Re: [mpeg2-dev] picture structure is FRMAE, still need do de-interlace?

[Keith W. <ke...@MI...>]

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=
=20
frame you get from libmpeg2 has the odd field on the odd lines and the=20
even field on the even lines, interlaced together. Hence, an interlaced=20
frame.

If the progressive flag is set on the frame (or it's in a progressive=20
sequence), the entire frame is meant to be displayed all at once.=20
Otherwise, the frame is meant to be displayed one field at a time, with=20
the fields separated by the field interval. All that is part of the=20
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=20
> de-interlace. but when the stream playing, there is some sawtooth, so it=
=20
> need do de-interlace.
>
> Frame picture need do de-interlace also?
>
>
>
> =3D=3D=3D=3D=3D=3D=3D 2007-05-10 13:54:28 =C4=FA=D4=DA=C0=B4=D0=C5=D6=D0=
=D0=B4=B5=C0=A3=BA=3D=3D=3D=3D=3D=3D=3D
>
>> 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 pictur=
es,
>>> but nobody seems to use those. I think it's still a frame even when fie=
ld
>>> 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, C=
b,
>>> and Cr -- and those will be different sizes. E.g. Y could be 1280x720 a=
nd
>>> Cb and Cr will be 640x360.
>>
>> I just display buf[] (convert YUV to RGB) on PC displayer, and can see s=
awtooth 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
>>>>
>>>>
>>>>
>>>> =3D=3D=3D=3D=3D=3D=3D 2007-05-08 13:09:18 =A3=BA=3D=3D=3D=3D=3D=3D=3D
>>>>
>>>>> Allison,
>>>>>
>>>>> I don't understand exactly what you mean by "SD DV mpeg2 data". DV (a=
ka,
>>>>> MiniDV) is a different format that does not use MPEG-2.
>>>>>
>>>>> Assuming you're just referring to interlaced content, there is no per=
fect
>>>>> way to display interlaced material on a progressive display like a
>>>>> computer monitor.
>>>>>
>>>>> Some deinterlacing techniques include "bobbing" (meaning doubling eac=
h
>>>>> line in a field) and "weaving" (meaning displaying each frame as a un=
it,
>>>>> 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 th=
e
>>>>> application that harnesses libmpeg2.
>>>>>
>>>>> Some of the applications that can use libmpeg2, and do implement vari=
ous
>>>>> deinterlacing methods, include mplayer, xine, and vlc. If you want
>>>>> good-looking results, you should either implement deinterlacing or us=
e 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 cle=
ar
>>>>>> when there is quick moving in picture.
>>>>>>
>>>>>> I think it because just deinterlacing is too slow or meet some wrong=
=2E PC
>>>>>> I used is high performance PC, and can decoder SD DV mpeg2 data abou=
t
>>>>>> more than 30fps.
>>>>>>
>>>>>>
>>>>>>
>>>>>> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1hdzhne
>>>>>> =A1=...@12...
>>>>>> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A12007-05-=
08
>>>>>>
>>>>>>
>>>>
>>>> =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =
=3D =3D =3D
>>>>
>>>>
>>>> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=D6=C2
>>>> =C0=F1=A3=A1
>>>>
>>>>
>>>> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1hdzhne
>>>> =A1=...@12...
>>>> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A12007-05-09
>>>>
>>>>
>>
>> =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =3D =
=3D =3D
>>
>>
>> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=D6=C2
>> =C0=F1=A3=A1
>>
>>
>> =A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1=A1hdzhne
>> =A1=...@12...
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>>
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