hpc-transcode

High-performance distributed video transcoding with CPU/GPU support

Features

• Distributed transcoding across multiple nodes using SSH
• CPU and GPU (NVIDIA CUDA) support
• Multi-resolution output (e.g. 240p, 480p, 720p)
• Audio track preservation
• HLS output support
• Segment-based processing

Usage

Usage: gpff.bash [options]

Options:
  -d | --work-dir <path>          Set working directory (default: /mnt/data/)
  -i | --input <file>             Input file (must be .mkv or .mp4)
  -b | --ffmpeg-bin-dir <path>    Directory containing ffmpeg binaries
  -l | --local-only               Run locally only
  -g | --with-gpu                 Use GPU acceleration
  -r | --resolutions <list>       Comma-separated resolutions (default: 240,480,720)
  -a | --audio-duration <secs>    Audio segment duration (default: 600)
  -v | --video-duration <secs>    Video segment duration (default: 60)
  -s | --hls-duration <secs>      HLS segment duration (default: 10)
  -V | --version                  Show version information
  -h | --help                     Show help message

Examples:
  # Basic distributed CPU transcoding
  gpff.bash -i video.mkv

  # Local CPU transcoding
  gpff.bash -i video.mkv -l

  # Custom resolutions
  gpff.bash -i video.mkv -r 480,720,1080

  # GPU acceleration with SSD path and custom FFmpeg build
  gpff.bash -i "./Akira.1988.mkv" -g -d "/mnt/data/" -b "/mnt/data/ffmpeg-n7.1-latest-linux64-gpl-7.1/bin/ffmpeg/"

Tip: Always run inside tmux for long transcoding jobs inside the servers

Requirements & Setup

Master Node

1. FFmpeg
   • CPU mode: Any recent build
   • GPU mode: Must have CUDA support (see FFmpeg Setup)
2. GNU Parallel (Installation Guide)
3. OpenSSH Client
4. tmux (recommended)

Worker Nodes

1. FFmpeg (same version/capabilities as master)
2. OpenSSH Server
3. For GPU mode:
   • NVIDIA GPU
   • NVIDIA drivers
   • CUDA Toolkit
   • FFmpeg with CUDA support

FFmpeg Setup

Choose one:

1. BtbN's FFmpeg Builds (GPL with CUDA)
2. Custom build with CUDA
3. Official static builds (verify CUDA support)

⚠️ Package manager versions typically lack CUDA support

Installation Steps

1. Install base packages:

# Master node (Debian/Ubuntu)
sudo apt install parallel tmux openssh-client   # Debian/Ubuntu

# Worker nodes
sudo apt install openssh-server                 # Debian/Ubuntu

# For GPU in Master and Workers: 
sudo apt install nvidia-cuda-toolkit            # Debian/Ubuntu
sudo dnf install cuda-toolkit                   # RHEL/Fedora

2. Setup SSH:

ssh-keygen -t ed25519 -C "transcode-cluster"
ssh-copy-id user@worker123
ssh-copy-id resu@1.2.3.4

3. Configure GNU Parallel (master only):

parallel --will-cite  # Acknowledge citation
echo "user@worker1" >> ~/.parallel/sshloginfile
echo "user@worker2" >> ~/.parallel/sshloginfile
echo "resu@1.2.3.4" >> ~/.parallel/sshloginfile

4. Prepare storage (all nodes):

sudo mkdir -p /mnt/data
sudo mount /dev/nvme0n1 /mnt/data    # Example for NVMe drive

Verification

Test your setup:

# Basic connectivity
parallel --nonall -S '..' hostname

# FFmpeg availability & version
parallel --nonall -S '..' ffmpeg -version

# GPU support (if using)
parallel --nonall -S '..' '
    if command -v nvidia-smi >/dev/null; then
        echo "=== $(hostname) ==="
        nvidia-smi
        ffmpeg -hide_banner -filters | grep cuda
    fi
'

Advanced Usage

Performance Tuning

# Adjust segment durations
gpff.bash -i video.mkv -a 300 -v 30

# Custom resolutions
gpff.bash -i video.mkv -r 360,720,1080

Output Types

• Resolution-specific files (MP4/MKV)
• HLS playlist with all qualities
• Original container format preserved
• All audio tracks included

Troubleshooting

1. GPU Issues

   • Verify CUDA in FFmpeg: ffmpeg -filters | grep cuda
   • Check GPU access: nvidia-smi
   • Confirm matching FFmpeg versions

2. Node Issues

   • Test SSH access
   • Verify work directory exists
   • Check file permissions

3. Processing Issues

   • Segment duration adjustments
   • Audio sync (-fps_mode passthrough)
   • Work directory space

Notes

• This is a proof-of-concept (POC) implementation. Expect potential changes and instability.
• Tested: FFmpeg n7.1+ (GPL build)
• Formats: MKV, MP4
• Subtitles are not handled in this script