From 0be48dd9bb6e89c1632fdc95185b24d0bec32843 Mon Sep 17 00:00:00 2001
From: Bryan Huh <bryan@box.com>
Date: Wed, 18 Nov 2015 01:13:14 -0800
Subject: [PATCH] avformat/dashenc: Add framerate to dash manifest

DASH manifest should have framerate specified as an attribute in the
AdaptationSet element and Representation elements. Though ISO/IEC
23009-1:2014 doesn't seem to define frameRate as a required attribute,
it is at least optional, and DASH-IF IOP 3.0 seems to require it. See
section 3.2.4 of http://dashif.org/w/2015/04/DASH-IF-IOP-v3.0.pdf

In the event that avg_frame_rate is not set in the muxer, we ignore the
frameRate tag altogther.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/dashenc.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
index 7a932147e5..9c2b4dd5af 100644
--- a/libavformat/dashenc.c
+++ b/libavformat/dashenc.c
@@ -24,10 +24,12 @@
 #include <unistd.h>
 #endif
 
+#include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
+#include "libavutil/rational.h"
 #include "libavutil/time_internal.h"
 
 #include "avc.h"
@@ -94,6 +96,8 @@ typedef struct DASHContext {
     const char *single_file_name;
     const char *init_seg_name;
     const char *media_seg_name;
+    AVRational min_frame_rate, max_frame_rate;
+    int ambiguous_frame_rate;
 } DASHContext;
 
 static int dash_write(void *opaque, uint8_t *buf, int buf_size)
@@ -503,7 +507,11 @@ static int write_manifest(AVFormatContext *s, int final)
     }
 
     if (c->has_video) {
-        avio_printf(out, "\t\t<AdaptationSet contentType=\"video\" segmentAlignment=\"true\" bitstreamSwitching=\"true\">\n");
+        avio_printf(out, "\t\t<AdaptationSet contentType=\"video\" segmentAlignment=\"true\" bitstreamSwitching=\"true\"");
+        if (c->max_frame_rate.num && !c->ambiguous_frame_rate)
+            avio_printf(out, " %s=\"%d/%d\"", (av_cmp_q(c->min_frame_rate, c->max_frame_rate) < 0) ? "maxFrameRate" : "frameRate", c->max_frame_rate.num, c->max_frame_rate.den);
+        avio_printf(out, ">\n");
+
         for (i = 0; i < s->nb_streams; i++) {
             AVStream *st = s->streams[i];
             OutputStream *os = &c->streams[i];
@@ -511,7 +519,11 @@ static int write_manifest(AVFormatContext *s, int final)
             if (st->codec->codec_type != AVMEDIA_TYPE_VIDEO)
                 continue;
 
-            avio_printf(out, "\t\t\t<Representation id=\"%d\" mimeType=\"video/mp4\" codecs=\"%s\"%s width=\"%d\" height=\"%d\">\n", i, os->codec_str, os->bandwidth_str, st->codec->width, st->codec->height);
+            avio_printf(out, "\t\t\t<Representation id=\"%d\" mimeType=\"video/mp4\" codecs=\"%s\"%s width=\"%d\" height=\"%d\"", i, os->codec_str, os->bandwidth_str, st->codec->width, st->codec->height);
+            if (st->avg_frame_rate.num)
+                avio_printf(out, " frameRate=\"%d/%d\"", st->avg_frame_rate.num, st->avg_frame_rate.den);
+            avio_printf(out, ">\n");
+
             output_segment_list(&c->streams[i], out, c);
             avio_printf(out, "\t\t\t</Representation>\n");
         }
@@ -552,6 +564,7 @@ static int dash_write_header(AVFormatContext *s)
         c->single_file = 1;
     if (c->single_file)
         c->use_template = 0;
+    c->ambiguous_frame_rate = 0;
 
     av_strlcpy(c->dirname, s->filename, sizeof(c->dirname));
     ptr = strrchr(c->dirname, '/');
@@ -655,10 +668,20 @@ static int dash_write_header(AVFormatContext *s)
         // already before being handed to this muxer, so we don't have mismatches
         // between the MPD and the actual segments.
         s->avoid_negative_ts = ctx->avoid_negative_ts;
-        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO)
+        if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
+            AVRational avg_frame_rate = s->streams[i]->avg_frame_rate;
+            if (avg_frame_rate.num > 0) {
+                if (av_cmp_q(avg_frame_rate, c->min_frame_rate) < 0)
+                    c->min_frame_rate = avg_frame_rate;
+                if (av_cmp_q(c->max_frame_rate, avg_frame_rate) < 0)
+                    c->max_frame_rate = avg_frame_rate;
+            } else {
+                c->ambiguous_frame_rate = 1;
+            }
             c->has_video = 1;
-        else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO)
+        } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
             c->has_audio = 1;
+        }
 
         set_codec_str(s, st->codec, os->codec_str, sizeof(os->codec_str));
         os->first_pts = AV_NOPTS_VALUE;