [review]
flvdemux: add flvversion 1 to src - allow using avdec_flv

flv current only support flvversion 1.
    
    avdec_flv set flvversion as 1 on its sink. But flvdemux does not.
    So in gst_element_factory_list_filter when the caps are checked if
    is_subset of the avdec_flv sink template capabilities, the check fails.
    
    NB: gst_caps_is_subset relies on gst_structure_is_subset. The latter
    fails if the superset has more fields than the subset (and even if that
    condition is removed latter fails in gst_caps_structure_is_superset_field
    if a field of the superset is not in the subset -
    but gst_caps_structure_is_superset_field also check that the subset
    value is a "subset" of the superset adhoc field value, so it is not
    as simple as switching superset and subset identifiers).
    
    With above nota bene diagnosis I hope it makes more sense.

NB2: in 0.10 flv sorenson works without this patch .

The attached patch let flv1 (here sorenson spark) play via gstreamer (gst-launch-1.0 and totem ).
It adds flvversion=1 field to flvdemux when it outputs x-flash-video.

ext/libav/gstavcodecmap.c:1008
caps =
          gst_ff_vid_caps_new (context, NULL, codec_id, encode,
          "video/x-flash-video", "flvversion", G_TYPE_INT, 1, NULL);


listing:
844	    templates = gst_element_factory_get_static_pad_templates (factory);
845	    for (walk = (GList *) templates; walk; walk = g_list_next (walk)) {
846	      GstStaticPadTemplate *templ = walk->data;
847	
848	      /* we only care about the sink templates */
849	      if (templ->direction == direction) {
850	        GstCaps *tmpl_caps;
851	
852	        /* try to intersect the caps with the caps of the template */
853	        tmpl_caps = gst_static_caps_get (&templ->static_caps);
(gdb) l
854	
855	        /* FIXME, intersect is not the right method, we ideally want to check
856	         * for a subset here */
857	
858	        /* check if the intersection is empty */
859	        if ((subsetonly && gst_caps_is_subset (caps, tmpl_caps)) ||
860	            (!subsetonly && gst_caps_can_intersect (caps, tmpl_caps))) {
861	          /* non empty intersection, we can use this element */
862	          g_queue_push_tail (&results, gst_object_ref (factory));



backtrace gst 1.0:

Breakpoint 3, gst_element_factory_list_filter (list=0x89fc40 = {...}, caps=0x7fffe401bb20, direction=GST_PAD_SINK, subsetonly=1)
    at gstelementfactory.c:844
844	    templates = gst_element_factory_get_static_pad_templates (factory);
(gdb) p *factory
$4 = {parent = {object = {object = {g_type_instance = {g_class = 0x6102a0}, ref_count = 6, qdata = 0x0}, lock = {p = 0x6c99b0, i = {7117232, 0}}, 
      name = 0x6c99e0 "avdec_flv", parent = 0x61b070, flags = 0, control_bindings = 0x0, control_rate = 100000000, last_sync = 18446744073709551615, 
      _gst_reserved = 0x0}, loaded = 0, rank = 64, plugin_name = 0x683410 "libav", plugin = 0x67b810, _gst_reserved = {0x0, 0x0, 0x0, 0x0}}, 
  type = 0, metadata = 0x6ca9a0, staticpadtemplates = 0x6caa00 = {0x6c9240, 0x6c9280}, numpadtemplates = 2, uri_type = GST_URI_UNKNOWN, 
  uri_protocols = 0x0, interfaces = 0x0, _gst_reserved = {0x0, 0x0, 0x0, 0x0}}

(gdb) p g_quark_to_string(((((GstCapsArrayElement *)((GstCapsImpl *)tmpl_caps)->array.data)[0]).structure).name)
$20 = (const gchar *) 0x7fffe4004cbd "video/x-flash-video"
(gdb) p g_quark_to_string(((((GstCapsArrayElement *)((GstCapsImpl *)caps)->array.data)[0]).structure).name)
$21 = (const gchar *) 0x64d067 "video/x-flv"
(gdb) p gst_structure_n_fields(((((GstCapsArrayElement *)((GstCapsImpl *)tmpl_caps)->array.data)[0]).structure))$22 = 1
(gdb) p gst_structure_n_fields(((((GstCapsArrayElement *)((GstCapsImpl *)caps)->array.data)[0]).structure))
$23 = 0
(gdb) p g_quark_to_string(((GstStructureField *)((GstStructureImpl *)((((GstCapsArrayElement *)((GstCapsImpl *)tmpl_caps)->array.data)[0]).structure))->fields->data)[0].name)




$24 = (const gchar *) 0x7fffe4004cd1 "flvversion"

+ Trace 232145