[FFmpeg-user] decklink SDI output with subtitles

Izhar Marinov izhar.m at novelsat.com
Thu May 30 18:28:26 EEST 2024

Thaks for the quick reply! 

I thought "Add support for EIA-708 output over SDI" patch is what required to support subtitles....

Any timeline for the OP-47/42 support ?


-----Original Message-----
From: ffmpeg-user <ffmpeg-user-bounces at ffmpeg.org> On Behalf Of Devin Heitmueller
Sent: Thursday, May 30, 2024 6:06 PM
To: FFmpeg user questions <ffmpeg-user at ffmpeg.org>
Subject: Re: [FFmpeg-user] decklink SDI output with subtitles

On Thu, May 30, 2024 at 10:57 AM Izhar Marinov <izhar.m at novelsat.com> wrote:
> I am trying to decode mpeg TS over UDP with subtitle stream into SDI port.
> Command:
> ffmpeg -i 
> "udp://
> fer_size=13107200&fifo_size=1000000" -map 0:i:0x7d1 -map 0:i:0xbb9 
> -map 0:i:0x1389  -teletext_lines all -c:v v210 -f decklink 
> 88:02a07762:00000000
> if I don’t use the map command, the video and audio are working fine but the subtitle stream is ignored, if I specify the subtitles stream (PID 0x1389 in this example), I get the following error:
> Input #0, mpegts, from 'udp://':
>   Duration: N/A, start: 43965.121844, bitrate: N/A
>   Program 1
>   Stream #0:0[0x7d1]: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p(tv, bt470bg, top first), 720x576 [SAR 16:11 DAR 20:11], 25 fps, 50 tbr, 90k tbn
>   Stream #0:1[0xbb9](eng): Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, s16p, 384 kb/s (clean effects)
>   Stream #0:2[0xfa1](eng): Audio: mp2 ([4][0][0][0] / 0x0004), 48000 Hz, stereo, s16p, 384 kb/s (clean effects)
>   Stream #0:3[0x1389](spa,spa,spa,spa,spa,spa,spa): Subtitle: 
> dvb_teletext (libzvbi_teletextdec) ([6][0][0][0] / 0x0006), 492x250
> [sost#0:2 @ 0x55b721f91b40] Automatic encoder selection failed Default encoder for format decklink (codec eia_608) is probably disabled. Please choose an encoder manually.
> [sost#0:2 @ 0x55b721f91b40] Error selecting an encoder

Output of teletext over the decklink output isn't supported currently.
It's on my TODO list, but I haven't gotten around to it yet.  I was looking to implement OP-47 for the HD domain and OP-42 for standard def.


Devin Heitmueller, Senior Software Engineer LTN Global Communications
o: +1 (301) 363-1001
w: https://ltnglobal.com  e: devin.heitmueller at ltnglobal.com _______________________________________________
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