Formats & Codecs

The source format and the optimization codec set the GPU and CPU decode load, file size, scrub response, maximum resolution, and alpha channel support. WATCHOUT groups codecs into two kinds. Ingest codecs are the source formats you add to the Asset Manager. Playout codecs are the formats the Runners decode during playback. The Optimizer converts each ingest codec to a playout codec, or passes it through unchanged when the source is already a playout codec.

Ingest Codecs

Ingest codecs are what you add to the Asset Manager. When a source file is added, the Optimizer reads its codec and looks it up in the codec mapping table. A source already in a playout codec passes through unchanged. Everything else is transcoded to the default playout codec.

A source codec marked Yes needs a license to optimize. For the HAP family, only plain HAP and HAP Alpha are license-free. For images, only 16-bit needs a license. Without a license the Asset Manager runs in Demo Mode. See Demo Mode.

Codec Mapping

The codec mapping is the rule set that decides which playout codec each ingest codec becomes. The Ingest Codecs table above lists the defaults, each chosen for fast GPU playback. Override any row when a default does not suit the show.

Override a mapping in the Asset Manager Settings dialog. In the Codecs (in → out) section, change a row's output codec. A colored arrow marks a row that differs from its default. See Asset Manager Settings for the dialog controls, including the per-row restore and Reset All.

Overriding a row to a codec other than the source forces a re-encode, even for a codec that would otherwise pass through. Mapping changes apply to future optimizations only. Assets already optimized keep their codec.

To re-optimize an existing asset to a different codec, delete it and re-add the source, or create a new version with the chosen output codec.

Common reasons to override the default:

• Improve playback performance. When a Runner struggles, remap to a more performant codec. For example, HEVC to HAP Q, which decodes faster and plays more simultaneous layers at a larger file size.
• Keep alpha. Route an alpha source to an alpha output (for example, ProRes 4444 Alpha to Notch LC Alpha) to keep transparency through the pipeline.
• Save storage. When disk space runs low, map to HEVC for much smaller files.

Playout Codecs

Playout codecs are the formats the Runners decode during playback. Every asset ends up in one of four families: HAP, Notch LC, HEVC, or Raw. Raw is the uncompressed family, a collection of pixel formats rather than a compressed codec.

Codec Details

Visual fidelity and bandwidth come down to bit depth, compression, and chroma subsampling. This section covers each playout codec in more depth. For the bandwidth and compression of each codec at a given resolution and layer count, see the bandwidth calculator in System Requirements.

HAP

The HAP family stores each frame as a compressed GPU texture, which the Runner's GPU decodes directly. An optional lossless second pass (Snappy) shrinks the file further. The CPU handles that Snappy step, but Snappy is fast and scales well across cores. The CPU is rarely the bottleneck. The read speed of the SSD usually is.

• HAP — lossy compression of 4x4 pixel blocks at 5-6-5 bits per color (32 levels of red, 64 of green, 32 of blue), no alpha. The lightest and fastest codec. Detailed content looks good, but smooth gradients such as a sunset sky can band because of the low color precision.
• HAP Alpha — HAP plus a full alpha channel, at about double the bandwidth.
• HAP Q — the same size as HAP Alpha, but spends that budget on color instead of alpha. Far less banding and smoother gradients. No alpha.
• HAP Q Alpha — HAP Q with a separate alpha channel. Larger than HAP Q.
• HAP R — a newer format for 8-bit RGB with optional alpha. The same bandwidth as HAP Q, with higher quality and fewer artifacts. Encoding is slow. WATCHOUT has no HAP R encoder, so a HAP R asset reaches a Runner only by pass-through.
• HAP Alpha Only — a single channel at the same bandwidth as HAP. WATCHOUT plays it as luma, and it can drive keying. It is the codec marked with an asterisk in the table above.

Notch LC

Notch LC ("Luma and Chroma") is a GPU-decoded codec with full 4:4:4 color at 12-bit luma and 8-bit chroma, plus an optional 8-bit alpha. This gives roughly 10-bit accuracy, a clear step above HAP Q. It compresses to about 1:4 to 1:5 of the source, helped by a lossless second pass (LZ4). That puts it in a similar bandwidth range to HAP Q (about 1:3, or 1 byte per pixel against uncompressed RGB), at higher fidelity. It is the default output for ProRes and a strong replacement for ProRes 4444.

Notch LC is the only codec with a quality level. The five presets run from Good to Best, with Optimal the default. A higher preset raises quality and file size. The compression ratio therefore depends on the preset. Set it in Asset Manager Settings.

Notch LC stores high bit depth but carries no HDR information. For HDR, use HEVC 10-bit or a high-bit-depth Raw format.

HEVC

HEVC (H.265) is a GOP-based delivery codec. It compresses across frames, not just within each frame, which makes decoding much heavier than HAP or Notch LC. It runs on the GPU's dedicated video decoder, or more slowly on the CPU, and a Runner plays fewer simultaneous HEVC layers than HAP or Notch LC. In return the files are far smaller, roughly 10 to 50 times smaller than HAP at similar quality, which makes HEVC the best choice for long-form content. Hardware video decoders top out near 8K (8192 pixels). The 10-bit version carries HDR with the PQ and HLG transfer functions, which makes it the codec for HDR delivery.

Raw

Raw formats are uncompressed. There is no compression loss, except in the 11-bit YUV 4:2:0 format, which subsamples chroma. The higher bit depths, 10-bit and 16-bit, reach the highest fidelity and dynamic range, ideal for LED walls. Raw places the heaviest load on SSD bandwidth.

Track Management and Bandwidth

For source files with both video and audio tracks, the Optimizer offers four track management modes: Skip Audio, Skip Video, Composition, and Individual Assets. A separate Bandwidth Limit caps the transfer rate to Runners. Both are set in the Asset Manager Settings dialog. See Asset Manager Settings for the controls and defaults.

Best Practices

• Deliver ProRes for easy collaboration. Most professional video tools export ProRes directly, while HAP and Notch LC need specialized plugins. ProRes is also more compact than HAP, and WATCHOUT converts it to Notch LC with no visible quality loss.
• Deliver a playout codec to skip transcoding. When your content pipeline can export HAP or Notch LC, the Optimizer passes it through unchanged, which saves optimization time.
• Mismatched frame rates are handled automatically. WATCHOUT blends frames for smooth frame-rate conversion, set per cue by the Frame Blending option. To play a video at the show frame rate without blending, reinterpret its frame rate by creating a new version. This changes metadata only and does not re-encode. See Asset Properties.

Related

• Asset Manager Settings — codec mapping, quality levels, track management, and bandwidth.
• Asset Transfer — how optimized files reach the Runners.
• Asset Properties — output codec, color space, and status of each asset.
• Asset Manager Issues — troubleshooting optimization, transfer, and asset problems.