ffmpeg-video-transcoding-pipeline

FFmpeg Video Transcoding Pipeline Skill Guide

This skill standardizes automated multi-bitrate transcoding pipelines for video-on-demand (VOD) streaming infrastructure.

1. Adaptive Bitrate (ABR) Transcoding Ladder

[ Raw Master Video ] (ProRes / High-Bitrate MP4)
         |
         +---> FFmpeg Multi-Output Transcoder
                 |
                 |-- 1080p @ 4500 kbps (fMP4 / H.264)
                 |-- 720p  @ 2500 kbps (fMP4 / H.264)
                 |-- 480p  @ 1200 kbps (fMP4 / H.264)
                 |-- 360p  @ 600 kbps  (fMP4 / H.264)
                 |-- Audio: AAC 128 kbps (EBU R128 Normalized)
                 |
                 v
[ Master Playlist: master.m3u8 / manifest.mpd ]

2. Production FFmpeg Commands & Scripts

A. Production Multi-Bitrate HLS Generation Script

#!/usr/bin/env bash
set -euo pipefail

INPUT_FILE="${1:?Usage: $0 <input_video.mp4> <output_dir>}"
OUT_DIR="${2:?Usage: $0 <input_video.mp4> <output_dir>}"

mkdir -p "${OUT_DIR}"

ffmpeg -hide_banner -y -i "${INPUT_FILE}" \
  # Video filter: scale and keyframe alignment (2-second GOP at 30fps = 60 frames)
  -filter_complex \
  "[0:v]split=3[v1080][v720][v480]; \
   [v1080]scale=w=1920:h=1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2[v1080out]; \
   [v720]scale=w=1280:h=720:force_original_aspect_ratio=decrease,pad=1280:720:(ow-iw)/2:(oh-ih)/2[v720out]; \
   [v480]scale=w=854:h=480:force_original_aspect_ratio=decrease,pad=854:480:(ow-iw)/2:(oh-ih)/2[v480out]" \
  \
  # 1080p Stream
  -map "[v1080out]" -c:v:0 libx264 -preset slow -b:v:0 4500k -maxrate:v:0 4800k -bufsize:v:0 9000k \
  -g 60 -keyint_min 60 -sc_threshold 0 \
  \
  # 720p Stream
  -map "[v720out]" -c:v:1 libx264 -preset slow -b:v:1 2500k -maxrate:v:1 2700k -bufsize:v:1 5000k \
  -g 60 -keyint_min 60 -sc_threshold 0 \
  \
  # 480p Stream
  -map "[v480out]" -c:v:2 libx264 -preset slow -b:v:2 1200k -maxrate:v:2 1350k -bufsize:v:2 2400k \
  -g 60 -keyint_min 60 -sc_threshold 0 \
  \
  # Audio Stream (Normalized)
  -map a:0 -c:a aac -b:a 128k -ar 48000 -ac 2 \
  -af "loudnorm=I=-16:TP=-1.5:LRA=11" \
  \
  # HLS Output Packaging
  -f hls \
  -hls_time 4 \
  -hls_playlist_type vod \
  -hls_flags independent_segments \
  -hls_segment_type fmp4 \
  -hls_segment_filename "${OUT_DIR}/stream_%v_data%03d.m4s" \
  -master_pl_name master.m3u8 \
  -var_stream_map "v:0,a:0 v:1,a:0 v:2,a:0" \
  "${OUT_DIR}/stream_%v.m3u8"

echo "Transcoding completed. Manifest at: ${OUT_DIR}/master.m3u8"