Hello, In an FLOSS project of my employer, in which I'm involved, we need a FLOSS implementation of a MPEG2 decoder. We're going to use libmpeg2, as it is widely used (MPlayer, VLC, xine-lib, GStreamer, etc.), and it has clean code. While determining the way the external projects use libmpeg2, I quickly saw some internal copies of libmpeg2, Therefore, I looked for differences with upstream... and there are indeed differences.
I sent three patches last week, and the third one inadvertently inclued an
unrelated change which
broke compilation... Here is an updated version, and four more patches (even
less warnings, a
number of Doxygen comments, etc.). The Doxygen comments will help for the
project I'm involved in.
NOTE: there are other potentially interesting (for upstream) patches in
external projects:
* in MPlayer, there's (at least) an ARM (iWMMXt-accelerated) version of the
motion compensation;
* in xine-lib, patches are much harder to port to upstream, as the local
libmpeg2 in xine-lib has
been using the internal xine API for a very long time. However, changesets like
the following one:
"
changeset: 8797:798b392c5024
user: Reinhard NiÃl <[EMAIL PROTECTED]>
date: Thu Apr 12 00:02:45 2007 +0200
files: src/libmpeg2/decode.c
description:
Speed up start code scanning.
The current code implements hardware (a shift register) in software
just to find the byte pattern 00 00 01 xx, which causes remarkable
CPU load on less powerful machines.
The new approach uses memchr() to find the 01 in the buffer, which
most often hits a start code. memchr() seems to be even faster then
implementing a real pattern search (i. e. by just looking at every
third byte to find 01). The new implementation causes significantly
fewer CPU load on less powerful machines.
"
look interesting.
Regards,
Lionel Debroux.
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patches_20071204.tar.bz2
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