update

README.md

@@ -51,6 +51,14 @@ git clone https://huggingface.co/datasets/Alibaba-NLP/XVBench
 
 XVBench provides question-answer annotations and reference clip filenames. To use the benchmark with the original video evidence, please download the corresponding source videos from the [HowTo100M official website](https://www.di.ens.fr/willow/research/howto100m/) and follow the HowTo100M usage instructions. The `video_name` and `reference` fields in `xvbench.jsonl` are used to identify the source video and supporting clips.
 
+## Video Preprocess
+
+We provide `split_video.sh`, a simplified video preprocessing script following the same fixed-duration splitting strategy as the VRAG video corpus pipeline. It converts non-MP4 videos to temporary MP4 files when needed, splits each source video into 60-second clips by default, and writes filenames in the same format as the `reference` field: `video_id_____1.mp4`, `video_id_____2.mp4`, and so on.
+
+```bash
+./split_video.sh -i /path/to/howto100m/videos -o ./video_chunks -d 60
+```
+
 ## Dataset Structure
 
 The dataset is provided as `xvbench.jsonl`. Each line is a JSON object with the following fields:

split_video.sh

@@ -0,0 +1,136 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+INPUT_DIR=""
+OUTPUT_DIR="./video_chunks"
+CHUNK_DURATION=60
+MIN_SOURCE_DURATION=1
+MIN_CHUNK_DURATION=2
+
+usage() {
+  cat <<'EOF'
+Usage: ./split_video.sh -i INPUT_DIR [-o OUTPUT_DIR] [-d CHUNK_DURATION]
+
+Split videos into fixed-duration chunks for XVBench-style video evidence.
+
+Options:
+  -i INPUT_DIR        Directory containing source videos.
+  -o OUTPUT_DIR       Directory for output clips. Default: ./video_chunks
+  -d CHUNK_DURATION   Clip duration in seconds. Default: 60
+  -h                  Show this help message.
+EOF
+}
+
+check_dependencies() {
+  command -v ffmpeg >/dev/null 2>&1 || { echo "ffmpeg is required." >&2; exit 1; }
+  command -v ffprobe >/dev/null 2>&1 || { echo "ffprobe is required." >&2; exit 1; }
+}
+
+duration_seconds() {
+  ffprobe -v error -show_entries format=duration \
+    -of default=noprint_wrappers=1:nokey=1 "$1" 2>/dev/null || echo "0"
+}
+
+float_lt() {
+  awk -v a="$1" -v b="$2" 'BEGIN { exit !(a < b) }'
+}
+
+float_add() {
+  awk -v a="$1" -v b="$2" 'BEGIN { printf "%.3f", a + b }'
+}
+
+parse_args() {
+  while getopts ":i:o:d:h" opt; do
+    case "$opt" in
+      i) INPUT_DIR="$OPTARG" ;;
+      o) OUTPUT_DIR="$OPTARG" ;;
+      d) CHUNK_DURATION="$OPTARG" ;;
+      h) usage; exit 0 ;;
+      *) usage; exit 1 ;;
+    esac
+  done
+
+  if [[ -z "$INPUT_DIR" || ! -d "$INPUT_DIR" ]]; then
+    echo "A valid input directory is required. Use -i INPUT_DIR." >&2
+    exit 1
+  fi
+
+  if ! [[ "$CHUNK_DURATION" =~ ^[0-9]+$ ]] || [[ "$CHUNK_DURATION" -le 0 ]]; then
+    echo "CHUNK_DURATION must be a positive integer." >&2
+    exit 1
+  fi
+}
+
+split_one_video() {
+  local input_file="$1"
+  local filename extension base_name total_duration process_file temp_mp4
+  local start_time=0
+  local chunk_index=1
+
+  filename=$(basename "$input_file")
+  extension="${filename##*.}"
+  extension=$(echo "$extension" | tr '[:upper:]' '[:lower:]')
+  base_name="${filename%.*}"
+  temp_mp4=""
+
+  total_duration=$(duration_seconds "$input_file")
+  if [[ -z "$total_duration" || "$total_duration" == "0" ]] || float_lt "$total_duration" "$MIN_SOURCE_DURATION"; then
+    echo "Skip invalid or too-short video: $filename" >&2
+    return 1
+  fi
+
+  if [[ "$extension" != "mp4" ]]; then
+    temp_mp4="${OUTPUT_DIR}/.tmp_${base_name}_$$.mp4"
+    if ! ffmpeg -i "$input_file" -c:v libx264 -c:a aac -strict experimental \
+      "$temp_mp4" -y -loglevel error; then
+      rm -f "$temp_mp4"
+      echo "Failed to convert video: $filename" >&2
+      return 1
+    fi
+    process_file="$temp_mp4"
+  else
+    process_file="$input_file"
+  fi
+
+  while float_lt "$start_time" "$total_duration"; do
+    local output_file chunk_duration
+    output_file="${OUTPUT_DIR}/${base_name}_____${chunk_index}.mp4"
+
+    if ffmpeg -i "$process_file" -ss "$start_time" -t "$CHUNK_DURATION" \
+      -c copy "$output_file" -y -loglevel error; then
+      chunk_duration=$(duration_seconds "$output_file")
+      if [[ -z "$chunk_duration" ]] || float_lt "$chunk_duration" "$MIN_CHUNK_DURATION"; then
+        rm -f "$output_file"
+      fi
+    else
+      rm -f "$output_file"
+      echo "Failed to create chunk: $output_file" >&2
+    fi
+
+    start_time=$(float_add "$start_time" "$CHUNK_DURATION")
+    chunk_index=$((chunk_index + 1))
+  done
+
+  [[ -n "$temp_mp4" && -f "$temp_mp4" ]] && rm -f "$temp_mp4"
+}
+
+main() {
+  parse_args "$@"
+  check_dependencies
+  mkdir -p "$OUTPUT_DIR"
+
+  while IFS= read -r -d '' input_file; do
+    local filename
+    filename=$(basename "$input_file")
+    if [[ "$filename" =~ _____[0-9]+\.mp4$ ]]; then
+      continue
+    fi
+    split_one_video "$input_file" || true
+  done < <(find "$INPUT_DIR" -maxdepth 1 -type f \( \
+    -iname "*.mp4" -o -iname "*.avi" -o -iname "*.mkv" -o \
+    -iname "*.mov" -o -iname "*.wmv" -o -iname "*.flv" -o \
+    -iname "*.webm" \) -print0)
+}
+
+main "$@"