为什么80%的码农都做不了架构师？>>> 
在使用MediaRecorder录制时，发现 setOrientationHint 并不会实际旋转改变视频流。 只是在视频文件中增加旋转参数。视频播放器需要根据这个旋转参数进行旋转播放。 部分视频播放器会选择忽略这个参数，如window media player。
Note that some video players may choose
to ignore the compostion matrix in a video during playback.
/**
* Sets the orientation hint for output video playback.
* This method should be called before prepare(). This method will not
* trigger the source video frame to rotate during video recording, but to
* add a composition matrix containing the rotation angle in the output
* video if the output format is OutputFormat.THREE_GPP or
* OutputFormat.MPEG_4 so that a video player can choose the proper
* orientation for playback. Note that some video players may choose
* to ignore the compostion matrix in a video during playback.
*
* @param degrees the angle to be rotated clockwise in degrees.
* The supported angles are 0, 90, 180, and 270 degrees.
* @throws IllegalArgumentException if the angle is not supported.
*
*/
public void setOrientationHint(int degrees) {
if (degrees != 0 &&
degrees != 90 &&
degrees != 180 &&
degrees != 270) {
throw new IllegalArgumentException("Unsupported angle: " + degrees);
}
setParameter("video-param-rotation-angle-degrees=" + degrees);
}
其他资料 https://blog.csdn.net/veilling/article/details/52421930
横屏角度为0：
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\hengping_0.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: isommp42
creation_time : 2016-08-29 02:57:07
Duration: 00:00:21.50, start: 0.000000, bitrate: 14198 kb/s
Stream #0:0(eng): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p, 1280x
720, 13987 kb/s, SAR 1:1 DAR 16:9, 29.89 fps, 29.92 tbr, 90k tbn, 180k tbc (defa
ult)
Metadata:
creation_time : 2016-08-29 02:57:07
handler_name : VideoHandle
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, flt
p, 96 kb/s (default)
Metadata:
creation_time : 2016-08-29 02:57:07
handler_name : SoundHandle
竖屏角度为90：
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\shuping_90.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: isommp42
creation_time : 2016-09-01 08:21:46
Duration: 00:00:16.32, start: 0.000000, bitrate: 2045 kb/s
Stream #0:0(eng): Video: h264 (Baseline) (avc1 / 0x31637661), yuv420p, 720x4
80, 1954 kb/s, SAR 1:1 DAR 3:2, 20.57 fps, 29.97 tbr, 90k tbn, 180k tbc (default
)
Metadata:
rotate : 90
creation_time : 2016-09-01 08:21:46
handler_name : VideoHandle
Side data:
displaymatrix: rotation of -90.00 degrees
Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, flt
p, 95 kb/s (default)
Metadata:
creation_time : 2016-09-01 08:21:46
handler_name : SoundHandle