Commit 64bfbd01 authored by Michel Lespinasse's avatar Michel Lespinasse

release notes :)

parent 582018ae
mpeg2dec-0.4.0 Tue Dec 23 03:04:35 PST 2003
-support for 4:2:2-profile streams as well as 4:4:4 format
-extra robustness with extensive test framework (including bad streams etc)
-support for concatenated streams
-helper library for common color conversion formats (currently rgb and uyvy)
-sparc VIS MC optimizations from David Miller
-new set-stride and decoder-reset functions
-some code samples for (very basic) documentation
mpeg2dec-0.3.1 Fri Dec 13 22:15:36 PST 2002
-integrated CPU detection code
-alpha IDCT/MC optimizations
......
mpeg2dec-0.4.0 Tue Dec 23 03:04:35 PST 2003
Jeez, it's been way too long since the last release.
The big functionality that warrants a 0.4.x version number is that we
added support for 4:2:2 for 4:4:4 chroma formats. Thanks to Peter
Gubanov for starting the effort there.
A large part of the development effort has been to fix corner cases
that happen with bad or corrupted streams, concatenated streams,
etc... Regis Duchesne created test cases for this, which was a huge
help. Right now the situation is that we don't know how to make
libmpeg2 crash even when we try hard.
There is a new helper library for color conversion to common format
(currently rgb and uyvy). The ABI between libmpeg2 and libmpeg2convert
might change in the future, but source code compatibility will be
preserved. In the past people were supposed to write their own color
conversion routines which was a pain since the API was messy.
David S. Miller contributed some very nice sparc VIS optimizations for
the motion compensation. There are no VIS optimizations for the IDCT
yet but the plan is to get these in for a future 0.4.1 release.
New functions have been added to set the buffer stride and to reset
the decoder (typically after seeking thru a file).
There is some very basic documentation in doc/* - it's still quite
limited though. My good resolution for 2004 is to write better
documentation :) In the mean time feel free to ask on mpeg2dec-devel
or on irc.freenode.net channel #livid
mpeg2dec-0.3.1 Fri Dec 13 22:15:36 PST 2002
This is mainly a maintainance release. On the API side, libmpeg2 now
......
The documentation is currently a mess. Sorry about that, hope to write
something better for the 0.4.1 release.
For people migrating code from 0.3.x to 0.4.0, the biggest thing to
note is that mpeg2_parse now returns a new state STATE_BUFFER when it
needs more data. Version 0.3.x used to return a -1 constant for this -
please update your code to replace that -1 with STATE_BUFFER. Otherwise
0.3.x code should mostly work with 0.4.0, hopefully.
For people new to libmpeg2, it's best to start by looking at
doc/sample1 and doc/sample2, which decode an mpeg2 elementary stream
and output their individual pictures as yuv frames (sample1) or rgb
frames (sample2). The main loop calls mpeg2_parse() which does some
work and then returns a state indicating what it just did -
STATE_BUFFER if it reached the end of the buffer and it needs a new
one, STATE_SEQUENCE if it just parsed a sequence header, STATE_PICTURE
if it just parsed a picture header, STATE_SLICE if it just decoded the
slice information associated with a picture (now is a good time to
save that decoded picture), etc...
To make more complex buffer management (basically allocate your own
buffers instead of letting the lib do it for you), look at
sample3/sample4 (giving your buffers to the lib at init time but
letting the lib chose a buffer for each picture) or sample5/sample6
(giving a new buffer to the lib for each picture).
Color conversion has been moved to a new helper library, libmpeg2convert.
The details of the mpeg2_convert_t type might change in the future,
but what won't change is that you should just take one of the
mpeg2_convert_t symbols exported from libmpeg2convert, and pass it to
the mpeg2_convert() function, and voila, you now get your output
buffers in the desired format. For example if you want rgb 32-bit
samples, you just call mpeg2_convert (mpeg2dec, mpeg2convert_rgb32, NULL)
and that's it.
There is a new mpeg2_stride function too. By default libmpeg2 choses
the smallest stride that will work for a given picture size, if you
want a larger stride you can set it (after the sequence header has
been decoded) by calling mpeg2_stride.
There is also a new function mpeg2_reset which should hopefully do the
right thing after skipping to a new position in the mpeg2 stream. If
full_reset is zero the lib starts decoding at the next picture, if
it's one the lib starts looking for the next sequence header.
The mpeg2_pts function is gone, because people complained about not
being to pass a 33-bit PTS thru it. So instead it's been replaced with
mpeg2_tag_picture(), which is identical except that it allows you to
pass two 32-bit values. You can use them to form a combined 64-bit
time stamp, or two 32-bit PTS/DTS stamps, or whatever you please -
libmpeg2 never uses these values, it just passes them around, hence
the name "tag". The semantics are what you want for a PTS function
though, i.e. the tags get associated to the next picture that starts
after the tag was set, where the start of a picture is defined as the
first byte of its picture start code.
That's all I can think of - sorry for the lack of proper
documentation, I'll try to help this before the 0.4.1 release.
I - simplest example
......
......@@ -37,7 +37,7 @@ mpeg2_convert_t mpeg2convert_bgr8;
typedef enum {
MPEG2CONVERT_RGB = 0,
MPEG2CONVERT_BGR = 1
MPEG2CONVERT_BGR = 1
} mpeg2convert_rgb_order_t;
mpeg2_convert_t * mpeg2convert_rgb (mpeg2convert_rgb_order_t order,
......
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