In the following backtrace for the deadlock, we can see that:
- In T8 `uridecodebin3` is exposing a new pad, in `pad_added_cb`,
`playbin3` is trying to get `GST_PLAY_BIN3_LOCK` in the callback. This
threads holds its `SELECTION_LOCK` in F17 `reconfigure_output_stream`,
which is looks right `decodebin3` is handling its selection state
in that code path
- In T7 `playbin3` holds the `GST_PLAY_BIN3_LOCK` when calling
`gst_element_post_message` in `gst_play_bin3_send_event` which is
not necessary in that section of the code.
``` bt
Thread 8 (Thread 0x7f0b78ee36c0 (LWP 2952467) "multiqueue0:src"):
#0 futex_wait (private=0, expected=2, futex_word=0x1fa6d60) at ../sysdeps/nptl/futex-internal.h:146
#1 __GI___lll_lock_wait (futex=futex@entry=0x1fa6d60, private=0) at lowlevellock.c:49
#2 0x00007f0b858cd46a in lll_mutex_lock_optimized (mutex=0x1fa6d60) at pthread_mutex_lock.c:48
#3 ___pthread_mutex_lock (mutex=0x1fa6d60) at pthread_mutex_lock.c:128
#4 0x00007f0b7e665720 in pad_added_cb (uridecodebin=0x1fb4050, pad=0x7f0b54022060, playbin=0x1fb00e0) at ../subprojects/gst-plugins-base/gst/playback/gstplaybin3.c:2463
#5 0x00007f0b85c00060 in g_closure_invoke (closure=0x1fa9eb0, return_value=0x0, n_param_values=2, param_values=0x7f0b78ee1dd0, invocation_hint=0x7f0b78ee1d50) at ../gobject/gclosure.c:832
#6 0x00007f0b85c2cf66 in signal_emit_unlocked_R.isra.0 (node=node@entry=0x1c5bf30, detail=detail@entry=0, instance=instance@entry=0x1fb4050, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7f0b78ee1dd0) at ../gobject/gsignal.c:3796
#7 0x00007f0b85c1d4da in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args@entry=0x7f0b78ee1f90) at ../gobject/gsignal.c:3549
#8 0x00007f0b85c1d6f3 in g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at ../gobject/gsignal.c:3606
#9 0x00007f0b85e20c3e in gst_element_add_pad (element=0x1fb4050, pad=0x7f0b54022060) at ../subprojects/gstreamer/gst/gstelement.c:802
#10 0x00007f0b7e632620 in add_output_pad (dec=0x1fb4050, target_pad=0x7f0b6400fda0) at ../subprojects/gst-plugins-base/gst/playback/gsturidecodebin3.c:717
#11 0x00007f0b7e632788 in db_pad_added_cb (element=0x1fb8020, pad=0x7f0b6400fda0, dec=0x1fb4050) at ../subprojects/gst-plugins-base/gst/playback/gsturidecodebin3.c:736
#12 0x00007f0b85c00060 in g_closure_invoke (closure=0x1fb7fc0, return_value=0x0, n_param_values=2, param_values=0x7f0b78ee2300, invocation_hint=0x7f0b78ee2280) at ../gobject/gclosure.c:832
#13 0x00007f0b85c2cf66 in signal_emit_unlocked_R.isra.0 (node=node@entry=0x1c5bf30, detail=detail@entry=0, instance=instance@entry=0x1fb8020, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7f0b78ee2300) at ../gobject/gsignal.c:3796
#14 0x00007f0b85c1d4da in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args@entry=0x7f0b78ee24c0) at ../gobject/gsignal.c:3549
#15 0x00007f0b85c1d6f3 in g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at ../gobject/gsignal.c:3606
#16 0x00007f0b85e20c3e in gst_element_add_pad (element=0x1fb8020, pad=0x7f0b6400fda0) at ../subprojects/gstreamer/gst/gstelement.c:802
#17 0x00007f0b7e6260b4 in reconfigure_output_stream (output=0x7f0b5400def0, slot=0x7f0b64013dd0, msg=0x7f0b78ee26b8) at ../subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c:3086
#18 0x00007f0b7e623700 in check_slot_reconfiguration (dbin=0x1fb8020, slot=0x7f0b64013dd0) at ../subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c:2455
#19 0x00007f0b7e623e62 in multiqueue_src_probe (pad=0x7f0b6001e600, info=0x7f0b78ee2930, slot=0x7f0b64013dd0) at ../subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c:2544
#20 0x00007f0b85e53aaa in probe_hook_marshal (hook=0x7f0b74040500, data=0x7f0b78ee28c0) at ../subprojects/gstreamer/gst/gstpad.c:3669
#21 0x00007f0b85c88a3e in g_hook_list_marshal (hook_list=0x7f0b6001e698, may_recurse=1, marshaller=0x7f0b85e53786 <probe_hook_marshal>, data=0x7f0b78ee28c0) at ../glib/ghook.c:674
#22 0x00007f0b85e541be in do_probe_callbacks (pad=0x7f0b6001e600, info=0x7f0b78ee2930, defaultval=GST_FLOW_OK) at ../subprojects/gstreamer/gst/gstpad.c:3853
#23 0x00007f0b85e5ac9c in gst_pad_push_event_unchecked (pad=0x7f0b6001e600, event=0x7f0b64002120, type=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at ../subprojects/gstreamer/gst/gstpad.c:5538
#24 0x00007f0b85e54bc2 in push_sticky (pad=0x7f0b6001e600, ev=0x7f0b78ee2a60, user_data=0x7f0b78ee2ac0) at ../subprojects/gstreamer/gst/gstpad.c:4057
#25 0x00007f0b85e4a13c in events_foreach (pad=0x7f0b6001e600, func=0x7f0b85e54a8e <push_sticky>, user_data=0x7f0b78ee2ac0) at ../subprojects/gstreamer/gst/gstpad.c:613
#26 0x00007f0b85e54f91 in check_sticky (pad=0x7f0b6001e600, event=0x7f0b64002120) at ../subprojects/gstreamer/gst/gstpad.c:4116
#27 0x00007f0b85e5b65e in gst_pad_push_event (pad=0x7f0b6001e600, event=0x7f0b64002120) at ../subprojects/gstreamer/gst/gstpad.c:5706
#28 0x00007f0b7e5888e7 in gst_single_queue_push_one (mq=0x1fbb000, sq=0x7f0b64013b70, object=0x7f0b64002120, allow_drop=0x7f0b78ee2c3c) at ../subprojects/gstreamer/plugins/elements/gstmultiqueue.c:2068
#29 0x00007f0b7e58a1bc in gst_multi_queue_loop (pad=0x7f0b6001e600) at ../subprojects/gstreamer/plugins/elements/gstmultiqueue.c:2347
#30 0x00007f0b85e96a36 in gst_task_func (task=0x7f0b64016050) at ../subprojects/gstreamer/gst/gsttask.c:399
#31 0x00007f0b85e97e41 in default_func (tdata=0x7f0b640138d0, pool=0x1fbe9c0) at ../subprojects/gstreamer/gst/gsttaskpool.c:70
#32 0x00007f0b85cd1ab2 in g_thread_pool_thread_proxy (data=<optimized out>) at ../glib/gthreadpool.c:352
#33 0x00007f0b85ccc982 in g_thread_proxy (data=0x7f0b6006f640) at ../glib/gthread.c:831
#34 0x00007f0b858ca12d in start_thread (arg=<optimized out>) at pthread_create.c:442
#35 0x00007f0b8594bbc0 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
Thread 7 (Thread 0x7f0b7a7646c0 (LWP 2952434) "multiqueue3:src"):
#0 syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
#1 0x00007f0b85cf470c in g_mutex_lock_slowpath (mutex=0x1fb81d0) at ../glib/gthread-posix.c:1494
#2 0x00007f0b7e6281a2 in gst_decodebin3_send_event (element=0x1fb8020, event=0x7f0b6800a650) at ../subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c:3561
#3 0x00007f0b85e23ca3 in gst_element_send_event (element=0x1fb8020, event=0x7f0b6800a650) at ../subprojects/gstreamer/gst/gstelement.c:1994
#4 0x00007f0b7e63806b in gst_uri_decodebin3_send_event (element=0x1fb4050, event=0x7f0b6800a650) at ../subprojects/gst-plugins-base/gst/playback/gsturidecodebin3.c:2227
#5 0x00007f0b85e23ca3 in gst_element_send_event (element=0x1fb4050, event=0x7f0b6800a650) at ../subprojects/gstreamer/gst/gstelement.c:1994
#6 0x00007f0b7e66375a in gst_play_bin3_send_event (element=0x1fb00e0, event=0x7f0b6800a650) at ../subprojects/gst-plugins-base/gst/playback/gstplaybin3.c:1863
#7 0x00007f0b85e23ca3 in gst_element_send_event (element=0x1fb00e0, event=0x7f0b6800a650) at ../subprojects/gstreamer/gst/gstelement.c:1994
#8 0x00007f0b85f61b5b in stream_selection_cb (bus=0x1dc2d80, message=0x7f0b68008b00, d=0x1d7de30) at ../subprojects/gst-devtools/validate/gst/validate/gst-validate-scenario.c:2235
#9 0x00007f0b85c00060 in g_closure_invoke (closure=0x1d2a5b0, return_value=0x0, n_param_values=2, param_values=0x7f0b7a7627b0, invocation_hint=0x7f0b7a762730) at ../gobject/gclosure.c:832
#10 0x00007f0b85c2cf66 in signal_emit_unlocked_R.isra.0 (node=node@entry=0x1c5e5f0, detail=detail@entry=235, instance=instance@entry=0x1dc2d80, emission_return=emission_return@entry=0x0, instance_and_params=instance_and_params@entry=0x7f0b7a7627b0) at ../gobject/gsignal.c:3796
#11 0x00007f0b85c1d4da in g_signal_emit_valist (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>, var_args=var_args@entry=0x7f0b7a762970) at ../gobject/gsignal.c:3549
#12 0x00007f0b85c1d6f3 in g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, detail=<optimized out>) at ../gobject/gsignal.c:3606
#13 0x00007f0b85e05be9 in gst_bus_sync_signal_handler (bus=0x1dc2d80, message=0x7f0b68008b00, data=0x0) at ../subprojects/gstreamer/gst/gstbus.c:1307
#14 0x00007f0b85e03834 in gst_bus_post (bus=0x1dc2d80, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstbus.c:364
#15 0x00007f0b85e2436c in gst_element_post_message_default (element=0x1fb00e0, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstelement.c:2127
#16 0x00007f0b85df42b1 in gst_bin_post_message (element=0x1fb00e0, msg=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstbin.c:2789
#17 0x00007f0b85e24627 in gst_element_post_message (element=0x1fb00e0, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstelement.c:2170
#18 0x00007f0b85df7c12 in gst_bin_handle_message_func (bin=0x1fb00e0, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstbin.c:4041
#19 0x00007f0b85e61bd3 in gst_pipeline_handle_message (bin=0x1fb00e0, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstpipeline.c:669
#20 0x00007f0b7e663fa4 in gst_play_bin3_handle_message (bin=0x1fb00e0, msg=0x7f0b68008b00) at ../subprojects/gst-plugins-base/gst/playback/gstplaybin3.c:2030
#21 0x00007f0b85df5a98 in bin_bus_handler (bus=0x1dc2cc0, message=0x7f0b68008b00, bin=0x1fb00e0) at ../subprojects/gstreamer/gst/gstbin.c:3263
#22 0x00007f0b85e037f1 in gst_bus_post (bus=0x1dc2cc0, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstbus.c:357
#23 0x00007f0b85e2436c in gst_element_post_message_default (element=0x1fb4050, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstelement.c:2127
#24 0x00007f0b85df42b1 in gst_bin_post_message (element=0x1fb4050, msg=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstbin.c:2789
#25 0x00007f0b85e24627 in gst_element_post_message (element=0x1fb4050, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstelement.c:2170
#26 0x00007f0b85df7c12 in gst_bin_handle_message_func (bin=0x1fb4050, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstbin.c:4041
#27 0x00007f0b7e638005 in gst_uri_decode_bin3_handle_message (bin=0x1fb4050, msg=0x7f0b68008b00) at ../subprojects/gst-plugins-base/gst/playback/gsturidecodebin3.c:2218
#28 0x00007f0b85df5a98 in bin_bus_handler (bus=0x1dc2e40, message=0x7f0b68008b00, bin=0x1fb4050) at ../subprojects/gstreamer/gst/gstbin.c:3263
#29 0x00007f0b85e037f1 in gst_bus_post (bus=0x1dc2e40, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstbus.c:357
#30 0x00007f0b85e2436c in gst_element_post_message_default (element=0x1fb8020, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstelement.c:2127
#31 0x00007f0b85df42b1 in gst_bin_post_message (element=0x1fb8020, msg=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstbin.c:2789
#32 0x00007f0b85e24627 in gst_element_post_message (element=0x1fb8020, message=0x7f0b68008b00) at ../subprojects/gstreamer/gst/gstelement.c:2170
#33 0x00007f0b7e61ee43 in sink_event_function (sinkpad=0x7f0b6400f8c0, dbin=0x1fb8020, event=0x7f0b6c097870) at ../subprojects/gst-plugins-base/gst/playback/gstdecodebin3.c:1450
#34 0x00007f0b85f51122 in gst_validate_pad_monitor_downstream_event_check (pad_monitor=0x7f0b6c094a80, parent=0x1fb8020, event=0x7f0b6c097870, handler=0x7f0b7e61e797 <sink_event_function>) at ../subprojects/gst-devtools/validate/gst/validate/gst-validate-pad-monitor.c:2101
#35 0x00007f0b85f535bf in gst_validate_pad_monitor_sink_event_full_func (pad=0x7f0b6400f8c0, parent=0x1fb8020, event=0x7f0b6c097870) at ../subprojects/gst-devtools/validate/gst/validate/gst-validate-pad-monitor.c:2406
#36 0x00007f0b85f537fa in gst_validate_pad_monitor_sink_event_func (pad=0x7f0b6400f8c0, parent=0x1fb8020, event=0x7f0b6c097870) at ../subprojects/gst-devtools/validate/gst/validate/gst-validate-pad-monitor.c:2418
#37 0x00007f0b85e5c523 in gst_pad_send_event_unchecked (pad=0x7f0b6400f8c0, event=0x7f0b6c097870, type=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at ../subprojects/gstreamer/gst/gstpad.c:5940
#38 0x00007f0b85e5ae65 in gst_pad_push_event_unchecked (pad=0x7f0b6400f650, event=0x7f0b6c097870, type=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at ../subprojects/gstreamer/gst/gstpad.c:5573
#39 0x00007f0b85e54bc2 in push_sticky (pad=0x7f0b6400f650, ev=0x7f0b7a763620, user_data=0x7f0b7a763680) at ../subprojects/gstreamer/gst/gstpad.c:4057
#40 0x00007f0b85e4a13c in events_foreach (pad=0x7f0b6400f650, func=0x7f0b85e54a8e <push_sticky>, user_data=0x7f0b7a763680) at ../subprojects/gstreamer/gst/gstpad.c:613
#41 0x00007f0b85e54f91 in check_sticky (pad=0x7f0b6400f650, event=0x7f0b6c097870) at ../subprojects/gstreamer/gst/gstpad.c:4116
#42 0x00007f0b85e5b65e in gst_pad_push_event (pad=0x7f0b6400f650, event=0x7f0b6c097870) at ../subprojects/gstreamer/gst/gstpad.c:5706
#43 0x00007f0b85e523e7 in event_forward_func (pad=0x7f0b6400f650, data=0x7f0b7a763820) at ../subprojects/gstreamer/gst/gstpad.c:3130
#44 0x00007f0b85e521e3 in gst_pad_forward (pad=0x7f0b6004f180, forward=0x7f0b85e522bd <event_forward_func>, user_data=0x7f0b7a763820) at ../subprojects/gstreamer/gst/gstpad.c:3084
#45 0x00007f0b85e525ab in gst_pad_event_default (pad=0x7f0b6004f180, parent=0x7f0b6400f650, event=0x7f0b6c097870) at ../subprojects/gstreamer/gst/gstpad.c:3181
#46 0x00007f0b85e5c523 in gst_pad_send_event_unchecked (pad=0x7f0b6004f180, event=0x7f0b6c097870, type=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at ../subprojects/gstreamer/gst/gstpad.c:5940
#47 0x00007f0b85e5ae65 in gst_pad_push_event_unchecked (pad=0x7f0b64008360, event=0x7f0b6c097870, type=GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) at ../subprojects/gstreamer/gst/gstpad.c:5573
#48 0x00007f0b85e54bc2 in push_sticky (pad=0x7f0b64008360, ev=0x7f0b7a763a60, user_data=0x7f0b7a763ac0) at ../subprojects/gstreamer/gst/gstpad.c:4057
#49 0x00007f0b85e4a13c in events_foreach (pad=0x7f0b64008360, func=0x7f0b85e54a8e <push_sticky>, user_data=0x7f0b7a763ac0) at ../subprojects/gstreamer/gst/gstpad.c:613
#50 0x00007f0b85e54f91 in check_sticky (pad=0x7f0b64008360, event=0x7f0b6c097870) at ../subprojects/gstreamer/gst/gstpad.c:4116
#51 0x00007f0b85e5b65e in gst_pad_push_event (pad=0x7f0b64008360, event=0x7f0b6c097870) at ../subprojects/gstreamer/gst/gstpad.c:5706
#52 0x00007f0b7e5888e7 in gst_single_queue_push_one (mq=0x7f0b60076540, sq=0x7f0b6c093300, object=0x7f0b6c097870, allow_drop=0x7f0b7a763c3c) at ../subprojects/gstreamer/plugins/elements/gstmultiqueue.c:2068
#53 0x00007f0b7e58a1bc in gst_multi_queue_loop (pad=0x7f0b64008360) at ../subprojects/gstreamer/plugins/elements/gstmultiqueue.c:2347
#54 0x00007f0b85e96a36 in gst_task_func (task=0x7f0b6c072050) at ../subprojects/gstreamer/gst/gsttask.c:399
#55 0x00007f0b85e97e41 in default_func (tdata=0x7f0b6c093ef0, pool=0x1fbe9c0) at ../subprojects/gstreamer/gst/gsttaskpool.c:70
#56 0x00007f0b85cd1ab2 in g_thread_pool_thread_proxy (data=<optimized out>) at ../glib/gthreadpool.c:352
#57 0x00007f0b85ccc982 in g_thread_proxy (data=0x7f0b70033800) at ../glib/gthread.c:831
#58 0x00007f0b858ca12d in start_thread (arg=<optimized out>) at pthread_create.c:442
#59 0x00007f0b8594bbc0 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
```
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5982>
The internal elements are only created when caps on both video and subtitle pads
are known.
Prior to that, a GST_QUERY_CAPS on a video sink pad would just return ANY
instead of giving a hint of what downstream can actually handle and
prefers. This could result in upstream elements (such as decoders) deciding on
chosing (in the best cases) a non-optimal caps or (in the worst case) caps that
couldn't be handled by the elements downstream of subtitleoverlay.
In order to fix that, we assume that all subtitle "elements" handle the subtitle
overlay composition feature/meta and handle `GST_QUERY_CAPS` ourselves if the
internal elements aren't present yet.
Fixes#3176
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5834>
We access fields that are protected by the lock and this was already
held in other places where we call the method. I have got cases where
we get the following stack/assertion:
```
#0 g_logv (log_domain=0x7fb9d84e6cd5 "GStreamer", log_level=G_LOG_LEVEL_CRITICAL, format=<optimized out>, args=args@entry=0x7fb9d4de54e0) at ../glib/gmessages.c:1433
#1 0x00007fb9d802d0f3 in g_log (log_domain=<optimized out>, log_level=<optimized out>, format=<optimized out>) at ../glib/gmessages.c:1471
#2 0x00007fb9d845bc2c in gst_pad_send_event (pad=0x7fb98c01e050, event=0x7fb9c4105b90) at ../subprojects/gstreamer/gst/gstpad.c:6096
#3 0x00007fb9d6541c35 in gst_uri_decode_bin3_set_uri (dec=0x7fb9bc450960 [GstURIDecodeBin3], uri=0x7fb9c40f5410 "file:///var/home/thiblahute/devel/gstreamer/gstreamer/subprojects/gst-integration-testsuites/medias/defaults/mp4/mp3_h264.0.mp4") at ../subprojects/gst-plugins-base/gst/playback/gsturidecodebin3.c:1918
#4 0x00007fb9d6540c40 in gst_uri_decode_bin3_set_property (object=0x7fb9bc450960 [GstURIDecodeBin3], prop_id=1, value=0x7fb9d4de57b0, pspec=0x7fb9bcee5280 [GParamString]) at ../subprojects/gst-plugins-base/gst/playback/gsturidecodebin3.c:1569
#5 0x00007fb9d7f8f73d in object_set_property (object=0x7fb9bc450960 [GstURIDecodeBin3], pspec=0x7fb9bcee5280 [GParamString], value=0x7fb9d4de57b0, nqueue=0x7fb9c40d0c40, user_specified=<optimized out>) at ../gobject/gobject.c:1794
```
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5968>
In `parse_chain_output_probe()` the corresponding input stream might receive EOS
and thus be removed before the actual pad is removed. So we cannot assert about
this in `parsebin_pad_removed_cb()`.
Also, driving-by, protect `find_input_stream_for_pad()` with the selection lock
similarly to other functions accessing the input streams list.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5887>
This causes a lot of nasty side effects (like decoders assuming they are
actually linked downstream).
The reason why this was done was to check whether a decoder could handle the
actual caps, but this is the wrong way to do it.
The proper way to query whether a decoder can handle certain caps is via
`GST_QUERY_ACCEPT_CAPS` which is already done just before.
Partially reverts !4677 and partially fixes#3160
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5821>
Update connection-speed at runtime in playbin, uridecodebin and decodebin
also do the same thing in urisourcebin.
With contributions from Philippe Normand <philn@igalia.com> (build fixes and
rebase on mono-repo).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4713>
When switching from a raw stream to an encoded stream we need to make sure the
slot is unlinked, there is code in place for this but it wasn't triggered
because the slot being reconfigured wasn't advertised as linked beforehand.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5126>
Do not attempt to send a streams-selected message when reassigning
an output slot in case upstream signalled that it is handling stream selection.
In this case decodebin3 doesn't keep track of stream
collections (`dbin->collection` is NULL).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5059>
Setting the input field on the empty slot prevents future linking of it and will
result in flow errors later on.
This was observed in WebKit's MediaStream source element, when it changes the
caps on one of its associated streams, from an encoded format to a raw video
format. The associated stream-id on the sticky stream-start event doesn´t
change, but the element creates a new GstStream with a different ID and sets it
on the stream-start event. Stream parsing is disabled in urisourcebin, so
decodebin3 handles the parsing. Without this patch we would end-up with unlinked
pads in decodebin3 after switching to the raw video format.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5048>
If the GST_MESSAGE_SRC of error message belongs to candidate decoders,
filter the error message and don't forward it as there might be a
following candidate decoder that can be used.
If the GST_MESSAGE_SRC of error message belongs to candidate decoders,
store the latency message and handle it after decoder is accepted.
This is to avoid the selection lock failure if decodebin3 needs to
handle latency message for candidate decoders when sending sticky event.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4677>
Send sticky events to the new created decoder after it switches
to PAUSED state. It it fails, just skip this decoder and try the
next one until finding one that works. Otherwise remove this
failing stream after trying all decoders and no one can work.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4677>
Generating the source element is done when urisourcebin is doing the READY to
PAUSED state change, so it is reasonable to set the new source element to that
state.
This also allows detecting early failures with backing libraries or
hardware (checks done in NULL->READY).
Finally it makes more sense to have an element in READY when attempting to query
information from it (such as SCHEDULING queries or probing live-ness).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3856>
self->eos was never reset after streamsynchronizer has sent EOS
(except on explicit flush or switching back to PAUSED).
As a result, synchronization was broken if new streams were pushed later
as gst_stream_synchronizer_wait() does not wait if self->eos is set.
Fix this by reseting self->eos on STREAM_START as that means a new
stream is being sent upstream and so a new EOS will follow later on.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4749>
While decodebin3 could handle changes in inputs (ex: changing codecs), there was
still one limitation which was when changing between sources which had
non-intersecting stream types (ex: switching from a video-only source to a
audio-only source). While the decoder *could* change to the proper codec ... it
would carry on using a `DecodebinOutputStream` associated to that stream
type (and therefore with pads with the wrong name).
In order to handle this:
* We notify the `MultiQueueSlot` of the change in `GstStreamType` if it already
had an associated inputstream (ex: the one associated with the static sink
pad)
* We detect such changes on the output of multiqueue as soon as
possible (i.e. when we get the GST_EVENT_STREAM_START for the new stream type)
by discarding the associated output.
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1669
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4703>
When reconfigure_output_stream entry missing decoder path,
requested_selection should been update with what is really
active/selected immdiately with SELECTION_LOCK hold. So
use an optional message return from reconfigure_output_stream
and post it after release SELECTION_LOCK. This can make sure
other thread call to check_slot_reconfiguration will got
a correct requested_selection.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4599>
decodebin3 will do its best to figure out whether a parsebin is required to
process the incoming stream.
The problem is that for push-based stream it could happen that the stream would
not provide any caps, resulting in nothing being linked internally.
Furthermore, there is the possibility that a stream *with* caps would not be
using a TIME segment, which is required for multiqueue to properly work.
In order to fix those two issues, we force the usage of parsebin on push-based
streams:
* When the pad is linked, if upstream can't provide any caps
* When we get a non-TIME segment
Fixes#2521
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4492>
This is a follow-up of the previous commit that enabled support for redirection.
The problem is that the urisourcebin that emitted the error redirection never
produced any pads, and therefore was never linked to decodebin3. This resulted
in the code waiting for that (output) item to finally switch over ... which will
never happen.
The fix is done by removing it early if it was never connected to decodebin3.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4252>
The goal of parsebin is to figure out which elements to link together in order
to provide elementary streams given any random input.
The problem is that deciding whether a given stream should still have more
elements plugged in or not was dependent on ... the presence of compatible
decoders (sic).
Instead of that, if we can't plug anymore elements on a given stream *and* it is
detected as being an elementary stream, expose it.
Fixes#2118
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4231>
If sticky events are present on parsebin source pads, we propagate them to the
multiqueue source pads. Those will be propagated on the new urisourcebin source
pads like in the other code paths.
This ensures that STREAM_START event are present on new source pads. If CAPS
event are also present (not guaranteed), they will also be available.
Fixes#2384
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4203>
Generating the source element is done when uridecodebin is doing the
READY to PAUSED state change, so it is reasonable to set the new source
element to that state.
This also allows detecting early failures with backing libraries or
hardware (checks done in NULL->READY).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3857>
The goal of the "global" group-id is to fix new inputs that do not come from the
same "source" as others. In order to ensure all "current" streams have the same
group-id we distribute the first valid group-id to all streams.
This commit fixes two issues with that:
* When inputs are unlinked they weren't always properly resetted (it would only
work if parsebin is used, which is no longer the default in
uridecodebin3/playbin3).
* When computing the global group-id, take into account unset
group-id (i.e. GST_GROUP_ID_INVALID).
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1698
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3712>
The number of expected pads was:
* Defaulting to 1
* Or being overriden by GST_MESSAGE_STREAMS_SELECTED
This fails if upstream isn't a selectable source and has multiple streams, and
would therefore cause failures with multi-stream gapless playback
Fixes#1672
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3658>
It is quite possible to have the blocking probe called from different streaming
threads when all expected pads are present.
* Notify all waiters by using g_cond_broadcast instead of g_cond_signal
* Properly remove the probe after waiting
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3658>
Using the "GstBin" flags to check if an adaptive demuxer is streams-aware isn't
a good idea since it prevents using elements which aren't bins.
Instead we see if a collection was posted by the demuxer by the time a pad is
added.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3601>
Make sure that group-id of a given play item are made consistent from the
start (sources) and all the way through the output.
This ensures that we can reliably detect that we have switched to the next play
item on the output of decodebin3 (and we can therefore properly free/release it)
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3457>
When shutting down, we want to remove the urisourcebin blocking probes ... but
we also want to propagate a GST_FLOW_FLUSHING upstream (and not
GST_FLOW_NOT_LINKED) to make the upstream task gracefully stop instead of
posting an error message.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3457>
When `is_selection_done` is called, it checks that all the requested streams are
present in the active stream list ...
... except there could very well be a (about to be removed) stream from the
previous selection present.
Therefore filter the list of streams we add to the message by the streams which
are actually requested.
Fixes issues when switching between different stream types (ex: video-only to
audio-only).
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3457>
This was the intention from the start, just took me a few years *cough* to
actually implement it properly.
Gapless is handled by re-using as much as possible the same decoders and sinks
if present, and only pre-rolling switching at the sources level (with buffering
if/when needed).
In order to enable "gapless" playback, the "next" uri should be set at any time
between the moment the `about-to-finish` signal is emitted and the moment the
current play item is done. Previously this could only be done with the signal
emission.
This new implementation also allows "Instantaneous URI switching". This allows a
much faster way of switching playback entries while re-using as many elements as
possible. To enable this set `instant-uri` property to TRUE, the default being
FALSE.
API: instant-uri properties
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2784>
DecodebinInput (and their backing parsebin or identity) are no longer released
when the corresponding sinkpad is unlinked, but when it's released.
The parsebin element will be resetted:
* If incoming caps are incompatible (was the case before)
* Or when unlinking and it was previously pull-based
This opens the way to use decodebin3 with changing inputs (i.e. gapless)
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2784>
Introduce the option to have the streams be parsed with `parsebin` for
compatible sources (i.e. which are eligible for buffering in the same way as
before this commit).
By parsing the inputs directly, this allows more accurate buffering control:
* Instead of relying on potential bitrate information coming from somewhere
* and *without* being linked downstream
If `parse-streams` is activated and the stream is eligible for buffering, then a
`multiqueue` will be used on the output of `parsebin` in order to handle the
buffering.
API: `parse-streams`
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2784>
If the incoming streams are already parsed, there is no need to add yet-another
parsebin to process it *IF* that stream is compatible with a decoder or the
decodebin3 output caps.
This only applies if all the following conditions are met:
* The incoming stream can *NOT* do pull-based scheduling
* The incoming stream provides a `GstStream` and `GstStreamCollection`
* The caps are compatible with either the decodebin3 output caps or a decoder
input
If all those conditions are met, a identity element is used instead of a
parsebin element and the same code paths are taken.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2784>
* Instead of creating temporary `PendingPad` structures, always create a
DecodebinInputStream for every pad of parsebin
* Remove never used `pending_stream` field from DecodebinInputStream
* When unblocking a given DecodebinInput (i.e. wrapping a parsebin), also make
sure that other parsebins from the same GstStreamCollection are unblocked
since they come from the same source
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2784>
