What is a Midroll?
A midroll is an advertisement or inserted segment presented during the primary audio or video program. Its placement distinguishes it from preroll content before the program and postroll content after it.
How Midrolls work
A midroll creates a scheduled interruption point inside continuous programming where advertising or another inserted item may play. The break can be assembled by the application, stitched into the stream upstream, or signaled for a downstream distributor to replace. Cue timing must align content, manifests, tracking, and playback state. Publishing systems place these opportunities after editorial timing and before final stream delivery or ad decisioning.
Key facts
- 1Client-side insertion switches the player to separately requested media, while server-side insertion can present ads and program content through one stream. Their tracking and failure behavior differ.
- 2Markers such as SCTE-35 messages or manifest date-range metadata can communicate break opportunities, but the player or distribution service decides how to interpret them.
- 3Seeking across a break, ad-decision timeouts, and mismatched segment boundaries are distinct edge cases. Each needs an explicit policy to avoid repeated ads or timeline jumps.
When Midrolls matter
Schedule midroll opportunities at natural breaks to limit disruption while meeting advertising requirements. Poor timing or failed ad transitions can interrupt playback, lose viewer context, and distort measurement.
Common use cases for video
These examples cover video broadly, not specifically Midrolls.
- Preparing uploaded video for web, mobile, connected-TV, social, or editorial playback.
- Creating clips, thumbnails, captions, alternate aspect ratios, and adaptive renditions.
- Normalizing camera, screen-recording, and user-generated files into predictable outputs.
Working with video
This guidance covers video broadly, not just Midrolls.
A demuxer separates tracks from the container, decoders turn compressed streams into frames or samples, and filters apply spatial or temporal changes. Encoders compress the transformed tracks before a muxer writes the chosen output container.
Video compatibility is the product of codec, container, profile, level, frame rate, color, audio, and subtitles. Validate the complete output on target devices because a playable file on one decoder may fail or look different on another.
What you gain
- Standardized derivatives make diverse source files playable on target devices.
- A retained master can feed many resolutions, aspect ratios, codecs, and channels.
- Automated inspection and transformation make large upload volumes consistent.
What it costs
- More efficient codecs can lower bitrate at similar quality but usually cost more compute and may have narrower support.
- Higher resolutions and frame rates preserve more detail and motion while increasing processing and delivery requirements.
- Fast encoding settings improve throughput but can produce larger files or lower quality than slower analysis.
Before production
- 1Inspect codec, container, dimensions, frame rate, color, audio, and subtitle tracks.
- 2Test visual quality and playback support across the slowest and oldest target devices.
- 3Preserve a suitable master before applying lossy, destructive, or delivery-specific changes.