FAST (Free Ad-Supported Streaming Television), SVOD (Subscription Video on Demand), and AVOD (Ad-Supported Video on Demand) are not just business model labels. Each model has distinct technical requirements for content delivery, ad insertion, DRM, user experience, and backend architecture. Choosing a model — or combining them — determines the engineering decisions downstream.
This guide covers the technical differences that matter when building and operating OTT services under each model.
FAST: linear channels, ad-supported
FAST channels simulate the traditional linear TV experience: a pre-programmed schedule of content that plays continuously. Viewers tune in and watch what is on, like cable TV, but delivered over the internet and free with ads.
Content delivery architecture
FAST channels are live streams, technically. The content is pre-recorded (VOD assets), but it is stitched into a continuous live stream by a channel playout system.
The playout architecture:
- Content scheduler — determines what plays when, typically managed by a CMS with an EPG (Electronic Program Guide) interface
- Playout engine — stitches VOD assets into a continuous live output, handling transitions, bumpers, and ad break markers
- Live encoder — encodes the playout output as a live stream (HLS/DASH)
- CDN delivery — distributes the live stream to viewers, same as any live streaming delivery
Alternative: manifest-level stitching. Instead of re-encoding VOD assets into a live stream, some FAST platforms stitch pre-encoded VOD segments into a live-like manifest. The viewer’s player receives a manifest that references VOD segments in scheduled order. This avoids the re-encoding cost but requires precise segment-level timing control.
Ad insertion for FAST
FAST monetisation is entirely ad-driven. Ad breaks are pre-defined in the channel schedule (typically matching traditional TV patterns: 2-3 minutes every 8-12 minutes).
SSAI is the standard for FAST channels because:
- The content is a continuous live stream — interrupting it for CSAI ad loads would break the linear experience
- Ad blocker resistance matters when ads are the only revenue source
- Smart TV platforms (Roku, Samsung Tizen, LG webOS) handle SSAI seamlessly
DRM for FAST
Most FAST content does not require DRM. The content is free and ad-supported — there is no paywall to protect. However, some content owners require DRM even for FAST distribution as a contractual condition. When DRM is required, the implementation is the same as SVOD/AVOD but adds cost per stream.
User experience
FAST channels are designed for passive viewing. The UX is:
- Channel guide (EPG) showing what is on across all channels
- Tune to a channel and watch — no content selection, no playback controls (except pause/resume and channel switch)
- Discovery through channel surfing, not search or browse
SVOD: subscription-gated on-demand
SVOD is the Netflix/Disney+ model: users pay a subscription fee and get access to a library of on-demand content.
Content delivery architecture
SVOD delivery is standard VOD:
- Content is pre-encoded into a full ABR ladder with multiple codecs and resolutions
- Segments are cached at CDN edges
- The player requests segments based on ABR decisions
- DRM protects content in transit and at rest on the device
The architectural emphasis is on:
- Quality. Premium content requires high bitrates, 4K/HDR, Dolby Atmos audio. The encoding pipeline needs to support the full quality range.
- Availability. Downtime means subscriber churn. The playback path must be highly available with redundancy at every layer.
- Global scale. SVOD services typically operate globally. CDN coverage, geo-aware routing, and regional edge infrastructure matter.
No ad integration
SVOD does not include ads (though hybrid models like ad-supported tiers add them). Without ads, the video pipeline is simpler: no ad decisioning, no SSAI, no ad tracking. The tradeoff is that all revenue comes from subscriptions, so subscriber acquisition and retention are the business-critical metrics.
DRM requirements
SVOD content almost always requires DRM. Studio licensing agreements mandate specific DRM systems and robustness levels:
- Premium content (first-run movies, exclusive originals) requires Widevine L1, FairPlay, and PlayReady SL3000
- Some content owners require forensic watermarking for high-value titles
- Output protection rules (HDCP enforcement, screen capture prevention) are contractually required
The multi-DRM architecture is a core infrastructure component for SVOD.
Concurrent stream management
SVOD services limit concurrent streams per account (typically 1-4 depending on subscription tier). This requires server-side session tracking with heartbeat-based validation, which adds backend complexity.
AVOD: free on-demand with ads
AVOD provides on-demand content for free, monetised with ads. Tubi, Pluto TV’s on-demand library, and YouTube are examples.
Content delivery architecture
AVOD delivery is similar to SVOD — pre-encoded VOD content with ABR delivery — but with ad insertion integrated into the playback experience.
Ad insertion for AVOD
AVOD uses both SSAI and CSAI, depending on the platform and implementation:
- Pre-roll ads before content playback (CSAI or SSAI)
- Mid-roll ads at defined points within the content (SSAI is preferred for seamless experience)
- Post-roll ads after content ends (less common, lower value)
The ad load (minutes of ads per hour of content) is a business decision that affects viewer retention. Too many ads drives viewers away. Too few ads does not generate enough revenue. The technical system must support configurable ad load per content item and per viewer segment.
DRM for AVOD
AVOD content DRM requirements vary:
- Licensed content from studios typically requires DRM even in an AVOD context
- User-generated or non-premium content may not require DRM
- Hybrid approach: apply DRM only to content that contractually requires it, reducing per-stream DRM license costs
Technical comparison
| Characteristic | FAST | SVOD | AVOD |
|---|---|---|---|
| Content delivery model | Live stream (playout-based) | VOD (pre-encoded, on-demand) | VOD with ad breaks |
| Ad integration | Required (primary revenue) | None (or hybrid tier) | Required (primary revenue) |
| Ad insertion approach | SSAI (standard) | N/A | SSAI or CSAI |
| DRM requirement | Optional (content-dependent) | Required (standard) | Varies by content |
| User experience | Linear (tune in, watch what is on) | On-demand (browse, select, watch) | On-demand with ad breaks |
| CDN pattern | Live edge (all viewers same content) | Long-tail VOD (distributed access) | Long-tail VOD |
| Backend complexity | Playout engine + EPG + SSAI | Catalog + entitlement + DRM + session mgmt | Catalog + ad decisioning + SSAI/CSAI |
| Infrastructure cost driver | Playout and live encoding | CDN egress and DRM licenses | CDN egress and ad infra |
Hybrid models
Most services in 2026 are hybrid, combining multiple models:
- SVOD with ad-supported tier (Netflix, Disney+): lower-priced subscription with ads, premium tier without. This requires the full SVOD infrastructure plus ad insertion for the ad tier.
- AVOD with FAST channels (Tubi, Pluto TV): on-demand library plus linear channels. This requires both VOD and live streaming infrastructure.
- SVOD with FAST channels (Peacock): subscriber-only content plus free linear channels.
Each combination multiplies the technical requirements. A service with SVOD + AVOD + FAST needs: VOD encoding and delivery, live playout, SSAI, DRM, session management, and separate UX flows for each model.
Platform implications
Each model interacts differently with connected TV platforms:
- FAST is well-supported on Roku (The Roku Channel is a FAST service), Samsung TV Plus (built into Samsung TVs), and LG Channels (built into LG webOS). Platform-native FAST integration can provide significant distribution.
- SVOD requires in-app purchase or subscriber authentication on each platform. Platform revenue share (typically 15-30% on Roku, Apple, Google) affects economics.
- AVOD on Roku requires integration with the Roku Advertising Framework (RAF). On other platforms, standard SSAI or CSAI works.
The business model choice affects not just the technical architecture but the platform relationships, certification requirements, and go-to-market strategy. Choose the model based on your content library, audience, and monetisation goals, and build the streaming app architecture to support it.