avformat/hlsenc: add support for microseconds since epoch based sequence number

Sequence numbers of segments should be unique, if an encoder is using shorter
than 1 second segments and it is restarted, then future segments will be using
already used sequence numbers if initial sequence number is based on the number
of seconds since epoch and not microseconds.
Signed-off-by: Marton Balint <cus@passwd.hu>

doc/muxers.texi

@@ -648,6 +648,9 @@ Set the starting sequence numbers according to @var{start_number} option value.
 @item epoch
 The start number will be the seconds since epoch (1970-01-01 00:00:00)
 
+@item epoch_us
+The start number will be the microseconds since epoch (1970-01-01 00:00:00)
+
 @item datetime
 The start number will be based on the current date/time as YYYYmmddHHMMSS. e.g. 20161231235759.
 

libavformat/hlsenc.c

@@ -41,6 +41,7 @@
 #include "libavutil/random_seed.h"
 #include "libavutil/opt.h"
 #include "libavutil/log.h"
+#include "libavutil/time.h"
 #include "libavutil/time_internal.h"
 
 #include "avformat.h"
@@ -56,6 +57,8 @@ typedef enum {
     HLS_START_SEQUENCE_AS_START_NUMBER = 0,
     HLS_START_SEQUENCE_AS_SECONDS_SINCE_EPOCH = 1,
     HLS_START_SEQUENCE_AS_FORMATTED_DATETIME = 2,  // YYYYMMDDhhmmss
+    HLS_START_SEQUENCE_AS_MICROSECONDS_SINCE_EPOCH = 3,
+    HLS_START_SEQUENCE_LAST, // unused
 } StartSequenceSourceType;
 
 typedef enum {
@@ -2788,9 +2791,12 @@ static int hls_init(AVFormatContext *s)
         pattern = "%d.m4s";
     }
     if ((hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_SECONDS_SINCE_EPOCH) ||
+        (hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_MICROSECONDS_SINCE_EPOCH) ||
         (hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_FORMATTED_DATETIME)) {
-        time_t t = time(NULL); // we will need it in either case
-        if (hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_SECONDS_SINCE_EPOCH) {
+        time_t t = time(NULL);
+        if (hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_MICROSECONDS_SINCE_EPOCH) {
+            hls->start_sequence = av_gettime();
+        } else if (hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_SECONDS_SINCE_EPOCH) {
             hls->start_sequence = (int64_t)t;
         } else if (hls->start_sequence_source_type == HLS_START_SEQUENCE_AS_FORMATTED_DATETIME) {
             char b[15];
@@ -3083,9 +3089,10 @@ static const AVOption options[] = {
     {"event", "EVENT playlist", 0, AV_OPT_TYPE_CONST, {.i64 = PLAYLIST_TYPE_EVENT }, INT_MIN, INT_MAX, E, "pl_type" },
     {"vod", "VOD playlist", 0, AV_OPT_TYPE_CONST, {.i64 = PLAYLIST_TYPE_VOD }, INT_MIN, INT_MAX, E, "pl_type" },
     {"method", "set the HTTP method(default: PUT)", OFFSET(method), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},
-    {"hls_start_number_source", "set source of first number in sequence", OFFSET(start_sequence_source_type), AV_OPT_TYPE_INT, {.i64 = HLS_START_SEQUENCE_AS_START_NUMBER }, 0, HLS_START_SEQUENCE_AS_FORMATTED_DATETIME, E, "start_sequence_source_type" },
+    {"hls_start_number_source", "set source of first number in sequence", OFFSET(start_sequence_source_type), AV_OPT_TYPE_INT, {.i64 = HLS_START_SEQUENCE_AS_START_NUMBER }, 0, HLS_START_SEQUENCE_LAST-1, E, "start_sequence_source_type" },
     {"generic", "start_number value (default)", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_START_SEQUENCE_AS_START_NUMBER }, INT_MIN, INT_MAX, E, "start_sequence_source_type" },
     {"epoch", "seconds since epoch", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_START_SEQUENCE_AS_SECONDS_SINCE_EPOCH }, INT_MIN, INT_MAX, E, "start_sequence_source_type" },
+    {"epoch_us", "microseconds since epoch", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_START_SEQUENCE_AS_MICROSECONDS_SINCE_EPOCH }, INT_MIN, INT_MAX, E, "start_sequence_source_type" },
     {"datetime", "current datetime as YYYYMMDDhhmmss", 0, AV_OPT_TYPE_CONST, {.i64 = HLS_START_SEQUENCE_AS_FORMATTED_DATETIME }, INT_MIN, INT_MAX, E, "start_sequence_source_type" },
     {"http_user_agent", "override User-Agent field in HTTP header", OFFSET(user_agent), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},
     {"var_stream_map", "Variant stream map string", OFFSET(var_stream_map), AV_OPT_TYPE_STRING, {.str = NULL},  0, 0,    E},

libavformat/version.h

@@ -33,7 +33,7 @@
 // Also please add any ticket numbers that you believe might be affected here
 #define LIBAVFORMAT_VERSION_MAJOR  58
 #define LIBAVFORMAT_VERSION_MINOR  42
-#define LIBAVFORMAT_VERSION_MICRO 101
+#define LIBAVFORMAT_VERSION_MICRO 102
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \