7 src negotiation recovery
8 ------------------------
12 filesrc -> mad -> osssink
14 perform negotiation strictly left to right. At some point during
15 iterate, mad will know the caps of the media stream and will need
16 to inform osssink of this before pushing out a buffer.
17 mad only has one set of fixed caps.
21 mad does a try_set_caps with the caps if all goes well, osssink
22 accepts and negotiation succeeds.
24 if the try_set_caps function fails, the application should have
27 - mad therefore calls gst_pad_caps_error_try_recover, this will
28 emit a signal on the pad that the app can catch. One of the
29 signal arguments will contain a list of possible caps.
31 - the app can use the allowed caps to find another element that
32 is compatible with the caps and the peer element caps.
34 - the app will connect the new element with mad, negotiation
35 will happen again, the link will fail or succeed, if it fails,
36 thr app knows because the link function returns FALSE.
38 - if the link succeeds, pad caps are set and the try_recover
39 function returns TRUE, mad then knows the issue was resolved
40 and can continue. It will have received the final caps in its
43 - if no signal handler is connected to the caps_nego_failure signal
44 the issue will remain unresolved and a big debug warning is
45 printed on the console to debug the issue. mad will get a
46 return value of FALSE and may stop.