avformat/hlsenc: Modularized audio rendition playlist write to allow reuse

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

libavformat/hlsenc.c

@@ -1169,10 +1169,8 @@ static int create_master_playlist(AVFormatContext *s,
             goto fail;
         }
 
-        avio_printf(hls->m3u8_out, "#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID=\"group_%s\"",
-                vs->agroup);
-        avio_printf(hls->m3u8_out, ",NAME=\"audio_0\",DEFAULT=YES,URI=\"%s\"\n",
-                m3u8_rel_name);
+        ff_hls_write_audio_rendition(hls->m3u8_out, vs->agroup, m3u8_rel_name);
+
         av_freep(&m3u8_rel_name);
     }
 

libavformat/hlsplaylist.c

@@ -35,6 +35,15 @@ void ff_hls_write_playlist_version(AVIOContext *out, int version) {
     avio_printf(out, "#EXT-X-VERSION:%d\n", version);
 }
 
+void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
+                                  char *filename) {
+    if (!out || !agroup || !filename)
+        return;
+
+    avio_printf(out, "#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID=\"group_%s\"", agroup);
+    avio_printf(out, ",NAME=\"audio_0\",DEFAULT=YES,URI=\"%s\"\n", filename);
+}
+
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
                               int bandwidth, char *filename, char *agroup) {
     if (!out || !filename)

libavformat/hlsplaylist.h

@@ -37,6 +37,7 @@ typedef enum {
 } PlaylistType;
 
 void ff_hls_write_playlist_version(AVIOContext *out, int version);
+void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup, char *filename);
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
                               int bandwidth, char *filename, char *agroup);
 void ff_hls_write_playlist_header(AVIOContext *out, int version, int allowcache,