Changelog
- Improve seek speed, fix drop too much frames after seek
- VideoFrameExtractor: seek faster if called many times. Speed up
progress bar preview
- Support media files from android assets. Use protocol 'assets:'
- Apply video decoder options when playing
- Better iOS support
- VideoToolbox:
 * Check profile to avoid crash
 * Support RGB output
 * Use `rgb422_apple` texture
 * Support iOS 0-copy rendering using OpenGLES
 * More interop types for OSX and iOS
- OpenGL
 * Use 16bit depth textures for >8bit videos (e.g. 10bit) if possible
 * Correct input/output color range. This fixes QtAV video different
from other players
 * Fix high opengl and core profile rendering
 * Better EGL detection
- VO:
 * Simplify signal emitting
 * Support background color, simplify background painting
 * VideoOutput delete crash, resize issues
 * Improve performance of QPainter based renderers
- AudioOutput:
 * remove setBufferSize, add a better API setBufferSamples
 * Add flush(), clear(). Not implemented for backends.
 * Fix OpenAL playback for some audio formats
 * Dynamic load OpenAL by default except iOS
 * Add AudioToolbox support for OSX/iOS and becomes the default backend
 * PulseAudio: workaround noise for multiple instance
- Subtitle:
 * Support ass font files in android assets
 * Fix srt decoding
- QML:
 * Add QtMultimedia compatible APIs VideoOutput.contentRect/sourceRect
- Simplify SurfaceType
- Fix strange behaviors near eof: seek, stepForward, exit etc.
- Fix playback block if audio duration is shorter than video
- VideoFrame constructed from QImage takes image's ownership
- Add VideoFrame.colorRange, AudioFrame.duration
- encoder: support start time
- Add AVPlayer.bufferSpeed, seekFinished(qint64)
- Fix abort when loading
- Examples:
 * Fix videos in videowall not synchronized
 * QMLPlayer has better touch screen experience
 * QMLPlayer supports win10 store (But Qt is not well supported)
 * Drag & Drop support on OSX
 * URL open dialog for QMLPlayer