lesavka/scripts/manual/client_rct_remote_capture.sh

#!/usr/bin/env bash
# scripts/manual/client_rct_remote_capture.sh
# Remote Tethys-side UVC/UAC capture helper for run_client_to_rct_transport_probe.sh.
set -euo pipefail
remote_capture=$1
capture_seconds=$2
width=$3
height=$4
fps=$5
capture_stack=$6
pulse_tool=$7
video_mode=$8
anchor_silence=$9
preroll_discard=${10}
preroll_settle=${11}
ready_settle=${12}
ready_marker=${13}

resolve_video_device() {
  find /dev/v4l/by-id -maxdepth 1 -type l \
    -name 'usb-Lesavka_Lesavka_Composite*video-index0' | sort | head -n 1
}

resolve_pulse_source() {
  pactl list short sources 2>/dev/null \
    | awk '
      /alsa_input\..*Lesavka_Lesavka_Composite/ { print $2; found=1; exit }
      /Lesavka_Lesavka_Composite/ && $2 !~ /\.monitor$/ && !fallback { fallback=$2 }
      END {
        if (found) exit 0
        if (fallback != "") { print fallback; exit 0 }
        exit 1
      }
    '
}

current_video_profile() {
  v4l2-ctl -d "${video_device}" --all 2>/dev/null \
    | awk '
      /Width\/Height[[:space:]]*:/ {
        split($0, a, ":")
        gsub(/^[ \t]+/, "", a[2])
        split(a[2], wh, "/")
        width=wh[1]
        height=wh[2]
        next
      }
      /Frames per second[[:space:]]*:/ {
        split($0, a, ":")
        gsub(/^[ \t]+/, "", a[2])
        split(a[2], fps_parts, "\\.")
        fps=fps_parts[1]
      }
      END {
        if (width && height && fps) {
          printf "%s %s %s\n", width, height, fps
          exit 0
        }
        exit 1
      }
    '
}

gst_audio_mixer_element() {
  if gst-inspect-1.0 audiomixer 2>/dev/null | grep -q 'ignore-inactive-pads'; then
    printf 'audiomixer name=amix ignore-inactive-pads=true'
  else
    printf 'audiomixer name=amix'
  fi
}

run_preroll() {
  local video_device=$1
  local seconds=$2
  [[ "${seconds}" =~ ^[0-9]+$ && "${seconds}" -gt 0 ]] || return 0
  printf 'discarding %ss of post-enumeration capture before probe\n' "${seconds}" >&2
  timeout --kill-after=5 --signal=INT "$((seconds + 5))" \
    gst-launch-1.0 -q -e v4l2src device="${video_device}" do-timestamp=true num-buffers="$((fps * seconds))" \
      ! "image/jpeg,width=${width},height=${height},framerate=${fps}/1" ! fakesink \
    >/dev/null 2>&1 || true
  if [[ "${preroll_settle}" =~ ^[0-9]+$ && "${preroll_settle}" -gt 0 ]]; then
    printf 'settling %ss after preroll discard\n' "${preroll_settle}" >&2
    sleep "${preroll_settle}"
  fi
}

run_gst_pulse_capture() {
  local video_device=$1
  local pulse_source=$2
  local video_caps="image/jpeg,width=${width},height=${height},framerate=${fps}/1"
  local decode_chain="jpegdec !"
  local audio_mixer
  audio_mixer="$(gst_audio_mixer_element)"
  local audio_anchor=()
  if [[ "${anchor_silence}" != "0" ]]; then
    printf 'anchoring Pulse capture audio timeline with generated silence\n' >&2
    audio_anchor=(audiotestsrc wave=silence is-live=true do-timestamp=true ! "audio/x-raw,rate=48000,channels=2" ! queue ! amix.)
  fi
  printf 'capture_start_unix_ns=%s\n' "$(date +%s%N)" >&2
  if [[ "${video_mode}" == "cfr" ]]; then
    timeout --kill-after=5 --signal=INT "$((capture_seconds + 3))" \
      gst-launch-1.0 -q -e \
        matroskamux name=mux ! filesink location="${remote_capture}" \
        v4l2src device="${video_device}" do-timestamp=true ! ${video_caps} ! \
          ${decode_chain} videoconvert ! videorate ! video/x-raw,framerate="${fps}"/1 ! \
          x264enc tune=zerolatency speed-preset=ultrafast key-int-max=1 bitrate=5000 ! \
          h264parse ! queue ! mux. \
        ${audio_mixer} ! audio/x-raw,rate=48000,channels=2 ! queue ! mux. \
        "${audio_anchor[@]}" \
        pulsesrc device="${pulse_source}" do-timestamp=true ! audio/x-raw,rate=48000,channels=2 ! \
          audioconvert ! audioresample ! audio/x-raw,rate=48000,channels=2 ! queue ! amix. &
  else
    timeout --kill-after=5 --signal=INT "$((capture_seconds + 3))" \
      gst-launch-1.0 -q -e \
        matroskamux name=mux ! filesink location="${remote_capture}" \
        v4l2src device="${video_device}" do-timestamp=true ! ${video_caps} ! queue ! mux. \
        ${audio_mixer} ! audio/x-raw,rate=48000,channels=2 ! queue ! mux. \
        "${audio_anchor[@]}" \
        pulsesrc device="${pulse_source}" do-timestamp=true ! audio/x-raw,rate=48000,channels=2 ! \
          audioconvert ! audioresample ! audio/x-raw,rate=48000,channels=2 ! queue ! amix. &
  fi
  local capture_pid=$!
  sleep "${ready_settle}"
  printf '%s\n' "${ready_marker}" >&2
  wait "${capture_pid}"
}

run_ffmpeg_pulse_capture() {
  local video_device=$1
  local pulse_source=$2
  printf 'capture_start_unix_ns=%s\n' "$(date +%s%N)" >&2
  timeout --kill-after=5 --signal=INT "$((capture_seconds + 5))" \
    ffmpeg -nostdin -hide_banner -loglevel error -y \
      -thread_queue_size 1024 -f video4linux2 -framerate "${fps}" \
      -video_size "${width}x${height}" -input_format mjpeg -i "${video_device}" \
      -thread_queue_size 1024 -f pulse -i "${pulse_source}" \
      -map 0:v:0 -map 1:a:0 -t "${capture_seconds}" \
      -c:v copy -c:a pcm_s16le "${remote_capture}" </dev/null &
  local capture_pid=$!
  sleep "${ready_settle}"
  printf '%s\n' "${ready_marker}" >&2
  wait "${capture_pid}"
}

rm -f "${remote_capture}"
video_device="$(resolve_video_device)"
if [[ -z "${video_device}" ]]; then
  printf 'Lesavka UVC video device not found on RCT host; refusing unrelated capture devices.\n' >&2
  exit 2
fi
if [[ "${width}" == "0" || "${height}" == "0" || "${fps}" == "0" ]]; then
  if read -r width height fps < <(current_video_profile); then
    :
  else
    printf 'unable to auto-detect current UVC mode; set LESAVKA_CLIENT_RCT_MODE=WIDTHxHEIGHT@FPS\n' >&2
    exit 2
  fi
fi
printf 'using video device: %s\n' "${video_device}" >&2
printf 'using video mode: %sx%s @ %s fps (mjpeg)\n' "${width}" "${height}" "${fps}" >&2

case "${capture_stack}" in
  pulse)
    pulse_source="$(resolve_pulse_source)"
    if [[ -z "${pulse_source}" ]]; then
      printf 'Lesavka Pulse audio source not found; refusing timing-sensitive fallback.\n' >&2
      exit 2
    fi
    printf 'using Pulse source: %s\n' "${pulse_source}" >&2
    run_preroll "${video_device}" "${preroll_discard}"
    case "${pulse_tool}" in
      gst) run_gst_pulse_capture "${video_device}" "${pulse_source}" ;;
      ffmpeg) run_ffmpeg_pulse_capture "${video_device}" "${pulse_source}" ;;
      *)
        printf 'unsupported REMOTE_PULSE_CAPTURE_TOOL=%s for client-to-RCT probe; use gst or ffmpeg\n' "${pulse_tool}" >&2
        exit 2
        ;;
    esac
    ;;
  *)
    printf 'unsupported REMOTE_CAPTURE_STACK=%s for client-to-RCT probe\n' "${capture_stack}" >&2
    exit 2
    ;;
esac