lavf: add output_ts_offset option to AVFormatContext

This option can be generally useful to set an output offset, needed when
setting an absolute index in the output.

4 files changed, 18 insertions, 2 deletions

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 76b0652cec..50b710816b 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1380,6 +1380,11 @@ typedef struct AVFormatContext {
      */
     av_format_control_message control_message_cb;
 
+    /**
+     * Output timestamp offset, in microseconds.
+     * Muxing: set by user via AVOptions (NO direct access)
+     */
+    int64_t output_ts_offset;
 } AVFormatContext;
 
 int av_format_get_probe_score(const AVFormatContext *s);
diff --git a/libavformat/mux.c b/libavformat/mux.c
index bd50191b87..70b60640a1 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -510,6 +510,16 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int ret, did_split;
 
+    if (s->output_ts_offset) {
+        AVStream *st = s->streams[pkt->stream_index];
+        int64_t offset = av_rescale_q(s->output_ts_offset, AV_TIME_BASE_Q, st->time_base);
+
+        if (pkt->dts != AV_NOPTS_VALUE)
+            pkt->dts += offset;
+        if (pkt->pts != AV_NOPTS_VALUE)
+            pkt->pts += offset;
+    }
+
     if (s->avoid_negative_ts > 0) {
         AVStream *st = s->streams[pkt->stream_index];
         int64_t offset = st->mux_ts_offset;
diff --git a/libavformat/options_table.h b/libavformat/options_table.h
index 32210422c9..b42a762738 100644
--- a/libavformat/options_table.h
+++ b/libavformat/options_table.h
@@ -78,6 +78,7 @@ static const AVOption avformat_options[] = {
 {"correct_ts_overflow", "correct single timestamp overflows", OFFSET(correct_ts_overflow), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, D},
 {"flush_packets", "enable flushing of the I/O context after each packet", OFFSET(flush_packets), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, E},
 {"metadata_header_padding", "set number of bytes to be written as padding in a metadata header", OFFSET(metadata_header_padding), AV_OPT_TYPE_INT, {.i64 = -1}, -1, INT_MAX, E},
+{"output_ts_offset", "set output timestamp offset", OFFSET(output_ts_offset), AV_OPT_TYPE_DURATION, {.i64 = 0}, -INT64_MAX, INT64_MAX, E},
 {NULL},
 };
 
diff --git a/libavformat/version.h b/libavformat/version.h
index a052d3c32c..38945a57fd 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,8 +30,8 @@
 #include "libavutil/version.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 55
-#define LIBAVFORMAT_VERSION_MINOR 28
-#define LIBAVFORMAT_VERSION_MICRO 101
+#define LIBAVFORMAT_VERSION_MINOR 29
+#define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \