This patch reworks the default behavior of the tool to output Y4M
instead of writing individual raw frames. The relevant controls are
now:
--yv12, --i420 - These options change the output format to be
raw planar data. The output will be Y4M unless
one of these options is specified.
--flipuv - Swaps the chroma planes. Works with Y4M output.
-o, --output - Sets the output filename. Defaults to stdout if
not specified. Supports escape character
expansion for frame width (%w) height (%h) and
sequence number (%1..%9). The --prefix option
has been removed in favor of this escape
expansion.
Since the output defaults to stdout if -o is not specified, an
error will be thrown if stdout is not connected to a pipe. This
can be overridden by specifying '-o -'.