What is a Postroll?
A postroll is an advertisement or other inserted segment presented after the primary video finishes. Its placement avoids interrupting the main program but depends on viewers remaining through the end.
How Postrolls work
A postroll is scheduled against the end boundary of a primary media item, either as a separate client-requested asset or as media appended by a server-side assembly process. The player or manifest logic must preserve the transition after the content timeline has completed and report the ad or message independently. It occupies the monetization or promotion stage of playback, where its noninterruptive placement trades reach for a cleaner main-program experience.
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.
Key facts
- 1Client-side insertion can be triggered by the primary media’s ended state, but player teardown, navigation, or a “next item” action may occur first and suppress the request.
- 2Server-side insertion can append postroll media to one continuous stream, yet analytics still need a distinct boundary so content completion is not mistaken for ad completion.
- 3A postroll impression is exposed to end-of-content abandonment by design. Testing should include autoplay restrictions and playlist advancement, not only successful standalone playback.
When Postrolls matter
Choose a postroll for closing promotions when preserving uninterrupted playback is more important than maximum exposure. Completion drop-off can sharply reduce impressions, and autoplay restrictions may block a separate segment.
- 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 at scale
Guidance that holds across every video term in this glossary, not just Postrolls.
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.
Answer these 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.
How Transloadit helps with Postrolls
When Postrolls are relevant to your workflow, you can hand the surrounding video work to Transloadit instead of maintaining the processing stack yourself. Transloadit can transcode, resize, rotate, trim, concatenate, merge, watermark, subtitle, and generate video derivatives, then export each result as part of the same observable workflow.
Support for a specific codec, container, parameter, or combination can vary by Robot and processing stack. Check the linked documentation for the exact inputs and outputs available for your use case.