DLS texts with CRC-DabPlus

[Ulrik Brinck - Kanal Plus]

Hi,
A couple of questions about DLS texts with CRC-DabPlus:

I got it working with the tcpserver://:port option - however when I upload some text, it seems that it is only being broadcasted once. So that if I afterwards tune the receiver away from the service and back again, the text is gone. Is it possible to have CRC-DabPlus automatically repeat the text over and over until a new text is uploaded, or do we have to upload the text again and again as often as we want it broadcasted?

Another question - if we don't want a tcpserver, but just want a fixed text (repeated over and over), is that possible? I tried with a file name instead of tcpserver://:port, but with no luck. But maybe it's just a matter of finding the correct syntax?

And also a question about TII (Transmitter Identification Information). I have been asked whether or not we will be using TII - does the software broadcast this? And if it does, can I set the value - as an option or perhaps just by editing a value in the source and recompile? Or does the software not send TII at all? I tried to search the source of CRC-DabMux and CRC-DabMod for words like "TII" and "Identification", but didn't find anything about it, but maybe I just don't know what I'm looking for.

Best wishes,
Ulrik.

[Rashid Mustapha]

Hi Ulrick,

Although I may be corrected, I think TII is only useful in a Single Frequency Network (SFN) group of transmitters in
order to determine which ones can be heard in any given location, normally for engineering purposes.

As far as I am aware, the CRC-DabMod has no support for this as it cannot be used in an SFN group anyway - the
reference oscillators in a USRP are not locked to GPS for starters, so therefore the transmitter must stand alone
and hence there is no point of transmitting TII!

Regards,

Rash.

[Pascal Charest]

Ulrik Brinck - Kanal Plus wrote:
> Hi,
> A couple of questions about DLS texts with CRC-DabPlus:
>
> I got it working with the tcpserver://:port option - however when I upload some text, it seems that it is only being broadcasted once. So that if I afterwards tune the receiver away from the service and back again, the text is gone. Is it possible to have CRC-DabPlus automatically repeat the text over and over until a new text is uploaded, or do we have to upload the text again and again as often as we want it broadcasted?
>

The text will be repeated as long as the connection is up.

> Another question - if we don't want a tcpserver, but just want a fixed text (repeated over and over), is that possible? I tried with a file name instead of tcpserver://:port, but with no luck. But maybe it's just a matter of finding the correct syntax?
>

The syntax of the file is any subtitle supported by Gstreamer. To get a
list, launch the command "gst-inspect | grep -i subtitle". The file
input is more useful to pre-encoded file that can be used at a later time.

> And also a question about TII (Transmitter Identification Information). I have been asked whether or not we will be using TII - does the software broadcast this? And if it does, can I set the value - as an option or perhaps just by editing a value in the source and recompile? Or does the software not send TII at all? I tried to search the source of CRC-DabMux and CRC-DabMod for words like "TII" and "Identification", but didn't find anything about it, but maybe I just don't know what I'm looking for.
>

Previous Rashid's answer about TII was perfect.

The only thing that I will add is that the latest version of CRC-Dabmux
now support TIST. This is required from some (if not all) commercial DAB
modulator to be able to insert TII. If you use CRC-Dabmod as the
modulator, it will not work as it is not supported

Regards,

Pascal

[Ulrik Brinck - Kanal Plus]

Thank you Pascal and Rashid. I didn't really know what TII was for, I was just asked if we would be using it - because if we did, we would better have to coordinate the value with the operator of the nationwide DAB networks here. But since it is for SFN, it makes sense that it is not supported by CRC-DabMod. Thank you for clearing this up.

About DLS:

> The text will be repeated as long as the connection is up.

Oh - why didn't I see through that? ;-)

> The syntax of the file is any subtitle supported by Gstreamer. To get a
> list, launch the command "gst-inspect | grep -i subtitle". The file
> input is more useful to pre-encoded file that can be used at a later time.

Thank you again, I will see if I can do something with that.

One more question about CRC-DabPlus. Yes, I should have written that in the previous message too, but I forgot to... -

I understand that encoding automatically becomes HE-AAC v2 (SBR and PS) at bitrates up to 48 kbps, and HE-AAC v1 (SBR without PS) from 56 to 88, and AAC (with neither SBR nor PS) from 96 to 192 kbps. But is there an option to overrule that, if we want to try with for example HE-AAC v2 @ 64 kbps ?

Best wishes,
Ulrik.

[Pascal Charest]

Ulrik Brinck - Kanal Plus wrote:

> One more question about CRC-DabPlus. Yes, I should have written that
> in the previous message too, but I forgot to... -
> I understand that encoding automatically becomes HE-AAC v2 (SBR and PS) at bitrates up to 48 kbps, and HE-AAC v1 (SBR without PS) from 56 to 88, and AAC (with neither SBR nor PS) from 96 to 192 kbps. But is there an option to overrule that, if we want to try with for example HE-AAC v2 @ 64 kbps ?
>

Hi Ulrick,

Sorry, but there is no way to force AAC encoding profile with CRC-Dabplus.

Regards,

Pascal

[Ulrik Brinck - Kanal Plus]

Hi Pascal,

> Sorry, but there is no way to force AAC encoding profile with CRC-Dabplus.
>
> Regards,
>
> Pascal

Ok, and thank you for your fast reply. :)

Best wishes,
Ulrik.