rhbz #813826
When playing a youtube video on Windows guest, the driver sometimes(**) sends
images which contain the video frames, but also other parts of the
screen (e.g., the youtube process bar). In order to prevent glitches, we send these
images as part of the stream, using SPICE_MSG_DISPLAY_STREAM_DATA_SIZED.
(**) It happens regularly with the you tube html5 player. With flash,
it occurs when moving the cursor in the player area.
It's not used when we use jpeg-turbo colorspaces, so it's better
to allocate it when we know we'll need it rather than always
allocating it even if it won't be used.
After the refactoring to optionally use libjpeg-turbo, some
of the functions that mjpeg-encoder used to provide are now no
longer used. This commit removes them.
When libjpeg-turbo is available, we can use the BGR and BGRX
colorspaces that it provides to avoid extra conversions of the
data we want to compress to mjpeg
This API is meant to allow us to move the pixel format conversion
into MjpegEncoder. This will allow us to be able to use the
additional pixel formats from libjpeg-turbo when available.
When encoding a frame, red_worker passes an allocated buffer to
libjpeg where it should encode the frame. When it fails, a new
bigger buffer is allocated and the encoding is restarted from
scratch. However, it's possible to use libjpeg to realloc this
buffer if it gets too small during the encoding process. Make use
of this feature, especially since it will make it easier to encore
one line at a time instead of a full frame in subsequent commits.
When using config.h, it must be the very first include in all source
files since it contains #define that may change the compilation process
(eg libc structure layout changes when it's used to enable large file
support on 32 bit x86 archs). This commit adds it at the beginning
of all .c and .cpp files
