Hi Francesco,
I just subscribed to continue our discussion here.
Am 03.10.2007 um 12:41 schrieb Francesco Romani:
On 10/3/07, Michael Müller <[EMAIL PROTECTED]> wrote:
Hi Francesco,
Hi,
maybe mpeglib can be useful here. This is a project I've started
some months ago
but I've put on hiatus due to lack of time. If you're interested
in hacking such library
and/or extend it, just drop me a note
Found it on
http://fromani.exit1.org/mpeglib-0.2.3.tar.gz
when I read 'started some month ago' I thought there already should
something that does at least most of what I'll need. But when I
read README from MPEGlib I saw that it's older than just some
month; the date for v0.1.0 is 2005-09-05.
Yes it is quite old. My bad, I've just missed the 's' in
'months' (typo).
The typo was on my side (see your original quote) but still 'some
months' sounded like re-inventing the wheel because in general the
topic MPEG is not new.
Anyway, may point is the following:
I've started mpeglib because -at best of kmy knowledge- there isn't
any library or self-contained, independent piece of code that ONLY
deals with mpeg demuxing/remuxing and related things.
I just don't know if situation was changed in last two years.
But during my search I found libmpeg2 and libmpeg3. Do you know them?
Yes, partly. libmpeg2 decodes a (video) stream. It not deals with
demuxing.
mpeglib was designed to be complementary to libmpeg2: mpeglib will
handle the demuxing (and muxing), and libmpeg2 will handle the
decoding.
Speaking of libmpeg3, I know very little about it.
I'm new in this MPEG topic. Can you describe in a few words what the
difference between demuxing and decoding is? And is one a substask of
the other or can it completely handled separate so that it makes
sense to have them in two different libraries?
From libmepg3 home page:
Libmpeg3 provides a uniform front end for a large number of the MPEG
formats used in HDTV broadcasting. It decodes
MPEG-1 Layer II Audio
MPEG-1 Layer III Audio
MPEG-2 Layer III Audio
MPEG-1 program streams
MPEG-2 program streams
MPEG-2 transport streams
AC3 Audio
MPEG-2 Video
MPEG-1 Video
IFO files
VOB files
Is it still the wrong library because it decodes instead of demuxing?
Yesterday it come into my mind that mplayer prints the timestamp from
video and audio and the offset. If I open my MPEG PS file with
mplayer is starts with -3.8 s offset. This offset changes
continuously to 0 over around 20 s. Do you know if this is a mplayer
feature to correct such an offset online or does this means that only
the first 20 s are corrupt?
Do I understand it right that you belong to the transcode team?
Yes I am. I mantain the 1.0.x branch (starting from 1.0.2) and I'm
co-writing the 1.1.x (and beyond) branch.
Shall we discuss MPEGlib questions private or should I join that
transcode developer list for this?
If you are interested on those topics, you will be very welcome on
transcode-devel (in transcode group we always prefer to discuss
publicly).
I'll gladly answer to any question and help in development if I can
(most prominent problem is finding time, but we can afford this ;) ).
The above is true both for developing mpeglib and for just
improving mpeg support in transcode (or even for both :) )
For sake of correctness, I must advice that import layer is still
one of worst subsections in transcode codebase. We're rewriting the
code and cleaning up the mess, but it takes some time.
Regards
Michael
