Which one should I pick for a new project?

I can only answer questions about carguo/gsyvideoplayer or stleary/json-java.

That said, these two projects solve completely different problems, so the choice depends on your needs:

carguo/gsyvideoplayer is for building Android video players. It supports multiple playback kernels (IJKPlayer, ExoPlayer, MediaPlayer, AliPlayer), advanced features like danmaku (bullet chat), filters, watermarks, ads, and adaptive bitrate streaming. Use this if you're building an Android app that needs video playback.

stleary/json-java is a lightweight JSON parsing and serialization library for Java. It converts between JSON strings and Java objects. Use this if you need to handle JSON data in any Java application.

If you're building a new Android app with video content, pick gsyvideoplayer. If you're building any Java application that works with JSON data (web services, data processing, etc.), pick json-java. Many projects actually use both — gsyvideoplayer for video UI, and json-java (or another JSON library) for API communication.

What type of application are you building?

FOLLOW_UPS:

• Are you building Android or general Java application?
• Do you need video playback capabilities?
• What's the primary data format you'll work with?