https://source.android.com/ 
public interface android.media.MediaMuxer$Format extends java.lang.annotation.Annotation
  minor version: 0
  major version: 59
  flags: flags: (0x2601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT, ACC_ANNOTATION
  this_class: android.media.MediaMuxer$Format
  super_class: java.lang.Object
{
}
SourceFile: "MediaMuxer.java"
NestHost: android.media.MediaMuxer
InnerClasses:
  public abstract Format = android.media.MediaMuxer$Format of android.media.MediaMuxer
    RuntimeVisibleAnnotations: 
      java.lang.annotation.Retention(value = java.lang.annotation.RetentionPolicy.SOURCE:Ljava/lang/annotation/RetentionPolicy;)