The values are returned via dtv_property.stat. If the property is supported, dtv_property.stat.len is bigger than zero.
For most delivery systems, dtv_property.stat.len will be 1 if the stats is supported, and the properties will return a single value for each parameter.
It should be noted, however, that new OFDM delivery systems like ISDB can use different modulation types for each group of carriers. On such standards, up to 3 groups of statistics can be provided, and dtv_property.stat.len is updated to reflect the “global” metrics, plus one metric per each carrier group (called “layer” on ISDB).
So, in order to be consistent with other delivery systems, the first value at dtv_property.stat.dtv_stats array refers to the global metric. The other elements of the array represent each layer, starting from layer A(index 1), layer B (index 2) and so on.
The number of filled elements are stored at dtv_property.stat.len.
Each element of the dtv_property.stat.dtv_stats array consists on two elements:
Indicates the signal strength level at the analog part of the tuner or of the demod.
Possible scales for this metric are:
Indicates the Signal to Noise ratio for the main carrier.
Possible scales for this metric are:
Measures the number of bit errors before the forward error correction (FEC) on the inner coding block (before Viterbi, LDPC or other inner code).
This measure is taken during the same interval as DTV_STAT_PRE_TOTAL_BIT_COUNT.
In order to get the BER (Bit Error Rate) measurement, it should be divided by DTV_STAT_PRE_TOTAL_BIT_COUNT.
This measurement is monotonically increased, as the frontend gets more bit count measurements. The frontend may reset it when a channel/transponder is tuned.
Possible scales for this metric are:
Measures the amount of bits received before the inner code block, during the same period as DTV_STAT_PRE_ERROR_BIT_COUNT measurement was taken.
It should be noted that this measurement can be smaller than the total amount of bits on the transport stream, as the frontend may need to manually restart the measurement, losing some data between each measurement interval.
This measurement is monotonically increased, as the frontend gets more bit count measurements. The frontend may reset it when a channel/transponder is tuned.
Possible scales for this metric are:
Measures the number of bit errors after the forward error correction (FEC) done by inner code block (after Viterbi, LDPC or other inner code).
This measure is taken during the same interval as DTV_STAT_POST_TOTAL_BIT_COUNT.
In order to get the BER (Bit Error Rate) measurement, it should be divided by DTV_STAT_POST_TOTAL_BIT_COUNT.
This measurement is monotonically increased, as the frontend gets more bit count measurements. The frontend may reset it when a channel/transponder is tuned.
Possible scales for this metric are:
Measures the amount of bits received after the inner coding, during the same period as DTV_STAT_POST_ERROR_BIT_COUNT measurement was taken.
It should be noted that this measurement can be smaller than the total amount of bits on the transport stream, as the frontend may need to manually restart the measurement, losing some data between each measurement interval.
This measurement is monotonically increased, as the frontend gets more bit count measurements. The frontend may reset it when a channel/transponder is tuned.
Possible scales for this metric are:
Measures the number of block errors after the outer forward error correction coding (after Reed-Solomon or other outer code).
This measurement is monotonically increased, as the frontend gets more bit count measurements. The frontend may reset it when a channel/transponder is tuned.
Possible scales for this metric are:
Measures the total number of blocks received during the same period as DTV_STAT_ERROR_BLOCK_COUNT measurement was taken.
It can be used to calculate the PER indicator, by dividing DTV_STAT_ERROR_BLOCK_COUNT by DTV-STAT_TOTAL_BLOCK_COUNT.
Possible scales for this metric are: