# Add a video

> Upload a lesson video and add chapters.

Source: https://paatya.net/docs/courses/add-a-video

Most topics are built around a video lesson. This page shows you how to upload a video to a topic, add chapter markers, and decide whether students can skip ahead.

## Before you start

- Your video must be an **MP4** file, **up to 512 MB** and **no larger than 1080p** (1920×1080, or 1080×1920 if recorded upright). MP4 is the one format that plays on iPhone, Android and every browser; WebM and other formats are not accepted.
- Have the topic open in its editor. See [Build the curriculum](https://paatya.net/docs/courses/curriculum) if you need to add one.
- Video storage and streaming use your academy's balance. See [How pay-as-you-go works](https://paatya.net/docs/billing/how-billing-works).

> **Tip:** Most phones and screen-recording tools save MP4 files. If a video is bigger than 512 MB, split it into two topics or export it at a lower quality. **720p** is the best choice for most lessons: it looks sharp on phones and laptops and costs your students less data to watch.

## Upload a video

1. Open the topic's editor and click the **Video** tab.
2. Drag the video file onto the box, or click **browse** and choose it.
3. Wait while it uploads. You'll see a progress bar and "Uploading… 45%". Keep the page open until it finishes.
4. Paatya reads the video's length from the file. Then the video appears with a player so you can check it.

![The Video tab with an uploaded video, video details and chapters](https://paatya.net/docs/img/courses-add-a-video-1.png)

To stop an upload part-way, click **Cancel upload**.

![Video: uploading a lesson video and adding chapters](https://paatya.net/docs/video/courses-add-a-video.mp4)

## Let students skip ahead, or not

Under **Video details**, the **Allow students to skip ahead** switch controls how students watch:

- **On:** students can jump anywhere in the video.
- **Off:** a student can't jump past the furthest point they have watched. Use this when every minute matters.

## Add chapter markers

Chapters let students jump straight to part of a lesson. They also show as marks along the video's progress bar.

1. Under **Chapters**, click **Add chapter marker**.
2. Type the time the chapter starts, such as `2:30`.
3. Type the chapter's title, such as "Common mistakes".
4. Repeat for each chapter. Chapters save by themselves and sort into time order.

To remove a chapter, click the bin icon next to it.

## Replace a video

1. Under the video, click **Replace video**.
2. Choose the new file.
3. If students have already started the topic, Paatya asks you to confirm. Click **Replace and reset progress** to go ahead, or **Keep the current video**.

> **Warning:** Replacing a video deletes the old file. Every student who started the topic goes back to the beginning of it.

## What you'll see

- On the Curriculum page, the topic shows a **Video** label and the video's length.
- Students watch the video in the lesson player. It remembers where each student stopped, so they can pick up from the same second next time.

## If something goes wrong

- **"… videos are not supported" or "Videos must be an MP4 file".** Convert the video to MP4 (H.264), then upload it again. WebM is refused because iPhones and iPads cannot play it.
- **"That video is … the limit is 512 MB".** Split the video into shorter parts, or export it at a lower quality.
- **"This video is … Videos can be at most 1080p".** The video was recorded or exported at a higher resolution, such as 1440p or 4K. Export it again at 1080p or 720p, then upload it.
- **"The upload did not finish."** Check your internet connection and upload the video again.
- **The length shows as "Unknown".** The file doesn't say how long it is. The video still plays, but chapter times aren't checked against its length.

## Next step

[Add a quiz](https://paatya.net/docs/courses/add-a-quiz) to check what students have learned.