Seems that NDK r4 adds stable api to access bitmap from native code. So method 3) is now officially supported :)
On Apr 14, 5:50 pm, Lauri Ehrenpreis <lauri...@gmail.com> wrote: > I need torendervideoon android. I got sw decoder which decodes > stream to YUV or RGB with very reasonable cpu usage, but so far > haven't found a nice way how torenderframes. > > I have tried 3 methods so far: > 1) using opengl from native code: > * create a texture of type GL_TEXTURE_2D > * set coordinates to fill full opengl rendering area > * torendera frame update the texture with glTexSubImage2D or > glTexImage2D function > (more or less the same method that is used in vlc media player) > > With this method the performance is most terrible.. VGA rendering > @5..7FPS uses up 100% of nexus one cpu! > > 2) rendering with canvas function Canvas.drawBitmap(int[] colors, int > offset, int stride, int x, int y, int width, int height, boolean > hasAlpha, Paint paint)Was hoping to use this via JNI. First i just > made a simple perfo test: > * colors array was initialized in java code > * then I just called mSurfaceHolder.lockCanvas(); > canvas.drawBitmap(colors, ... ); > mSurfaceHolder.unlockCanvasAndPost(canvas); in sequence > > Perfo is better than with opengl - v...@30fps uses up 40% of nexus one- > s cpu... > > 3) Rendering with canvas function Canvas.drawBitmap(Bitmap bitmap, > float left, float top, Paint paint), while updating bitmap in native > code > * in java code i do: mSurfaceHolder.lockCanvas(); nativeUpdate(); > canvas.drawBitmap(mybitmap, ... ); > mSurfaceHolder.unlockCanvasAndPost(canvas); > * in native code i get value of a variable > myrenderclass.mybitmap.mNativeBitmap via JNI > * cast it to SkBitmap * pVideoBuffer > * use pVideoBuffer->allocPixels(); && pVideoBuffer->getPixels(); to > get native pointer to memory (need to link to native android library > libskia.so to get these functions) > * copy or decode thevideoframe to this memory > > With this method i get only 10% cpu usage when doing v...@30fps... but > lets face it - its a hack which may break in future > > Am I missing something or there really isn't any better way torendervideo? > for example some opengl extension function etc..? > > Br, > Lauri -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
