Xcode 调试 iOS 时 GStreamer 不需要的启动延迟和单元测试崩溃
GStreamer unwanted startup delay and unit test crashes when Xcode debugging for iOS
我有一个 iOS 应用程序，它使用 Gstreamer 通过 UDP 从源流式传输实时视频。当我 运行 这个应用程序附加了 Xcode 调试器时，在视频出现之前会有 5-10 秒 的延迟。然后它似乎快速显示所有以前的帧，直到它 "catches up" 到当前时间戳。起初我以为这是由我的管道转换为动态代码引起的，但后来我将问题隔离到仅在调试时：
- 如果我停止管道并重新创建它，则没有明显的延迟。
- 如果我停止调试并使用该应用程序，那很好（也可以从多任务处理中杀死）。
- TestFlight 版本也可以。
这是我的控制台输出，其中包含一些调试消息、GStreamer 回调以及我在代码注释语法中的注释：
WARNING: no real random source present!
GST_STATE_READY
playOrStopVideo
2019-09-26 15:45:19.442411-0400 pipeline is null
2019-09-26 15:45:19.502487-0400 pad_added_handler: tee
2019-09-26 15:45:19.534644-0400 Metal GPU Frame Capture Enabled
2019-09-26 15:45:19.535959-0400 Metal API Validation Enabled
[GStreamer check_initialization_complete]:[00m Initialization complete, notifying application.
ViewController gstreamerInitialized()
2019-09-26 15:45:19.646378-0400 message NEED_CONTEXT
2019-09-26 15:45:19.646436-0400 message HAVE_CONTEXT
2019-09-26 15:45:19.646465-0400 message NEED_CONTEXT
2019-09-26 15:45:19.646492-0400 message ELEMENT
2019-09-26 15:45:19.646547-0400 message NEED_CONTEXT
2019-09-26 15:45:19.646636-0400 message NEED_CONTEXT
2019-09-26 15:45:19.646685-0400 message NEED_CONTEXT
GST_STATE_READY
2019-09-26 15:45:19.649381-0400 message STREAM_STATUS CREATE for src
2019-09-26 15:45:19.652090-0400 message STREAM_STATUS CREATE for src
2019-09-26 15:45:19.652148-0400 message STREAM_STATUS CREATE for src
GST_STATE_PAUSED
2019-09-26 15:45:19.652808-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:19.652926-0400 message NEW_CLOCK
2019-09-26 15:45:19.652980-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:19.653166-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:19.987250-0400 pad_added_handler: decodebin0
2019-09-26 15:45:19.999452-0400 message STREAM_START
2019-09-26 15:45:20.032557-0400 message TAG
=================================================================
Main Thread Checker: UI API called on a background thread: -[UIView frame]
PID: 3788, TID: 1475176, Thread name: (none), Queue name: org.freedesktop.gstreamer.glwindow, QoS: 0
Backtrace:
4 MyApp 0x0000000105ef14f8 gst_gl_context_eagl_update_layer + 652
5 MyApp 0x0000000105edd4b8 gst_gl_window_eagl_set_window_handle + 92
6 MyApp 0x0000000105ef5f6c _set_window_handle_cb + 104
7 MyApp 0x0000000105edd790 __gst_gl_window_eagl_send_message_async_block_invoke + 36
8 libdispatch.dylib 0x00000001097e51dc _dispatch_call_block_and_release + 24
9 libdispatch.dylib 0x00000001097e519c _dispatch_client_callout + 16
10 libdispatch.dylib 0x00000001097f3dfc _dispatch_queue_serial_drain + 768
11 libdispatch.dylib 0x00000001097e86ac _dispatch_queue_invoke + 328
12 libdispatch.dylib 0x00000001097f4d54 _dispatch_root_queue_drain_deferred_wlh + 352
13 libdispatch.dylib 0x00000001097fbe38 _dispatch_workloop_worker_thread + 676
14 libsystem_pthread.dylib 0x0000000184c83e70 _pthread_wqthread + 860
15 libsystem_pthread.dylib 0x0000000184c83b08 start_wqthread + 4
2019-09-26 15:45:20.049748-0400 MyApp[3788:1475176] [reports] Main Thread Checker: UI API called on a background thread: -[UIView frame]
PID: 3788, TID: 1475176, Thread name: (none), Queue name: org.freedesktop.gstreamer.glwindow, QoS: 0
Backtrace:
4 MyApp 0x0000000105ef14f8 gst_gl_context_eagl_update_layer + 652
5 MyApp 0x0000000105edd4b8 gst_gl_window_eagl_set_window_handle + 92
6 MyApp 0x0000000105ef5f6c _set_window_handle_cb + 104
7 MyApp 0x0000000105edd790 __gst_gl_window_eagl_send_message_async_block_invoke + 36
8 libdispatch.dylib 0x00000001097e51dc _dispatch_call_block_and_release + 24
9 libdispatch.dylib 0x00000001097e519c _dispatch_client_callout + 16
10 libdispatch.dylib 0x00000001097f3dfc _dispatch_queue_serial_drain + 768
11 libdispatch.dylib 0x00000001097e86ac _dispatch_queue_invoke + 328
12 libdispatch.dylib 0x00000001097f4d54 _dispatch_root_queue_drain_deferred_wlh + 352
13 libdispatch.dylib 0x00000001097fbe38 _dispatch_workloop_worker_thread + 676
14 libsystem_pthread.dylib 0x0000000184c83e70 _pthread_wqthread + 860
15 libsystem_pthread.dylib 0x0000000184c83b08 start_wqthread + 4
=================================================================
Main Thread Checker: UI API called on a background thread: -[UIView layer]
PID: 3788, TID: 1475176, Thread name: (none), Queue name: org.freedesktop.gstreamer.glwindow, QoS: 0
Backtrace:
4 MyApp 0x0000000105ef1300 gst_gl_context_eagl_update_layer + 148
5 MyApp 0x0000000105edd4b8 gst_gl_window_eagl_set_window_handle + 92
6 MyApp 0x0000000105ef5f6c _set_window_handle_cb + 104
7 MyApp 0x0000000105edd790 __gst_gl_window_eagl_send_message_async_block_invoke + 36
8 libdispatch.dylib 0x00000001097e51dc _dispatch_call_block_and_release + 24
9 libdispatch.dylib 0x00000001097e519c _dispatch_client_callout + 16
10 libdispatch.dylib 0x00000001097f3dfc _dispatch_queue_serial_drain + 768
11 libdispatch.dylib 0x00000001097e86ac _dispatch_queue_invoke + 328
12 libdispatch.dylib 0x00000001097f4d54 _dispatch_root_queue_drain_deferred_wlh + 352
13 libdispatch.dylib 0x00000001097fbe38 _dispatch_workloop_worker_thread + 676
14 libsystem_pthread.dylib 0x0000000184c83e70 _pthread_wqthread + 860
15 libsystem_pthread.dylib 0x0000000184c83b08 start_wqthread + 4
2019-09-26 15:45:27.554390-0400 MyApp[3788:1475176] [reports] Main Thread Checker: UI API called on a background thread: -[UIView layer]
PID: 3788, TID: 1475176, Thread name: (none), Queue name: org.freedesktop.gstreamer.glwindow, QoS: 0
Backtrace:
4 MyApp 0x0000000105ef1300 gst_gl_context_eagl_update_layer + 148
5 MyApp 0x0000000105edd4b8 gst_gl_window_eagl_set_window_handle + 92
6 MyApp 0x0000000105ef5f6c _set_window_handle_cb + 104
7 MyApp 0x0000000105edd790 __gst_gl_window_eagl_send_message_async_block_invoke + 36
8 libdispatch.dylib 0x00000001097e51dc _dispatch_call_block_and_release + 24
9 libdispatch.dylib 0x00000001097e519c _dispatch_client_callout + 16
10 libdispatch.dylib 0x00000001097f3dfc _dispatch_queue_serial_drain + 768
11 libdispatch.dylib 0x00000001097e86ac _dispatch_queue_invoke + 328
12 libdispatch.dylib 0x00000001097f4d54 _dispatch_root_queue_drain_deferred_wlh + 352
13 libdispatch.dylib 0x00000001097fbe38 _dispatch_workloop_worker_thread + 676
14 libsystem_pthread.dylib 0x0000000184c83e70 _pthread_wqthread + 860
15 libsystem_pthread.dylib 0x0000000184c83b08 start_wqthread + 4
//
// THIS IS WHERE IT HANGS (check the timestamps)
//
2019-09-26 15:45:27.692918-0400 message ASYNC_DONE
GST_STATE_PLAYING
2019-09-26 15:45:28.023985-0400 message QOS
2019-09-26 15:45:28.190131-0400 message QOS
2019-09-26 15:45:28.418494-0400 message QOS
2019-09-26 15:45:28.657004-0400 message QOS
2019-09-26 15:45:28.665464-0400 message QOS
2019-09-26 15:45:28.668784-0400 message QOS
2019-09-26 15:45:28.672105-0400 message QOS
2019-09-26 15:45:28.675492-0400 message QOS
//
// Sometimes I see output with QoS about "a lot of buffers being dropped"
//
//
// STOPPING VIDEO VIA UI AND RESTARTING (plays immediately)
//
playOrStopVideo
2019-09-26 15:45:32.959316-0400 SENT EOS OK
2019-09-26 15:45:32.962257-0400 GST_MESSAGE_EOS
2019-09-26 15:45:32.969720-0400 Pipeline set to NULL
GST_STATE_NULL
[GStreamer setupVideoWithRecording:]:[00m Exited main loop
2019-09-26 15:45:32.970650-0400 Exited main loop
2019-09-26 15:45:32.970712-0400 destroy()
playOrStopVideo
2019-09-26 15:45:35.330103-0400 pipeline is null
2019-09-26 15:45:35.369882-0400 pad_added_handler: tee
[GStreamer check_initialization_complete]:[00m Initialization complete, notifying application.
ViewController gstreamerInitialized()
2019-09-26 15:45:35.385008-0400 message NEED_CONTEXT
2019-09-26 15:45:35.385064-0400 message HAVE_CONTEXT
2019-09-26 15:45:35.385099-0400 message NEED_CONTEXT
2019-09-26 15:45:35.385134-0400 message ELEMENT
2019-09-26 15:45:35.385241-0400 message NEED_CONTEXT
2019-09-26 15:45:35.385305-0400 message NEED_CONTEXT
2019-09-26 15:45:35.385368-0400 message NEED_CONTEXT
GST_STATE_READY
2019-09-26 15:45:35.389410-0400 message STREAM_STATUS CREATE for src
2019-09-26 15:45:35.389992-0400 message STREAM_STATUS CREATE for src
2019-09-26 15:45:35.390051-0400 message STREAM_STATUS CREATE for src
GST_STATE_PAUSED
2019-09-26 15:45:35.390270-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:35.390301-0400 message NEW_CLOCK
2019-09-26 15:45:35.390437-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:35.390519-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:35.659082-0400 pad_added_handler: decodebin1
2019-09-26 15:45:35.676625-0400 message STREAM_START
2019-09-26 15:45:35.682690-0400 message TAG
2019-09-26 15:45:35.693208-0400 message ASYNC_DONE
GST_STATE_PLAYING
这没什么大不了的，因为它只是在调试时，但是这给我的开发增加了很多不必要的时间。这似乎与 iOS 线程投诉有关。自从我使用它以来，它们就一直在 GStreamer 中（甚至可能已经提交了错误），而且我不确定是否有解决方法，因为它在库本身中。想法？
编辑
此处报告：
https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/issues/568
https://www.bountysource.com/issues/48924739-glwindow-eagl-bug-with-ios11-and-xcode-9-0-beta-4
https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/issues/372
https://gitlab.freedesktop.org/gstreamer/gstreamer/issues/394
不确定正确的修复方法是什么。我正在尝试各种调度队列组合。
编辑 2：
使用 XCTWaiter 创建一些单元测试，但 运行ning 应用程序在同一时间停止。假设这也与线程有关，因为在测试（主）线程中等待 GStreamer 在后台修改应该在主线程（UIView 属性视图和框架）上修改的内容。
我能够通过重新编译 GStreamer 并添加一些调度调用来解决这个问题，其中 [UIView layer] 和 [UIView frame] 用于 gst_gl_context_eagl_update_layer 和 window 的 draw_cb.
使用此提交作为参考，但您也可以查看堆栈跟踪，因为我需要的调用更少。
gstglcontext_eagl.m
gstglwindow_eagl.m
调度依据：
我有一个 iOS 应用程序，它使用 Gstreamer 通过 UDP 从源流式传输实时视频。当我 运行 这个应用程序附加了 Xcode 调试器时，在视频出现之前会有 5-10 秒 的延迟。然后它似乎快速显示所有以前的帧，直到它 "catches up" 到当前时间戳。起初我以为这是由我的管道转换为动态代码引起的，但后来我将问题隔离到仅在调试时：
- 如果我停止管道并重新创建它，则没有明显的延迟。
- 如果我停止调试并使用该应用程序，那很好（也可以从多任务处理中杀死）。
- TestFlight 版本也可以。
这是我的控制台输出，其中包含一些调试消息、GStreamer 回调以及我在代码注释语法中的注释：
WARNING: no real random source present!
GST_STATE_READY
playOrStopVideo
2019-09-26 15:45:19.442411-0400 pipeline is null
2019-09-26 15:45:19.502487-0400 pad_added_handler: tee
2019-09-26 15:45:19.534644-0400 Metal GPU Frame Capture Enabled
2019-09-26 15:45:19.535959-0400 Metal API Validation Enabled
[GStreamer check_initialization_complete]:[00m Initialization complete, notifying application.
ViewController gstreamerInitialized()
2019-09-26 15:45:19.646378-0400 message NEED_CONTEXT
2019-09-26 15:45:19.646436-0400 message HAVE_CONTEXT
2019-09-26 15:45:19.646465-0400 message NEED_CONTEXT
2019-09-26 15:45:19.646492-0400 message ELEMENT
2019-09-26 15:45:19.646547-0400 message NEED_CONTEXT
2019-09-26 15:45:19.646636-0400 message NEED_CONTEXT
2019-09-26 15:45:19.646685-0400 message NEED_CONTEXT
GST_STATE_READY
2019-09-26 15:45:19.649381-0400 message STREAM_STATUS CREATE for src
2019-09-26 15:45:19.652090-0400 message STREAM_STATUS CREATE for src
2019-09-26 15:45:19.652148-0400 message STREAM_STATUS CREATE for src
GST_STATE_PAUSED
2019-09-26 15:45:19.652808-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:19.652926-0400 message NEW_CLOCK
2019-09-26 15:45:19.652980-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:19.653166-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:19.987250-0400 pad_added_handler: decodebin0
2019-09-26 15:45:19.999452-0400 message STREAM_START
2019-09-26 15:45:20.032557-0400 message TAG
=================================================================
Main Thread Checker: UI API called on a background thread: -[UIView frame]
PID: 3788, TID: 1475176, Thread name: (none), Queue name: org.freedesktop.gstreamer.glwindow, QoS: 0
Backtrace:
4 MyApp 0x0000000105ef14f8 gst_gl_context_eagl_update_layer + 652
5 MyApp 0x0000000105edd4b8 gst_gl_window_eagl_set_window_handle + 92
6 MyApp 0x0000000105ef5f6c _set_window_handle_cb + 104
7 MyApp 0x0000000105edd790 __gst_gl_window_eagl_send_message_async_block_invoke + 36
8 libdispatch.dylib 0x00000001097e51dc _dispatch_call_block_and_release + 24
9 libdispatch.dylib 0x00000001097e519c _dispatch_client_callout + 16
10 libdispatch.dylib 0x00000001097f3dfc _dispatch_queue_serial_drain + 768
11 libdispatch.dylib 0x00000001097e86ac _dispatch_queue_invoke + 328
12 libdispatch.dylib 0x00000001097f4d54 _dispatch_root_queue_drain_deferred_wlh + 352
13 libdispatch.dylib 0x00000001097fbe38 _dispatch_workloop_worker_thread + 676
14 libsystem_pthread.dylib 0x0000000184c83e70 _pthread_wqthread + 860
15 libsystem_pthread.dylib 0x0000000184c83b08 start_wqthread + 4
2019-09-26 15:45:20.049748-0400 MyApp[3788:1475176] [reports] Main Thread Checker: UI API called on a background thread: -[UIView frame]
PID: 3788, TID: 1475176, Thread name: (none), Queue name: org.freedesktop.gstreamer.glwindow, QoS: 0
Backtrace:
4 MyApp 0x0000000105ef14f8 gst_gl_context_eagl_update_layer + 652
5 MyApp 0x0000000105edd4b8 gst_gl_window_eagl_set_window_handle + 92
6 MyApp 0x0000000105ef5f6c _set_window_handle_cb + 104
7 MyApp 0x0000000105edd790 __gst_gl_window_eagl_send_message_async_block_invoke + 36
8 libdispatch.dylib 0x00000001097e51dc _dispatch_call_block_and_release + 24
9 libdispatch.dylib 0x00000001097e519c _dispatch_client_callout + 16
10 libdispatch.dylib 0x00000001097f3dfc _dispatch_queue_serial_drain + 768
11 libdispatch.dylib 0x00000001097e86ac _dispatch_queue_invoke + 328
12 libdispatch.dylib 0x00000001097f4d54 _dispatch_root_queue_drain_deferred_wlh + 352
13 libdispatch.dylib 0x00000001097fbe38 _dispatch_workloop_worker_thread + 676
14 libsystem_pthread.dylib 0x0000000184c83e70 _pthread_wqthread + 860
15 libsystem_pthread.dylib 0x0000000184c83b08 start_wqthread + 4
=================================================================
Main Thread Checker: UI API called on a background thread: -[UIView layer]
PID: 3788, TID: 1475176, Thread name: (none), Queue name: org.freedesktop.gstreamer.glwindow, QoS: 0
Backtrace:
4 MyApp 0x0000000105ef1300 gst_gl_context_eagl_update_layer + 148
5 MyApp 0x0000000105edd4b8 gst_gl_window_eagl_set_window_handle + 92
6 MyApp 0x0000000105ef5f6c _set_window_handle_cb + 104
7 MyApp 0x0000000105edd790 __gst_gl_window_eagl_send_message_async_block_invoke + 36
8 libdispatch.dylib 0x00000001097e51dc _dispatch_call_block_and_release + 24
9 libdispatch.dylib 0x00000001097e519c _dispatch_client_callout + 16
10 libdispatch.dylib 0x00000001097f3dfc _dispatch_queue_serial_drain + 768
11 libdispatch.dylib 0x00000001097e86ac _dispatch_queue_invoke + 328
12 libdispatch.dylib 0x00000001097f4d54 _dispatch_root_queue_drain_deferred_wlh + 352
13 libdispatch.dylib 0x00000001097fbe38 _dispatch_workloop_worker_thread + 676
14 libsystem_pthread.dylib 0x0000000184c83e70 _pthread_wqthread + 860
15 libsystem_pthread.dylib 0x0000000184c83b08 start_wqthread + 4
2019-09-26 15:45:27.554390-0400 MyApp[3788:1475176] [reports] Main Thread Checker: UI API called on a background thread: -[UIView layer]
PID: 3788, TID: 1475176, Thread name: (none), Queue name: org.freedesktop.gstreamer.glwindow, QoS: 0
Backtrace:
4 MyApp 0x0000000105ef1300 gst_gl_context_eagl_update_layer + 148
5 MyApp 0x0000000105edd4b8 gst_gl_window_eagl_set_window_handle + 92
6 MyApp 0x0000000105ef5f6c _set_window_handle_cb + 104
7 MyApp 0x0000000105edd790 __gst_gl_window_eagl_send_message_async_block_invoke + 36
8 libdispatch.dylib 0x00000001097e51dc _dispatch_call_block_and_release + 24
9 libdispatch.dylib 0x00000001097e519c _dispatch_client_callout + 16
10 libdispatch.dylib 0x00000001097f3dfc _dispatch_queue_serial_drain + 768
11 libdispatch.dylib 0x00000001097e86ac _dispatch_queue_invoke + 328
12 libdispatch.dylib 0x00000001097f4d54 _dispatch_root_queue_drain_deferred_wlh + 352
13 libdispatch.dylib 0x00000001097fbe38 _dispatch_workloop_worker_thread + 676
14 libsystem_pthread.dylib 0x0000000184c83e70 _pthread_wqthread + 860
15 libsystem_pthread.dylib 0x0000000184c83b08 start_wqthread + 4
//
// THIS IS WHERE IT HANGS (check the timestamps)
//
2019-09-26 15:45:27.692918-0400 message ASYNC_DONE
GST_STATE_PLAYING
2019-09-26 15:45:28.023985-0400 message QOS
2019-09-26 15:45:28.190131-0400 message QOS
2019-09-26 15:45:28.418494-0400 message QOS
2019-09-26 15:45:28.657004-0400 message QOS
2019-09-26 15:45:28.665464-0400 message QOS
2019-09-26 15:45:28.668784-0400 message QOS
2019-09-26 15:45:28.672105-0400 message QOS
2019-09-26 15:45:28.675492-0400 message QOS
//
// Sometimes I see output with QoS about "a lot of buffers being dropped"
//
//
// STOPPING VIDEO VIA UI AND RESTARTING (plays immediately)
//
playOrStopVideo
2019-09-26 15:45:32.959316-0400 SENT EOS OK
2019-09-26 15:45:32.962257-0400 GST_MESSAGE_EOS
2019-09-26 15:45:32.969720-0400 Pipeline set to NULL
GST_STATE_NULL
[GStreamer setupVideoWithRecording:]:[00m Exited main loop
2019-09-26 15:45:32.970650-0400 Exited main loop
2019-09-26 15:45:32.970712-0400 destroy()
playOrStopVideo
2019-09-26 15:45:35.330103-0400 pipeline is null
2019-09-26 15:45:35.369882-0400 pad_added_handler: tee
[GStreamer check_initialization_complete]:[00m Initialization complete, notifying application.
ViewController gstreamerInitialized()
2019-09-26 15:45:35.385008-0400 message NEED_CONTEXT
2019-09-26 15:45:35.385064-0400 message HAVE_CONTEXT
2019-09-26 15:45:35.385099-0400 message NEED_CONTEXT
2019-09-26 15:45:35.385134-0400 message ELEMENT
2019-09-26 15:45:35.385241-0400 message NEED_CONTEXT
2019-09-26 15:45:35.385305-0400 message NEED_CONTEXT
2019-09-26 15:45:35.385368-0400 message NEED_CONTEXT
GST_STATE_READY
2019-09-26 15:45:35.389410-0400 message STREAM_STATUS CREATE for src
2019-09-26 15:45:35.389992-0400 message STREAM_STATUS CREATE for src
2019-09-26 15:45:35.390051-0400 message STREAM_STATUS CREATE for src
GST_STATE_PAUSED
2019-09-26 15:45:35.390270-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:35.390301-0400 message NEW_CLOCK
2019-09-26 15:45:35.390437-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:35.390519-0400 message STREAM_STATUS ENTER for src
2019-09-26 15:45:35.659082-0400 pad_added_handler: decodebin1
2019-09-26 15:45:35.676625-0400 message STREAM_START
2019-09-26 15:45:35.682690-0400 message TAG
2019-09-26 15:45:35.693208-0400 message ASYNC_DONE
GST_STATE_PLAYING
这没什么大不了的，因为它只是在调试时，但是这给我的开发增加了很多不必要的时间。这似乎与 iOS 线程投诉有关。自从我使用它以来，它们就一直在 GStreamer 中（甚至可能已经提交了错误），而且我不确定是否有解决方法，因为它在库本身中。想法？
编辑
此处报告：
https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/issues/568 https://www.bountysource.com/issues/48924739-glwindow-eagl-bug-with-ios11-and-xcode-9-0-beta-4 https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/issues/372 https://gitlab.freedesktop.org/gstreamer/gstreamer/issues/394
不确定正确的修复方法是什么。我正在尝试各种调度队列组合。
编辑 2：
使用 XCTWaiter 创建一些单元测试，但 运行ning 应用程序在同一时间停止。假设这也与线程有关，因为在测试（主）线程中等待 GStreamer 在后台修改应该在主线程（UIView 属性视图和框架）上修改的内容。
我能够通过重新编译 GStreamer 并添加一些调度调用来解决这个问题，其中 [UIView layer] 和 [UIView frame] 用于 gst_gl_context_eagl_update_layer 和 window 的 draw_cb.
使用此提交作为参考，但您也可以查看堆栈跟踪，因为我需要的调用更少。
gstglcontext_eagl.m
gstglwindow_eagl.m
调度依据：