TiVo App - Streaming .m3u8 playlists

I had been curious how the actual Tivo Stream was .... streaming... the video to the iPhone, in looking at some logs that run during an actual streaming session I found something interesting:

Mar 30 22:55:13 XXXXX-iPod Quicksilver[1286] <Warning>: Preflighter: Transcoder is happy to stream

Mar 30 22:55:13 XXXXX-iPod Quicksilver[1286] <Warning>: TiVoStreamPreflighter: prereqs:2

Mar 30 22:55:13 XXXXX-iPod Quicksilver[1286] <Warning>: backgroundFetchTranscoderInfo done for XXXXXXXXXXXXXX!

Mar 30 22:55:13 XXXXX-iPod tccd[1299] <Notice>: MS:Notice: Installing: (null) [tccd] (793.00)

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: Response for passkey session request: 200, error: (null)

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: TiVoStreamPreflighter: Pass Key success

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: TiVoStreamPreflighter: prereqs:0

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: urlForMFSID:forTSN: string is http://10.0.0.109:49152/live-streaming/{TIVO_GUID}/10160.m3u8

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: Creating TiVoViewerViewController with url=http://10.0.0.109:49152/live-streaming/{TIVO_GUID}/10160.m3u8

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: Displaying status text: Loading Show

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: TiVoViewer: setURL:http://10.0.0.109:49152/live-streaming/{TIVO_GUID}/10160.m3u8

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: removeTimeObserver: self.player=0x0, pat.player=0x0, pat.token=0x0

Mar 30 22:55:14 XXXXX-iPod Quicksilver[1286] <Warning>: Sending POST request to http://10.0.0.109:49152/sysinfo/control?config=session&action=releaseclient

Retrieving m3u8 file

I grabbed the url from the log and retrieved its content in my browser, it contained the following:

#EXTM3U

#EXT-X-TIVO-CONTEXT:7

#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=8431425,CODECS="avc1.77.31,mp4a.40.2",RESOLUTION=1280x720,TIVOQUAL=BEST

10160/7/2240/playlist.m3u8

#EXT-X-ENDLIST

This file looks like it holds different quality streams, each with their own playlist.m3u8 file.

Retrieving playlist.m3u8 file

Following the path in the previous .m3u8 file I grabbed the playlist.m3u8, it contained the following:

#EXTM3U

#EXT-X-TARGETDURATION:2

#EXT-X-MEDIA-SEQUENCE:0

#EXT-X-KEY:METHOD=AES-128,URI="tivocrypt:///29919494ac3b53ab93ba79b17cd06819"

#EXTINF:2,

0

#EXTINF:2,

1

#EXTINF:2,

2

#EXTINF:2,

3

(I truncated the output, it has many parts)

This is VERY interesting!  It appears that the TiVo Stream sends the data in small pieces specified in playlist.m3u8, encrypted with aes-128.

This appears to be called "HTTP Live Streaming" by Apple in iOS, "HLS" for short: https://developer.apple.com/library/ios/#technotes/tn2288/_index.html#//apple_ref/doc/uid/DTS40012238

Given what I have read about the m3u8 format, it appears that iOS will attempt to hit the given url and it will expect a 128-bit AES key in response to decrypt each file...