Channels configuration for rmt examples in esp-idf-5.2 do not follow structure definition in rmt_tx.h
rmt_tx_channel_config_t tx_chan_config = {
.clk_src = RMT_CLK_SRC_DEFAULT, // select clock source
.gpio_num = STEP_MOTOR_GPIO_STEP,
.mem_block_symbols = 64,
.resolution_hz = STEP_MOTOR ...

Documentation error about RMT_symbol
Drawing of bit levels should not be in lsb positions of words but in msb positions
rmt doc.png
According to rmt_types.h
It seems that level bits are msb and not lsb
/**
* @brief The layout of RMT symbol stored in memory, which is decided by the hardware ...

In esp-idf v5.2.1 the rmt driver has been modified and some examples are provided in the SDK.
In ir_nec_transceiver example I modified the example to send a nec ir with address 0 and command 0
const ir_nec_scan_code_t scan_code = {
.address = 0x0,
.command = 0x0,
};
The nec_encoder do not seem ...