Best Substack Video Upload Settings 2026: Codec, Bitrate and Size
Quick answer: For fast Substack video processing, export H.264 video at 1080p or 1440p, keep bitrate at 8 Mbps or below, use AAC audio, and choose a frame rate between 5 and 120 fps. Substack recommends a maximum file size of 20 GB, but most creators should upload a much smaller controlled MP4.
Last verified: August 31, 2026
Substack video upload settings at a glance
| Setting | Official processing recommendation | Practical creator setting |
|---|---|---|
| Resolution | 1080p/1440p (2K) or smaller | 1920×1080 |
| Video codec | H.264 | H.264 High Profile |
| Bitrate | 8 Mbps or below | 6–8 Mbps |
| Frame rate | 5–120 fps | 24 or 30 fps |
| Audio codec | AAC | AAC, 48 kHz, 192–320 kbps |
| Recommended maximum size | 20 GB | Keep files only as large as quality requires |
Best export preset for most Substack videos
Use a 1920×1080 sequence and export an H.264 MP4 at a constant 30 fps with a target bitrate around 6–8 Mbps. Use AAC stereo audio at 48 kHz. This stays within Substack’s July 2026 processing recommendations and produces a manageable file for interviews, tutorials and video essays.
- Finish the edit and duplicate the sequence for delivery.
- Set resolution to 1920×1080 unless the project truly benefits from 1440p.
- Export H.264 video with a bitrate no higher than 8 Mbps.
- Use AAC audio and check speech loudness and clarity.
- Watch the exported file and confirm audio synchronization.
- Upload through Create → Video and continue writing while it processes.
Video post versus embedded video
Substack distinguishes a dedicated video post from a video embedded inside a regular post. Dedicated video posts can automatically generate transcripts, share audio to a podcast RSS feed, create clips and offer a free preview for paid content. Those tools do not all apply to ordinary embedded videos, so choose the post type before building the publishing workflow.
Transcripts, captions and podcast audio
Substack automatically generates a transcript for a video post with audio. Review it before publishing, correct names and technical terms, and merge or reassign speakers when required. You can also upload a TXT, SRT or VTT transcript. If the publication has a podcast, the video’s audio can be added to the podcast RSS feed or replaced with a separate higher-quality audio file.
Thumbnail and free preview
A video post can use a selected still or an uploaded thumbnail. Choose an image that remains legible at small sizes and accurately represents the content. For paid video, Substack lets the publisher choose a portion of the timeline as a free preview. Pick a segment that demonstrates value without removing the reason to subscribe.
Why a Substack upload processes slowly
- The file is much larger than necessary.
- The resolution is above 1440p.
- The bitrate exceeds the 8 Mbps processing recommendation.
- The codec is not H.264 or the audio is not AAC.
- The export uses an unusual frame rate or damaged metadata.
- The connection is interrupted during a large upload.
FAQ
Can I upload 4K video to Substack?
Substack’s current fast-processing recommendation is 1080p/1440p or smaller. A 4K master can be archived, but export a dedicated delivery version.
What bitrate should I use?
Substack recommends 8 Mbps or below. Start around 6–8 Mbps for 1080p H.264.
Does Substack create captions?
Video posts with audio receive an AI-generated transcript that can be reviewed, edited or replaced with a supported transcript file.
