diff mbox

[FFmpeg-devel,v7,1/3] avformat/hlsenc:addition of #EXT-X-MEDIA tag and AUDIO attribute

Message ID 1513601569-27823-1-git-send-email-vdixit@akamai.com
State Superseded
Headers show

Commit Message

Dixit, Vishwanath Dec. 18, 2017, 12:52 p.m. UTC
From: Vishwanath Dixit <vdixit@akamai.com>

---
 doc/muxers.texi           | 12 +++++++++
 libavformat/dashenc.c     |  3 ++-
 libavformat/hlsenc.c      | 62 ++++++++++++++++++++++++++++++++++++++++++++---
 libavformat/hlsplaylist.c |  4 ++-
 libavformat/hlsplaylist.h |  2 +-
 5 files changed, 77 insertions(+), 6 deletions(-)

Comments

Steven Liu Dec. 19, 2017, 3:53 a.m. UTC | #1
> On 18 Dec 2017, at 20:52, vdixit@akamai.com wrote:
> 
> From: Vishwanath Dixit <vdixit@akamai.com>
> 
> ---
> doc/muxers.texi           | 12 +++++++++
> libavformat/dashenc.c     |  3 ++-
> libavformat/hlsenc.c      | 62 ++++++++++++++++++++++++++++++++++++++++++++---
> libavformat/hlsplaylist.c |  4 ++-
> libavformat/hlsplaylist.h |  2 +-
> 5 files changed, 77 insertions(+), 6 deletions(-)
> 
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index 3d0c7bf..93db549 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -834,6 +834,18 @@ be a video only stream with video bitrate 1000k, the second variant stream will
> be an audio only stream with bitrate 64k and the third variant stream will be a
> video only stream with bitrate 256k. Here, three media playlist with file names
> out_1.m3u8, out_2.m3u8 and out_3.m3u8 will be created.
> +@example
> +ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k -b:v:1 3000k  \
> +  -map 0:a -map 0:a -map 0:v -map 0:v -f hls \
> +  -var_stream_map "a:0,agroup:aud_low a:1,agroup:aud_high v:0,agroup:aud_low v:1,agroup:aud_high" \
> +  -master_pl_name master.m3u8 \
> +  http://example.com/live/out.m3u8
> +@end example
> +This example creates two audio only and two 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 two video only variant streams with audio group names
> +'aud_low' and 'aud_high'.
> 
> By default, a single hls variant containing all the encoded streams is created.
> 
> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
> index 5687530..f363418 100644
> --- a/libavformat/dashenc.c
> +++ b/libavformat/dashenc.c
> @@ -759,7 +759,8 @@ static int write_manifest(AVFormatContext *s, int final)
>             char playlist_file[64];
>             AVStream *st = s->streams[i];
>             get_hls_playlist_name(playlist_file, sizeof(playlist_file), NULL, i);
> -            ff_hls_write_stream_info(st, out, st->codecpar->bit_rate, playlist_file);
> +            ff_hls_write_stream_info(st, out, st->codecpar->bit_rate,
> +                    playlist_file, NULL);
>         }
>         avio_close(out);
>         if (use_rename)
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index e3442c3..2903e4e 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -144,6 +144,7 @@ typedef struct VariantStream {
>     AVStream **streams;
>     unsigned int nb_streams;
>     int m3u8_created; /* status of media play-list creation */
> +    char *agroup; /* audio group name */
>     char *baseurl;
> } VariantStream;
> 
> @@ -1085,7 +1086,7 @@ static int create_master_playlist(AVFormatContext *s,
>                                   VariantStream * const input_vs)
> {
>     HLSContext *hls = s->priv_data;
> -    VariantStream *vs;
> +    VariantStream *vs, *temp_vs;
>     AVStream *vid_st, *aud_st;
>     AVDictionary *options = NULL;
>     unsigned int i, j;
> @@ -1117,6 +1118,34 @@ static int create_master_playlist(AVFormatContext *s,
> 
>     ff_hls_write_playlist_version(hls->m3u8_out, hls->version);
> 
> +    /* For audio only variant streams add #EXT-X-MEDIA tag with attributes*/
> +    for (i = 0; i < hls->nb_varstreams; i++) {
> +        vs = &(hls->var_streams[i]);
> +
> +        if (vs->has_video || vs->has_subtitle || !vs->agroup)
> +            continue;
> +
> +        m3u8_name_size = strlen(vs->m3u8_name) + 1;
> +        m3u8_rel_name = av_malloc(m3u8_name_size);
> +        if (!m3u8_rel_name) {
> +            ret = AVERROR(ENOMEM);
> +            goto fail;
> +        }
> +        av_strlcpy(m3u8_rel_name, vs->m3u8_name, m3u8_name_size);
> +        ret = get_relative_url(hls->master_m3u8_url, vs->m3u8_name,
> +                               m3u8_rel_name, m3u8_name_size);
> +        if (ret < 0) {
> +            av_log(s, AV_LOG_ERROR, "Unable to find relative URL\n");
> +            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);
> +        av_freep(&m3u8_rel_name);
> +    }
> +
>     /* For variant streams with video add #EXT-X-STREAM-INF tag with attributes*/
>     for (i = 0; i < hls->nb_varstreams; i++) {
>         vs = &(hls->var_streams[i]);
> @@ -1149,6 +1178,25 @@ static int create_master_playlist(AVFormatContext *s,
>             continue;
>         }
> 
> +        /**
> +         * Traverse through the list of audio only rendition streams and find
> +         * the rendition which has highest bitrate in the same audio group
> +         */
> +        if (vs->agroup) {
> +            for (j = 0; j < hls->nb_varstreams; j++) {
> +                temp_vs = &(hls->var_streams[j]);
> +                if (!temp_vs->has_video && !temp_vs->has_subtitle &&
> +                    temp_vs->agroup &&
> +                    !strcmp(temp_vs->agroup, vs->agroup)) {
Why don’t use av_strcasecmp,
> +                    if (!aud_st)
> +                        aud_st = temp_vs->streams[0];
> +                    if (temp_vs->streams[0]->codecpar->bit_rate >
> +                            aud_st->codecpar->bit_rate)
> +                        aud_st = temp_vs->streams[0];
> +                }
> +            }
> +        }
> +
>         bandwidth = 0;
>         if (vid_st)
>             bandwidth += vid_st->codecpar->bit_rate;
> @@ -1156,7 +1204,8 @@ static int create_master_playlist(AVFormatContext *s,
>             bandwidth += aud_st->codecpar->bit_rate;
>         bandwidth += bandwidth / 10;
> 
> -        ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name);
> +        ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
> +                aud_st ? vs->agroup : NULL);
> 
>         av_freep(&m3u8_rel_name);
>     }
> @@ -1508,6 +1557,7 @@ 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 a:1,agroup:a1 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.
> @@ -1516,6 +1566,7 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
>      * respectively. Allowed values are 0 to 9 digits (limited just based on
>      * practical usage)
>      *
> +     * agroup: is key to specify audio group. A string can be given as value.
>      */
>     p = av_strdup(hls->var_stream_map);
>     q = p;
> @@ -1554,7 +1605,10 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
>         while (keyval = av_strtok(varstr, ",", &saveptr2)) {
>             varstr = NULL;
> 
> -            if (av_strstart(keyval, "v:", &val)) {
> +            if (av_strstart(keyval, "agroup:", &val)) {
> +                vs->agroup = av_strdup(val);
What will happen when av_strdup failed?
> +                continue;
> +            } else if (av_strstart(keyval, "v:", &val)) {
>                 codec_type = AVMEDIA_TYPE_VIDEO;
>             } else if (av_strstart(keyval, "a:", &val)) {
>                 codec_type = AVMEDIA_TYPE_AUDIO;
> @@ -1915,6 +1969,7 @@ static int hls_write_trailer(struct AVFormatContext *s)
>     av_free(old_filename);
>     av_freep(&vs->m3u8_name);
>     av_freep(&vs->streams);
> +    av_freep(&vs->agroup);
>     av_freep(&vs->baseurl);
>     }
> 
> @@ -2255,6 +2310,7 @@ fail:
>             av_freep(&vs->m3u8_name);
>             av_freep(&vs->vtt_m3u8_name);
>             av_freep(&vs->streams);
> +            av_freep(&vs->agroup);
>             av_freep(&vs->baseurl);
>             if (vs->avf)
>                 avformat_free_context(vs->avf);
> diff --git a/libavformat/hlsplaylist.c b/libavformat/hlsplaylist.c
> index 3349eb7..42f059a 100644
> --- a/libavformat/hlsplaylist.c
> +++ b/libavformat/hlsplaylist.c
> @@ -36,7 +36,7 @@ void ff_hls_write_playlist_version(AVIOContext *out, int version) {
> }
> 
> void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
> -                              int bandwidth, char *filename) {
> +                              int bandwidth, char *filename, char *agroup) {
>     if (!out || !filename)
>         return;
> 
> @@ -50,6 +50,8 @@ void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
>     if (st && st->codecpar->width > 0 && st->codecpar->height > 0)
>         avio_printf(out, ",RESOLUTION=%dx%d", st->codecpar->width,
>                 st->codecpar->height);
> +    if (agroup && strlen(agroup) > 0)
> +        avio_printf(out, ",AUDIO=\"group_%s\"", agroup);
>     avio_printf(out, "\n%s\n\n", filename);
> }
> 
> diff --git a/libavformat/hlsplaylist.h b/libavformat/hlsplaylist.h
> index 48d71b7..a3ce26c 100644
> --- a/libavformat/hlsplaylist.h
> +++ b/libavformat/hlsplaylist.h
> @@ -43,7 +43,7 @@ static inline int hls_get_int_from_double(double val)
> 
> void ff_hls_write_playlist_version(AVIOContext *out, int version);
> void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
> -                              int bandwidth, char *filename);
> +                              int bandwidth, char *filename, char *agroup);
> void ff_hls_write_playlist_header(AVIOContext *out, int version, int allowcache,
>                                   int target_duration, int64_t sequence,
>                                   uint32_t playlist_type);
> -- 
> 1.9.1
> 
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
Dixit, Vishwanath Dec. 19, 2017, 8:25 a.m. UTC | #2
On 12/19/17 9:23 AM, 刘歧 wrote:
>> On 18 Dec 2017, at 20:52, vdixit@akamai.com wrote:
>>
>> From: Vishwanath Dixit <vdixit@akamai.com>
>>
>> ---
>> doc/muxers.texi           | 12 +++++++++
>> libavformat/dashenc.c     |  3 ++-
>> libavformat/hlsenc.c      | 62 ++++++++++++++++++++++++++++++++++++++++++++---
>> libavformat/hlsplaylist.c |  4 ++-
>> libavformat/hlsplaylist.h |  2 +-
>> 5 files changed, 77 insertions(+), 6 deletions(-)
>>
>> diff --git a/doc/muxers.texi b/doc/muxers.texi
>> index 3d0c7bf..93db549 100644
>> --- a/doc/muxers.texi
>> +++ b/doc/muxers.texi
>> @@ -834,6 +834,18 @@ be a video only stream with video bitrate 1000k, the second variant stream will
>> be an audio only stream with bitrate 64k and the third variant stream will be a
>> video only stream with bitrate 256k. Here, three media playlist with file names
>> out_1.m3u8, out_2.m3u8 and out_3.m3u8 will be created.
>> +@example
>> +ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k -b:v:1 3000k  \
>> +  -map 0:a -map 0:a -map 0:v -map 0:v -f hls \
>> +  -var_stream_map "a:0,agroup:aud_low a:1,agroup:aud_high v:0,agroup:aud_low v:1,agroup:aud_high" \
>> +  -master_pl_name master.m3u8 \
>> +  http://example.com/live/out.m3u8
>> +@end example
>> +This example creates two audio only and two 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 two video only variant streams with audio group names
>> +'aud_low' and 'aud_high'.
>>
>> By default, a single hls variant containing all the encoded streams is created.
>>
>> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
>> index 5687530..f363418 100644
>> --- a/libavformat/dashenc.c
>> +++ b/libavformat/dashenc.c
>> @@ -759,7 +759,8 @@ static int write_manifest(AVFormatContext *s, int final)
>>              char playlist_file[64];
>>              AVStream *st = s->streams[i];
>>              get_hls_playlist_name(playlist_file, sizeof(playlist_file), NULL, i);
>> -            ff_hls_write_stream_info(st, out, st->codecpar->bit_rate, playlist_file);
>> +            ff_hls_write_stream_info(st, out, st->codecpar->bit_rate,
>> +                    playlist_file, NULL);
>>          }
>>          avio_close(out);
>>          if (use_rename)
>> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
>> index e3442c3..2903e4e 100644
>> --- a/libavformat/hlsenc.c
>> +++ b/libavformat/hlsenc.c
>> @@ -144,6 +144,7 @@ typedef struct VariantStream {
>>      AVStream **streams;
>>      unsigned int nb_streams;
>>      int m3u8_created; /* status of media play-list creation */
>> +    char *agroup; /* audio group name */
>>      char *baseurl;
>> } VariantStream;
>>
>> @@ -1085,7 +1086,7 @@ static int create_master_playlist(AVFormatContext *s,
>>                                    VariantStream * const input_vs)
>> {
>>      HLSContext *hls = s->priv_data;
>> -    VariantStream *vs;
>> +    VariantStream *vs, *temp_vs;
>>      AVStream *vid_st, *aud_st;
>>      AVDictionary *options = NULL;
>>      unsigned int i, j;
>> @@ -1117,6 +1118,34 @@ static int create_master_playlist(AVFormatContext *s,
>>
>>      ff_hls_write_playlist_version(hls->m3u8_out, hls->version);
>>
>> +    /* For audio only variant streams add #EXT-X-MEDIA tag with attributes*/
>> +    for (i = 0; i < hls->nb_varstreams; i++) {
>> +        vs = &(hls->var_streams[i]);
>> +
>> +        if (vs->has_video || vs->has_subtitle || !vs->agroup)
>> +            continue;
>> +
>> +        m3u8_name_size = strlen(vs->m3u8_name) + 1;
>> +        m3u8_rel_name = av_malloc(m3u8_name_size);
>> +        if (!m3u8_rel_name) {
>> +            ret = AVERROR(ENOMEM);
>> +            goto fail;
>> +        }
>> +        av_strlcpy(m3u8_rel_name, vs->m3u8_name, m3u8_name_size);
>> +        ret = get_relative_url(hls->master_m3u8_url, vs->m3u8_name,
>> +                               m3u8_rel_name, m3u8_name_size);
>> +        if (ret < 0) {
>> +            av_log(s, AV_LOG_ERROR, "Unable to find relative URL\n");
>> +            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);
>> +        av_freep(&m3u8_rel_name);
>> +    }
>> +
>>      /* For variant streams with video add #EXT-X-STREAM-INF tag with attributes*/
>>      for (i = 0; i < hls->nb_varstreams; i++) {
>>          vs = &(hls->var_streams[i]);
>> @@ -1149,6 +1178,25 @@ static int create_master_playlist(AVFormatContext *s,
>>              continue;
>>          }
>>
>> +        /**
>> +         * Traverse through the list of audio only rendition streams and find
>> +         * the rendition which has highest bitrate in the same audio group
>> +         */
>> +        if (vs->agroup) {
>> +            for (j = 0; j < hls->nb_varstreams; j++) {
>> +                temp_vs = &(hls->var_streams[j]);
>> +                if (!temp_vs->has_video && !temp_vs->has_subtitle &&
>> +                    temp_vs->agroup &&
>> +                    !strcmp(temp_vs->agroup, vs->agroup)) {
> Why don’t use av_strcasecmp,
>> +                    if (!aud_st)
>> +                        aud_st = temp_vs->streams[0];
>> +                    if (temp_vs->streams[0]->codecpar->bit_rate >
>> +                            aud_st->codecpar->bit_rate)
>> +                        aud_st = temp_vs->streams[0];
>> +                }
>> +            }
>> +        }
>> +
>>          bandwidth = 0;
>>          if (vid_st)
>>              bandwidth += vid_st->codecpar->bit_rate;
>> @@ -1156,7 +1204,8 @@ static int create_master_playlist(AVFormatContext *s,
>>              bandwidth += aud_st->codecpar->bit_rate;
>>          bandwidth += bandwidth / 10;
>>
>> -        ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name);
>> +        ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
>> +                aud_st ? vs->agroup : NULL);
>>
>>          av_freep(&m3u8_rel_name);
>>      }
>> @@ -1508,6 +1557,7 @@ 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 a:1,agroup:a1 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.
>> @@ -1516,6 +1566,7 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
>>       * respectively. Allowed values are 0 to 9 digits (limited just based on
>>       * practical usage)
>>       *
>> +     * agroup: is key to specify audio group. A string can be given as value.
>>       */
>>      p = av_strdup(hls->var_stream_map);
>>      q = p;
>> @@ -1554,7 +1605,10 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
>>          while (keyval = av_strtok(varstr, ",", &saveptr2)) {
>>              varstr = NULL;
>>
>> -            if (av_strstart(keyval, "v:", &val)) {
>> +            if (av_strstart(keyval, "agroup:", &val)) {
>> +                vs->agroup = av_strdup(val);
> What will happen when av_strdup failed?
>> +                continue;
>> +            } else if (av_strstart(keyval, "v:", &val)) {
>>                  codec_type = AVMEDIA_TYPE_VIDEO;
>>              } else if (av_strstart(keyval, "a:", &val)) {
>>                  codec_type = AVMEDIA_TYPE_AUDIO;
>> @@ -1915,6 +1969,7 @@ static int hls_write_trailer(struct AVFormatContext *s)
>>      av_free(old_filename);
>>      av_freep(&vs->m3u8_name);
>>      av_freep(&vs->streams);
>> +    av_freep(&vs->agroup);
>>      av_freep(&vs->baseurl);
>>      }
>>
>> @@ -2255,6 +2310,7 @@ fail:
>>              av_freep(&vs->m3u8_name);
>>              av_freep(&vs->vtt_m3u8_name);
>>              av_freep(&vs->streams);
>> +            av_freep(&vs->agroup);
>>              av_freep(&vs->baseurl);
>>              if (vs->avf)
>>                  avformat_free_context(vs->avf);
>> diff --git a/libavformat/hlsplaylist.c b/libavformat/hlsplaylist.c
>> index 3349eb7..42f059a 100644
>> --- a/libavformat/hlsplaylist.c
>> +++ b/libavformat/hlsplaylist.c
>> @@ -36,7 +36,7 @@ void ff_hls_write_playlist_version(AVIOContext *out, int version) {
>> }
>>
>> void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
>> -                              int bandwidth, char *filename) {
>> +                              int bandwidth, char *filename, char *agroup) {
>>      if (!out || !filename)
>>          return;
>>
>> @@ -50,6 +50,8 @@ void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
>>      if (st && st->codecpar->width > 0 && st->codecpar->height > 0)
>>          avio_printf(out, ",RESOLUTION=%dx%d", st->codecpar->width,
>>                  st->codecpar->height);
>> +    if (agroup && strlen(agroup) > 0)
>> +        avio_printf(out, ",AUDIO=\"group_%s\"", agroup);
>>      avio_printf(out, "\n%s\n\n", filename);
>> }
>>
>> diff --git a/libavformat/hlsplaylist.h b/libavformat/hlsplaylist.h
>> index 48d71b7..a3ce26c 100644
>> --- a/libavformat/hlsplaylist.h
>> +++ b/libavformat/hlsplaylist.h
>> @@ -43,7 +43,7 @@ static inline int hls_get_int_from_double(double val)
>>
>> void ff_hls_write_playlist_version(AVIOContext *out, int version);
>> void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
>> -                              int bandwidth, char *filename);
>> +                              int bandwidth, char *filename, char *agroup);
>> void ff_hls_write_playlist_header(AVIOContext *out, int version, int allowcache,
>>                                    int target_duration, int64_t sequence,
>>                                    uint32_t playlist_type);
>> -- 
>> 1.9.1
>>
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
>
I have made updates for the above review comments and have submitted the 
new patch with version v8 (https://patchwork.ffmpeg.org/patch/6863/)
diff mbox

Patch

diff --git a/doc/muxers.texi b/doc/muxers.texi
index 3d0c7bf..93db549 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -834,6 +834,18 @@  be a video only stream with video bitrate 1000k, the second variant stream will
 be an audio only stream with bitrate 64k and the third variant stream will be a
 video only stream with bitrate 256k. Here, three media playlist with file names
 out_1.m3u8, out_2.m3u8 and out_3.m3u8 will be created.
+@example
+ffmpeg -re -i in.ts -b:a:0 32k -b:a:1 64k -b:v:0 1000k -b:v:1 3000k  \
+  -map 0:a -map 0:a -map 0:v -map 0:v -f hls \
+  -var_stream_map "a:0,agroup:aud_low a:1,agroup:aud_high v:0,agroup:aud_low v:1,agroup:aud_high" \
+  -master_pl_name master.m3u8 \
+  http://example.com/live/out.m3u8
+@end example
+This example creates two audio only and two 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 two video only variant streams with audio group names
+'aud_low' and 'aud_high'.
 
 By default, a single hls variant containing all the encoded streams is created.
 
diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
index 5687530..f363418 100644
--- a/libavformat/dashenc.c
+++ b/libavformat/dashenc.c
@@ -759,7 +759,8 @@  static int write_manifest(AVFormatContext *s, int final)
             char playlist_file[64];
             AVStream *st = s->streams[i];
             get_hls_playlist_name(playlist_file, sizeof(playlist_file), NULL, i);
-            ff_hls_write_stream_info(st, out, st->codecpar->bit_rate, playlist_file);
+            ff_hls_write_stream_info(st, out, st->codecpar->bit_rate,
+                    playlist_file, NULL);
         }
         avio_close(out);
         if (use_rename)
diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index e3442c3..2903e4e 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -144,6 +144,7 @@  typedef struct VariantStream {
     AVStream **streams;
     unsigned int nb_streams;
     int m3u8_created; /* status of media play-list creation */
+    char *agroup; /* audio group name */
     char *baseurl;
 } VariantStream;
 
@@ -1085,7 +1086,7 @@  static int create_master_playlist(AVFormatContext *s,
                                   VariantStream * const input_vs)
 {
     HLSContext *hls = s->priv_data;
-    VariantStream *vs;
+    VariantStream *vs, *temp_vs;
     AVStream *vid_st, *aud_st;
     AVDictionary *options = NULL;
     unsigned int i, j;
@@ -1117,6 +1118,34 @@  static int create_master_playlist(AVFormatContext *s,
 
     ff_hls_write_playlist_version(hls->m3u8_out, hls->version);
 
+    /* For audio only variant streams add #EXT-X-MEDIA tag with attributes*/
+    for (i = 0; i < hls->nb_varstreams; i++) {
+        vs = &(hls->var_streams[i]);
+
+        if (vs->has_video || vs->has_subtitle || !vs->agroup)
+            continue;
+
+        m3u8_name_size = strlen(vs->m3u8_name) + 1;
+        m3u8_rel_name = av_malloc(m3u8_name_size);
+        if (!m3u8_rel_name) {
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+        av_strlcpy(m3u8_rel_name, vs->m3u8_name, m3u8_name_size);
+        ret = get_relative_url(hls->master_m3u8_url, vs->m3u8_name,
+                               m3u8_rel_name, m3u8_name_size);
+        if (ret < 0) {
+            av_log(s, AV_LOG_ERROR, "Unable to find relative URL\n");
+            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);
+        av_freep(&m3u8_rel_name);
+    }
+
     /* For variant streams with video add #EXT-X-STREAM-INF tag with attributes*/
     for (i = 0; i < hls->nb_varstreams; i++) {
         vs = &(hls->var_streams[i]);
@@ -1149,6 +1178,25 @@  static int create_master_playlist(AVFormatContext *s,
             continue;
         }
 
+        /**
+         * Traverse through the list of audio only rendition streams and find
+         * the rendition which has highest bitrate in the same audio group
+         */
+        if (vs->agroup) {
+            for (j = 0; j < hls->nb_varstreams; j++) {
+                temp_vs = &(hls->var_streams[j]);
+                if (!temp_vs->has_video && !temp_vs->has_subtitle &&
+                    temp_vs->agroup &&
+                    !strcmp(temp_vs->agroup, vs->agroup)) {
+                    if (!aud_st)
+                        aud_st = temp_vs->streams[0];
+                    if (temp_vs->streams[0]->codecpar->bit_rate >
+                            aud_st->codecpar->bit_rate)
+                        aud_st = temp_vs->streams[0];
+                }
+            }
+        }
+
         bandwidth = 0;
         if (vid_st)
             bandwidth += vid_st->codecpar->bit_rate;
@@ -1156,7 +1204,8 @@  static int create_master_playlist(AVFormatContext *s,
             bandwidth += aud_st->codecpar->bit_rate;
         bandwidth += bandwidth / 10;
 
-        ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name);
+        ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
+                aud_st ? vs->agroup : NULL);
 
         av_freep(&m3u8_rel_name);
     }
@@ -1508,6 +1557,7 @@  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 a:1,agroup:a1 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.
@@ -1516,6 +1566,7 @@  static int parse_variant_stream_mapstring(AVFormatContext *s)
      * respectively. Allowed values are 0 to 9 digits (limited just based on
      * practical usage)
      *
+     * agroup: is key to specify audio group. A string can be given as value.
      */
     p = av_strdup(hls->var_stream_map);
     q = p;
@@ -1554,7 +1605,10 @@  static int parse_variant_stream_mapstring(AVFormatContext *s)
         while (keyval = av_strtok(varstr, ",", &saveptr2)) {
             varstr = NULL;
 
-            if (av_strstart(keyval, "v:", &val)) {
+            if (av_strstart(keyval, "agroup:", &val)) {
+                vs->agroup = av_strdup(val);
+                continue;
+            } else if (av_strstart(keyval, "v:", &val)) {
                 codec_type = AVMEDIA_TYPE_VIDEO;
             } else if (av_strstart(keyval, "a:", &val)) {
                 codec_type = AVMEDIA_TYPE_AUDIO;
@@ -1915,6 +1969,7 @@  static int hls_write_trailer(struct AVFormatContext *s)
     av_free(old_filename);
     av_freep(&vs->m3u8_name);
     av_freep(&vs->streams);
+    av_freep(&vs->agroup);
     av_freep(&vs->baseurl);
     }
 
@@ -2255,6 +2310,7 @@  fail:
             av_freep(&vs->m3u8_name);
             av_freep(&vs->vtt_m3u8_name);
             av_freep(&vs->streams);
+            av_freep(&vs->agroup);
             av_freep(&vs->baseurl);
             if (vs->avf)
                 avformat_free_context(vs->avf);
diff --git a/libavformat/hlsplaylist.c b/libavformat/hlsplaylist.c
index 3349eb7..42f059a 100644
--- a/libavformat/hlsplaylist.c
+++ b/libavformat/hlsplaylist.c
@@ -36,7 +36,7 @@  void ff_hls_write_playlist_version(AVIOContext *out, int version) {
 }
 
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
-                              int bandwidth, char *filename) {
+                              int bandwidth, char *filename, char *agroup) {
     if (!out || !filename)
         return;
 
@@ -50,6 +50,8 @@  void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
     if (st && st->codecpar->width > 0 && st->codecpar->height > 0)
         avio_printf(out, ",RESOLUTION=%dx%d", st->codecpar->width,
                 st->codecpar->height);
+    if (agroup && strlen(agroup) > 0)
+        avio_printf(out, ",AUDIO=\"group_%s\"", agroup);
     avio_printf(out, "\n%s\n\n", filename);
 }
 
diff --git a/libavformat/hlsplaylist.h b/libavformat/hlsplaylist.h
index 48d71b7..a3ce26c 100644
--- a/libavformat/hlsplaylist.h
+++ b/libavformat/hlsplaylist.h
@@ -43,7 +43,7 @@  static inline int hls_get_int_from_double(double val)
 
 void ff_hls_write_playlist_version(AVIOContext *out, int version);
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
-                              int bandwidth, char *filename);
+                              int bandwidth, char *filename, char *agroup);
 void ff_hls_write_playlist_header(AVIOContext *out, int version, int allowcache,
                                   int target_duration, int64_t sequence,
                                   uint32_t playlist_type);