oggenc: add a page_duration option and deprecate the pagesize option

This uses page duration instead of byte size to determine when to buffer
the page. Also, it tries to avoid continued pages by buffering the current
page if there are already packets in the page and adding the next packet
would require it to be continued on a new page. This can improve seeking
performance.

The default page duration is 1 second, which is much saner than filling
all page segments by default.

1 files changed, 42 insertions, 7 deletions

diff --git a/libavformat/oggenc.c b/libavformat/oggenc.c
index c1f22d15cc..6212d16373 100644
--- a/libavformat/oggenc.c
+++ b/libavformat/oggenc.c
@@ -34,6 +34,7 @@
 #define MAX_PAGE_SIZE 65025
 
 typedef struct {
+    int64_t start_granule;
     int64_t granule;
     int stream_index;
     uint8_t flags;
@@ -67,14 +68,17 @@ typedef struct {
     const AVClass *class;
     OGGPageList *page_list;
     int pref_size; ///< preferred page size (0 => fill all segments)
+    int64_t pref_duration;      ///< preferred page duration (0 => fill all segments)
 } OGGContext;
 
 #define OFFSET(x) offsetof(OGGContext, x)
 #define PARAM AV_OPT_FLAG_ENCODING_PARAM
 
 static const AVOption options[] = {
-    { "pagesize", "preferred page size in bytes",
+    { "pagesize", "preferred page size in bytes (deprecated)",
         OFFSET(pref_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, MAX_PAGE_SIZE, PARAM },
+    { "page_duration", "preferred page duration, in microseconds",
+        OFFSET(pref_duration), AV_OPT_TYPE_INT, { .i64 = 1000000 }, 0, INT64_MAX, PARAM },
     { NULL },
 };
 
@@ -177,6 +181,7 @@ static int ogg_buffer_page(AVFormatContext *s, OGGStreamContext *oggstream)
         return AVERROR(ENOMEM);
     l->page = oggstream->page;
 
+    oggstream->page.start_granule = oggstream->page.granule;
     oggstream->page_count++;
     ogg_reset_cur_page(oggstream);
 
@@ -210,6 +215,12 @@ static int ogg_buffer_data(AVFormatContext *s, AVStream *st,
         flush = 1;
     }
 
+    // avoid a continued page
+    if (!header && oggstream->page.size > 0 &&
+        MAX_PAGE_SIZE - oggstream->page.size < size) {
+        ogg_buffer_page(s, oggstream);
+    }
+
     for (i = 0; i < total_segments; ) {
         OGGPage *page = &oggstream->page;
 
@@ -232,9 +243,19 @@ static int ogg_buffer_data(AVFormatContext *s, AVStream *st,
         if (i == total_segments)
             page->granule = granule;
 
-        if (!header && (page->segments_count == 255 ||
-            (ogg->pref_size > 0 && page->size >= ogg->pref_size))) {
-           ogg_buffer_page(s, oggstream);
+        if (!header) {
+            AVStream *st = s->streams[page->stream_index];
+
+            int64_t start = av_rescale_q(page->start_granule, st->time_base,
+                                         AV_TIME_BASE_Q);
+            int64_t next  = av_rescale_q(page->granule, st->time_base,
+                                         AV_TIME_BASE_Q);
+
+            if (page->segments_count == 255 ||
+                (ogg->pref_size     > 0 && page->size   >= ogg->pref_size) ||
+                (ogg->pref_duration > 0 && next - start >= ogg->pref_duration)) {
+                ogg_buffer_page(s, oggstream);
+            }
         }
     }
 
@@ -367,9 +388,13 @@ static int ogg_build_opus_headers(AVCodecContext *avctx,
 
 static int ogg_write_header(AVFormatContext *s)
 {
+    OGGContext *ogg = s->priv_data;
     OGGStreamContext *oggstream;
     int i, j;
 
+    if (ogg->pref_size)
+        av_log(s, AV_LOG_WARNING, "The pagesize option is deprecated\n");
+
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st = s->streams[i];
         unsigned serial_num = i;
@@ -489,6 +514,9 @@ static int ogg_write_header(AVFormatContext *s)
         }
         ogg_buffer_page(s, oggstream);
     }
+
+    oggstream->page.start_granule = AV_NOPTS_VALUE;
+
     return 0;
 }
 
@@ -538,6 +566,9 @@ static int ogg_write_packet(AVFormatContext *s, AVPacket *pkt)
     else
         granule = pkt->pts + pkt->duration;
 
+    if (oggstream->page.start_granule == AV_NOPTS_VALUE)
+        oggstream->page.start_granule = pkt->pts;
+
     ret = ogg_buffer_data(s, st, pkt->data, pkt->size, granule, 0);
     if (ret < 0)
         return ret;
@@ -553,9 +584,13 @@ static int ogg_write_trailer(AVFormatContext *s)
 {
     int i;
 
-    /* flush current page */
-    for (i = 0; i < s->nb_streams; i++)
-        ogg_buffer_page(s, s->streams[i]->priv_data);
+    /* flush current page if needed */
+    for (i = 0; i < s->nb_streams; i++) {
+        OGGStreamContext *oggstream = s->streams[i]->priv_data;
+
+        if (oggstream->page.size > 0)
+            ogg_buffer_page(s, oggstream);
+    }
 
     ogg_write_pages(s, 1);