Партнёры:
Хостинг:
NAME
mpeg_rc - convert MPEG-1 bitstream to a rate-controlled
MPEG-1 bitstream
SYNOPSIS
mmppeegg_rrcc -i input-filename [ -o output-filename ]
[ -I intra-distance ] [ -R reference-distance ]
[ -N num-pics-per-gop ] [ -D name-of-rtvc-device ]
[ -b bit-rate ] [ -f frames-todo ] [ -s ] [ -t frames-to-
toss ]
[ -wi weight ] [ -wp weight ] [ -wb weight ]
DESCRIPTION
mpeg_rc is a program that converts an MPEG-1 bitstream to a
bit rate controlled MPEG-1 bitstream. XIL is used to
decompress the source MPEG-1 bitstream. The decompressed
images are supplied to the SunVideo card for re-compression.
Quality of the resultant bitstream can be affected by the
types of pictures in the group of pictures, the bit rate and
the bit allocation weights assigned to each picture type.
The default re-compression group of pictures pattern is
IBBPBBPBBPBBPBB but this can be modified by changing the
intra frame distance, the reference frame distance, and/or
the number of pictures per group of pictures pattern. The
default bit rate is 1,115,000 bits/sec.
SunVideo allocates a certain number of bits to each picture
type. Bit allocation is a function of the bit rate, the
weights of the picture types and the number of pictures of
each type in 1 second. See the SunVideo manual under the
MPEG_WEIGHTS attribute section for more information on how
weights effect bitstream quality. For this application, the
default weight for I-pictures is 8, P-pictures is 4 and B-
pictures is 1.
OPTIONS
-i filename name of input MPEG-1 bitstream.
-o filename name of rate-controlled MPEG-1 output
bitstream file.
-I n intra distance - number of frames to the next
I-picture. Default is 15.
-R n reference distance - number of frames to the
next reference (I or P) picture. Default is
3.
-N n number of pictures per GOP (group of
pictures). Default is 15. This must be a
integer multiple of the reference distance.
-D name name of the rtvc device to use for
recompression. Default is /dev/rtvc0.
-b bitrate bitrate in bits per second. Default is
1150000 bits per second.
-f frames frames to do - Default is to recompress all
frames in source.
-s show compression statistics. This will output
for each frame the size of the frame in bytes
(in decimal and hex), the bits/pixel, and
bits per second as a total average and a
running average over the last second of
frames.
-t n frames to toss from the source bitstream
before starting compress.
-wi weight Weight associated with I-pictures. Default 8.
-wp weight Weight associated with P-pictures. Default 4.
-wb weight Weight associated with B-pictures. Default 1.
NOTES
This program only produces bitstreams which have an image
width of 320 and height of 240. If the source bitstream's
width is greater than 320 and/or the height is greater than
240, a centered 320x240 child image will be compressed.
SEE ALSO
SUNWrtvc(3).
|
Закладки на сайте Проследить за страницей |
Created 1996-2025 by Maxim Chirkov Добавить, Поддержать, Вебмастеру |