ioshttp-live-streaming

How to download HLS stream into a local machine?

Sometimes it is useful to download a stream into our local machine.

Reasons could be

If we try to use curl or wget to download the asset which is pointed by the URL for the stream, we end up downloading a small text file. It is surely not the video asset.

So how can we download the stream itself?

Solution

  • The actual script which does the download is given in the link at the bottom of my answer. But before we proceed to the how-to, let's first understand the steps for downloading a stream.

    Without going into too much details, the URL pointing to the stream is typically named with the m3u8 extension. That file is called the manifest of the stream and is actually a text file containing, among other things, a list of pairs: a bitrate and a corresponding URL for the matching playlist file. Here is an excerpt from a manifest file:

    #EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=380600,CODECS="avc1.4d00c,mp4a.40.2",RESOLUTION=320x180
http://f24hls-i.akamaihd.net/hls/live/221193-b/F24_EN_LO_HLS/master_250.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=655600,CODECS="avc1.77.30,mp4a.40.2",RESOLUTION=640x360
http://f24hls-i.akamaihd.net/hls/live/221193/F24_EN_LO_HLS/master_500.m3u8

    A playlist file is another text file which tell the player which TS file is to be playing on each position of the playback head.

    Here is the beginning of a typical playlist file:

    #EXTM3U
#EXT-X-VERSION:3
#EXT-X-TARGETDURATION:10
#EXT-X-MEDIA-SEQUENCE:303165
#EXTINF:10.000,
20170216T114458/master_500/00151/master_500_01165.ts
#EXTINF:10.000,
20170216T114458/master_500/00151/master_500_01166.ts

    So after downloading the playlist file for each of the bitrates, we can start downloading the TS files required to play the stream at each of the possible bitrates.

    All this is done using a quite simple and self-explaining script which I was putting in GitHub: https://github.com/ishahak/HLS_Downloader

    I hope it will be useful for others.