Duolian Terms of Service

1. Services

Duolian is an application focused on badminton technique analysis. Using computer vision and pose recognition technology, it provides:

• Recording and uploading badminton movement videos.
• Comparison against reference coach movements.
• Personalized technique improvement suggestions.
• Training records and progress tracking.
• Other related functions and services.

We may adjust and optimize these services based on technical progress and user needs.

2. Account registration and use

2.1 Registration requirements

• This app is suitable for users aged 4 and above. Minors should use it under the guidance of parents or legal guardians.
• You must provide true, accurate, and complete registration information and keep it up to date.
• Each user may register only one account and may not create multiple accounts maliciously.

2.2 Account security

• You are responsible for keeping your account information secure and for all activity under your account.
• If you discover theft or security risks involving your account, contact us immediately.
• You may not transfer, sell, or share your account with anyone else without permission.

3. User conduct

When using the app, you agree to comply with the following rules:

3.1 Lawful use

• Comply with the laws and regulations of the People's Republic of China.
• Do not use the app to engage in unlawful or prohibited activities.
• Do not interfere with or damage the normal operation of the app.

3.2 Content rules

Uploaded video content must not include:

• Content that violates laws or regulations.
• Content that infringes intellectual property, privacy, or other lawful rights of others.
• False or misleading information.
• Malware, viruses, or other harmful programs.
• Any other inappropriate content.

3.3 Prohibited actions

• No reverse engineering, decompiling, or disassembling the app.
• No bypassing or destroying technical protection measures.
• No exploiting vulnerabilities or errors to obtain improper benefits.
• No malicious attacks on or defamation of the app or other users.

4. Subscriptions

4.1 Paid offer types

Duolian may currently offer the following digital paid products, subject to the public pricing page and the live checkout page:

• Starter Pack: a one-time purchase that grants fixed analysis usage with no auto-renewal.
• Website monthly subscription: may include a trial period and then renew monthly unless canceled.
• App Store subscription: if you purchase through Apple, Apple's subscription and billing rules apply.

4.2 Auto-renewal and checkout

• Website subscriptions renew automatically as described at checkout until you cancel before the next renewal date.
• Eligible international website orders may be charged through Paddle or another authorized payment processor.
• If you subscribe through the App Store, renewal charges are billed to your Apple ID account and managed under Apple's rules.

4.3 Canceling a subscription

You may manage or cancel subscriptions as follows:

1. Website orders: use the billing link provided at checkout, account settings if available, or contact support@duolian.cc to stop future renewals.
2. App Store orders: open iPhone Settings, tap your Apple ID, select "Subscriptions", then select "Duolian" and cancel.
3. After cancellation, the already-paid current period usually remains available until the end of that period unless the product page or applicable law says otherwise.

4.4 Refund policy

Website orders are governed by the published Refund Policy. If an order was processed by Paddle, the refund flow may also be handled through Paddle's billing process. Under Apple's policy, refund requests for subscriptions purchased through the App Store must be made directly to Apple.

5. Intellectual property

5.1 App content

All content in the app, including but not limited to:

• Software code, interface design, icons, and graphics.
• Text, audio, video, and other materials.
• Data analysis algorithms and models.
• Trademarks, logos, and related identifiers.

is protected by intellectual property law and may not be used without authorization.

5.2 User content

• You retain intellectual property rights in the videos you upload.
• You grant us the rights necessary to use that content in order to provide the service.
• We may use anonymized data to improve algorithms and services.

6. Disclaimers

Please note the following limitations of liability:

1. Health risk: Analysis and suggestions provided by the app are for reference only. Make sure you are physically fit before exercising and consult a doctor when necessary. We are not liable for injuries caused by exercising based on guidance from the app.
2. Analysis accuracy: We strive for accurate analysis, but technical limitations may cause deviation. Use the results together with guidance from professional coaches.
3. Third-party content: We are not responsible for content or links provided by third parties.
4. Force majeure: We are not responsible for service interruptions or data loss caused by force majeure events.

7. Service changes, suspension, or termination

7.1 Service changes

We may:

• Add or remove functions.
• Adjust subscription pricing, with advance notice where required.
• Modify these service terms.

7.2 Service interruption

The following situations may interrupt service:

• System maintenance or upgrades.
• Network failures.
• Force majeure events.

7.3 Account termination

If you violate these terms, we may:

• Warn or suspend your account.
• Delete violating content.
• Terminate your account and service.

8. Governing law and dispute resolution

1. These terms are governed by the laws of the People's Republic of China.
2. If a dispute arises, both parties should attempt to resolve it through friendly consultation first.
3. If consultation fails, either party may bring the dispute before a court with jurisdiction where our company is located.

9. Other terms

9.1 Entire agreement

These terms form the entire agreement between you and us regarding use of the app and replace any prior arrangements.

9.2 Severability

If any provision of these terms is held invalid, the remaining provisions remain effective.

9.3 Contact us

If you have any questions about these terms, contact us here:

9.4 Term updates

We may update these terms from time to time. For material changes, we will notify you through in-app notices or other appropriate methods. Continued use of the app means you accept the updated terms.