Allison,
You're a bit confused on the terminology.
MPEG-2 can use FRAME PICTURES or FIELD PICTURES.
If it uses frame pictures, they can be INTERLACED or PROGRESSIVE.
Much ATSC HDTV content is sent as interlaced frame pictures. The resulting
frame you get from libmpeg2 has the odd field on the odd lines and the
even field on the even lines, interlaced together. Hence, an interlaced
frame.
If the progressive flag is set on the frame (or it's in a progressive
sequence), the entire frame is meant to be displayed all at once.
Otherwise, the frame is meant to be displayed one field at a time, with
the fields separated by the field interval. All that is part of the
display process, which libmpeg2 doesn't perform.
Hope this helps.
Best regards,
Keith
On Mon, 14 May 2007, hdzhne wrote:
hi,
I receive mpeg2 data, but it seems strange:
Structure of very picture is FRAME, I think frame picture need not do
de-interlace. but when the stream playing, there is some sawtooth, so it
need do de-interlace.
Frame picture need do de-interlace also?
======= 2007-05-10 13:54:28 您在来信中写道：=======
hi ,
how to realize de-interlace in libmpeg2?
which varibles and where can I process de-interlacing(put two fiels into one
frame)?
best,
allison
Allison,
On Wed, 9 May 2007, hdzhne wrote:
Is "info->display_fbuf->buf" one field or one frame data (my mpeg2
source is interlaced)?
I think it's always a frame. (Not 100% sure in the case of field pictures,
but nobody seems to use those. I think it's still a frame even when field
pictures are used, in any event.)
If buf[] is always a frame, we need not do any de-interlace.
If I want to do de-interlace before display , may I process
info->display_fbuf->buf directly?
Sure. Keep in mind that buf[] is an array of three framebuffers -- Y, Cb,
and Cr -- and those will be different sizes. E.g. Y could be 1280x720 and
Cb and Cr will be 640x360.
I just display buf[] (convert YUV to RGB) on PC displayer, and can see sawtooth
clear. so I think I need do de-interlace.
So, I am still not sure whether de-interlace should be done about
diplay_fbuf->buf[] or not.
Cheers,
Keith
Best,
allison
======= 2007-05-08 13:09:18 ：=======
Allison,
I don't understand exactly what you mean by "SD DV mpeg2 data". DV (aka,
MiniDV) is a different format that does not use MPEG-2.
Assuming you're just referring to interlaced content, there is no perfect
way to display interlaced material on a progressive display like a
computer monitor.
Some deinterlacing techniques include "bobbing" (meaning doubling each
line in a field) and "weaving" (meaning displaying each frame as a unit,
with separate fields woven together).
libmpeg2 does not implement any deinterlacing techniques. It _only_
performs the MPEG-2 decoding process. The display process is up to the
application that harnesses libmpeg2.
Some of the applications that can use libmpeg2, and do implement various
deinterlacing methods, include mplayer, xine, and vlc. If you want
good-looking results, you should either implement deinterlacing or use one
of those applications. libmpeg2 does not do this.
Best regards,
Keith
On Tue, 8 May 2007, hdzhne wrote:
hi,
When I use mpeg2lib to decoder SD DV data, I can see sawtooth clear
when there is quick moving in picture.
I think it because just deinterlacing is too slow or meet some wrong. PC
I used is high performance PC, and can decoder SD DV mpeg2 data about
more than 30fps.
hdzhne
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2007-05-08
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礼！
hdzhne
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2007-05-09
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致
礼！
hdzhne
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2007-05-09
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