firmware/general/package/wifibroadcast-ext/files/set_bitrate.sh

#!/bin/sh
#
# set_bitrate.sh
#
# Usage:
#    set_bitrate.sh <target_bitrate_in_kbps> [max_mcs] [--cap <cap_value>] [--max_bw <20|40>]
#
# This script reads FEC settings from /etc/wfb.yaml and allowed bandwidths
# from /etc/vtx_info.yaml, then calls bitrate_calculator.sh (with the given
# target, FEC ratio, max_mcs, and maximum bandwidth limit) to compute the best
# settings (MCS, BW, GI).
#
# The FEC ratio is constructed by swapping the YAML values so that a file with:
#
#   broadcast:
#     fec_n: 12
#     fec_k: 8
#
# produces a ratio "8/12" as expected by bitrate_calculator.sh.
#
# The output from bitrate_calculator.sh is expected in the format:
#      <mcs>:<bw>:<gi>:<fec>
#
# Then the script updates the YAML configuration files and sets the radio
# settings in the running session.
#
# Note: If the candidate BW is 40, and the system’s allowed maximum bandwidth
# (read from /etc/vtx_info.yaml) is 40, then wireless.mode is forced to "HT40+".
#

# --- Parse arguments ---
if [ "$#" -lt 1 ]; then
    echo "Usage: $0 <target_bitrate_in_kbps> [max_mcs] [--cap <cap_value>] [--max_bw <20|40>]"
    exit 1
fi

TARGET="$1"
shift

# Default max_mcs is 5.
max_mcs=5
if [ "$#" -gt 0 ]; then
    case "$1" in
        --*) ;;  # if next arg starts with --
        *) max_mcs="$1"; shift;;
    esac
fi

# Default cap is 20000 kbps unless overridden.
CAP=20000
# Default max_bw for candidate search is 40 (both 20 and 40 will be searched).
MAX_BW=40

while [ "$#" -gt 0 ]; do
    case "$1" in
        --cap)
            shift
            if [ -z "$1" ]; then
                echo "Error: --cap requires a value."
                exit 1
            fi
            CAP="$1"
            shift
            ;;
        --max_bw)
            shift
            if [ -z "$1" ]; then
                echo "Error: --max_bw requires a value (20 or 40)."
                exit 1
            fi
            if [ "$1" != "20" ] && [ "$1" != "40" ]; then
                echo "Error: --max_bw must be either 20 or 40."
                exit 1
            fi
            MAX_BW="$1"
            shift
            ;;
        *)
            echo "Unknown argument: $1"
            exit 1
            ;;
    esac
done

# --- Read FEC settings from /etc/wfb.yaml ---
# Example YAML:
#   broadcast:
#     fec_n: 12
#     fec_k: 8
fec_n=$(yaml-cli -i /etc/wfb.yaml -g .broadcast.fec_n)
fec_k=$(yaml-cli -i /etc/wfb.yaml -g .broadcast.fec_k)
if [ -z "$fec_n" ] || [ -z "$fec_k" ]; then
    echo "Error: Could not read FEC settings from /etc/wfb.yaml."
    exit 1
fi
# Swap the order so that a YAML with fec_n:12 and fec_k:8 produces "8/12".
fec_ratio="${fec_k}/${fec_n}"

# --- Read allowed bandwidths from /etc/vtx_info.yaml ---
# Expected format: [5,10,20,40]
bw_array=$(yaml-cli -i /etc/vtx_info.yaml -g .wifi.bw)
max_bw_allowed=$(echo "$bw_array" | sed 's/[][]//g' | awk -F, '{print $NF}' | tr -d ' ')
if [ -z "$max_bw_allowed" ]; then
    echo "Error: Could not read allowed bandwidths from /etc/vtx_info.yaml."
    exit 1
fi
# Our bitrate_calculator.sh supports 20 and 40 MHz.
if [ "$max_bw_allowed" -ge 40 ]; then
    ALLOWED_BW="40"
else
    ALLOWED_BW="20"
fi

# --- Call bitrate_calculator.sh ---
# We now pass the optional --max_bw parameter.
RESULT=$(bitrate_calculator.sh "$TARGET" "$fec_ratio" "$max_mcs" --cap "$CAP" --gi long --max_bw "$MAX_BW")
#echo ""$TARGET" "$fec_ratio" "$max_mcs" --cap "$CAP" --gi long --max_bw "$MAX_BW" and exit code $?"
if [ $? -ne 0 ]; then
    echo "Error: bitrate_calculator.sh failed. Setting fallback, please retry with a lower bitrate."
    #Fallback
    set_bitrate.sh 2800 0 --max_bw 20
    exit 1
fi

# RESULT is expected in the format: <mcs>:<bw>:<gi>:<fec>
candidate_mcs=$(echo "$RESULT" | cut -d: -f1)
candidate_bw=$(echo "$RESULT" | cut -d: -f2)
candidate_gi=$(echo "$RESULT" | cut -d: -f3)
candidate_fec=$(echo "$RESULT" | cut -d: -f4)

# --- Adjust candidate if its bandwidth exceeds allowed maximum ---
if [ "$candidate_bw" -gt "$max_bw_allowed" ]; then
    echo "Warning: Candidate BW ${candidate_bw} MHz exceeds allowed maximum (${max_bw_allowed} MHz)."
    candidate_bw="$max_bw_allowed"
fi

echo "Setting new configuration:"
echo "   Target bitrate: ${TARGET} kbps"
echo "   Selected settings: MCS=${candidate_mcs}, BW=${candidate_bw} MHz, GI=${candidate_gi}, FEC=${candidate_fec}"
echo "   Bitrate cap: ${CAP} kbps"
echo "   Allowed max BW: ${max_bw_allowed} MHz"

# --- Update YAML configuration ---
# Update /etc/wfb.yaml:
yaml-cli -i /etc/wfb.yaml -s .broadcast.mcs_index "$candidate_mcs" > /dev/null
yaml-cli -i /etc/wfb.yaml -s .broadcast.fec_k "$fec_k" > /dev/null
yaml-cli -i /etc/wfb.yaml -s .broadcast.fec_n "$fec_n" > /dev/null
yaml-cli -i /etc/wfb.yaml -s .broadcast.guard_interval "$candidate_gi" > /dev/null

# Determine wireless mode:
# If the allowed maximum BW is 40, then force mode "HT40+"
if [ "$max_bw_allowed" -eq 40 ]; then
    mode="HT40+"
else
    mode="HT${candidate_bw}"
fi

yaml-cli -i /etc/wfb.yaml -s .wireless.mode "$mode" > /dev/null
yaml-cli -i /etc/wfb.yaml -s .broadcast.bw "$candidate_bw" > /dev/null
yaml-cli -i /etc/majestic.yaml -s .video0.bitrate "$TARGET" > /dev/null

set +e
/etc/init.d/S98wifibroadcast stop
ret=$?

if [ $ret -ne 0 ]; then
    echo "wifibroadcast stop failed (exit code $ret), sleeping 5 seconds before retrying..."
    sleep 5
    /etc/init.d/S98wifibroadcast stop
fi
set -e

curl -s localhost/api/v1/set?video0.bitrate=$TARGET 2> /dev/null

if ! pgrep -f majestic >/dev/null 2>&1; then
    echo "Majestic is not running. Starting majestic..."
    /etc/init.d/S95majestic start
else
    echo "Majestic is running."
fi

set +e
/etc/init.d/S98wifibroadcast start
ret=$?
if [ $ret -ne 0 ]; then
    echo "wifibroadcast start failed (exit code $ret), sleeping 5 seconds before retrying..."
    sleep 5
    /etc/init.d/S98wifibroadcast start
fi
set -e

echo "Bitrate settings applied successfully."