网球发球训练 · 技术支持
开发者：Dave Well
用手机拍自己发球，统计球速、进区率、一区/二区和每次训练的发球数。遇到问题请先看下面的常见问题，解决不了再给我发邮件。
请在邮件里写上手机型号、iOS 版本、App 版本，并尽量描述出现问题的步骤。通常 1–3 个工作日内回复。
常见问题
怎么摆放手机？
把三脚架放在接发球一侧、发球线延长线上，双打边线外约 1.5–2 米，升到最高，手机横屏、镜头朝球网转 30–40 度，画面里要同时看到发球者、球网和两个发球区。App 内「学习与指南」里有图文摆位指南。
校正是做什么的？
录像前需要标出球场上的 4 个点（球网与单打边线、发球线与单打边线的交点），App 才能换算球速和落点。App 会先自动识别球场线，你确认或微调即可。
测速准确吗？
球速是根据录像估算的，适合业余训练对比进步，不是雷达级的精确数值。无法看到落点的球会以「估」标注。
录像占多少空间？
高帧率录像体积较大，20 分钟可能达到数 GB。可在摆位面板关闭「保留录像」，分析完后只保留每球片段。
Apple Watch 有什么用？
手表可以远程开始/结束训练，并用手腕动作辅助统计发球次数。需要 iPhone 与手表配对，并允许运动权限。
怎么删除数据？
在「记录」页左滑某次训练即可删除；卸载 App 会删除所有本地数据。
怎么切换语言？
「我的 › 语言」，可选跟随系统、简体中文或 English。
隐私政策请见 隐私政策。
Tennis Serve Trainer · Support
Developer: Dave Well
Film your own serves with your phone and get serve speed, in-rate, deuce/ad side and serves per session. Check the FAQ below first; if that doesn't help, email me.
Please include your phone model, iOS version, app version and the steps that led to the problem. I usually reply within 1–3 business days.
FAQ
Where should I place the phone?
Put the tripod on the receiver's side, in line with the service line, about 1.5–2 m outside the doubles sideline, raised as high as possible. Hold the phone in landscape, angled 30–40° toward the net, so the server, the net and both service boxes are all in view. The in-app Guide has an illustrated setup guide.
What is calibration?
Before recording you mark 4 points on the court (where the net and service line meet the singles sidelines) so the app can convert pixels into speed and landing positions. The app detects the court lines automatically; you just confirm or fine-tune.
How accurate is the speed?
Speeds are estimated from video. They are good for tracking your own progress, not radar-grade. Serves whose landing can't be seen are marked as estimates.
How much storage do videos use?
High-frame-rate video is large; 20 minutes can reach several GB. Turn off "Keep full video" in the setup panel to keep only per-serve clips after analysis.
What does the Apple Watch do?
The watch can start/stop training remotely and uses wrist motion to help count serves. It needs to be paired with your iPhone and have Motion permission.
How do I delete my data?
Swipe left on a session in the Records tab. Uninstalling the app removes all local data.
How do I change the language?
Me › Language: follow system, 简体中文 or English.
See the Privacy Policy.