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[FFmpeg-devel,v1,3/4] avformat: add subtitle support in master playlist m3u8

Message ID 20200326135700.11167-3-lance.lmwang@gmail.com
State Superseded
Headers show
Series [FFmpeg-devel,v1,1/4] avformat/hlsenc: remove the first slash of the relative path line in the master m3u8 file
Related show

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Context Check Description
andriy/ffmpeg-patchwork pending
andriy/ffmpeg-patchwork success Applied patch
andriy/ffmpeg-patchwork success Configure finished
andriy/ffmpeg-patchwork success Make finished
andriy/ffmpeg-patchwork success Make fate finished

Commit Message

Limin Wang March 26, 2020, 1:56 p.m. UTC
From: Limin Wang <lance.lmwang@gmail.com>

Test with the following command for the webvtt subtitle:
$ ./ffmpeg -y -i input_with_subtitle.mkv \
 -b:v:0 5250k -c:v h264 -pix_fmt yuv420p -profile:v main -level 4.1 \
 -b:a:0 256k \
 -c:s webvtt -c:a mp2 -ar 48000 -ac 2 -map 0:v -map 0:a:0 -map 0:s:0 \
 -f hls -var_stream_map "v:0,a:0,s:0,sgroup:subtitle" \
 -master_pl_name master.m3u8 -t 300 -hls_time 10 -hls_init_time 4 -hls_list_size \
 10 -master_pl_publish_rate 10  -hls_flags \
 delete_segments+discont_start+split_by_time ./tmp/video.m3u8

Check the master m3u8:
$ cat tmp/master.m3u8
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subtitle",NAME="subtitle_0",DEFAULT=YES,URI="video_vtt.m3u8"
#EXT-X-STREAM-INF:BANDWIDTH=6056600,RESOLUTION=1280x720,CODECS="avc1.4d4829,mp4a.40.33",SUBTITLES="subtitle"
video.m3u8

Check the result by convert to mkv:
$ ./ffmpeg -strict experimental -i ./tmp/master.m3u8 -c:v copy -c:a mp2 -c:s srt ./test.mkv

Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
---
 libavformat/dashenc.c     |  2 +-
 libavformat/hlsenc.c      | 26 ++++++++++++++++++++++++--
 libavformat/hlsplaylist.c | 17 ++++++++++++++++-
 libavformat/hlsplaylist.h |  4 +++-
 4 files changed, 44 insertions(+), 5 deletions(-)

Comments

Steven Liu March 29, 2020, 8:32 a.m. UTC | #1
> 2020年3月26日 下午9:56,lance.lmwang@gmail.com 写道:
> 
> From: Limin Wang <lance.lmwang@gmail.com>
> 
> Test with the following command for the webvtt subtitle:
> $ ./ffmpeg -y -i input_with_subtitle.mkv \
> -b:v:0 5250k -c:v h264 -pix_fmt yuv420p -profile:v main -level 4.1 \
> -b:a:0 256k \
> -c:s webvtt -c:a mp2 -ar 48000 -ac 2 -map 0:v -map 0:a:0 -map 0:s:0 \
> -f hls -var_stream_map "v:0,a:0,s:0,sgroup:subtitle” \
What about add the example into doc/muxer.texi ?
> -master_pl_name master.m3u8 -t 300 -hls_time 10 -hls_init_time 4 -hls_list_size \
> 10 -master_pl_publish_rate 10  -hls_flags \
> delete_segments+discont_start+split_by_time ./tmp/video.m3u8
> 
> Check the master m3u8:
> $ cat tmp/master.m3u8
> #EXTM3U
> #EXT-X-VERSION:3
> #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subtitle",NAME="subtitle_0",DEFAULT=YES,URI="video_vtt.m3u8"
> #EXT-X-STREAM-INF:BANDWIDTH=6056600,RESOLUTION=1280x720,CODECS="avc1.4d4829,mp4a.40.33",SUBTITLES="subtitle"
> video.m3u8
> 
> Check the result by convert to mkv:
> $ ./ffmpeg -strict experimental -i ./tmp/master.m3u8 -c:v copy -c:a mp2 -c:s srt ./test.mkv
> 
> Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> ---
> libavformat/dashenc.c     |  2 +-
> libavformat/hlsenc.c      | 26 ++++++++++++++++++++++++--
> libavformat/hlsplaylist.c | 17 ++++++++++++++++-
> libavformat/hlsplaylist.h |  4 +++-
> 4 files changed, 44 insertions(+), 5 deletions(-)
> 
> diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
> index 94d463972a..d1fe90b00c 100644
> --- a/libavformat/dashenc.c
> +++ b/libavformat/dashenc.c
> @@ -1311,7 +1311,7 @@ static int write_manifest(AVFormatContext *s, int final)
>             get_hls_playlist_name(playlist_file, sizeof(playlist_file), NULL, i);
>             ff_hls_write_stream_info(st, c->m3u8_out, stream_bitrate,
>                                      playlist_file, agroup,
> -                                     codec_str_ptr, NULL);
> +                                     codec_str_ptr, NULL, NULL);
>         }
>         dashenc_io_close(s, &c->m3u8_out, temp_filename);
>         if (use_rename)
> diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> index a0a3a4647b..d7b9c0e20a 100644
> --- a/libavformat/hlsenc.c
> +++ b/libavformat/hlsenc.c
> @@ -164,6 +164,7 @@ typedef struct VariantStream {
>     int is_default; /* default status of audio group */
>     char *language; /* audio lauguage name */
>     char *agroup; /* audio group name */
> +    char *sgroup; /* subtitle group name */
>     char *ccgroup; /* closed caption group name */
>     char *baseurl;
>     char *varname; // variant name
> @@ -1289,7 +1290,9 @@ static int create_master_playlist(AVFormatContext *s,
>     unsigned int i, j;
>     int ret, bandwidth;
>     const char *m3u8_rel_name = NULL;
> +    const char *vtt_m3u8_rel_name = NULL;
>     char *ccgroup;
> +    char *sgroup = NULL;
>     ClosedCaptionsStream *ccs;
>     const char *proto = avio_find_protocol_name(hls->master_m3u8_url);
>     int is_file_proto = proto && !strcmp(proto, "file");
> @@ -1412,13 +1415,24 @@ static int create_master_playlist(AVFormatContext *s,
>                         vs->ccgroup);
>         }
> 
> +        if (vid_st && vs->sgroup) {
> +            sgroup = vs->sgroup;
> +            vtt_m3u8_rel_name = get_relative_url(hls->master_m3u8_url, vs->vtt_m3u8_name);
> +            if (!vtt_m3u8_rel_name) {
> +                av_log(s, AV_LOG_WARNING, "Unable to find relative subtitle URL\n");
> +                break;
> +            }
> +
> +            ff_hls_write_subtitle_rendition(hls->m3u8_out, sgroup, vtt_m3u8_rel_name, vs->language, i, hls->has_default_key ? vs->is_default : 1);
> +        }
> +
>         if (!hls->has_default_key || !hls->has_video_m3u8) {
>             ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
> -                    aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup);
> +                    aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup, sgroup);
>         } else {
>             if (vid_st) {
>                 ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
> -                                         aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup);
> +                                         aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup, sgroup);
>             }
>         }
>     }
> @@ -1893,6 +1907,7 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
>      * practical usage)
>      *
>      * agroup: is key to specify audio group. A string can be given as value.
> +     * sgroup: is key to specify subtitle group. A string can be given as value.
>      */
>     p = av_strdup(hls->var_stream_map);
>     if (!p)
> @@ -1960,6 +1975,12 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
>                 if (!vs->agroup)
>                     return AVERROR(ENOMEM);
>                 continue;
> +            } else if (av_strstart(keyval, "sgroup:", &val)) {
> +                av_free(vs->sgroup);
> +                vs->sgroup = av_strdup(val);
> +                if (!vs->sgroup)
> +                    return AVERROR(ENOMEM);
> +                continue;
>             } else if (av_strstart(keyval, "ccgroup:", &val)) {
>                 av_free(vs->ccgroup);
>                 vs->ccgroup = av_strdup(val);
> @@ -2516,6 +2537,7 @@ 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->sgroup);
>         av_freep(&vs->language);
>         av_freep(&vs->ccgroup);
>         av_freep(&vs->baseurl);
> diff --git a/libavformat/hlsplaylist.c b/libavformat/hlsplaylist.c
> index 56244496c0..43f9d281ba 100644
> --- a/libavformat/hlsplaylist.c
> +++ b/libavformat/hlsplaylist.c
> @@ -48,9 +48,22 @@ void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
>     avio_printf(out, "URI=\"%s\"\n", filename);
> }
> 
> +void ff_hls_write_subtitle_rendition(AVIOContext *out, char *sgroup,
> +                                  const char *filename, char *language, int name_id, int is_default) {
> +    if (!out || !filename)
> +        return;
> +
> +    avio_printf(out, "#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID=\"%s\"", sgroup);
> +    avio_printf(out, ",NAME=\"subtitle_%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,
>                               int bandwidth, const char *filename, char *agroup,
> -                              char *codecs, char *ccgroup) {
> +                              char *codecs, char *ccgroup, char *sgroup) {
> 
>     if (!out || !filename)
>         return;
> @@ -71,6 +84,8 @@ void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
>         avio_printf(out, ",AUDIO=\"group_%s\"", agroup);
>     if (ccgroup && ccgroup[0])
>         avio_printf(out, ",CLOSED-CAPTIONS=\"%s\"", ccgroup);
> +    if (sgroup && sgroup[0])
> +        avio_printf(out, ",SUBTITLES=\"%s\"", sgroup);
>     avio_printf(out, "\n%s\n\n", filename);
> }
> 
> diff --git a/libavformat/hlsplaylist.h b/libavformat/hlsplaylist.h
> index a8d29d62d3..a124bdcffb 100644
> --- a/libavformat/hlsplaylist.h
> +++ b/libavformat/hlsplaylist.h
> @@ -39,9 +39,11 @@ typedef enum {
> void ff_hls_write_playlist_version(AVIOContext *out, int version);
> void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
>                                   const char *filename, char *language, int name_id, int is_default);
> +void ff_hls_write_subtitle_rendition(AVIOContext *out, char *sgroup,
> +                                  const char *filename, char *language, int name_id, int is_default);
> void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
>                               int bandwidth, const char *filename, char *agroup,
> -                              char *codecs, char *ccgroup);
> +                              char *codecs, char *ccgroup, char *sgroup);
> void ff_hls_write_playlist_header(AVIOContext *out, int version, int allowcache,
>                                   int target_duration, int64_t sequence,
>                                   uint32_t playlist_type, int iframe_mode);
> -- 
> 2.21.0
> 
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Thanks

Steven Liu
Limin Wang March 29, 2020, 11:15 a.m. UTC | #2
On Sun, Mar 29, 2020 at 04:32:06PM +0800, Steven Liu wrote:
> 
> 
> > 2020年3月26日 下午9:56,lance.lmwang@gmail.com 写道:
> > 
> > From: Limin Wang <lance.lmwang@gmail.com>
> > 
> > Test with the following command for the webvtt subtitle:
> > $ ./ffmpeg -y -i input_with_subtitle.mkv \
> > -b:v:0 5250k -c:v h264 -pix_fmt yuv420p -profile:v main -level 4.1 \
> > -b:a:0 256k \
> > -c:s webvtt -c:a mp2 -ar 48000 -ac 2 -map 0:v -map 0:a:0 -map 0:s:0 \
> > -f hls -var_stream_map "v:0,a:0,s:0,sgroup:subtitle” \
> What about add the example into doc/muxer.texi ?

Sure, I have add one example into muxer.texi and send updated the patch.

> > -master_pl_name master.m3u8 -t 300 -hls_time 10 -hls_init_time 4 -hls_list_size \
> > 10 -master_pl_publish_rate 10  -hls_flags \
> > delete_segments+discont_start+split_by_time ./tmp/video.m3u8
> > 
> > Check the master m3u8:
> > $ cat tmp/master.m3u8
> > #EXTM3U
> > #EXT-X-VERSION:3
> > #EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subtitle",NAME="subtitle_0",DEFAULT=YES,URI="video_vtt.m3u8"
> > #EXT-X-STREAM-INF:BANDWIDTH=6056600,RESOLUTION=1280x720,CODECS="avc1.4d4829,mp4a.40.33",SUBTITLES="subtitle"
> > video.m3u8
> > 
> > Check the result by convert to mkv:
> > $ ./ffmpeg -strict experimental -i ./tmp/master.m3u8 -c:v copy -c:a mp2 -c:s srt ./test.mkv
> > 
> > Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
> > ---
> > libavformat/dashenc.c     |  2 +-
> > libavformat/hlsenc.c      | 26 ++++++++++++++++++++++++--
> > libavformat/hlsplaylist.c | 17 ++++++++++++++++-
> > libavformat/hlsplaylist.h |  4 +++-
> > 4 files changed, 44 insertions(+), 5 deletions(-)
> > 
> > diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
> > index 94d463972a..d1fe90b00c 100644
> > --- a/libavformat/dashenc.c
> > +++ b/libavformat/dashenc.c
> > @@ -1311,7 +1311,7 @@ static int write_manifest(AVFormatContext *s, int final)
> >             get_hls_playlist_name(playlist_file, sizeof(playlist_file), NULL, i);
> >             ff_hls_write_stream_info(st, c->m3u8_out, stream_bitrate,
> >                                      playlist_file, agroup,
> > -                                     codec_str_ptr, NULL);
> > +                                     codec_str_ptr, NULL, NULL);
> >         }
> >         dashenc_io_close(s, &c->m3u8_out, temp_filename);
> >         if (use_rename)
> > diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> > index a0a3a4647b..d7b9c0e20a 100644
> > --- a/libavformat/hlsenc.c
> > +++ b/libavformat/hlsenc.c
> > @@ -164,6 +164,7 @@ typedef struct VariantStream {
> >     int is_default; /* default status of audio group */
> >     char *language; /* audio lauguage name */
> >     char *agroup; /* audio group name */
> > +    char *sgroup; /* subtitle group name */
> >     char *ccgroup; /* closed caption group name */
> >     char *baseurl;
> >     char *varname; // variant name
> > @@ -1289,7 +1290,9 @@ static int create_master_playlist(AVFormatContext *s,
> >     unsigned int i, j;
> >     int ret, bandwidth;
> >     const char *m3u8_rel_name = NULL;
> > +    const char *vtt_m3u8_rel_name = NULL;
> >     char *ccgroup;
> > +    char *sgroup = NULL;
> >     ClosedCaptionsStream *ccs;
> >     const char *proto = avio_find_protocol_name(hls->master_m3u8_url);
> >     int is_file_proto = proto && !strcmp(proto, "file");
> > @@ -1412,13 +1415,24 @@ static int create_master_playlist(AVFormatContext *s,
> >                         vs->ccgroup);
> >         }
> > 
> > +        if (vid_st && vs->sgroup) {
> > +            sgroup = vs->sgroup;
> > +            vtt_m3u8_rel_name = get_relative_url(hls->master_m3u8_url, vs->vtt_m3u8_name);
> > +            if (!vtt_m3u8_rel_name) {
> > +                av_log(s, AV_LOG_WARNING, "Unable to find relative subtitle URL\n");
> > +                break;
> > +            }
> > +
> > +            ff_hls_write_subtitle_rendition(hls->m3u8_out, sgroup, vtt_m3u8_rel_name, vs->language, i, hls->has_default_key ? vs->is_default : 1);
> > +        }
> > +
> >         if (!hls->has_default_key || !hls->has_video_m3u8) {
> >             ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
> > -                    aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup);
> > +                    aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup, sgroup);
> >         } else {
> >             if (vid_st) {
> >                 ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
> > -                                         aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup);
> > +                                         aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup, sgroup);
> >             }
> >         }
> >     }
> > @@ -1893,6 +1907,7 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
> >      * practical usage)
> >      *
> >      * agroup: is key to specify audio group. A string can be given as value.
> > +     * sgroup: is key to specify subtitle group. A string can be given as value.
> >      */
> >     p = av_strdup(hls->var_stream_map);
> >     if (!p)
> > @@ -1960,6 +1975,12 @@ static int parse_variant_stream_mapstring(AVFormatContext *s)
> >                 if (!vs->agroup)
> >                     return AVERROR(ENOMEM);
> >                 continue;
> > +            } else if (av_strstart(keyval, "sgroup:", &val)) {
> > +                av_free(vs->sgroup);
> > +                vs->sgroup = av_strdup(val);
> > +                if (!vs->sgroup)
> > +                    return AVERROR(ENOMEM);
> > +                continue;
> >             } else if (av_strstart(keyval, "ccgroup:", &val)) {
> >                 av_free(vs->ccgroup);
> >                 vs->ccgroup = av_strdup(val);
> > @@ -2516,6 +2537,7 @@ 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->sgroup);
> >         av_freep(&vs->language);
> >         av_freep(&vs->ccgroup);
> >         av_freep(&vs->baseurl);
> > diff --git a/libavformat/hlsplaylist.c b/libavformat/hlsplaylist.c
> > index 56244496c0..43f9d281ba 100644
> > --- a/libavformat/hlsplaylist.c
> > +++ b/libavformat/hlsplaylist.c
> > @@ -48,9 +48,22 @@ void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
> >     avio_printf(out, "URI=\"%s\"\n", filename);
> > }
> > 
> > +void ff_hls_write_subtitle_rendition(AVIOContext *out, char *sgroup,
> > +                                  const char *filename, char *language, int name_id, int is_default) {
> > +    if (!out || !filename)
> > +        return;
> > +
> > +    avio_printf(out, "#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID=\"%s\"", sgroup);
> > +    avio_printf(out, ",NAME=\"subtitle_%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,
> >                               int bandwidth, const char *filename, char *agroup,
> > -                              char *codecs, char *ccgroup) {
> > +                              char *codecs, char *ccgroup, char *sgroup) {
> > 
> >     if (!out || !filename)
> >         return;
> > @@ -71,6 +84,8 @@ void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
> >         avio_printf(out, ",AUDIO=\"group_%s\"", agroup);
> >     if (ccgroup && ccgroup[0])
> >         avio_printf(out, ",CLOSED-CAPTIONS=\"%s\"", ccgroup);
> > +    if (sgroup && sgroup[0])
> > +        avio_printf(out, ",SUBTITLES=\"%s\"", sgroup);
> >     avio_printf(out, "\n%s\n\n", filename);
> > }
> > 
> > diff --git a/libavformat/hlsplaylist.h b/libavformat/hlsplaylist.h
> > index a8d29d62d3..a124bdcffb 100644
> > --- a/libavformat/hlsplaylist.h
> > +++ b/libavformat/hlsplaylist.h
> > @@ -39,9 +39,11 @@ typedef enum {
> > void ff_hls_write_playlist_version(AVIOContext *out, int version);
> > void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
> >                                   const char *filename, char *language, int name_id, int is_default);
> > +void ff_hls_write_subtitle_rendition(AVIOContext *out, char *sgroup,
> > +                                  const char *filename, char *language, int name_id, int is_default);
> > void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
> >                               int bandwidth, const char *filename, char *agroup,
> > -                              char *codecs, char *ccgroup);
> > +                              char *codecs, char *ccgroup, char *sgroup);
> > void ff_hls_write_playlist_header(AVIOContext *out, int version, int allowcache,
> >                                   int target_duration, int64_t sequence,
> >                                   uint32_t playlist_type, int iframe_mode);
> > -- 
> > 2.21.0
> > 
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel@ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> > 
> > To unsubscribe, visit link above, or email
> > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
> 
> Thanks
> 
> Steven Liu
> 
> 
>
diff mbox series

Patch

diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
index 94d463972a..d1fe90b00c 100644
--- a/libavformat/dashenc.c
+++ b/libavformat/dashenc.c
@@ -1311,7 +1311,7 @@  static int write_manifest(AVFormatContext *s, int final)
             get_hls_playlist_name(playlist_file, sizeof(playlist_file), NULL, i);
             ff_hls_write_stream_info(st, c->m3u8_out, stream_bitrate,
                                      playlist_file, agroup,
-                                     codec_str_ptr, NULL);
+                                     codec_str_ptr, NULL, NULL);
         }
         dashenc_io_close(s, &c->m3u8_out, temp_filename);
         if (use_rename)
diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
index a0a3a4647b..d7b9c0e20a 100644
--- a/libavformat/hlsenc.c
+++ b/libavformat/hlsenc.c
@@ -164,6 +164,7 @@  typedef struct VariantStream {
     int is_default; /* default status of audio group */
     char *language; /* audio lauguage name */
     char *agroup; /* audio group name */
+    char *sgroup; /* subtitle group name */
     char *ccgroup; /* closed caption group name */
     char *baseurl;
     char *varname; // variant name
@@ -1289,7 +1290,9 @@  static int create_master_playlist(AVFormatContext *s,
     unsigned int i, j;
     int ret, bandwidth;
     const char *m3u8_rel_name = NULL;
+    const char *vtt_m3u8_rel_name = NULL;
     char *ccgroup;
+    char *sgroup = NULL;
     ClosedCaptionsStream *ccs;
     const char *proto = avio_find_protocol_name(hls->master_m3u8_url);
     int is_file_proto = proto && !strcmp(proto, "file");
@@ -1412,13 +1415,24 @@  static int create_master_playlist(AVFormatContext *s,
                         vs->ccgroup);
         }
 
+        if (vid_st && vs->sgroup) {
+            sgroup = vs->sgroup;
+            vtt_m3u8_rel_name = get_relative_url(hls->master_m3u8_url, vs->vtt_m3u8_name);
+            if (!vtt_m3u8_rel_name) {
+                av_log(s, AV_LOG_WARNING, "Unable to find relative subtitle URL\n");
+                break;
+            }
+
+            ff_hls_write_subtitle_rendition(hls->m3u8_out, sgroup, vtt_m3u8_rel_name, vs->language, i, hls->has_default_key ? vs->is_default : 1);
+        }
+
         if (!hls->has_default_key || !hls->has_video_m3u8) {
             ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
-                    aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup);
+                    aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup, sgroup);
         } else {
             if (vid_st) {
                 ff_hls_write_stream_info(vid_st, hls->m3u8_out, bandwidth, m3u8_rel_name,
-                                         aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup);
+                                         aud_st ? vs->agroup : NULL, vs->codec_attr, ccgroup, sgroup);
             }
         }
     }
@@ -1893,6 +1907,7 @@  static int parse_variant_stream_mapstring(AVFormatContext *s)
      * practical usage)
      *
      * agroup: is key to specify audio group. A string can be given as value.
+     * sgroup: is key to specify subtitle group. A string can be given as value.
      */
     p = av_strdup(hls->var_stream_map);
     if (!p)
@@ -1960,6 +1975,12 @@  static int parse_variant_stream_mapstring(AVFormatContext *s)
                 if (!vs->agroup)
                     return AVERROR(ENOMEM);
                 continue;
+            } else if (av_strstart(keyval, "sgroup:", &val)) {
+                av_free(vs->sgroup);
+                vs->sgroup = av_strdup(val);
+                if (!vs->sgroup)
+                    return AVERROR(ENOMEM);
+                continue;
             } else if (av_strstart(keyval, "ccgroup:", &val)) {
                 av_free(vs->ccgroup);
                 vs->ccgroup = av_strdup(val);
@@ -2516,6 +2537,7 @@  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->sgroup);
         av_freep(&vs->language);
         av_freep(&vs->ccgroup);
         av_freep(&vs->baseurl);
diff --git a/libavformat/hlsplaylist.c b/libavformat/hlsplaylist.c
index 56244496c0..43f9d281ba 100644
--- a/libavformat/hlsplaylist.c
+++ b/libavformat/hlsplaylist.c
@@ -48,9 +48,22 @@  void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
     avio_printf(out, "URI=\"%s\"\n", filename);
 }
 
+void ff_hls_write_subtitle_rendition(AVIOContext *out, char *sgroup,
+                                  const char *filename, char *language, int name_id, int is_default) {
+    if (!out || !filename)
+        return;
+
+    avio_printf(out, "#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID=\"%s\"", sgroup);
+    avio_printf(out, ",NAME=\"subtitle_%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,
                               int bandwidth, const char *filename, char *agroup,
-                              char *codecs, char *ccgroup) {
+                              char *codecs, char *ccgroup, char *sgroup) {
 
     if (!out || !filename)
         return;
@@ -71,6 +84,8 @@  void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
         avio_printf(out, ",AUDIO=\"group_%s\"", agroup);
     if (ccgroup && ccgroup[0])
         avio_printf(out, ",CLOSED-CAPTIONS=\"%s\"", ccgroup);
+    if (sgroup && sgroup[0])
+        avio_printf(out, ",SUBTITLES=\"%s\"", sgroup);
     avio_printf(out, "\n%s\n\n", filename);
 }
 
diff --git a/libavformat/hlsplaylist.h b/libavformat/hlsplaylist.h
index a8d29d62d3..a124bdcffb 100644
--- a/libavformat/hlsplaylist.h
+++ b/libavformat/hlsplaylist.h
@@ -39,9 +39,11 @@  typedef enum {
 void ff_hls_write_playlist_version(AVIOContext *out, int version);
 void ff_hls_write_audio_rendition(AVIOContext *out, char *agroup,
                                   const char *filename, char *language, int name_id, int is_default);
+void ff_hls_write_subtitle_rendition(AVIOContext *out, char *sgroup,
+                                  const char *filename, char *language, int name_id, int is_default);
 void ff_hls_write_stream_info(AVStream *st, AVIOContext *out,
                               int bandwidth, const char *filename, char *agroup,
-                              char *codecs, char *ccgroup);
+                              char *codecs, char *ccgroup, char *sgroup);
 void ff_hls_write_playlist_header(AVIOContext *out, int version, int allowcache,
                                   int target_duration, int64_t sequence,
                                   uint32_t playlist_type, int iframe_mode);