问题
The Problem: Certain Android devices (listed at the bottom of the question) exhibit unexpected behavior when utilizing the setOrientationHint(int degrees) function for videos taken with the front facing camera. The expected behavior is for the video to be rotated clockwise, but these devices rotate the video counterclockwise.
My Goal: To identify a variable within either the camera settings or hardware orientations that allows me to predictably know when this will occur. Specifically, I would like to avoid special casing these phones in my code!
Further Explanation: I am recording video using the standard MediaRecorder object, and in preparing for recording, I set the orientation of the video using setOrientationHint(). In the documentation for setOrientationHint(), the following is specified for the degrees parameter:
degrees –– the angle to be rotated clockwise in degrees. The supported angles are 0, 90, 180, and 270.
The function is intended to add a composition matrix containing the rotation angle so that a video player can display the video as intended. So, what I do is that I get the camera hardware's orientation using the CameraInfo class and use that as the degrees parameter in the setOrientationHint fn. (I have tried variation on this code using the AOSP as a guide, but I had the exact same result.)
A Real Example: The Samsung Galaxy S3 front-facing camera (and most others, in fact) will have a hardware orientation of 270, so I use this when recording, and the resulting video is displayed correctly. An HTC Vivid will similarly return a hardware orientation of 270 for the same camera, but will only be displayed correctly if I use 90 as the degrees parameter in the setOrientationHint fn. If I use the 270 of the hardware orientation like any other phone, the video will be upside down.
NB: The setOrientationHint() function includes a warning:
Note that some video players may choose to ignore the compostion matrix in a video during playback.
However, this is not what is happening, because I can easily fix this issue on these phones if I fake it and put in 90 instead of 270.
Phones that I have seen specifically exhibit this issue: HTC Vivid (PH39100) running Android 4.0.3, HTC EVO 4G (PG86100) running Android 4.0.3, HTC Thunderbolt (ADR6400L) running Android 2.3.4. Notice that they are all HTC phones. Perhaps someone at HTC mistook clockwise for counterclockwise.
回答1:
Yes, the HTC phones rotate in the wrong direction for the front facing cameras. Instead of trying to guess, I ended up adding a settings screen that would take two pictures with the second one rotating 90 degrees. Then the user could keep hitting next as I cycled through the different rotation direction and angle combinations until both pictures appeared oriented the same way.
来源：https://stackoverflow.com/questions/14763204/setorientationhint-rotates-video-counterclockwise-on-some-phones-front-facing-c