[FFmpeg-devel] [PATCH 3/4] avformat/nutenc: add option to periodically insert global headers

[Andriy Gelman]

From: Andriy Gelman <andriy.gelman at gmail.com>

Signed-off-by: Andriy Gelman <andriy.gelman at gmail.com>
---
 doc/muxers.texi      |  6 ++++++
 libavformat/nut.h    |  3 ++-
 libavformat/nutenc.c | 10 ++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/doc/muxers.texi b/doc/muxers.texi
index 813b4678f4..ace236fca6 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -1822,6 +1822,12 @@ Change the syncpoint usage in nut:
 The @var{none} and @var{timestamped} flags are experimental.
 @item -write_index @var{bool}
 Write index at the end, the default is to write an index.
+ at item -header_period @var{value}
+Sets how often global headers are re-inserted into the bytestream.
+Default value is -1. This inserts headers at exponentially increasing locations
+ at math{2^23, 2^26, 2^29,...} etc.
+Setting parameter in the range @math{[0,62]}, will insert headers periodically
+after each @math{2^header_period} bytes at the next possible location.
 @end table
 
 @example
diff --git a/libavformat/nut.h b/libavformat/nut.h
index a990d3832e..c0928306c1 100644
--- a/libavformat/nut.h
+++ b/libavformat/nut.h
@@ -104,7 +104,8 @@ typedef struct NUTContext {
     int64_t last_syncpoint_pos;
     int64_t last_resync_pos;
     int header_count;           // elision header count
-    int header_rep_count;       // number of times headers written
+    int64_t header_rep_count;   // number of times headers written
+    int header_period;          // header insertion option
     AVRational *time_base;
     struct AVTreeNode *syncpoints;
     int sp_count;
diff --git a/libavformat/nutenc.c b/libavformat/nutenc.c
index 0646f72af2..5a775a92fe 100644
--- a/libavformat/nutenc.c
+++ b/libavformat/nutenc.c
@@ -988,11 +988,20 @@ static int nut_write_packet(AVFormatContext *s, AVPacket *pkt)
         data_size += sm_size;
     }
 
+    if (nut->header_period >= 0) {
+        if (avio_tell(bc) >> nut->header_period > nut->header_rep_count) {
+            ret = write_headers(s, bc);
+            nut->header_rep_count = avio_tell(bc) >> nut->header_period;
+            if (ret < 0)
+                goto fail;
+        }
+    } else {
     if (1LL << (20 + 3 * nut->header_rep_count) <= avio_tell(bc)) {
         ret = write_headers(s, bc);
         if (ret < 0)
             goto fail;
     }
+    }
 
     if (key_frame && !(nus->last_flags & FLAG_KEY))
         store_sp = 1;
@@ -1221,6 +1230,7 @@ static const AVOption options[] = {
     { "none",        "Disable syncpoints, low overhead and unseekable", 0,             AV_OPT_TYPE_CONST, {.i64 = NUT_PIPE},      INT_MIN, INT_MAX, E, "syncpoints" },
     { "timestamped", "Extend syncpoints with a wallclock timestamp",    0,             AV_OPT_TYPE_CONST, {.i64 = NUT_BROADCAST}, INT_MIN, INT_MAX, E, "syncpoints" },
     { "write_index", "Write index",                               OFFSET(write_index), AV_OPT_TYPE_BOOL,  {.i64 = 1},                   0,       1, E, },
+    { "header_period", "Header insertion parameter",              OFFSET(header_period), AV_OPT_TYPE_INT, {.i64 =-1},                  -1,      62, E, },
     { NULL },
 };
 
-- 
2.28.0