How do I create an master HLS playlist using existing .m3u8 playlists

Question

I'm using FFmpeg to generate streaming files for a single resolution initially. Here is how my playlist and master-playlist looks like.

master.m3u8

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-STREAM-INF:BANDWIDTH=2305600,RESOLUTION=852x480,CODECS="avc1.640034,mp4a.40.2"
stream_480p.m3u8

stream_480p.m3u8

#EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:0
#EXT-X-PLAYLIST-TYPE:EVENT
#EXTINF:10.000000,
stream_480p0.ts
#EXTINF:10.000000,
stream_480p1.ts
#EXT-X-ENDLIST

later, if I add another stream, say 720p. I want my master.m3u8 to include that stream and serve the clients. How to achieve this? Are there any existing commands in FFmpeg that I can use here? or create the master.m3u8 programmatically?

Answer 1

Here is how I programmatically created the master playlist, reading from 2 different master playlists using python.

        streams = list()

        # read from 1st master playlist
        primary_master_playlist = open("master_1.m3u8", "r")
        while True:
            line = primary_master_playlist.readline()
            if not line:
                break
            elif line.lower().startswith("#ext-x-stream-inf"):
                streams.append(line + primary_master_playlist.readline() + "\n")

        # read from 2nd master playlist
        secondary_master_playlist = open("master_2.m3u8", "r")
        while True:
            line = secondary_master_playlist.readline()
            if not line:
                break
            elif line.lower().startswith("#ext-x-stream-inf"):
                streams.append(line + secondary_master_playlist.readline() + "\n")

        # write to final master playlist
        final_master_playlist = open("master.m3u8", "w")
        final_master_playlist.write("#EXTM3U\n")
        final_master_playlist.write("#EXT-X-VERSION:3\n")

        for stream in streams:
            final_master_playlist.write(stream)
        final_master_playlist.close()