When using HTTP Live Streaming (HLS), a common use case is to use MPEG-TS segments or fragmented MP4 fragments. This is done so that the overall stream is available as a sequence of small HTTP-based file downloads, each being one short chunk of an overall bounded or unbounded media stream.
The playlist file (.m3u8) contains a list of these small segments or fragments. This is the standard and most common approach for HLS. For the HLS CMAF case, a multi-segment playlist would look like below.
#EXTM3U
#EXT-X-VERSION:6
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-TARGETDURATION:5
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-MAP:URI="init00000.mp4"
#EXTINF:5,
segment00000.m4s
#EXTINF:5,
segment00001.m4s
#EXTINF:5,
segment00002.m4s
An alternative approach is to use a single media file with the EXT-X-BYTERANGE tag. This method is primarily used for on-demand (VOD) streaming where the complete media file already exists and can reduce the number of files that needs to be managed on the server. Single file with byte-ranges requires the server and client to support HTTP byte range requests and 206 Partial Content responses.
The single media file use case wasn't supported so far with either of hlssink3 or hlscmafsink. A new property single-media-file has been added, which lets users specify the use of a single media file.
hlscmafsink.set_property("single-media-file", "main.mp4");
hlssink3.set_property("single-media-file", "main.ts");For the HLS CMAF case, this would generate a playlist like below.
#EXTM3U
#EXT-X-VERSION:6
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-TARGETDURATION:5
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-MAP:URI="main.mp4",BYTERANGE="768@0"
#EXT-X-BYTERANGE:100292@768
#EXTINF:5,
main.mp4
#EXT-X-BYTERANGE:98990@101060
#EXTINF:5,
main.mp4
#EXT-X-BYTERANGE:99329@200050
#EXTINF:5,
main.mp4
This can be useful if one has storage requirements where the use of a single media file for HLS might be favourable.