avformat/mux: set avoid_negative_ts based on flags if not overridden by user or muxer

This changes the default to avoid negative timestamps.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

2 files changed, 11 insertions, 1 deletions

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index d26964a165..c8f4912fd5 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -370,7 +370,10 @@ typedef struct AVProbeData {
                                         timestamps. If not set the timestamp
                                         will be shifted in av_write_frame and
                                         av_interleaved_write_frame so they
-                                        start from 0. */
+                                        start from 0.
+                                        The user or muxer can override this through
+                                        AVFormatContext.avoid_negative_ts
+                                        */
 
 #define AVFMT_SEEK_TO_PTS   0x4000000 /**< Seeking is based on PTS */
 
diff --git a/libavformat/mux.c b/libavformat/mux.c
index 4781a3e8de..eba4ec3c5a 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -398,6 +398,13 @@ int avformat_write_header(AVFormatContext *s, AVDictionary **options)
     if ((ret = init_pts(s)) < 0)
         return ret;
 
+    if (s->avoid_negative_ts < 0) {
+        if (s->oformat->flags & (AVFMT_TS_NEGATIVE | AVFMT_NOTIMESTAMPS)) {
+            s->avoid_negative_ts = 0;
+        } else
+            s->avoid_negative_ts = 1;
+    }
+
     return 0;
 }