avformat: add subtitle support in master playlist m3u8

[ffmpeg] / doc / muxers.texi

diff --git a/doc/muxers.texi b/doc/muxers.texi
index d304181671b6dd16e8199afd9b470e87ba2b99d9..4b6ffaaf58a987a7f992c011f0ba4d384df05375 100644 (file)
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -1062,6 +1062,21 @@ 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.
 
+@example
+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
+@end example
+
+This example adds @code{#EXT-X-MEDIA} tag with @code{TYPE=SUBTITLES} in
+the master playlist with webvtt subtitle group name 'subtitle'. Please make sure
+the input file has one text subtitle stream at least.
+
 @item cc_stream_map
 Map string which specifies different closed captions groups and their
 attributes. The closed captions stream groups are separated by space.
@@ -1352,8 +1367,9 @@ index at the beginning of the file.
 
 If this option is set to a non-zero value, the muxer will reserve a given amount
 of space in the file header and then try to write the cues there when the muxing
-finishes. If the available space does not suffice, muxing will fail. A safe size
-for most use cases should be about 50kB per hour of video.
+finishes. If the reserved space does not suffice, no Cues will be written, the
+file will be finalized and writing the trailer will return an error.
+A safe size for most use cases should be about 50kB per hour of video.
 
 Note that cues are only written if the output is seekable and this option will
 have no effect if it is not.