[FFmpeg-user] inject an mpeg2 radio station (mpeg2 encoded from alsa) to a DVB-t multiplexer (via ASI)

Federico Allegretti allegfede at gmail.com
Mon Aug 14 14:43:36 EEST 2017

Hello everybody.

I'm trying to add a radio station to the multiplex of out broadcasting

We actually use a real cheap 6 channels wellav encoder, that has 6 analog
a/v inputs but can accect 2 incoming signals from ASI ports.

I got a DVeo ASi i/o card (acquired from ebay) and i plan to capture audio
from PC integrated sound card -> encode with ffmpeg -> pipe to the ASI card
-> mux to the 6 a/v channels of the wellav -> broadcast.

Now i got this command line on a simple cheap pc (i got if from the
trashcan of my neighboor :D ) provided with ubuntu server:

ffmpeg -threads 0 -f alsa -ac 2 -ar 48000 -i default -c:a mp2 -b:a 224k -ar
48000 -ac 2 -mpegts_flags resend_headers -f mpegts -muxrate 384k -flags
cgop -sc_threshold 500  -mpegts_original_network_id 12293
-mpegts_service_id 7 -mpegts_pmt_start_pid 95 -streamid 0:96 -streamid
1:97  -mpegts_service_type 0x02 -metadata service_provider="MEDIANOV"
-metadata service_name="Radio Galileo" -metadata service_type=0x02  - |
txtest /dev/asitx0 0 105560 0 0 0 0

and multiplexer successfully get the incoming stream, BUT there are some
strange things:

If i look to an internally encoded a/v stream i got those IDs:
A/V6 [pmt:35] =  pcr:38 | video:36 | audio:37
but my asi input trasport stream is:
ASI1 [pmt:95] = pcr:96 | audio:96

have to mention tv scan do not detect the transported stream of the radio
station ...

What i'm missing? Someone has an idea?

Open TV Architecture project: http://sourceforge.net/projects/otva/

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