[linux-dvb] Re: Finding in-the-clear digital cable channels: a few questions.

Luis Ochoa luis.m.ochoa at gmail.com
Fri Oct 21 17:29:13 CEST 2005


Ok, found a README in CVS that answers azap related questions, I'm
duplicating it here for future tinkerers benefit.

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Hi,

this are some trivial zapping applications explaining how to use the frontend
and demux API. They are also pretty useful to test your hardware.

For DVB-S, Astra Channel config file:

$ ./szap -c channels-conf/dvb-s/Astra-19.2E n24

will tune to N24. For DVB-C, Berlin Cable channel config:

$ ./czap -c channels-conf/dvb-c/de-Berlin Arte

For DVB-T, Berlin Config:

$ ./tzap -c channels-conf/dvb-t/de-Berlin phoenix

For ATSC, Raleigh Durham Config:

$ ./azap -c channels-conf/atsc/us-Raleigh-Durham WRAL

will tune to WRAL's Digital Channel 5-1.

By default the MPEG stream is routed to a hardware decoder. If you want to
record the stream to disk you will route it to the DVR device by using the
'-r' option:

$ ./tzap -c channels-conf/dvb-t/de-Berlin phoenix -r
[keep it running in one console]
$ cat /dev/dvb/adapter0/dvr0 > /tmp/recording.ts
[in a second console, will dump the MPEG transport stream to /tmp/recording.ts]

The status messages have the following meaning:

status 0x1f              --- The demodulator status bits.
			      0x1f means all bits set, everything ok.

signal [0x0000...0xffff] --- Signal Strength. Values above 0x8000 should be ok.

snr [0x0000...0xffff]    --- Signal/Noise Ratio. Values above 0x8000 are ok.

ber [0...0xffffffff]     --- Bit Error Rate. The less the better.

unc [0...0xffffffff]     --- Number of Uncorrectable Blocks.
			     Small numbers are Preferable.

If everything is alright and all frontend circuits are working stable
(are locked) you should see a FE_HAS_LOCK in the rightmost line.

Good luck,

Holger
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On 10/21/05, Luis Ochoa <luis.m.ochoa at gmail.com> wrote:
> I wanted to use mplayer, and I read I had to do "azap -r", but don't know
> why.
> What does the -r option do?
>
> this is what I get:
>
> azap -r c1
> using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
> tuning to 621012500 Hz
> video pid 0x0000, audio pid 0x0211
> status 00 | signal 0000 | snr 0000 | ber 00000000 | unc 0000ffff |
> status 1f | signal 0000 | snr feb6 | ber 00000000 | unc 0000ffff |
> FE_HAS_LOCK



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