ReMPEG2 is a program to transcode an MPEG-2 video file to
half D1 resolution (352x480 for NTSC, 352x576 for PAL) or
SVCD resolution (480x480 for NTSC, 480x576 for PAL).
Alternatively, it can keep the resolution and just lower the
bitrate.
There are several scenarios in which this might be useful.
(no need to mention a special one...)
Until now the original MPEG-2 video file had to be decoded into
an AVI file (or similar) in the first step and then reencoded
to MPEG.
There are several disadvantages in this procedure:
lots of storage space is needed for the temporary AVI file
2GB AVI file size limit
no characteristics of the input file can be exploited since
they are all lost when converting to AVI.
This leads to loosing a/v sync for NTSC videos in some cases
as well as the need for the encoder to examine the video
to detect scene changes etc. for optimal performance.
ReMPEG2 is a combined decoder/encoder which avoids these
problems by preserving the sequence of picture types (IPB) and
trying to follow the original stream's bitrate flow.
This means that the user can choose a bitrate scaling factor
which is used to calculate the number of bits available for each
encoded picture from the number of bits in the corresponding
input picture.
