HAP Codec - GPU-Accelerated Playback

What is HAP?

HAP is a video codec designed specifically for real-time playback. Unlike H.264 or H.265 which require CPU decoding, HAP uses GPU-native compression that your graphics card can decompress directly.

Key Characteristics

• DXT/BC texture compression - Same format used in video games
• Direct GPU upload - No CPU decoding step required
• Developed for live visuals - Created for VJ software and video walls
• Open source - Freely available, widely supported

HAP Format Variants

MultiMon supports all major HAP variants:

Format	Compression	Quality	File Size	Best For
HAP	DXT1 (BC1)	Good	Smallest	RGB video without transparency
HAP Alpha	DXT5 (BC3)	Good	Medium	Videos with alpha channel
HAP Q	BC7 + YCoCg	Excellent	Largest	Highest quality requirements

Choosing a Format

• HAP - Use for most content, best balance of quality and size
• HAP Alpha - Required when your video has transparency
• HAP Q - Use when quality is critical and storage is available

Benefits of HAP

Minimal CPU Usage

Traditional codecs like H.264 require significant CPU power to decode. With HAP:

• GPU handles all decompression
• CPU free for other tasks
• Consistent performance regardless of CPU speed

Smooth Multi-Monitor Playback

HAP excels at multi-monitor setups:

• Single decode even for video walls
• Parallel chunk decoding for large frames
• Frame-accurate timing

Lower Latency

• Compressed texture uploads directly to GPU
• No decode buffer delays
• Ideal for interactive applications

Consistent Timing

• Frame boundaries are explicit
• No variable decode times
• Most reliable format for synchronization

Converting to HAP

Requirements

MultiMon’s built-in converter requires FFmpeg installed on your system.

FFmpeg Installation

The converter automatically searches for FFmpeg in these locations:

1. Bundled location - {MultiMon folder}/ffmpeg/ffmpeg.exe
2. System PATH - Any folder in your PATH environment variable
3. Common locations:
   • C:\ffmpeg\bin\
   • C:\Program Files\ffmpeg\bin\
   • %LOCALAPPDATA%\ffmpeg\bin\

Download FFmpeg from ffmpeg.org and place it in one of these locations.

Using the Converter

1. Open MultiMon’s Convert to HAP dialog
2. Select your source video file
3. Choose HAP variant (HAP, HAP Alpha, or HAP Q)
4. Select output location
5. Click Convert

Manual FFmpeg Command

If you prefer command line, use:

# Standard HAP (best balance)
ffmpeg -i input.mp4 -c:v hap -format hap -chunks 4 output.mov

# HAP Alpha (with transparency)
ffmpeg -i input.mov -c:v hap -format hap_alpha -chunks 4 output.mov

# HAP Q (highest quality)
ffmpeg -i input.mp4 -c:v hap -format hap_q -chunks 4 output.mov

Conversion Options

Option	Description	Recommended
-format	HAP variant	hap_q for quality, hap for size
-chunks	Parallel decode chunks	4 (default)
-threads	CPU threads for encoding	0 (auto)
-c:a copy	Keep original audio	Yes

Using HAP Files

Loading HAP Videos

HAP files work like any other video:

1. Drag and drop onto a monitor panel
2. MultiMon automatically detects HAP format
3. Uses the dedicated GPU-accelerated renderer

Automatic Detection

MultiMon identifies HAP files by:

1. Checking file extension (.mov, .avi)
2. Scanning file header for HAP codec signatures
3. Routing to appropriate playback engine

Recommended Containers

Container	Extension	Notes
QuickTime	.mov	Recommended, best compatibility
AVI	.avi	Alternative option

File Size Considerations

HAP files are significantly larger than H.264/H.265. Plan your storage accordingly.

Approximate File Sizes (1080p @ 30fps)

Format	Size per Second	1 Minute	1 Hour
H.264	~1-2 MB	60-120 MB	3.6-7.2 GB
HAP	~6-8 MB	360-480 MB	21-28 GB
HAP Alpha	~12-16 MB	720-960 MB	43-57 GB
HAP Q	~12-16 MB	720-960 MB	43-57 GB

Storage Recommendations

• SSD strongly recommended - HAP’s high bitrate benefits from fast storage
• NVMe preferred - For 4K or multi-video playback
• RAID for long content - Consider RAID 0 for extended video walls

When to Use HAP

Ideal Use Cases

• Video walls - Single decode, GPU-efficient
• 4K and higher resolution - CPU savings significant
• Looping content - Consistent frame timing
• Multi-monitor setups - Reliable synchronization
• Live events - Predictable performance

When H.264 May Suffice

• Single monitor playback
• Storage-constrained situations
• One-time presentations
• Preview/editing workflows

Performance Comparison

CPU Usage (4K playback)

Codec	Typical CPU	Notes
H.264	30-60%	Varies by content
H.265	40-70%	More efficient but heavier decode
HAP	5-15%	Mostly I/O, minimal decode
HAP Q	5-15%	Same as HAP

GPU Memory (per 1080p frame)

Format	VRAM per Frame
HAP (DXT1)	~0.5 MB
HAP Alpha (DXT5)	~1 MB
HAP Q (BC7)	~1 MB

Troubleshooting

Video Won’t Play

• Verify FFmpeg detected HAP correctly during conversion
• Check file isn’t corrupted (try playing in VLC)
• Ensure GPU drivers are up to date

Stuttering Playback

• Move files to SSD
• Check disk isn’t at capacity
• Close other disk-intensive applications

Conversion Fails

• Verify FFmpeg is properly installed
• Check source video plays correctly
• Ensure sufficient disk space for output

Next Steps

• Set up a Video Wall using HAP files
• Configure Audio Routing for multi-channel setups
• Review Settings for hardware acceleration modes and performance options