From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Sat, 14 Apr 2018 21:47:13 +0000 (+0200)
Subject: Add a feature on VideoInput to interrupt the playing video.
X-Git-Tag: 1.7.2~40
X-Git-Url: https://git.sesse.net/?p=nageru;a=commitdiff_plain;h=6f578d03677866ad1135a21b807ab0167295e38f

Add a feature on VideoInput to interrupt the playing video.

Useful for when using FFmpeg sources to play network streams,
since FFmpeg can sometimes hang forever if the remote server
goes away.
---

diff --git a/ffmpeg_capture.cpp b/ffmpeg_capture.cpp
index bbbb941..50b4fa4 100644
--- a/ffmpeg_capture.cpp
+++ b/ffmpeg_capture.cpp
@@ -288,6 +288,7 @@ void FFmpegCapture::producer_thread_func()
 			producer_thread_should_quit.sleep_for(seconds(1));
 			continue;
 		}
+		should_interrupt = false;
 		if (!play_video(pathname)) {
 			// Error.
 			fprintf(stderr, "Error when playing %s, sleeping one second and trying again...\n", pathname.c_str());
@@ -352,7 +353,7 @@ bool FFmpegCapture::play_video(const string &pathname)
 	AVDictionary *opts = nullptr;
 	av_dict_set(&opts, "fflags", "nobuffer", 0);
 
-	auto format_ctx = avformat_open_input_unique(pathname.c_str(), nullptr, &opts);
+	auto format_ctx = avformat_open_input_unique(pathname.c_str(), nullptr, &opts, AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
 	if (format_ctx == nullptr) {
 		fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
 		return false;
@@ -801,3 +802,13 @@ UniqueFrame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &
 
 	return video_frame;
 }
+
+int FFmpegCapture::interrupt_cb_thunk(void *unique)
+{
+	return reinterpret_cast<FFmpegCapture *>(unique)->interrupt_cb();
+}
+
+int FFmpegCapture::interrupt_cb()
+{
+	return should_interrupt.load();
+}
diff --git a/ffmpeg_capture.h b/ffmpeg_capture.h
index f718c70..705d25f 100644
--- a/ffmpeg_capture.h
+++ b/ffmpeg_capture.h
@@ -78,6 +78,12 @@ public:
 		producer_thread_should_quit.wakeup();
 	}
 
+	// Will stop the stream even if it's hung on blocking I/O.
+	void disconnect()
+	{
+		should_interrupt = true;
+	}
+
 	// CaptureInterface.
 	void set_video_frame_allocator(bmusb::FrameAllocator *allocator) override
 	{
@@ -207,6 +213,9 @@ private:
 	bmusb::VideoFormat construct_video_format(const AVFrame *frame, AVRational video_timebase);
 	UniqueFrame make_video_frame(const AVFrame *frame, const std::string &pathname, bool *error);
 
+	static int interrupt_cb_thunk(void *unique);
+	int interrupt_cb();
+
 	std::string description, filename;
 	uint16_t timecode = 0;
 	unsigned width, height;
@@ -215,6 +224,7 @@ private:
 	bool running = false;
 	int card_index = -1;
 	double rate = 1.0;
+	std::atomic<bool> should_interrupt{false};
 
 	bool has_dequeue_callbacks = false;
 	std::function<void()> dequeue_init_callback = nullptr;
diff --git a/ffmpeg_raii.cpp b/ffmpeg_raii.cpp
index a11075f..746e03d 100644
--- a/ffmpeg_raii.cpp
+++ b/ffmpeg_raii.cpp
@@ -18,16 +18,25 @@ void avformat_close_input_unique::operator() (AVFormatContext *format_ctx) const
 }
 
 AVFormatContextWithCloser avformat_open_input_unique(
-	const char *pathname, AVInputFormat *fmt, AVDictionary **options)
+	const char *pathname, AVInputFormat *fmt,
+	AVDictionary **options)
 {
-	AVFormatContext *format_ctx = nullptr;
+	return avformat_open_input_unique(pathname, fmt, options, AVIOInterruptCB{ nullptr, nullptr });
+}
+
+AVFormatContextWithCloser avformat_open_input_unique(
+	const char *pathname, AVInputFormat *fmt,
+	AVDictionary **options,
+	const AVIOInterruptCB &interrupt_cb)
+{
+	AVFormatContext *format_ctx = avformat_alloc_context();
+	format_ctx->interrupt_callback = interrupt_cb;
 	if (avformat_open_input(&format_ctx, pathname, fmt, options) != 0) {
 		format_ctx = nullptr;
 	}
 	return AVFormatContextWithCloser(format_ctx);
 }
 
-
 // AVCodecContext
 
 void avcodec_free_context_unique::operator() (AVCodecContext *codec_ctx) const
diff --git a/ffmpeg_raii.h b/ffmpeg_raii.h
index c0c4a47..33d2334 100644
--- a/ffmpeg_raii.h
+++ b/ffmpeg_raii.h
@@ -19,6 +19,7 @@ struct AVFormatContext;
 struct AVFrame;
 struct AVInputFormat;
 struct SwsContext;
+typedef struct AVIOInterruptCB AVIOInterruptCB;
 
 // AVFormatContext
 struct avformat_close_input_unique {
@@ -29,7 +30,13 @@ typedef std::unique_ptr<AVFormatContext, avformat_close_input_unique>
 	AVFormatContextWithCloser;
 
 AVFormatContextWithCloser avformat_open_input_unique(
-	const char *pathname, AVInputFormat *fmt, AVDictionary **options);
+	const char *pathname, AVInputFormat *fmt,
+	AVDictionary **options);
+
+AVFormatContextWithCloser avformat_open_input_unique(
+	const char *pathname, AVInputFormat *fmt,
+	AVDictionary **options,
+	const AVIOInterruptCB &interrupt_cb);
 
 
 // AVCodecContext
diff --git a/theme.cpp b/theme.cpp
index 32a00ff..45df66f 100644
--- a/theme.cpp
+++ b/theme.cpp
@@ -463,6 +463,14 @@ int VideoInput_rewind(lua_State* L)
 	return 0;
 }
 
+int VideoInput_disconnect(lua_State* L)
+{
+	assert(lua_gettop(L) == 1);
+	FFmpegCapture **video_input = (FFmpegCapture **)luaL_checkudata(L, 1, "VideoInput");
+	(*video_input)->disconnect();
+	return 0;
+}
+
 int VideoInput_change_rate(lua_State* L)
 {
 	assert(lua_gettop(L) == 2);
@@ -759,6 +767,7 @@ const luaL_Reg ImageInput_funcs[] = {
 const luaL_Reg VideoInput_funcs[] = {
 	{ "new", VideoInput_new },
 	{ "rewind", VideoInput_rewind },
+	{ "disconnect", VideoInput_disconnect },
 	{ "change_rate", VideoInput_change_rate },
 	{ "get_signal_num", VideoInput_get_signal_num },
 	{ NULL, NULL }