vdr-xine used a padding packet to push out any remaining data before
input_vdr executed "clear" to drop that data. But depending on the way
how input_vdr is connected to vdr-xine it could happen that the padding
packet reached input_vdr after executing "clear" and therefore "clear"
didn't work as expected.
To fix this issue, sync points are introduced by making the padding
packets "unique" in the stream. input_vdr will now drop all data up to
the sync point packet. So even if the padding packet arrives later than
the "clear" command, only data following the sync point will be fed to
the demuxer.

--HG--
extra : transplant_source : %A1%5E%8C%E1vmW%98D%1EW%A7%AF%B4V%5D%84%26%D0%DA

--HG--
extra : transplant_source : %FFP%FFI%1EgE%7F%15%AAwQt%AD%08%FB6aO%19

(This can happen when you revert & patch when merging.)

--HG--
rename : include/xine.h.in => include/xine.h
rename : src/libdts/xine_dts_decoder.c => src/audio_dec/xine_dts_decoder.c
rename : src/libmpeg2/decode.c => src/video_dec/libmpeg2/decode.c

--HG--
rename : src/libffmpeg/ff_dvaudio_decoder.c => src/combined/ffmpeg/ff_dvaudio_decoder.c
rename : src/libffmpeg/ff_video_decoder.c => src/combined/ffmpeg/ff_video_decoder.c
rename : src/libffmpeg/ffmpeg_decoder.h => src/combined/ffmpeg/ffmpeg_decoder.h

HAVE_FFMPEG_AVUTIL_H wasn't being defined, and there were some incorrect checks.

xine_get_current_frame() relies on the caller to provide a sufficiently
sized buffer. To calculate the required size of the buffer, one has to
call xine_get_current_frame() to retrieve the necessary parameters. But
as the image can change between two successive calls one has to pause
the stream for consistency.
To improve the situation, xine_get_current_frame_s() has been introduced
which requires to specify the buffer size when an image is going to be
retrieved. Furthermore, it will return the required/used buffer size.
In that way, it can prevent copying data into a too small buffer and
therefore can be considered safe.
For convenience, xine_get_current_frame_alloc() is provided which takes
care to allocate a sufficiently sized buffer. This function avoids
pausing the stream as the image will be returned in a single call.