dvb-t tuner produces lots of UNC and bad MPEG streams randomly (1/2 of the times, but not deterministic)

[JoseO]

Tuning of some dvb-t channels produces bad MPEG streams pseudo-randomly.

Consecutively tuning several times to the same channel results in 1/2 of the time channel lock with almost 0 UNC and 1/2 of the time with high rates of UNC. That second scenario makes the mpeg stream unwatchable (even no output in dvr0 most of the time)

A sequence of "tzap -r channel_name" results in a cycle of OK/KO tuning results. After an "OK" tuning (no BER, no UNC, signal level aprox 0x6600)
I always get a "KO" tuning (high BER, high UNC, signal level aprox 0x7700)

Note that "pseudo-randomly" means that sometimes it doesn't happen at all but, when it happens, you always get the 50%-50% KO-OK sequence. Unfortunatelly, I'm not able to reproduce it on demand, it depends on some unknown conditions.

Additional information:

Channel example (this specific channel -Spain DVB-T- in channels.conf (tzap) format

Antena3 HD:578000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_2_3:FEC_AUTO:QAM_64:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_4:HIERARCHY_NONE:501:503:148

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04.4 LTS
Release: 12.04
Codename: precise

[JoseO (primijos)]

Although right now I'm not able to reproduce this bug, I'm attaching an output example in which the difference of signal strenght between consecutive tunings is noticeable. When the bug appears, in the cases with high signal strength, UNC rate is very high, and in the case of low signal strength, UNC does not occur.

[Thomas Mashos (tgm4883)]

We really do appreciate you opening this ticket to help improve Mythbuntu, but it needs to be closed for a number of reasons. The biggest one is that upstream has moved on to a new version and believes this to be fixed. Could you please verify if this issue still exists in the latest version?

Please do not let the closing of this ticket dissuade you from opening a new ticket if this (or any other) problem occurs with the newer versions.