lavf: Add an option for avoiding negative timestamps

This is the same logic as is invoked on AVFMT_TS_NEGATIVE,
but which can be enabled manually, or can be enabled
in muxers which only need it in certain conditions.

Also allow using the same mechanism to force streams to start
at 0.

Signed-off-by: Martin Storsjö <martin@martin.st>

diff --git a/doc/APIchanges b/doc/APIchanges
index 69da4428a409d37993fd31e9236cadc1e7f9a69a..44af215507a54792236f4bb5968000cb4c4ec4c4 100644 (file)
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -13,6 +13,9 @@ libavutil:     2014-08-09
 
 API changes, most recent first:
 
+2014-11-xx - xxxxxxx - lavf 56.06.3 - avformat.h
+  Add AVFormatContext.avoid_negative_ts.
+
 2014-11-xx - xxxxxxx - lavc 56.6.0 - vorbis_parser.h
   Add a public API for parsing vorbis packets.
 

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index f28186f7c73adbf791c587ebc5b48e76ffe924e3..ade5d2f9dc80db43a6f2a43b8c1d967c6eadac43 100644 (file)
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1198,6 +1198,18 @@ typedef struct AVFormatContext {
      */
     int max_ts_probe;
 
+    /**
+     * Avoid negative timestamps during muxing.
+     * Any value of the AVFMT_AVOID_NEG_TS_* constants.
+     * Note, this only works when using av_interleaved_write_frame.
+     * - muxing: Set by user
+     * - demuxing: unused
+     */
+    int avoid_negative_ts;
+#define AVFMT_AVOID_NEG_TS_AUTO             -1 ///< Enabled when required by target format
+#define AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE 1 ///< Shift timestamps so they are non negative
+#define AVFMT_AVOID_NEG_TS_MAKE_ZERO         2 ///< Shift timestamps so that they start at 0
+
     /*****************************************************************
      * All fields below this line are not part of the public API. They
      * may not be used outside of libavformat and can be changed and

diff --git a/libavformat/mux.c b/libavformat/mux.c
index c80eb5bfb7a3887abd2708a386a0be49bbcb711e..1e80e105d73285ec2cbfd1fdd971b8e66f053ebc 100644 (file)
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -248,6 +248,13 @@ int avformat_write_header(AVFormatContext *s, AVDictionary **options)
             return ret;
     }
 
+    if (s->avoid_negative_ts == AVFMT_AVOID_NEG_TS_AUTO) {
+        if (s->oformat->flags & (AVFMT_TS_NEGATIVE | AVFMT_NOTIMESTAMPS)) {
+            s->avoid_negative_ts = 0;
+        } else
+            s->avoid_negative_ts = AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE;
+    }
+
     return 0;
 }
 
@@ -318,11 +325,12 @@ static int compute_pkt_fields2(AVFormatContext *s, AVStream *st, AVPacket *pkt)
 static int write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int ret;
-    if (!(s->oformat->flags & (AVFMT_TS_NEGATIVE | AVFMT_NOTIMESTAMPS))) {
+    if (s->avoid_negative_ts > 0) {
         AVRational time_base = s->streams[pkt->stream_index]->time_base;
         int64_t offset = 0;
 
-        if (!s->offset && pkt->dts != AV_NOPTS_VALUE && pkt->dts < 0) {
+        if (!s->offset && pkt->dts != AV_NOPTS_VALUE &&
+            (pkt->dts < 0 || s->avoid_negative_ts == AVFMT_AVOID_NEG_TS_MAKE_ZERO)) {
             s->offset = -pkt->dts;
             s->offset_timebase = time_base;
         }

diff --git a/libavformat/options_table.h b/libavformat/options_table.h
index 0f7207ccf14774da605fce6db866af0ad5e67939..8372ef36501bf71d9bee79c38d35717aaa8c6608 100644 (file)
--- a/libavformat/options_table.h
+++ b/libavformat/options_table.h
@@ -66,6 +66,10 @@ static const AVOption avformat_options[] = {
 {"normal", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_COMPLIANCE_NORMAL }, INT_MIN, INT_MAX, D|E, "strict"},
 {"experimental", "allow non-standardized experimental variants", 0, AV_OPT_TYPE_CONST, {.i64 = FF_COMPLIANCE_EXPERIMENTAL }, INT_MIN, INT_MAX, D|E, "strict"},
 {"max_ts_probe", "maximum number of packets to read while waiting for the first timestamp", OFFSET(max_ts_probe), AV_OPT_TYPE_INT, { .i64 = 50 }, 0, INT_MAX, D },
+{"avoid_negative_ts", "shift timestamps so they start at 0", OFFSET(avoid_negative_ts), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 2, E, "avoid_negative_ts"},
+{"auto",              "enabled when required by target format",    0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_AVOID_NEG_TS_AUTO },              INT_MIN, INT_MAX, E, "avoid_negative_ts"},
+{"make_non_negative", "shift timestamps so they are non negative", 0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_AVOID_NEG_TS_MAKE_NON_NEGATIVE }, INT_MIN, INT_MAX, E, "avoid_negative_ts"},
+{"make_zero",         "shift timestamps so they start at 0",       0, AV_OPT_TYPE_CONST, {.i64 = AVFMT_AVOID_NEG_TS_MAKE_ZERO },         INT_MIN, INT_MAX, E, "avoid_negative_ts"},
 {NULL},
 };
 

diff --git a/libavformat/version.h b/libavformat/version.h
index dfb60894085fcd2e43bba68450c4e1d471b3e2b5..c477d5d49c316364480974dfa72c0c4999116da0 100644 (file)
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -31,7 +31,7 @@
 
 #define LIBAVFORMAT_VERSION_MAJOR 56
 #define LIBAVFORMAT_VERSION_MINOR  6
-#define LIBAVFORMAT_VERSION_MICRO  2
+#define LIBAVFORMAT_VERSION_MICRO  3
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \