Execution halts if a single source block is used to feed analog & digital paths in parallel

[pclov3r]

It appears that low bitrates such as 24 Kbps doesn't work. If you bump the bitrate up slightly higher to say like 24.1 Kbps it will work but then https://github.com/theori-io/nrsc5 will complain about unexpected block type 0.

I was using the mode MP1 and not sure if this requires use of MP3?

Not sure if I'm doing something wrong but figured I'd mention it.

[pclov3r]

Just to update you need more then 24.1 instead more like 24.5.

Still results in unexpected block type 0.

It appears though with mono at 24 Kbps it will encode but still spits out Unexpected block type: 0, expected 6

[pclov3r]

Upon further testing it appears that 24 Kbps stereo will work with MP3 mode if you put the 24 Kbps stream into the P3 channel. It does not work with the P1 channel in either MP1 or MP3 modes.

[argilo]

I tried modifying hd_tx_usrp.grc by setting the HDC Encoder bitrate to 24000, and it works just fine. Lower values also seem to work.

Could you share your flow graph?

[argilo]

It looks like the issue stems from the fact that your flow graph uses the same Wav File Source to feed both HD1 and analog. When a flow graph diverges and then converges again, the GNU Radio scheduler can grind to a halt if the parallel paths' sample rates or latencies are not equal. I'll have to look into whether this can be done safely, and whether any of the gr-nrsc5 custom blocks are causing trouble.