avformat/hlsenc: add var_stream_map LANGUAGE field string parameter

use a:0,agroup:aud_low,default:Yes,language:CHN a:1,agroup:aud_low,language:ENG
        a:2,agroup:aud_high,default:YesYes,language:CHN a:3,agroup:aud_high,language:ENG
        v:0,agroup:aud_low v:1,agroup:aud_high
        create master m3u8 list.

result:
EXTM3U
EXT-X-VERSION:3
EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="group_aud_low",NAME="audio_0",DEFAULT=YES,LANGUAGE="CHN",URI="out_0.m3u8"
EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="group_aud_low",NAME="audio_1",DEFAULT=NO,LANGUAGE="ENG",URI="out_1.m3u8"
EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="group_aud_high",NAME="audio_2",DEFAULT=YES,LANGUAGE="CHN",URI="out_2.m3u8"
EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="group_aud_high",NAME="audio_3",DEFAULT=NO,LANGUAGE="ENG",URI="out_3.m3u8"
EXT-X-STREAM-INF:BANDWIDTH=1170400,RESOLUTION=640x480,CODECS="avc1.64001e,mp4a.40.2",AUDIO="group_aud_low"
out_4.m3u8
EXT-X-STREAM-INF:BANDWIDTH=3440800,RESOLUTION=640x480,CODECS="avc1.64001e,mp4a.40.2",AUDIO="group_aud_high"
out_5.m3u8

Signed-off-by: Steven Liu <lq@chinaffmpeg.org>

doc/muxers.texi

@@ -982,6 +982,22 @@ and they are mapped to the one video only variant streams with audio group name
 
 By default, a single hls variant containing all the encoded streams is created.
 
+@example
+ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k \
+  -map 0:a -map 0:a -map 0:v -f hls \
+  -var_stream_map "a:0,agroup:aud_low,default:yes,language=ENG a:1,agroup:aud_low,language:CHN v:0,agroup:aud_low" \
+  -master_pl_name master.m3u8 \
+  http://example.com/live/out_%v.m3u8
+@end example
+This example creates two audio only and one video only variant streams. In
+addition to the #EXT-X-STREAM-INF tag for each variant stream in the master
+playlist, #EXT-X-MEDIA tag is also added for the two audio only variant streams
+and they are mapped to the one video only variant streams with audio group name
+'aud_low', and the audio group have default stat is NO or YES, and one audio
+have and language is named ENG, the other audio language is named CHN.
+
+By default, a single hls variant containing all the encoded streams is created.
+
 @item cc_stream_map
 Map string which specifies different closed captions groups and their
 attributes. The closed captions stream groups are separated by space.

libavformat/dashenc.c

@@ -998,7 +998,7 @@ static int write_manifest(AVFormatContext *s, int final)
                 continue;
             get_hls_playlist_name(playlist_file, sizeof(playlist_file), NULL, i);
             ff_hls_write_audio_rendition(c->m3u8_out, (char *)audio_group,
-                                         playlist_file, i, is_default);
+                                         playlist_file, NULL, i, is_default);
             max_audio_bitrate = FFMAX(st->codecpar->bit_rate +
                                       os->muxer_overhead, max_audio_bitrate);
             if (!av_strnstr(audio_codec_str, os->codec_str, sizeof(audio_codec_str))) {

libavformat/hlsenc.c

@@ -154,6 +154,7 @@ typedef struct VariantStream {
     unsigned int nb_streams;
     int m3u8_created; /* status of media play-list creation */
     int is_default; /* default status of audio group */
+    char *language; /* audio lauguage name */
     char *agroup; /* audio group name */
     char *ccgroup; /* closed caption group name */
     char *baseurl;
@@ -1261,7 +1262,7 @@ static int create_master_playlist(AVFormatContext *s,
             goto fail;
         }
 
-        ff_hls_write_audio_rendition(hls->m3u8_out, vs->agroup, m3u8_rel_name, i, hls->has_default_key ? vs->is_default : 1);
+        ff_hls_write_audio_rendition(hls->m3u8_out, vs->agroup, m3u8_rel_name, vs->language, i, hls->has_default_key ? vs->is_default : 1);
 
         av_freep(&m3u8_rel_name);
     }
@@ -1829,7 +1830,7 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
     /**
      * Expected format for var_stream_map string is as below:
      * "a:0,v:0 a:1,v:1"
-     * "a:0,agroup:a0,default:1 a:1,agroup:a1,defalut:0 v:0,agroup:a0  v:1,agroup:a1"
+     * "a:0,agroup:a0,default:1,language:ENG a:1,agroup:a1,defalut:0 v:0,agroup:a0  v:1,agroup:a1"
      * This string specifies how to group the audio, video and subtitle streams
      * into different variant streams. The variant stream groups are separated
      * by space.
@@ -1879,8 +1880,12 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
         nb_streams = 0;
         while (keyval = av_strtok(varstr, ",", &saveptr2)) {
             varstr = NULL;
-
-            if (av_strstart(keyval, "default:", &val)) {
+            if (av_strstart(keyval, "language:", &val)) {
+                vs->language = av_strdup(val);
+                if (!vs->language)
+                    return AVERROR(ENOMEM);
+                continue;
+            } else if (av_strstart(keyval, "default:", &val)) {
                 vs->is_default = (!av_strncasecmp(val, "YES", strlen("YES")) ||
                                   (!av_strncasecmp(val, "1", strlen("1"))));
                 hls->has_default_key = 1;
@@ -2392,6 +2397,7 @@ static void hls_free_variant_streams(struct HLSContext *hls)
         av_freep(&vs->m3u8_name);
         av_freep(&vs->streams);
         av_freep(&vs->agroup);
+        av_freep(&vs->language);
         av_freep(&vs->ccgroup);
         av_freep(&vs->baseurl);
     }
@@ -2843,6 +2849,7 @@ fail:
             av_freep(&vs->m3u8_name);
             av_freep(&vs->vtt_m3u8_name);
             av_freep(&vs->streams);
+            av_freep(&vs->language);
             av_freep(&vs->agroup);
             av_freep(&vs->ccgroup);
             av_freep(&vs->baseurl);

libavformat/hlsplaylist.c

@@ -36,13 +36,16 @@ void ff_hls_write_playlist_version(AVIOContext *out, int version) {
 }
 
 void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
-                                  char *filename, int name_id, int is_default) {
+                                  char *filename, char *language, int name_id, int is_default) {
     if (!out || !agroup || !filename)
         return;
 
     avio_printf(out, "#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID=\"group_%s\"", agroup);
-    avio_printf(out, ",NAME=\"audio_%d\",DEFAULT=%s,URI=\"%s\"\n", name_id,
-                     is_default ? "YES" : "NO", filename);
+    avio_printf(out, ",NAME=\"audio_%d\",DEFAULT=%s,", name_id, is_default ? "YES" : "NO");
+    if (language) {
+        avio_printf(out, "LANGUAGE=\"%s\",", language);
+    }
+    avio_printf(out, "URI=\"%s\"\n", filename);
 }
 
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,

libavformat/hlsplaylist.h

@@ -38,7 +38,7 @@ typedef enum {
 
 void ff_hls_write_playlist_version(AVIOContext *out, int version);
 void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
-                                  char *filename, int name_id, int is_default);
+                                  char *filename, char *language, int name_id, int is_default);
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
                               int bandwidth, char *filename, char *agroup,
                               char *codecs, char *ccgroup);