Fix PTS when not monotonically increasing

Some decoders fail to guarantee that PTS must be strictly
monotonically increasing. Fix the (rescaled) PTS when it does not
respect this constraint.

Fixes #4054 <https://github.com/Genymobile/scrcpy/issues/4054>

app/src/recorder.c

@@ -96,23 +96,29 @@ sc_recorder_rescale_packet(AVStream *stream, AVPacket *packet) {
 }
 
 static bool
-sc_recorder_write_stream(struct sc_recorder *recorder, int stream_index,
-                         AVPacket *packet) {
-    AVStream *stream = recorder->ctx->streams[stream_index];
+sc_recorder_write_stream(struct sc_recorder *recorder,
+                         struct sc_recorder_stream *st, AVPacket *packet) {
+    AVStream *stream = recorder->ctx->streams[st->index];
     sc_recorder_rescale_packet(stream, packet);
+    if (st->last_pts != AV_NOPTS_VALUE && packet->pts <= st->last_pts) {
+        LOGW("Fixing PTS non monotonically increasing "
+             "(%" PRIi64 " >= %" PRIi64 ")", st->last_pts, packet->pts);
+        packet->pts = ++st->last_pts;
+        packet->dts = packet->pts;
+    } else {
+        st->last_pts = packet->pts;
+    }
     return av_interleaved_write_frame(recorder->ctx, packet) >= 0;
 }
 
 static inline bool
 sc_recorder_write_video(struct sc_recorder *recorder, AVPacket *packet) {
-    return sc_recorder_write_stream(recorder, recorder->video_stream_index,
-                                    packet);
+    return sc_recorder_write_stream(recorder, &recorder->video_stream, packet);
 }
 
 static inline bool
 sc_recorder_write_audio(struct sc_recorder *recorder, AVPacket *packet) {
-    return sc_recorder_write_stream(recorder, recorder->audio_stream_index,
-                                    packet);
+    return sc_recorder_write_stream(recorder, &recorder->audio_stream, packet);
 }
 
 static bool
@@ -178,9 +184,10 @@ static bool
 sc_recorder_process_header(struct sc_recorder *recorder) {
     sc_mutex_lock(&recorder->mutex);
 
-    while (!recorder->stopped && (!recorder->video_init
-                               || !recorder->audio_init
-                               || sc_recorder_has_empty_queues(recorder))) {
+    while (!recorder->stopped &&
+              ((recorder->video && !recorder->video_init)
+            || (recorder->audio && !recorder->audio_init)
+            || sc_recorder_has_empty_queues(recorder))) {
         sc_cond_wait(&recorder->cond, &recorder->mutex);
     }
 
@@ -214,9 +221,9 @@ sc_recorder_process_header(struct sc_recorder *recorder) {
             goto end;
         }
 
-        assert(recorder->video_stream_index >= 0);
+        assert(recorder->video_stream.index >= 0);
         AVStream *video_stream =
-            recorder->ctx->streams[recorder->video_stream_index];
+            recorder->ctx->streams[recorder->video_stream.index];
         bool ok = sc_recorder_set_extradata(video_stream, video_pkt);
         if (!ok) {
             goto end;
@@ -229,9 +236,9 @@ sc_recorder_process_header(struct sc_recorder *recorder) {
             goto end;
         }
 
-        assert(recorder->audio_stream_index >= 0);
+        assert(recorder->audio_stream.index >= 0);
         AVStream *audio_stream =
-            recorder->ctx->streams[recorder->audio_stream_index];
+            recorder->ctx->streams[recorder->audio_stream.index];
         bool ok = sc_recorder_set_extradata(audio_stream, audio_pkt);
         if (!ok) {
             goto end;
@@ -504,7 +511,7 @@ sc_recorder_video_packet_sink_open(struct sc_packet_sink *sink,
         return false;
     }
 
-    recorder->video_stream_index = stream->index;
+    recorder->video_stream.index = stream->index;
 
     recorder->video_init = true;
     sc_cond_signal(&recorder->cond);
@@ -548,7 +555,7 @@ sc_recorder_video_packet_sink_push(struct sc_packet_sink *sink,
         return false;
     }
 
-    rec->stream_index = recorder->video_stream_index;
+    rec->stream_index = recorder->video_stream.index;
 
     bool ok = sc_vecdeque_push(&recorder->video_queue, rec);
     if (!ok) {
@@ -585,7 +592,7 @@ sc_recorder_audio_packet_sink_open(struct sc_packet_sink *sink,
         return false;
     }
 
-    recorder->audio_stream_index = stream->index;
+    recorder->audio_stream.index = stream->index;
 
     recorder->audio_init = true;
     sc_cond_signal(&recorder->cond);
@@ -631,7 +638,7 @@ sc_recorder_audio_packet_sink_push(struct sc_packet_sink *sink,
         return false;
     }
 
-    rec->stream_index = recorder->audio_stream_index;
+    rec->stream_index = recorder->audio_stream.index;
 
     bool ok = sc_vecdeque_push(&recorder->audio_queue, rec);
     if (!ok) {
@@ -662,6 +669,12 @@ sc_recorder_audio_packet_sink_disable(struct sc_packet_sink *sink) {
     sc_mutex_unlock(&recorder->mutex);
 }
 
+static void
+sc_recorder_stream_init(struct sc_recorder_stream *stream) {
+    stream->index = -1;
+    stream->last_pts = AV_NOPTS_VALUE;
+}
+
 bool
 sc_recorder_init(struct sc_recorder *recorder, const char *filename,
                  enum sc_record_format format, bool video, bool audio,
@@ -693,8 +706,8 @@ sc_recorder_init(struct sc_recorder *recorder, const char *filename,
     recorder->video_init = false;
     recorder->audio_init = false;
 
-    recorder->video_stream_index = -1;
-    recorder->audio_stream_index = -1;
+    sc_recorder_stream_init(&recorder->video_stream);
+    sc_recorder_stream_init(&recorder->audio_stream);
 
     recorder->format = format;
 

app/src/recorder.h

@@ -14,6 +14,11 @@
 
 struct sc_recorder_queue SC_VECDEQUE(AVPacket *);
 
+struct sc_recorder_stream {
+    int index;
+    int64_t last_pts;
+};
+
 struct sc_recorder {
     struct sc_packet_sink video_packet_sink;
     struct sc_packet_sink audio_packet_sink;
@@ -45,8 +50,8 @@ struct sc_recorder {
     bool video_init;
     bool audio_init;
 
-    int video_stream_index;
-    int audio_stream_index;
+    struct sc_recorder_stream video_stream;
+    struct sc_recorder_stream audio_stream;
 
     const struct sc_recorder_callbacks *cbs;
     void *cbs_userdata;