PlaybackSpeed class
慢动作回放档位规则（与 Android SDK RecordSpeedOptions 一致）：
设备以 60 / 120 fps 录制，回放按 ½x / ¼x / ⅛x 播放得到慢动作效果。
- framerate ≥ 120 → 1x, ½x, ¼x, ⅛x
- framerate ≥ 60 → 1x, ½x, ¼x
- 其它 / 未知 / 图片事件 → 仅 1x
本插件当前不含云端 / SD 卡文件回放播放器，档位需由接入方的播放器
应用（ijkplayer setSpeed / AVPlayer rate）；非 1x 时原生 App 会静音。
Properties
- hashCode → int
-
The hash code for this object.
no setterinherited
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited
Static Methods
-
isSlowMotion(
int? highFramerate) → bool -
RecordEventBean.highFramerate == 1即慢动作素材（UI 显示角标 / 档位条的闸门）。 -
isValidDownloadRatio(
double ratio) → bool -
label(
double speed) → String -
supportedSpeeds(
{required int? framerate, bool isImage = false}) → List< double>