Add start and stop callbacks for audio and video renderers

src/AudioStream.c

@@ -250,6 +250,8 @@ static void DecoderThreadProc(void* context) {
 }
 
 void stopAudioStream(void) {
+    AudioCallbacks.stop();
+
     PltInterruptThread(&udpPingThread);
     PltInterruptThread(&receiveThread);
     if ((AudioCallbacks.capabilities & CAPABILITY_DIRECT_SUBMIT) == 0) {        
@@ -301,8 +303,11 @@ int startAudioStream(void) {
         return err;
     }
 
+    AudioCallbacks.start();
+
     err = PltCreateThread(ReceiveThreadProc, NULL, &receiveThread);
     if (err != 0) {
+        AudioCallbacks.stop();
         PltInterruptThread(&udpPingThread);
         PltJoinThread(&udpPingThread);
         PltCloseThread(&udpPingThread);
@@ -314,6 +319,7 @@ int startAudioStream(void) {
     if ((AudioCallbacks.capabilities & CAPABILITY_DIRECT_SUBMIT) == 0) {
         err = PltCreateThread(DecoderThreadProc, NULL, &decoderThread);
         if (err != 0) {
+            AudioCallbacks.stop();
             PltInterruptThread(&udpPingThread);
             PltInterruptThread(&receiveThread);
             PltJoinThread(&udpPingThread);

src/FakeCallbacks.c

@@ -1,21 +1,29 @@
 #include "Limelight-internal.h"
 
 static int fakeDrSetup(int videoFormat, int width, int height, int redrawRate, void* context, int drFlags) { return 0; }
+static void fakeDrStart(void) {}
+static void fakeDrStop(void) {}
 static void fakeDrCleanup(void) {}
 static int fakeDrSubmitDecodeUnit(PDECODE_UNIT decodeUnit) { return DR_OK; }
 
 static DECODER_RENDERER_CALLBACKS fakeDrCallbacks = {
     .setup = fakeDrSetup,
+    .start = fakeDrStart,
+    .stop = fakeDrStop,
     .cleanup = fakeDrCleanup,
     .submitDecodeUnit = fakeDrSubmitDecodeUnit,
 };
 
 static int fakeArInit(int audioConfiguration, POPUS_MULTISTREAM_CONFIGURATION opusConfig) { return 0; }
+static void fakeArStart(void) {}
+static void fakeArStop(void) {}
 static void fakeArCleanup(void) {}
 static void fakeArDecodeAndPlaySample(char* sampleData, int sampleLength) {}
 
 AUDIO_RENDERER_CALLBACKS fakeArCallbacks = {
     .init = fakeArInit,
+    .start = fakeArStart,
+    .stop = fakeArStop,
     .cleanup = fakeArCleanup,
     .decodeAndPlaySample = fakeArDecodeAndPlaySample,
 };
@@ -48,6 +56,12 @@ void fixupMissingCallbacks(PDECODER_RENDERER_CALLBACKS* drCallbacks, PAUDIO_REND
         if ((*drCallbacks)->setup == NULL) {
             (*drCallbacks)->setup = fakeDrSetup;
         }
+        if ((*drCallbacks)->start == NULL) {
+            (*drCallbacks)->start = fakeDrStart;
+        }
+        if ((*drCallbacks)->stop == NULL) {
+            (*drCallbacks)->stop = fakeDrStop;
+        }
         if ((*drCallbacks)->cleanup == NULL) {
             (*drCallbacks)->cleanup = fakeDrCleanup;
         }
@@ -63,6 +77,12 @@ void fixupMissingCallbacks(PDECODER_RENDERER_CALLBACKS* drCallbacks, PAUDIO_REND
         if ((*arCallbacks)->init == NULL) {
             (*arCallbacks)->init = fakeArInit;
         }
+        if ((*arCallbacks)->start == NULL) {
+            (*arCallbacks)->start = fakeArStart;
+        }
+        if ((*arCallbacks)->stop == NULL) {
+            (*arCallbacks)->stop = fakeArStop;
+        }
         if ((*arCallbacks)->cleanup == NULL) {
             (*arCallbacks)->cleanup = fakeArCleanup;
         }

src/Limelight.h

@@ -105,9 +105,16 @@ typedef struct _DECODE_UNIT {
 // Returns 0 on success, non-zero on failure.
 typedef int(*DecoderRendererSetup)(int videoFormat, int width, int height, int redrawRate, void* context, int drFlags);
 
-// This callback performs the teardown of the video decoder
+// This callback notifies the decoder that the stream is starting. No frames can be submitted before this callback returns.
+typedef void(*DecoderRendererStart)(void);
+
+// This callback notifies the decoder that the stream is stopping. Frames may still be submitted but they may be safely discarded.
+typedef void(*DecoderRendererStop)(void);
+
+// This callback performs the teardown of the video decoder. No more frames will be submitted when this callback is invoked.
 typedef void(*DecoderRendererCleanup)(void);
 
+
 // This callback provides Annex B formatted elementary stream data to the
 // decoder. If the decoder is unable to process the submitted data for some reason,
 // it must return DR_NEED_IDR to generate a keyframe.
@@ -117,6 +124,8 @@ typedef int(*DecoderRendererSubmitDecodeUnit)(PDECODE_UNIT decodeUnit);
 
 typedef struct _DECODER_RENDERER_CALLBACKS {
     DecoderRendererSetup setup;
+    DecoderRendererStart start;
+    DecoderRendererStop stop;
     DecoderRendererCleanup cleanup;
     DecoderRendererSubmitDecodeUnit submitDecodeUnit;
     int capabilities;
@@ -152,7 +161,13 @@ typedef struct _OPUS_MULTISTREAM_CONFIGURATION {
 // specified in the stream configuration. Returns 0 on success, non-zero on failure.
 typedef int(*AudioRendererInit)(int audioConfiguration, POPUS_MULTISTREAM_CONFIGURATION opusConfig);
 
-// This callback performs the final teardown of the audio decoder
+// This callback notifies the decoder that the stream is starting. No audio can be submitted before this callback returns.
+typedef void(*AudioRendererStart)(void);
+
+// This callback notifies the decoder that the stream is stopping. Audio samples may still be submitted but they may be safely discarded.
+typedef void(*AudioRendererStop)(void);
+
+// This callback performs the final teardown of the audio decoder. No additional audio will be submitted when this callback is invoked.
 typedef void(*AudioRendererCleanup)(void);
 
 // This callback provides Opus audio data to be decoded and played. sampleLength is in bytes.
@@ -160,6 +175,8 @@ typedef void(*AudioRendererDecodeAndPlaySample)(char* sampleData, int sampleLeng
 
 typedef struct _AUDIO_RENDERER_CALLBACKS {
     AudioRendererInit init;
+    AudioRendererStart start;
+    AudioRendererStop stop;
     AudioRendererCleanup cleanup;
     AudioRendererDecodeAndPlaySample decodeAndPlaySample;
     int capabilities;

src/VideoStream.c

@@ -151,6 +151,8 @@ int readFirstFrame(void) {
 
 // Terminate the video stream
 void stopVideoStream(void) {
+    VideoCallbacks.stop();
+
     // Wake up client code that may be waiting on the decode unit queue
     stopVideoDepacketizer();
     
@@ -209,8 +211,11 @@ int startVideoStream(void* rendererContext, int drFlags) {
         return LastSocketError();
     }
 
+    VideoCallbacks.start();
+
     err = PltCreateThread(ReceiveThreadProc, NULL, &receiveThread);
     if (err != 0) {
+        VideoCallbacks.stop();
         closeSocket(rtpSocket);
         VideoCallbacks.cleanup();
         return err;
@@ -219,6 +224,7 @@ int startVideoStream(void* rendererContext, int drFlags) {
     if ((VideoCallbacks.capabilities & CAPABILITY_DIRECT_SUBMIT) == 0) {
         err = PltCreateThread(DecoderThreadProc, NULL, &decoderThread);
         if (err != 0) {
+            VideoCallbacks.stop();
             PltInterruptThread(&receiveThread);
             PltJoinThread(&receiveThread);
             PltCloseThread(&receiveThread);
@@ -233,6 +239,7 @@ int startVideoStream(void* rendererContext, int drFlags) {
         firstFrameSocket = connectTcpSocket(&RemoteAddr, RemoteAddrLen,
                                             FIRST_FRAME_PORT, FIRST_FRAME_TIMEOUT_SEC);
         if (firstFrameSocket == INVALID_SOCKET) {
+            VideoCallbacks.stop();
             stopVideoDepacketizer();
             PltInterruptThread(&receiveThread);
             if ((VideoCallbacks.capabilities & CAPABILITY_DIRECT_SUBMIT) == 0) {
@@ -256,6 +263,7 @@ int startVideoStream(void* rendererContext, int drFlags) {
     // to send UDP data
     err = PltCreateThread(UdpPingThreadProc, NULL, &udpPingThread);
     if (err != 0) {
+        VideoCallbacks.stop();
         stopVideoDepacketizer();
         PltInterruptThread(&receiveThread);
         if ((VideoCallbacks.capabilities & CAPABILITY_DIRECT_SUBMIT) == 0) {