1 files changed, 37 insertions, 0 deletions

diff --git a/fftools/ffmpeg_mux.c b/fftools/ffmpeg_mux.c
index 08a76f0066..24f638d0e5 100644
--- a/fftools/ffmpeg_mux.c
+++ b/fftools/ffmpeg_mux.c
@@ -29,6 +29,7 @@
 #include "libavutil/intreadwrite.h"
 #include "libavutil/log.h"
 #include "libavutil/mem.h"
+#include "libavutil/time.h"
 #include "libavutil/timestamp.h"
 #include "libavutil/thread.h"
 
@@ -69,6 +70,10 @@ struct Muxer {
     atomic_int_least64_t last_filesize;
     int header_written;
 
+    int live_started;
+    int64_t header_write_wallclock;
+    int64_t live_ts_offset;
+
     AVPacket *sq_pkt;
 };
 
@@ -100,6 +105,37 @@ static int write_packet(OutputFile *of, OutputStream *ost, AVPacket *pkt)
     if (fs >= of->mux->limit_filesize)
         return AVERROR_EOF;
 
+    if (of->live) {
+        if (!of->mux->live_started) {
+            int64_t ts = av_rescale_q(pkt->dts, ost->mux_timebase, AV_TIME_BASE_Q);
+
+            of->mux->live_ts_offset = FFMAX(of->mux->live_ts_offset, ts);
+
+            // drop all packets that were demuxed before avformat_write_header()
+            if ((int64_t)pkt->opaque < of->mux->header_write_wallclock) {
+                fprintf(stderr, "live drop %s pts %g\n",
+                        av_get_media_type_string(st->codecpar->codec_type),
+                        pkt->pts * av_q2d(ost->mux_timebase));
+                av_packet_unref(pkt);
+                return 0;
+            }
+
+            of->mux->live_started = 1;
+            fprintf(stderr, "live started, ts offset %g\n", of->mux->live_ts_offset / (double)AV_TIME_BASE);
+        }
+
+        pkt->pts -= av_rescale_q(of->mux->live_ts_offset, AV_TIME_BASE_Q, ost->mux_timebase);
+        pkt->dts -= av_rescale_q(of->mux->live_ts_offset, AV_TIME_BASE_Q, ost->mux_timebase);
+
+        if (pkt->pts < 0) {
+            fprintf(stderr, "live drop %s pts %g\n",
+                    av_get_media_type_string(st->codecpar->codec_type),
+                    pkt->pts * av_q2d(ost->mux_timebase));
+            av_packet_unref(pkt);
+            return 0;
+        }
+    }
+
     if ((st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && ost->vsync_method == VSYNC_DROP) ||
         (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO && audio_sync_method < 0))
         pkt->pts = pkt->dts = AV_NOPTS_VALUE;
@@ -478,6 +514,7 @@ int of_check_init(OutputFile *of)
     }
     //assert_avoptions(of->opts);
     of->mux->header_written = 1;
+    of->mux->header_write_wallclock = av_gettime_relative();
 
     av_dump_format(fc, of->index, fc->url, 1);
     nb_output_dumped++;