DVB PID subtitles for live streaming

Wowza Streaming Engine
1

Hi

I’m using a MPTS UDP ingest, I’m able to join the program and audio (Spanish and English) channels, also the video program, now I need add the subtitles to the HLS stream, the SMIL file is using the stream of each PID for video and audios, I can’t find is Wowza Streaming Engine can support this feature.

Smil file:

stream example:

{
uri : “udp://225.10.10.11:1234”,
mpegtsVideoPID : “0x490”,
mpegtsVideoIsAligned : “true”,
mpegtsProgramID : “3”,
mpegtsImportAC3 : “true”,
mpegtsDVBTeletextMagazineNumber : “”,
mpegtsAudioIsAligned : “true”,
mpegtsAdjustBFrameTimecodes : “true”

FFPROBE to check the MPTS:

Program 3
Stream #0:9[0x490]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuv420p(top first), 1920x1080 [SAR 1:1 DAR 16:9], Closed Captions, 29.97 fps, 60 tbr, 90k tbn
Stream #0:230x4a0: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 192 kb/s
Stream #0:240x4a1: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, stereo, fltp, 192 kb/s
Stream #0:25[0x4b0]: Data: scte_35
Stream #0:260x4d0: Unknown: none ([130][0][0][0] / 0x0082)
Stream #0:270x4d1: Unknown: none ([130][0][0][0] / 0x0082) (clean effects)
Stream #0:280x4d2: Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)
Stream #0:290x4d3: Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006) (clean effects)

2

WSE out of the box will not handle this. You would need to create a custom module that pulls the captions out of the stream, convert them to individual text lines and reinject them as “onTextData” into the stream. WSE will pick them up as WebVTT or CEA608 depending upon how the WSE is configured.

I seem to remember there were some custom modules on Wowza’s site, back in the day, that handled data in ts.

Scott Kellicker
Streaming Video Consultant