Stop stream immediately on quit

If the stream is stopped, av_read_frame() will be woken up and yield a
corrupted packet. Do not try to decode or record it.

app/src/stream.c

@@ -207,6 +207,13 @@ run_stream(void *data) {
     packet.size = 0;
 
     while (!av_read_frame(format_ctx, &packet)) {
+        if (SDL_AtomicGet(&stream->stopped)) {
+            // if the stream is stopped, the socket had been shutdown, so the
+            // last packet is probably corrupted (but not detected as such by
+            // FFmpeg) and will not be decoded correctly
+            av_packet_unref(&packet);
+            goto quit;
+        }
         if (stream->decoder && !decoder_push(stream->decoder, &packet)) {
             av_packet_unref(&packet);
             goto quit;
@@ -259,6 +266,7 @@ stream_init(struct stream *stream, socket_t socket,
     stream->socket = socket;
     stream->decoder = decoder,
     stream->recorder = recorder;
+    SDL_AtomicSet(&stream->stopped, 0);
 }
 
 bool
@@ -275,6 +283,7 @@ stream_start(struct stream *stream) {
 
 void
 stream_stop(struct stream *stream) {
+    SDL_AtomicSet(&stream->stopped, 1);
     if (stream->decoder) {
         decoder_interrupt(stream->decoder);
     }

app/src/stream.h

@@ -3,6 +3,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <SDL2/SDL_atomic.h>
 #include <SDL2/SDL_thread.h>
 
 #include "net.h"
@@ -18,6 +19,7 @@ struct stream {
     socket_t socket;
     struct video_buffer *video_buffer;
     SDL_Thread *thread;
+    SDL_atomic_t stopped;
     struct decoder *decoder;
     struct recorder *recorder;
     struct receiver_state {