PlayOn Closed Captions on Windows

I have PlayOn setup as a source in Channels. (latest Windows Beta). When I play a recording from within Windows (DVR->Manage->Play), there are no closed captions available. However, when I play the same recording through my FireStick, I get the closed captions.

Can anyone explain this?

Are they 720p (h.264) or 1080p (hevc) PlayOn recordings?
Channels DVR is probably transcoding them to play in the web UI and losing closed captions.
I know there were some issues w/hardware transcoding and closed captions.

They are 720P. I am too cheap to spend triple the price for the 1080 transmissions.

1 Like

If you open another web browser tab to view your Channels DVR web UI settings page while you're playing one of the recordings in the first web UI browser tab, what does it say under activity?

Does the player window have a CC button when you play it?

It says: " Watching recording New Tricks - S1E4 - Episode 3.mp4 from (Transcoder Ready)."

There is no "CC" button showing on the PlayOn recordings, but it does show on other things Channels has recorded.

The problem is definitely with the Channels Player. If I go directly to the .MP4 file in ...\Channels Data\PlayOn\TV\New Tricks, and run it through VLC Media Player, I can get closed captions just fine.

Does mediainfo show it having EIA-608 captions muxed in the video?

ID                                       : 258 (0x102)-CC1
Menu ID                                  : 1 (0x1)
Format                                   : EIA-608
Muxing mode                              : SCTE 128 / DTVCC Transport
Muxing mode, more info                   : Muxed in Video #1
Duration                                 : 1 h 29 min
Bit rate mode                            : Constant
Stream size                              : 0.00 Byte (0%)
CaptionServiceName                       : CC1

ID : 2
Format : Timed Text
Muxing mode : sbtl
Codec ID : tx3g
Duration : 55 min 44 s
Bit rate mode : Variable
Bit rate : 76 b/s
Stream size : 31.2 KiB (0%)
Language : English
Default : Yes
Forced : No
Alternate group : 3
Menus : 4


That's the reason. Timed text (XML-based) subtitles are not presently supported. It's on the todo list, as TTML subtitles are the required standard in ATSC3 for closed captions.

Edit: Saw the codec ID of tx3g, which are older style MPEG/QuickTime subtitles. In either case, they're not standard broadcast subtitle types.

The intersection of internet standards with broadcast is going slower in the software development process than one would like.

In short: it's not there yet, but hopefully soon.

You seem to have missed a point. I get subtitles with Channels feeding the FireStick Channels. I don't get subtitles when Channels feeds Windows Channels. Should they not work the same?

There is no Windows version of Channels. You're using a web browser, and the browser only supports certain types of captions.

1 Like

Your post has make things clearer to me.

I tried 3 different browsers (FireFox, Edge, and Chrome). All three used the same exact video player which does not decode some variations of closed captions that are embedded in the MP4 file.

This leaves me to believe that something is telling the browser which video player to use. My guess is that it is some setting in Windows, but it may be in some instructions Channels is sending to the browser.

What I'm getting to here is the question, is there some way to alter which video player gets used?