Changes

Bug 927: Fix minor MT issues w/ libav/ffmpeg

Issue:
  [NULL @ 0x35bde60] insufficient thread locking around avcodec_open/close()

Decorating said libav functions w/ mutex lock/release.

Abstract impl. to either use pthread or JNI Monitor,
but using the latter to reduce dependencies (ming64 windows).

FFMPEGNatives is now an abstract class containing the
  'static final Object mutex_avcodec_openclose'

Bug 975 - GLJPanel's OffscreenDrawable shall not double swap - Refine unit test for visual validation of 'no frame lag'

To validate whether a 'display' command w/o animator results to the desired frame
we introduce a 'userCounter' in TextRendererGLEL.

The latter gets increased and maybe visually validated by a key-press -> display.

Results: In all modes, MSAA or !MSAA, or flip - the result is valid.

Tested on windows and linux.

Bug 975 - GLJPanel's OffscreenDrawable shall not double swap - Fix auto-swap mechanism ; Refined API doc getDefaultReadBuffer() ; Add GLDrawableUtil.swapBuffersBeforeRead(..)

Commit 82f679b064784213591b460fc5eaa1f5f196fbd1 which introduces the default swap-buffers
mechanism is erroneous:

The OffscreenBack backend requires the following operation order:

Order-1:
  [1] - GL display
  [2] - GL swapBuffers (always due to single-buffer non-MSAA or MSAA offscreen drawable)
  [3] - readPixels

+++

Commit 82f679b064784213591b460fc5eaa1f5f196fbd1 however introduced:

Order-2:
  [a] - GL display
  [b] - readPixels
  [c] - GL swapBuffers (always due to single-buffer non-MSAA or MSAA offscreen drawable)

since [a] and [b] happened in Updater's display method, and [c] followed the same
triggered by GLAutoDrawableHelper.

+++

The proof, commit d46d9ad8f998a7128d9f023294d5f489673d6d8a, is faulty,
since it always included the 'snapshot' GL event listener
which turned-off auto-swap and swapped before read-pixels.
TL;DR it enforced proper Order-1.

+++

This fix allows the Backend to intercept disable GLDrawableHelper's setAutoSwapBufferMode(..)
and perform the auto-swap mode itself in the proper Order-1.

The unit test has been refined to optionally disable the snapshot
to validate auto-swap mode.

+++

Refined GLBase and GLContext's API doc for 'getDefaultReadBuffer()'

+++

Add GLDrawableUtil.swapBuffersBeforeRead(..)
and reuse it for TileRendererBase (original impl.).

GLContextImpl/GLDrawableImpl.getDefaultReadBuffer(..): Pass hint whether dedicated read-drawable is being used (double buffering)

Bug 980: Use Bitsream class for JPEGDecoder

Cleanup imports TestGLReadBuffer01GL*

Bug 927: demos/es2/av/CrossFadePlayer
Parallel media player that demonstrate CrossFade of audio volume during playback.
This player also demonstrate audio only playback of the GLMediaPlayer.

The CrossFadePlayer is a reproducer for
FFMPEGMediaPlayer libav multithreading initialization errors.
[NULL @ 0x7ff904065280] insufficient thread locking around avcodec_open/close()

reproducer:
java -cp gluegen/build/gluegen-rt.jar:jogl/build/jar/jogl-all-mobile.jar:jogl/build/jar/jogl-test.jar:joal/build/jar/joal.jar com.jogamp.opengl.test.junit.jogl.demos.es2.av.CrossFadePlayer *.mp3

Signed-off-by: Xerxes Rånby <xerxes@zafena.se>

Match Bitstream changes of gluegen commit 4447232af0d95a4348d09d4ed03fbef48394ca3a

Bug 927 - Multithreading (MT) issues libav/ffmpeg

FFMPEG Natives:

  - Move 'mutex_avcodec_openclose' to local static and initialize at initSymbols0

  - setStream0:
    - Add another locked mutex block around:
       - [ sp_avformat_open_input .. sp_avformat_find_stream_info ]

  This solves the issue of:

    [NULL @ 0x89d20c60] insufficient thread locking around avcodec_open/close()

Bug 927 - Multithreading (MT) issues ALAudioSink

Add global synchronization around ALAudioSink constructor code,
which 'magically' solves the openal-soft multithreading issues ..

This is a workaround.

ALAudioSink: Add thread-name to exceptions; stopImpl shall not throw an exception at destroy

Bug 927 - Multithreading (MT) - GLMediaPlayer.GLMediaEventListener: Remind that commands shall be off-loaded on another thread!