[MPlayer-users] mencoder and Interlaced XviDs

[Florian Schaefer]

Hello again,

as there's seemingly nobody who can help me this way, I'll try to be a
bit more specific. 

If I play the original interlaced XviD with "mplayer -v" I get:

-------------------------snip---------------------
==> Found video stream: 0
====== STREAM Header =====
Type: vids   FCC: XVID (44495658)
Flags: 0
Priority: 0   Language: 0
InitialFrames: 0
Rate: 25/1 = 25,000
Start: 0   Len: 63420
Suggested BufferSize: 152217
Quality 0
Sample size: 0
==========================
found 'bih', 40 bytes of 40
======= VIDEO Format ======
  biSize 40
  biWidth 720
  biHeight 576
  biPlanes 1
  biBitCount 24
  biCompression 1145656920='XVID'
  biSizeImage 1244160
===========================
======= Video Properties Header =======
Format: 0  VideoStandard: 0
VRefresh: 25  HTotal: 720  VTotal: 576
FrameAspect: 4:3  Framewidth: 720  Frameheight: 576
Fields: 1
  == Field 0 description ==
  CompressedBMHeight: 576  CompressedBMWidth: 720
  ValidBMHeight: 576  ValidBMWidth: 720
  ValidBMXOffset: 0  ValidBMYOffset: 0
  VideoXOffsetInT: 0  VideoYValidStartLine: 0
=======================================
list_end=0x192
-------------------------snap---------------------

If I now take a part of this video with "mencoder -oac copy -ovc copy
..." I see only

-------------------------snip---------------------
==> Found video stream: 0
====== STREAM Header =====
Type: vids   FCC: XVID (44495658)
Flags: 0
Priority: 0   Language: 0
InitialFrames: 0
Rate: 25/1 = 25,000
Start: 0   Len: 1873
Suggested BufferSize: 142286
Quality 0
Sample size: 0
==========================
found 'bih', 40 bytes of 40
======= VIDEO Format ======
  biSize 40
  biWidth 720
  biHeight 576
  biPlanes 1
  biBitCount 24
  biCompression 1145656920='XVID'
  biSizeImage 1244160
===========================
list_end=0x146
-------------------------snap---------------------

Could the missing "Video Properties Header" be responsible for losing the
interlacing information (and my aspect ratio of 4:3)? The "fields=1" flag
looks suspicious to me.

Ciao
Florian

On Mon, 20 Sep 2004 20:00:44 +0200, Florian Schaefer said:

> Hi!
> 
> I have captured an interlaced video signal as a NuppelVideo and encoded
> it afterwards into an interlaced XviD:
> 
> mencoder -oac copy -ovc xvid -xvidencopts interlaced:vhq=1:fixed_quant=5
> -o encoded.avi raw.avi
> 
> So far so good.
> 
> But now I'd like to split the result up into several parts. Therefore I
> did something like this:
> 
> mencoder -oac copy -ovc copy -ss <sometime> -endpos <someothertime> -o
> part.avi encoded.avi
> 
> This gives me a part of the encoded.avi _but_ it isn't interlaced
> anymore, the video now looks like it is badly deinterlaced. I suppose
> that mencoder hasn't set something like a interlaced-flag in the header
> of the new part.avi.
> 
> How do I fix this? (Using avidemux2 for cutting gives me the same
> problem.)
> 
> Is there any more information I can provide?
> 
> Ciao
> Florian
> 
> PS: I'm using cvs mencoder and cvs xvid from last Saturday.

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